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Q: That all makes perfect sense, of course. However, one thing I've noticed is that, in a previous issue of one or two years ago, we provided a link to Angel Wings' excellent step-by-step photo tutorial on installing their Spit-Fire kit on a cruiser frame. I presume that most of our readership was exposed to that kit through that piece. Yet, until recently, when all those cheapo versions of the engines started showing up on eBay, we hadn't had one machine show up for our Gallery with that particular engine fitted. Since the eBay point, they've been coming in regularly.

Maybe that just means that our audience is more interested in looks and cheapness than actual function. This is a fairly safe bet, considering that most kustomizing treatments have a negative impact on bicycle performance; and I've seen some extremely junky donor bikes used as the basis for high-labor kustoms. The ironic thing is that the same people who start from cheap junk seem perfectly willing to then spend a giant wad of money on billet wheels and such to dress them up. People are strange, especially in this segment of the cycling demographic.

That said, I gotta admit that I fall into pretty much the same pattern, as, if I don't build it from scratch, which is theoretically sort of cheap, I think it's fun to start with something I find in the trash; and you hardly ever find a quality bike frame in the trash- if it's in the trash, it's usually because it started out that way, then got worse. Of course, I always replace all the mechanical bits with good stuff, but that's gotta be the most expensive way of ending up with a decent bicycle. Or car, for that matter.

Not to say there won't be demand for quality engine replacements after people get sucked in by the cheapo setups, but I have a sneaking suspicion that the big bucks in this activity will be made in selling expensive, quality-made dress-up parts to people who start out with those comparatively junky eBay engines.
Q: I suppose most people would think that it's crazy to consider making parts and accessories that would be easily more expensive than the engine itself. But, it seems to me that there really isn't that much out there in good-looking small engines made specifically for this purpose; and it sounds like when you get one of the good ones that it's worth a lot more than the price you pay for it. Tanaka (TAS) had a really nice-looking bike motor, at one time, pre-BikeBug:
http://bikerodnkustom3.homestead.com/gallery165.html and
http://www.bikerodnkustom3.homestead.com/gallery187.html 

But at the moment, these Chinese engines are pretty much it. I'm not considering the new Whizzers really, as they seem to be coasting on the original name, are ridiculously expensive for a Taiwanese repro, and seem to have their own quality-control issues, in spite of the high price.
Aftermarket clutch lever assembly by Pazzaz.
A: The problem with the carburetor is being addressed. A couple of different people are working on it. One guy is trying to make one out of steel tube.  Don Grube is having some cast with
The restrictions of the stock front engine and carburetor mounts are less problematic
when kustom frames are constructed around them, as in this clever but odd-looking solution by Firebikes' Sam McKay.
The factory carburetor mount is an alloy casting of fixed angle and position, which is quite restrictive on the type of frames suitable for mounting of these engines; to the extent that Spit-Fire has a set of fitting charts on their site. A more adjustable mount, as found on other engines, would allow greater fitting and angle options.
A: The way an expansion chamber works is, as the piston dumps the exhaust (the piston acts as a valve in a 2-stroke) the front cone of the expansion chamber allows the gases to expand and it has a sucking effect on the exhaust port. This also helps pull the fuel/air mix into the cylinder, and on out the exhaust port. The sound wave that comes out with the exhaust is bounced off the rear cone and back up the pipe where it crams that little extra fuel air mix that came out with the exhaust, back in the cylinder just before the piston comes up and blocks the port off. It is a supercharger in a way. That's why it's called a tuned pipe, as it's tuned to the rpm and how long the exhaust port is open. It's a nice little math problem if you like that sort of thing. But yes, the carb would have to be changed some to keep from fouling or burning up spark plugs. The carb is the same one for all the different displacement engines. The jet is replaceable, and I know a guy who has had some success drilling out the jet.

On that front mount, I have an idea for a billet thing that would fit most frames. But it would be huge and have sleeves to adapt it down. I don't see that looking any better than all the nuts and bolts. But it's worth keeping in mind. I'm sure something will be made that solves the problem. The rear mount is used to shim for the drive chain and is
movable and/or replaceable. I have seen a real nice billet piece that a guy did.  I've seen a set that allowed the engine to be offset to the side for a real wide rear tire. (O.C.C. Stingray)  It was pretty hacked up. The thing is, the guy got the engine in the frame.

Another thing someone was talking to me about is that a lot of guys are trying to put these engines in frames that it is impossible to get the carb on without cutting or bending the frame. So there are a lot of little things that could be made to help the kid or not-so-mechanical Dad who're bonding in the garage.
Coincidentally, I just discovered that DupliColor Metal Cast anodizing simulator spray-can paint. When I read the can and saw that it's rated to 500 degrees F, I immediately thought of Chinese bike engines. These are fairly attractive engines, and I think one would look great sprayed transparent red or whatever, with polished-off fin edges. Some nice chrome or stainless bolt heads or acorn nuts and some tasty billet parts, and you'd have something pretty snazzy, I think.

What's the story on the larger (60, 70, 80cc) displacement sizes?  Are the engines externally pretty much the same size and appearance? And is there as much difference in build quality as in the smaller ones?
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Fairly frequently, I run a search of eBay using the keywords "bicycle", "engine", and "motor", due to my philosophy that an engine is one of the coolest dress-up and performance accessories you can stick on a bicycle. In the past, I've run into quite a few kits this way, based on weed-whacker-style engines, and some classic motorbike repro setups, such as the Whizzer. Prices have generally been in the $400 neighborhood for the conversions, with the Whizzer kits starting at about $800. Lately, however, that search turns up dozens of people selling little purpose-built bicycle motorization kits made in China, starting at $150 or less, with displacements ranging from 48 CC up to a very interesting 80 CC, in 10 CC increments. Some of the listings are quite interesting, with all the new competition between sellers. In a recent search under this topic, I ran into a listing for a one-off billet air cleaner designed specifically for these engines.

"Aha!" I said to myself,  "Here's our kind of guy; and I'll bet he's fairly expert on the subject of these engines". Using the "Ask the seller a question" function, I contacted him about doing something on the subject with BR&K.

His name is Arlo Kraus, and indeed, he's our kind of guy, very knowledgeable on the subject, and he agreed to talk to us about these engine kits.

Q: Hi Arlo. I first noticed this type of Chinese bike engine on the Angel Wings site a few years ago, as the "Spit-Fire". But lately I've been seeing what looks superficially like the same engine kit all over eBay, at considerably lower prices. From the different sources bad-mouthing each other's wares, though, there seem to be some differences. What can you tell us about this; are they all the same basic design from different factories in China, or are they all from the same factory, with the bad-mouth comparisons just being made by fiercely-competing vendors?
A: There is a difference. There are a couple of dealers who are selling bad engines. They have become known as
"weak puppies" These are a run of engines that were manufactured in early 2004. The Spit-Fire and the StarFire 48cc square head had the exhaust ports cast in the wrong place, I understand they are cast 2mm. too high in the cylinder, and this caused a great loss of power. I also have heard that the intake runners are full of flashing from the casting process, and that causes problems also. The only cure is to install a 55cc hop-up kit that costs another $75. One of the dealers is still selling this engine and not telling the customers, in hopes they will never know the difference. I know my distributor (Star Fire) is not even selling these engines, unless he has installed the hop-up kit himself.
Arlo Kraus' typical stock Star Fire Gru-Bee 48 CC engine kit installation on cruiser frame.
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As I also understand it, there are six or seven factories in China that produce these engines. There are only two of the importers that have quality-control people in place at the factories,  that I know of, and even then there have been problems. I'm a dealer for Gru-Bee, and Don Grube lives in China, and he's at the factory almost every day. He has higher-quality bearings installed, that I've been told he gets from Europe. Some of the eBay sellers (not all of them) get their engines from whoever will sell them the cheapest. So the old adage of "you get what you pay for" is very much a part of these engines. 
I have had the pleasure of riding a bike with a Skyhawk Pico Wing-Ding and a Spit-Fire. I have to say the Pico has more power- in the 48CC-size engine.
Q: Gru-Bee? That answers another question I had. I was wondering if the Gru-Bee name was a reference to one of Art Clokey's Gumby TV films- the one about a little bee character called that, which built things really fast. I thought it was a pretty hip reference if that was the basis.
Arlo Kraus' billet air-cleaner cover for Chinese bike engine carburetors.
A: Ya! if you get two guys next to each other with shopping carts they're gonna race. The thing is, this hobby is somewhat new to mainstream America, so we really don't have guys lining up next to each other yet. But it's coming. The market is wide open for aftermarket products. There are a couple of guys who have been doing a little head milling and port polishing. But in a two-stroke engine this only gives the illusion of more speed, but it does increase power. The top end is mostly in the port timing, and that is built into the cylinder when it is cast. These are a cast aluminum cylinder with a flash chrome bore so they cannot be bored out or even honed. The cylinder head is cast real thin and supported with the fins, so even head work is something that is very limited, and needs to be done by a machine shop that can do very precise milling or you'll have a hole in your head, so to speak. I am a machinist by trade and have the ability to do this type of work. In fact, I have done one head and some port work
on an engine and I'm waiting on some guy to pull up next to me. But 'til then, I'm happy to putt around with a stock engine.

But custom billet accessories is a thing that I and some others have started doing. Right at the moment it's one-off parts by guys who just have to have it look kustom. That starts right after most guys take it out of the box. You know, I'm gonna use chrome bolts here and use this anodized or crinkle paint. That air cleaner and sprocket spacer I had on eBay was a test-market thing.  I'm working on some other top-secret things that I'm sure a lot of guys are going to want. But right now the market to sell these kind of things is so limited that it's not cost-effective to mass-produce. So it's real expensive to make. You have to imagine what the first guy to do a lowrider Stingray had to spend and hand-make. Just look at that market today.
Arlo Kraus' billet spacer for Chinese engine kit sprockets. It allows the use of a fatter tire.
Q: Yes, I can just imagine the work that went into building an OG lowrider bike- twisting that rod by hand, then having it polished and chromed, drilling all those extra holes in wheel hub flanges and rims, etc. That stuff took real dedication, back in the day.

My theory on these engines is that as soon as somebody starts making a lot of trick-out parts, these engines will become a lot more popular- especially once the factory chopper-style bicycles start hitting the streets in quantity. I'm sure that a lot of people buy Harleys just because all those goodies are available for dressing them up- kind of a grown-up Barbie doll deal for guys. Futzing around with them is easily as much fun as riding them, for this kind of folk.

Coincidentally, I just discovered that DupliColor Metal Cast anodizing simulator spray-can paint. When I read the can and saw that it's rated to 500 degrees F, I immediately thought of Chinese bike engines. These are fairly attractive engines, and I think one would look great sprayed transparent red or whatever, with polished-off fin edges. Some nice chrome or stainless bolt heads or acorn nuts and some tasty billet parts, and you'd have something pretty snazzy, I think.

What's the story on the larger (60, 70, 80cc) displacement sizes?  Are the engines externally pretty much the same size and appearance? And is there as much difference in build quality as in the smaller ones?
80CC Square Head engine, "blueprinted" and installed by Gary Newcomb.
A: OK, the 55cc hop up kit, 60, 70, and 80 CC engines, are all a larger displacement than is legally allowed, without a title, registration, insurance, safety inspection, and on and on and on. it makes your bicycle a constructed motorcycle in most states. So I cannot recommend that anybody install one on a bicycle frame. That being said, and guys being guys: they have the same dealer- versus-quality issues found in the smaller engines, sometimes more 'cause some think, since it's a larger engine, that less break-in time is required; or they just can't stand running at half throttle or less that long. And there go the bearings. The 80cc engines run at close to the same RPM but have a lot more power so you can gear them higher for more speed, or the same and carry a larger load.

To the average guy, the engines look the same. The 80cc is a little larger but I don't think you could tell it from a 48cc unless they were sitting on a table side by side. So a policeman isn't going to pull you over and say your engine's too big, unless you go by him at 50mph on a bicycle. By the way, most states say 30 mph is the max on a moped.  That is the law that most police would use to define your machine.
I think you're right about the hobby getting bigger when more kustom stuff is available. I'd like nothing more than to make things for these bikes and engines all day long. But at the present time the market just isn't there, it is picking up, but I just don't think I can feed the family off of it yet. I will say that some others and myself are getting some ideas and prototypes together and we will be slowly making more and more stuff
Q: You pretty much nailed the reason I was asking about the external differences in the bigger engines. I'm preparing to build a bike with a 1980 Honda Elsinore 250 CC motocross engine shoehorned into it. Nobody in law enforcement could possibly believe that mutant monster would be a street legal motorbike, but it's mostly a show bike anyway; although I might possibly go through the hassle of motorcycle registration, etc, if it's a lot of fun to ride.

But, with discretion, the speed potential of an 80cc engine would be there if you needed it. And it would be cool to have the knowledge that the potential's there. But yeah, if you do 60 in a 35 MPH zone on anything, you'll get nailed for it if you're spotted.

Kevin Waddle's polished Pico Wing-Ding 48 CC,  ported and polished internally, with high compression head
A lot of people say that bicycles can't handle high speeds. I went along with that, too, until I was researching gravity bikes a while back. They're all based on 20" BMX bikes, with the chain drive removed. In the advanced classes, the bikes are fitted with streamlined fairings and carry ballast for gravity to better work on. Those things are fairly routinely clocked at 80 MPH, I hear. And that's not with anything too out of the ordinary, as far as components go. Four-ply tires would be good, and they are available, and, of course suspension and really good brakes would be a good idea, too; but I'd think an 80 CC engine would be a fairly realistic power plant for a bike to run, if you kept a fairly low profile in your driving practices.
One performance aspect I've been wondering about is the stock exhaust system on these engines. It's a little bit dorky-looking, in my opinion, and a good place to start with aftermarket goodies. I've discovered, with this project, that modern 2-strokes, such as my Elsinore 250, make use of an exhaust expansion chamber, followed by a muffler, if they bother with silencing. In use, it functions as a sort of
supercharger, which acts by sucking, rather than blowing. And actually, the expansion chamber is so important to the function of the design that the Elsinore might barely run without it. Since they're so specific to the particular engine's characteristics I felt compelled to buy a stock pipe which will need considerable reconfiguring to work in my layout- without actually changing the lengths of the various elements.

Do the stock exhaust pipes incorporate an expansion chamber, and if not, would a properly-designed expansion chamber deliver a perceptible performance gain?
A: The speed potential of an 80cc, on a good day with the wind at your back, would be in the 45 mph range. Twice the horsepower does not produce twice the speed. But you're right, a person does have to show some respect for the law, If you're blasting through a school zone at the top end of a 48cc's range you couldn't stop in time to avoid hitting someone. Believe it or not, it probably takes twice as long to stop just putting at 15 or 20 mph; so being aware is all-important.

I live out in the desert between Tucson and Phoenix. It's not uncommon for the temperature to be 104* in the shade, and the asphalt has to be at least 150* at noon .So tires must be in good shape. I take a ride that is up hill for almost 15 miles. Of course it takes a while to get up there- probably 45 minutes to an hour. But coming down, I am doing 35 MPH in some places and this is a winding desert road. Brakes are a necessity. I adjust my brakes often. It's cool to go fast but ya gotta be able to stop.
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Arlo Kraus' "beater"/demonstrator based on Sears Free Spirit MTB frame.
As far as the frame being able to take the punishment of the higher speeds, I check mine every time I get off it. It takes some pretty good licks on these country roads where I live. I'm using an old
15-speed Free Spirit MTB frame that was laying out in the yard. I bought some cheap Wally World tires and tubes, Slime-filled, of course. This is my beater bike I let the kids use it and anybody that wants to take a test ride. It doesn't scare anybody that they may wreck it while test riding. Needless to say, it takes some pretty hard knocks, and keeps coming back for more. But this is a heavy-duty frame, wheels, bearings, and axles. I think that if someone is thinking of using a $79 cruiser bike as a frame to mount one of these engines on, that they should make sure the wheels, axles, and bearings are up to the abuse. Those downhill racers have the real high-dollar frames and a mile
of travel in their suspension, if I'm not mistaken; and if they weigh what I do, they don't need ballast. Most of the people that I've talked with do recommend 4-ply tires, and balancing your wheels for long high-speed (28mph)
highway use.

As far as this stock exhaust system goes, it's nothing more than a noise reducer and a way to keep the two-stroke oil off your pant leg. An expansion chamber is needed badly, even if it only worked a little bit, and it would look a lot better. And guess what one of those top-secret projects is? I'm working on the tooling to weld a few of these up right now. I worked up the numbers to make it a mid-range power pipe. So, it will be out there in not too long of a time. I don't think that it will make these little engines any faster, but they will increase the power output; and when you're dealing with 2 HP any increase is good. The cool factor goes up more than anything.  
Q: This being BR&K, the cool factor is naturally a high priority, but it's always nice to have that performance factor as a side benefit. You've mentioned that there isn't much of a market, at this point, for kustom parts for these engines. I also mentioned a while ago that chopper-style bicycles are about to be the big thing in the retail market here. This is in addition to our audience's being very involved in building their own choppers. This is shaping up to be a pretty heavy mass bike-style shift. Since most chopper bikes tend to look like motorcycles without engines, I'm convinced that these little engines are going to start to fill that void pretty quickly. Another factor is that the huge baby-boomer market segment, of which I'm a part, is starting to get a little creaky in the knees, and maybe lazier. I gotta admit, having some power assist is looking pretty attractive right about now. For guys like us, of course, that assistance pretty much has to not detract from the cool factor. Most of the auxiliary drive units out there are pretty dorky-looking, especially the ones which rub the front or rear tire. A system that drives a rear sprocket, like these Chinese kits, is easily twice as cool-looking, especially since the motor itself is sharper-looking than your typical weed-whacker mill, with the flywheel-blower shroud and all. Throw in the trick factor of kustom parts, and I think you might be feeding your family with it a lot sooner than you might think.

One slight style deficit I see is that the engine's integral mounting system is designed around the traditional English-style diamond frame, which has hardly been a major style in the US for maybe 20 years or longer. There are varying workaround adaptations everyone uses with other frames, but they all seem to look a little "nutsy-boltsy". Have you considered designing and producing a more substantial and cooler-looking front adapter mount?

A:  I'm gonna tell you, I think the mounting is an eyesore, but it works. There are so many different styles of frames and front down tubes, I'd need a warehouse just for front mounts. That is one of the first things that is asked by most every body that's building their first bike. What do I do with this front mount? One of the dealers has a design for a generic "kinda fits all", but even it's got a lot of nuts and bolts. I have a couple of ideas for the bike that I'm building right now, but it wouldn't fit anything except the frame I'm building. Of course these are generic little engines and they have to be massaged into most bikes. That's kinda what makes them fun. If everybody had the same mount that worked on every bike, I'd have to have something different. The guys that are building these bikes like to tinker; in fact if you don't like to adjust and tinker on your machine, this isn't your kinda hobby. These are a perfect platform for the
back-yard engineer. I think that is where you will see the most ideas come from.
I think you're right about the major change of bike styles, and this engine is perfect for it. The mid-frame location and chain drive make a cool set up on a plain-Jane stock bike, but you throw in the chopper look, and it's a gotta-have. The engines that mount on the fork or over the rear wheel have that "I added an engine and I don't care what it looks like", kind of feel to me. If I just wanted an engine I'd ride my Harley. These have
coolness written all over them.

I was riding on my little moto a couple days ago, and a guy on a brand-new 2004 Triumph had me pull over so he could check out my 10-year-old MTN bike with this really cool engine. I tell you, this guy was ga-ga.  What's that say about these little engines?

You mentioned Baby boomers. We did a little poll the other day on one of the message boards about the average age of the person that owns one of these bikes. It seems that the average kid was 47.  I'm on the high side of the average, overweight, and don't care. The more assist I get the better.
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Factory front engine mount, designed for use on diamond frames is fairly sanitary.
Use of them on other frame designs is more
problematic. Inset is Arlo Kraus' mount adapter for a cruiser frame.
Q: I don't think I remember the details of your specific front mount, and I wouldn't call most of the ones I've seen eyesores, anyway. But they all seem to have that "Erector Set" look about them, which clashes a bit with the design of the engine as a whole. I'd think, considering the expanding market for them, that both the front and rear mounts could be modified in the casting dies by one of the more quality-oriented factories. Something that allowed a bit of flexibility in the mounts, without being quite so nutsy-boltsy seems conceivable to me.

And you're certainly right, that as things are now, most of the people building the bikes around these engines tend to be mature gadgeteer types who have been around long enough to have developed the skills and perseverance to like messing around with the setup. But, as these things catch on with the larger market, kids and "nimrod" adults are going to need or demand less futzing to achieve the end product. Of course, this could result in a whole cottage industry deal, in which gadgeteer types specialize in building motorized turnkey machines based on specific frames. Come to think of it, both Firebikes and JAKZ seem to be leaning in that direction.

Getting back to an earlier topic- expansion chambers: It occurred to me today that the use of an expansion chamber- which in effect is the rough equivalent of supercharging, would probably call for differences in the carburetion. Are the carbs on these things capable of producing a greater fuel/air volume on the intake side? Sorry if I've just blown something else on your secret project list.
A: The way an expansion chamber works is, as the piston dumps the exhaust (the piston acts as a valve in a 2-stroke) the front cone of the expansion chamber allows the gases to expand and it has a sucking effect on the exhaust port. This also helps pull the fuel/air mix into the cylinder, and on out the exhaust port. The sound wave that comes out with the exhaust is bounced off the rear cone and back up the pipe where it crams that little extra fuel air mix that came out with the exhaust, back in the cylinder just before the piston comes up and blocks the port off. It is a supercharger in a way. That's why it's called a tuned pipe, as it's tuned to the rpm and how long the exhaust port is open. It's a nice little math problem if you like that sort of thing. But yes, the carb would have to be changed some to keep from fouling or burning up spark plugs. The carb is the same one for all the different displacement engines. The jet is replaceable, and I know a guy who has had some success drilling out the jet.

On that front mount, I have an idea for a billet thing that would fit most frames. But it would be huge and have sleeves to adapt it down. I don't see that looking any better than all the nuts and bolts. But it's worth keeping in mind. I'm sure something will be made that solves the problem. The rear mount is used to shim for the drive chain and is
movable and/or replaceable. I have seen a real nice billet piece that a guy did.  I've seen a set that allowed the engine to be offset to the side for a real wide rear tire. (O.C.C. Stingray)  It was pretty hacked up. The thing is, the guy got the engine in the frame.

Another thing someone was talking to me about is that a lot of guys are trying to put these engines in frames that it is impossible to get the carb on without cutting or bending the frame. So there are a lot of little things that could be made to help the kid or not-so-mechanical Dad who're bonding in the garage.
It's my understanding that trying to get the Chinese to change anything is next to impossible.  After all, these engines are tools to them, not toys. That's why they don't make any hop-up stuff. These are made for Joe Factory Worker to save up for a year, to be able to buy one for the bike he's been riding to work for ten years. To them, it ain't broke so they're not gonna fix it.

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The factory carburetor mount is an alloy casting of fixed angle and position, which is quite restrictive on the type of frames suitable for mounting of these engines; to the extent that Spit-Fire has a set of fitting charts on their site. A more adjustable mount, as found on other engines, would allow greater fitting and angle options.
Q: I'm not so sure that still applies. Even before the recent capitalism explosion over there, the government was discouraging bicycle transport, due to the congestion of the roads and streets by everyone being on bikes. The government was encouraging/ordering everyone to use public trains and buses instead. Then the boom of entrepreneurship took off. As a result of this, a huge number of Chinese were suddenly bringing in fairly decent money for a change. According to reports I've seen, so many Chinese have already bought cars for personal transport that it's having a negative
impact on the air quality of our west coast. And it's safe to assume that the trend will continue. With the Chinese domestic bicycle market in a downward trend, at a time when the American export market is booming for, among other things, bicycle motors, my feeling is that the American market will be of increasing importance to almost every segment of bike manufacturing over there. This should mean that American desires will be catered to, much more than in the past. Somebody just has to tell them what's wanted, and sign a contract to buy them.

I have a strong feeling that the junky motors coming from China at this point are only being sold to the lowball-price American importers you mentioned earlier. After all, those Chinese who still need that sort of thing need them to be reasonably well-made and reliable.

We have a family member who's a partner in a manufacturing brokerage over there. He's told me that he can get just about anything made, at any quality level the buyer would be willing to pay for. As an example, if you need a titanium knee joint installed right now, it will probably have been made in a Chinese factory and marked up about 1000% by the time it's installed in you.

The conclusion I draw from this is that someone who's not content with just buying a container full of off-the-shelf stuff at the lowest price possible can come up with a really amazing quality product from China that Americans, or anybody else, will pay serious money for; and that especially applies to things like bike engines.

A couple of months ago, I visited a friend in the Baton Rouge area. In his garage, mounted in a test stand was a new Chinese-made 90 CC 4-stroke engine with a 4-speed gearbox, electric starter/generator, and all the usual bells and whistles. It was basically a clone of a Honda ATV engine from the '70s, and it was beautifully made and ran like a top. He'd bought it for about $180 from an eBay seller. It sure made me think.
I ran into that carburetor accommodation problem you were talking about during that same research session in which I spotted your billet air cleaner. I'd just finished a new frame for a bike I was building for myself, not thinking at the time about motorizing it. While looking at all those cute little inexpensive engine kits, I started thinking that it would be pretty cool to get one for mounting on my new chopper. Unfortunately, the combination of the existing motor mounts and the carburetor placement made it impossible to fit one to that particular frame, without pretty much starting from scratch. What are the possibilities for an adjustable adapter to re-position the carburetors on these engines? Seems to me that would be a popular item, too.
The restrictions of the stock front engine and carburetor mounts are less problematic
when kustom frames are constructed around them, as in this clever but odd-looking solution by Firebikes' Sam McKay.
A: The problem with the carburetor is being addressed. A couple of different people are working on it. One guy is trying to make one out of steel tube.  Don Grube is having some cast with