Another Motorbike Build

I like Worksman wheels, but I use brake drums from 125cc motocross motorcycles laced into a heavy bicycle rim. Still has the look and great stopping power.


 
msrfan said:
I like Worksman wheels, but I use brake drums from 125cc motocross motorcycles laced into a heavy bicycle rim. Still has the look and great stopping power.


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That gets my vote...way better option than the Worksman when it comes to stopping you. I've had good luck with older Schwinn rims.
SB
 
nate25tenn said:
Got a particular model to look for that drum assembly? There's a few salvage shops nearby to scrounge parts from.
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Any of the japanese bikes with 36 spokes. Most have the cast in speedo cable hole even though they're motocrossers. Enduro bike hubs are usually the same.
 
More questions everyone. The inside of the crankcase looks new. The reed valves all look to be in great shape. I removed the plugs and there is a ton of carbon on top of the pistons. I was going to remove the heads and clean them only to discover the head/jug are one piece. I'm terrified ill break a ring trying to reinstall it and there is pretty much no spare parts at all. Should I risk it or is there another way to clean the motor out? Also it calls for one pint of 50w per gallon. Can I use modern 2 stroke oil?
 
Can't help you regarding the carbon buildup.

I will pass along what I was told about using modern oil in an old vintage 2 stroke. Don't. I have two vintage motors. One is a British villiars midget cast iron two stroke of 98CCs made in the 1940's or 50's. The other is a German made model 1932 Fitchel & Sachs 2 stroke motorcycle engine of 98CCs. Mine was manufactured in 1934. I was advised by an old fellow who restores Whizzer, Cushman, Sachs, villiars... you name it vintage motors and for mine he recommended Shell Aero 30 weight which is made for aircraft engines. He emphatically said not to use modern synthetics in those antique motors. I was planning to use Opti 2, but respect this man who is recognized internationally for his expertise in restoring these old motors. So I defer to those who know more than I do. My friend Fasteddy and I went in together on a case of the Shell aero which was not cheap and had to be sent away for. Hassle, but I did not want to damage my old motors. I don't know enough to say it is really necessary, but at least I know that the oil I have is good stuff.
SB
 
An old school trick to remove carbon is to drizzle water into the intake while it's running.
Supposedly the water flashes to steam during combustion and removes carbon.
Don't know if it actually works or not, but I've seen some old gearheads doing this.
 
maniac57 said:
An old school trick to remove carbon is to drizzle water into the intake while it's running.
Supposedly the water flashes to steam during combustion and removes carbon.
Don't know if it actually works or not, but I've seen some old gearheads doing this.
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I know this works on 4 strokes but I assume it won't work on a 2 stroke. I would think there's no way to guarantee the water would make it into the cylinder and would puddle in the case. Am I overthinking that or am I correct?
 
Have to keep it revving. I don't think anything is going to settle in the bottom end, but it would be fairly east to drain it afterwards by turning the engine over?
Actually never seen it done on a piston port engine, but I assume it would still work.
 
Ok guys in my stupidity I've somehow managed to lose the jet to the carb in my car. No idea how and can't seem to find it at all. Pisses me off because it was ready to fire up in theory. No rebuild kits available and no models on eBay for sale. So here's what I'm looking at. They have universal carbs on eBay for pit bikes, atv's, and such. The tillotson carb has a 27mm throat which I cam get for cheap online. The tillotson in a downdraft so I'd have to make a elbow manifold for it once again no big deal. My question is does the carb have to sit directly above the reed valves or does that not matter?

Something like these:
http://www.ebay.com/itm/27mm-w-Cable-Carburetor-Carb-Honda-XR200-XR200R-XL200-Quads-Dirt-Bike-ATV-PZ27-/310768142578?pt=Motorcycles_Parts_Accessories&hash=item485b3988f2&vxp=mtr

http://www.ebay.com/itm/AIR-INTAKE-...pt=UK_Motorcycle_Parts_13&hash=item485a77d5ba
 
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Forget about using bicycle wheels and/or rims on that build. You're going to need a motorcycle rear hub/wheel assembly (preferably with a rubber dampened sprocket) for that engine. Note: your engine looks like it has a pretty long Effective Stroke; i.e. the distance from TDC to where the piston starts to open the exhaust port (this distance is also known as the Power Stroke). This indicates to me that it's going to have a tremendous amount of torque, and therefor a very strong rear wheel assembly (hub/sprocket/spoke/rim) will required. I also agree with Ron334 in that you're going to have a lot of problems building a frame that will handle such an engine (the weight of that engine alone could be a serious problem for most any bicycle frame).

I'd also recommend a front brake and wheel assembly from a 200cc (or larger) motorcycle.


nate25tenn said:
If it breaks no big deal ill build a stronger frame.
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Actually, it is a big deal. You and others could be seriously injured if does break.
 
FMB42 said:
Forget about using bicycle wheels and/or rims on that build. You're going to need a motorcycle rear hub/wheel assembly (preferably with a rubber dampened sprocket) for that engine. Note: your engine looks like it has a pretty long Effective Stroke; i.e. the distance from TDC to where the piston starts to open the exhaust port (this distance is also known as the Power Stroke). This indicates to me that it's going to have a tremendous amount of torque, and therefor a very strong rear wheel assembly (hub/sprocket/spoke/rim) will required. I also agree with Ron334 in that you're going to have a lot of problems building a frame that will handle such an engine (the weight of that engine alone could be a serious problem for most any bicycle frame).

I'd also recommend a front brake and wheel assembly from a 200cc (or larger) motorcycle.




Actually, it is a big deal. You and others could be seriously injured if does break.
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I was thinking that if you could find a basket case light motorcycle with a title which had the wheels and good frame, fork but no engine you'd have yourself a roller to work with and in the end something legal and up to snuff for the motor. Just a thought. Might be a lot less expensive than trying to build it all and still end up with something unique and very cool.
SB
 
Oh, Man! Would I love to have that! I would put my 212 with torque converter in there, a a pair of 300 x 18 motorcycle wheels and have a classic ride with newish components. I love the Simplex, made in America! I think you should go get it, Harold...
SB
 
I was half way there SB and thought I should at least come close to finishing something before starting another project! Nice price and he had the fork too. It would be a dandy frame for the beast the OP is looking to mount.
 
coming to exactly the same conclusion motorized bicycle or motorcycle with pedal appendage!!!

when you get into anything above 100ccs why build a frame unless you want to consider production or as a i can do it exercise / satisfaction
best to use a light weight motorcycle frame and wheels and???? from the closest junk yard motorcycle scrap yard and go from there modify frame if you like to your desired appearance with equal or greater tube stock and you are ready to go for cheap!!! and practical and certainly more safe

i have here in belgium an 87 aprilla dirt bike 50cc without a cylinder and head and carb for 20 euros but here in belgium the laws regarding do it yourself and homemade builds are very restrictive and it is illegal if not approved by a lengthy- extensive and costly inspection procedure in Brussels so!!??? maybe electrify but that too is highly regulated so!!??? maybe just go for it and see what happens--
soooooo if i end up in jail will anyone come bail me out?????!!!!!!!
 
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Basically I like experimenting. This is a hobby so money or time doesnt really matter. Building a frame is great because I can say its mine. I have every major tool available at my job. I work as maintenance in a factory with a complete fabrication and tool and die shop. To me getting another frame and modifying it is no less time consuming than building one from scratch. All of that though comes later. Having a **** of a time getting the engine operational lol.
 
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