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Yamaha Chappy

Started by Djg8493, November 16, 2022, 02:37:47 PM

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Djg8493

Ok, sometimes things just jump into your truck unplanned.  The price was right but now need to figure out what I am going to do with it.  I was told it was an Lb80 but need to go through and find the marks on the engine to confirm. 

My question is does anyone know anything about these, if it is the 72cc engine is it really worth salvaging it?  It is missing both engine covers and some other odds and ends, the problem is it seems some of these parts are pretty expensive.

My thought is it may be a better route to just go with a Piranha engine for now, I know its moving to a 4t but it would be a big increase over the original engine and could make this a fun little bike that could at least keep up with local traffic. 

Any thoughts?

Thanks,
Dave
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6

m in sc


Djg8493

Thanks, that's pretty much what I was thinking! Although I have heard those 190s are pretty wild. 
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6

m in sc

they are. i've ridden a mini bike with one. .. lots of oomph.  :olaf:

soonerbillz

I've got one buried up in the barn.
Not thinking a engine swap is really workable as these are shaft driven and those other motors are conventional chain drive.

Djg8493

Interesting, I am not sure on the model history but mine is chain driven. 

It also turns out the guy that sold it to me was incorrect, it is in fact a 49cc version.  I suspected that as it had a petal start option. 
It make my decision easier though, fixing up that little motor is not worth it, 140cc Piranha motor it is.

I'll take some pics as the project kicks off over the holidays. 
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6

Djg8493

Ok, little progress update.  In speaking with a local contact at Tbolt USA, (pitbike supply site for those that want to go down a wormhole) I landed on a Piranha 140 engine with a 22MM Mikuni.  I will see how it goes as some recommend jumping up to a VM26 but my guess is this should be enough to start with.

I am in the process of making the engine mount brackets, the top engine mount I was able to modify to fit on the Piranha and it bolts onto the frame from the top down.  For the lower I made out cardboard templates to see if I could get the 2 frame mounts with the engine mount in the middle.  First pass with Steel last night and I have it pretty close, need to shim it out in the middle and test out how the chain lines up. 
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6

SoCal250

 :thumbs: Nice, fits right it there like it came with it.
75 Yamaha RD125B   75 Yamaha RD125B (project)
75 Yamaha RD250B   75 Yamaha RD200B (project)
73 Yamaha RD350     77 Yamaha RD400D   79 Yamaha RD400F  
91 Yamaha TZR250R  89 Yamaha FZR400   05 Yamaha FZ6   
05 Yamaha XT225TC  82 Honda MB5  02 Aprilia RS250 Cup (sold)

m in sc

thats going to rowdy. i rode a CT70 with a 140 setup like that, (local guy had one i fixed the cdi wiring on) would do 70+  :eek:  looks great.  :olaf:

Djg8493

Rowdiness has been confirmed!  Got a few shakedown runs in and this thing is a blast, yes it wants to pull the front wheel up all the time but I was rather surprised that the suspension is actually pretty decent. The stock shocks are KYB and hold up pretty well.  Had to run a second lever on the left to hook up the rear brake, a bit weird to get used to as I'm not a stunt guy :cheers:
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6

automan

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cliff