11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Hey Everyone,

Glad to be back. I used to frequent the Moped Army site for help and inspiration on my old Yamaha QT50.

I now own (2) 1981 Yamaha Chappy's with the 50cc (LB50) engine.

I know they made two version of this moped with 50cc and 72cc (LB80) engines. I was hoping there would be a kit to convert the 50cc model up tot he 72cc model. Seems like there would be a desire to do that. However the first few pages of Google produce not much in line of kits for sale.

Does anyone know if this is possible, and or a link to a place to buy the parts?

As always, your help and insight is much appreciated,

Jeff

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Dirty30 Dillon /

The LB80 has different throat diamter, and stroke, so retrofitting the 80 cylinder to the LB50 is not an option.

There's only one option for kits, and I'm fairly certain it's harder to get.

I would send an email to Blake at Dos Cycles to see if they have one on a shelf somewhere.

I have this kit on a chappy, and I can tell you now it's probably not the best investment if you're looking to get LB80 performance. Better bet is to retrofit a PW80 motor, or get an actual LB80 motor.

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Thanks for the speedy reply.

I always remembered the Yamaha's had a very versitile lineup that was pretty easy to swap parts for. My luck to get the 1 bike that doesn't really have a good matchup.

I did find a kit that noone has in stock, a Polini 70cc 45mm cylinder kit -and then use a new 70cc head for better peformance, but as you said the commenter indicated it was not really as peppy as the stock 72cc bikes.

I'll keep looking around and see if there are maybe some performance parts for the LB50 that could add a little pep.

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Dirty30 Dillon /

> Jeff Panian Wrote:

> -------------------------------------------------------

> Thanks for the speedy reply.

>

> I always remembered the Yamaha's had a very versitile lineup that was

> pretty easy to swap parts for. My luck to get the 1 bike that doesn't

> really have a good matchup.

>

> I did find a kit that noone has in stock, a Polini 70cc 45mm cylinder

> kit -and then use a new 70cc head for better peformance, but as you said

> the commenter indicated it was not really as peppy as the stock 72cc

> bikes.

>

> I'll keep looking around and see if there are maybe some performance

> parts for the LB50 that could add a little pep.

I mean, I have the Polini 45mm, and Polini Snake pipe on my chappy and it has gone from 23mph to 33~ mph, but for thoseupgrades on any other bike you'd have a very fun 40-45 mph bike, not a still slow to take off 33 mph bike.

The problem comes down to the gearing on the chappy and the inability to tune the clutches

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

If you know of a resource that has those Polini kits please let me know. I would love to upgrade, because I was just running it down the street and I think I hit maybe 20mph. :). an extra 10mph would be amazing.

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

https://www.motorkit.com/fr/engine/1123-cylinder-bore-up-polini-kit-for-yamaha-chappy.html

Seems to be way to get in Europe. If you want to pay for the shipping?

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Jack Rutherford /

You could probably bore out that stock cylinder a couple few mm and find a piston and rings.

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Sip has them!

Screenshot_20200610-184916_Google.jpg

Re: 11 Yrs from my last post..... Yamaha Chappy 50cc to 72cc kit?

Overpriced Parts /

Yeah Chappys basically a worthless bike on a 35 Mph Rd. no matter what you do to it

It is great for a 25mph development bike or campground bike:) had much fun going to the campgrounds store, bathrooms and showers with them !

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