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350cc OHV to 500cc OHV
Posted: Wed Jul 21, 2021 10:46 pm
by Happychipy
Hi I’m looking for information , I have a 1942 350cc OHV WD/CO outfit. I would like to fit a 500cc OHV engine (J2) or can I put the Barrel and head from a J2 on a 350cc Engine casing ? Thanks
Re: 350cc OHV to 500cc OHV
Posted: Thu Jul 22, 2021 7:51 am
by vince
Hi, a quick look at the parts books shows different base gaskets and bearing in mind that there is a 14mm difference in bore size I doubt if the top end with interchange. However I am lead to believe the complete engine will fit. Vince
Re: 350cc OHV to 500cc OHV
Posted: Thu Jul 22, 2021 5:30 pm
by Happychipy
Thanks for that. So need to find a early 500cc engine
Re: 350cc OHV to 500cc OHV
Posted: Thu Jul 22, 2021 5:39 pm
by Adrian
Probably a lot easier to do that.
For the later Bullet engines it is possible to modify a set of 350 crankcases to take the 500 top end. The crankcase mouth has to be bored out, and the cylinder stud holes welded or plugged up , then re-drilled and tapped for the 500 cylinder's studs on a wider spacing. Not rocket science, but I don't know if this could be done with the WDCO or Model G crankcases.
A.
Re: 350cc OHV to 500cc OHV
Posted: Fri Jul 23, 2021 8:36 am
by Allanfox
I would think a more recent 500 iron barrel engine would fit, probably easier to find and they don't look that different?
Re: 350cc OHV to 500cc OHV
Posted: Mon Aug 09, 2021 2:55 pm
by Marko
I dont think it can be done; a friend of mine in France looked into it & decided to give it a miss. Although the 350 & 500 (G, CO, j2) share lots of components & look very similar i'm pretty sure the frames are different too. The crankcase mouth would have to be machined out & a host of other things too