ScottaKR wrote:The other I dea I've had for the tandem engine is doing a 300cc over-bore useing something like RG150 pistons. There's a lot more meat in the tandem barells so wouldn't be as weak after the bore out.
The RG150 pistons are 61mm diameter. Not sure how common they are, as I only found them in a piston catalogue while looking for other posible replacements for the standard slugs. I was thinking aboout doing the over-bore on a couple of really badly scored barells I have.
It's only been basic research so far, and the conversion would most likely also require head work and maybe skimming the top of the barell a bit.
I don't know about the crankcase compression issue, but peaky is just fine with me.Sheik Yerbouti wrote:The other thing to check out is the crankcase compression. I dont know if it'll make any difference with such a small increase in bore, but the greater volume of air being moved by the bigger piston raises the crankcase compression which can (correct me if I'm way off here, I know theres some racers on here who know way more about this than me) make the engine peaky.
61mm could be feasable though, as you said there's plenty of meat in these barrels. If the gudgeon pin is the same diameter and the same distance from the piston crown, then it should be a peice of the proverbial p*ss.
Gudgeon pin diameter is the same and it's distance from the crown is about the same as far as I can tell.
Here's a link to the companies webpage which has a link to the catalogue.
http://www.mingyang-group.2u.com.tw/private/english.htm
Unfortunately, they don't seem to sell direct to the public, and I havn't found a supplier for them yet.