Quote:
Originally Posted by smiffy  hi guys,
im building a engine for a 50 class, however its a bit of a cheat.
the spec is:
takegawa 50mm crank
powroll 15:1 hc piston
takegawa h/d oil pump
takegawa c/r gearbox
takegawa r10 cam
takegawa 18mm carb kit
stock 50 head
to make the setup work i have had to cut the base of the sleave off about 5mm so that the conrod doesnt touch the side.
however the increase in stroke length has meant the piston skirts come out the barrel by 4mm at bdc.
do you think this is a problem?
need someone with some real tech knowledge here!!!!!
the engine will be running at full tilt 12,000 rpm for an hour at a time, a cant afford for the piston to come through the side of the jug.
PLEASE NOTE IM USING 98 OCTANE WITH 10% METHANOL MIX |
I personally think youd' be better off with a big bore cheat kit than a stroke cheat kit. You can get an 85cc top end marked 49cc and it will run circles around this setup and be much cheaper to boot. Your stroke to bore ratio isn't likely going to let you run 12k all day and a stock head probably won't allow it anyway. Your clutch isn't going to hold at 12k either if you run it like that all day.
If you are going to run a powroll 15:1 piston what will the compression ratio be when you put the stroker in? 17:1? Did you check to see that a takegawa crank has the same connecting rod length in that the piston comes to TDC? I think the takegawa crank is different than the stock....not sure.
As for the skirt sticking out the bottom, I'm a believer that as long as the piston pin is covered you should be ok. If you are trimming the skirt anyway, may as well trim it up further. Just make sure you get the edges perfectly smooth or your cylinder wont last long.