Has anyone every bored out the cylinder and used oversized rings?

most 2 stroke engines have a thin nikasil plating on the cylinder wall...not much you can bore there :(
some of the new grubees have a steel cylinder liner,,,a much better prospect for boring :)
 
These engines are not bore-able, except as azbill mentioned some of the 50cc engines being sold have a steel liner....but then why not just buy a 70cc if you want a bigger engine?
 
Steel lined (I have one) or not, there is nothing to bore. Cylinders perform poorly when constructed of aluminum foil. :)
 
if you bored it over and reused the stock piston it would be to loose and probably get a lot of piston knock no mater what size rings you used. the bore must be sized for the piston, not the rings. the rings will be gaped so many .00's per inch of bore.
 
If these cylinders are nikasil (which is ****in awesome) then you can bore your cylinder and send it off to be replated. Problem is then finding oversized pistons.
 
It appears those who are enthusiastic about re-boring never bothered to measure HT cyclinder wall thickness.
 
NickDK said:
Anyone done this to one of our two strokes?
Click to expand...

There is not enough cylinder liner thickness to bore. You would have to buy another
over sized piston with rings to fit it, and there are none available anyway. You also
would have to take your cylinder to a reputable machine shop to have it bored out and honed to properly fit. I'd suggest spending your money on a good expansion chamber and you will notice a much better improvement in performance and reliability!
 
Well for the skinny.. I helped develpe the inner workings of the newer 4 stroke gearbox and ended up helping engineers of the Nantong Jiali Gasoline engine factory and have since helped them with US Precision refining in thier 2 stroke engines and kits and can say this they are the Factory that produced the Steel Sleeved 2 strokers and the only barrel cast they had was for a
49cc commonly known as the Starfire I know it was thier only steel sleeved engine barrell(49ccer) because I had to source a supplier of a 66 cc sleeve in order to get them to produce a steel sleeved 66, we have'nt gotten around to it. this is thee only factory I know of. Rick Shy (BGF) sourced WHAT SAID 66CC Orange or yellow labeled engine with the carb affixed directly to the cyclinder and it ran like a raped ape and by looking at the jug it looked to me to be a 49ccer But when it was ordered the customer had actually payed for in auction a 49cc sticker said 66 I remember thinking it was smalll. Anyway I think he is partially in bed with this Nantong Jiali but if He isn't there is a chance one of the 66cc ,if it actually was, could be had from him.

Plus, don't Quote me on this, bI do beleive the cast for the 49cc and the 49cc Starfire were the same but the cast had to bored out wider for clearance for the sleeve which are really thick but if you talk to wiseco send them a 66cc jug theyll tel you if you have clearance enough to bore for a sleeve. Youd need to use electrolysis process for removing the nickel (nikasil) or chrome. chrome
 
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Spreading misinformation, ALL HT's have steel lined cylinders with bright plating.

I'd use a whole different jug and head before polishing a turd.
 
I was thinking my last response was too cynical, you can do good stuff with stock parts if you have time for porting and decking and truing.
 
I still cringe every time I see the words "steel liner".

Steel is a lousy cylinder liner. A proper cylinder liner is ductile iron with a freegin crosshatch!
 
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