Cylinder/Bore question

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computerguy50
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Cylinder/Bore question

Post by computerguy50 »

Hi guys, been away awhile. Got an 03 220, RB'd head and carb, good FMF pipe, good reeds. Just looking for a little more power. My understanding from reading here is there was a 240 bore option, but now the parts are hard to find.

Question is if bored just 1 or 2 mm over will I notice anything? If it is overbored like this do you have to replate? Any concerns with head lining up at some point?

What typical compression readings do you guys see before and after re-ring/re-boring?

Thanks in advance
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Julien D
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Post by Julien D »

Any overbore will require a replate. Performance gain from a +1 or +2 piston will be unnoticeable.

I'm not entirely sure what the compression specs for a 220 are.
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KarlP
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Post by KarlP »

I don't have my manual handy for the compression spec.
It doesn't really matter, though. The RBD head increases compression quite a bit on the 220. Hopefully you got a reading shortly after putting the head on for a baseline. If not, now would be as good a time as any.

1 or 2 mm isn't going to do anything. I wonder about reliability of a 240 bore.
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Deseret Rider
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Post by Deseret Rider »

My experience on two bikes----220's----with stock heads and new Wiseco pistons----137 # and 138# compression. I'd expect yours to be a little higher if your head has been shaved? For whatever this information may be worth? Like the others---I don't think the slightly larger bore will gain you much.
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computerguy50
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Post by computerguy50 »

Thx, Guys
cornishwrecker220
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Post by cornishwrecker220 »

i have a 03 220 with fmf gnarley front pipe & powercore 2 tail pipe, boysen rad valve & reeds ..bike ran very well but i too wished for a little more on top, i fitted the 35mm carb off a 200 kdx but kept the slide/needle & jetting from my 220..i also changed the gearing from 13/48 to 13/45 now i get a good noticable improvement in the mid range/top end pull without any real sacrafice in the good bottom end grunt that the 220 already had..yes fuel ecconomy goes down a little if you keep it on the pipe but then who cares. :grin:
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Julien D
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Post by Julien D »

He's already sporting an RB carb, so throwing on a stock 200 carb would actually be a downgrade.

I'd say the easiest way to make that 220 go faster would be to slap a 200 jug on it. :mrgreen:
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island220
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Post by island220 »

I had the same problem, I have 05 220, des pipe, v3, fredette carb, didnt have enough top end, I ended up taking the dremel tool and opened up the ports, found some pics of fredettes porting and I think eric gores and went a lot milder then fredettes, it seems to work great a lot more top end, and didnt seem to efect bottom end at all
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