# 100cc four stroke dirt bike engine help??



## Dante (Nov 23, 2008)

im buy a running dirtbike for 50 bucks, its an older suzuki 100, it runs fine but has low power due to a slightly scratched cylinder wall and it may need new rings. my main question is how much would it cost to get the cylinder rebored and to buy an oversized piston?


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## paulr44 (Oct 14, 2008)

Call your local automotive machine shop or specialty bike shop for boring prices.
Call your local Suzuki dealer for parts prices.

A bike cylinder has to be set-up in a special boring bar jig, and requires more time in set-up than on a V-8 block boring machine. Also, if it's a 2-stroke the ports have to be chamfered with a die grinder after the bore job, which doesn't take terribly long but it is another step they need to take.
These days, on the east coast, I'd expect to pay between 50 and 100 bucks for what you're looking for. *AND* they're probably going to want a new piston to work from so they can size the bore correctly.


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## Dante (Nov 23, 2008)

its a 4 stroke, and its a 21 year old bike, i have a honing tool that you can attach to the end of a power drill, will that work?

i'll most likely just use it as it is now if its goings to cost a good 100 o so bucks to get rebore/honed.


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## paulr44 (Oct 14, 2008)

A "honing tool" you can attach to a power drill is most likely a spring-loaded tool, that's actually considered a glaze-breaker. True machine-shop hones have an adjustment collar that applies force to the stones. They're also powered by a good size motor. 
While a glaze breaker in terms is a hone, it's not up to boring out a cylinder unless you don't care about the results being highly accurate, and being there for what may be hours moving it up and down. AND, you have to have a lubricant circulating in the bore while doing this. Kerosene can be used, solvent or obviously honing oil. Don't want the stones becoming clogged up or wearing out in minutes.

If you had a true hone, you'd still be there a long time to machine it oversize, and you'd have to worry about taper, and you'd want 2 grits or more. The bore needs to be true top to bottom - else you can have compression, oil control or other problems.


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## Dante (Nov 23, 2008)

paulr44 said:


> A "honing tool" you can attach to a power drill is most likely a spring-loaded tool, that's actually considered a glaze-breaker. True machine-shop hones have an adjustment collar that applies force to the stones. They're also powered by a good size motor.
> While a glaze breaker in terms is a hone, it's not up to boring out a cylinder unless you don't care about the results being highly accurate, and being there for what may be hours moving it up and down. AND, you have to have a lubricant circulating in the bore while doing this. Kerosene can be used, solvent or obviously honing oil. Don't want the stones becoming clogged up or wearing out in minutes.
> 
> If you had a true hone, you'd still be there a long time to machine it oversize, and you'd have to worry about taper, and you'd want 2 grits or more. The bore needs to be true top to bottom - else you can have compression, oil control or other problems.


alright, well i got the bike last night, 1987 suzuki dr 100 for 50 bucks, its runs but needs new rings and a possible re-bore, but i could get away with just new rings. anyways i learned its already been re-bored and completely re-built once so i only get 1 more chance at a re-bore and im going to have a pro do it if i have it done at all.


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## paulr44 (Oct 14, 2008)

If you like older Suzuki's, I'm thinking about selling mine, but it's a street bike:
http://www.bikepics.com/members/bigfootx7/77gs750/


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## Dante (Nov 23, 2008)

paulr44 said:


> If you like older Suzuki's, I'm thinking about selling mine, but it's a street bike:
> http://www.bikepics.com/members/bigfootx7/77gs750/


its not so much that i like old suzuki's, its just that 50 bucks for a running trail bike cant be beat. I'm more into dirt than street bikes, so no thanks to you offer, but nice bike.


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## paulr44 (Oct 14, 2008)

Yeah, I didn't get into street bikes until my mid 20's. Thanks for the comment. Good luck with your restoration...
Paul


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