How to get my cylinder bored

[nick20555]

Ok I finally went out and got a blaster I can officially call my own. I got it for 100 from a friend who just wanted it gone. Apparently he bought it not running and put a working bottom end on it and tried to rebuild the top end himself. He said there was scared and tried to hone it out but might still have small scratches. He put a new piston in and said he had it running for 5 minutes and then the next time he tried to start it it wouldn't start. Now I have it. I did a compression test and after about 20 kicks it made its way to 85 psi so I'm guessing he didn't do the top end right and it probably needs a small bore to get the scaring out. But I don't know how you go about a bore. Do you take it to a machine shop and just say hey I want it this size or do I need to take them an oversized piston and say make this fit?

 

[nick20555]

Oh and before I get flamed for starting a thread for a stupid simple question like that, I plan on using this thread in the future because it's got a major air leak in it as well so I'll probably just do a full rebuild and will have questions on that in the future.

 

[ikilledcasey]

860 230 5003
kenoconnorracing.com


Thats who you call, he's got my whole engine right now doing a bore and whole new top end plus all freshened up bottom. He's cool as sh*t and will talk to you like he's known you forever Everyone on here sends their stuff to him. A+ reputation.

 

[nick20555]

I don't want to spend the money for someone to do it all. I'm going to do the work myself I just need it bored by someone and don't know the process for it.

 

[dirtysquared]

Its best to have the shop measure and let them bore to the next acceptable oversize with the piston in hand. That way everything is in spec.

Give Ken a call tomorrow. He also can sell you all the needed gaskets, seals, and bearings if you plan on going into it and making it fresh.

 

[Awk08]

I don't want to spend the money for someone to do it all. I'm going to do the work myself I just need it bored by someone and don't know the process for it.

IF....you have a reputable shop nearby, take it to them, they'll measure it and compare those measurements to that of oversize pistons, you or they buy the piston, and then they bore/hone it to match that exact piston and the clearences it calls for.
cast vs. forged pistons ....some come with the clearence built in, other it must be acoomodated for,
and each calls for different clearences.

the above mentioned shop can do all or as little as you want....TO PERFECTION

 

[speedyslyder]

people are people
and alot of people that get hired at a shop are idiots
or so i have seen were i am

 

[jus_me]

Most do it yourselfers can accomplish quite a bit with the proper knowledge and tools. But when it comes to cylinder boring and honing, sure you/ we can hone/deglaze a cylinder and slap in new rings with proper ring gap. but when it comes to boring the cyl that's a bit more involved and something you would want an experienced shop to perform. There is bore taper, out of round, cast/forged clearances, not to mention chamfering the ports. Some shops don't even do that (the mentioned above does) Send it out and get it done right the first time and don't worry about it. The rest you can do yourself if you wish, just have a reputable shop do the boring, honing, end gap and chamfering..

 

[Jeff Bennett]

Yeah, I sent my cylinder to KOR to have bored and cr500 studs put in and he ordered me all my parts and champhered the ports. And like was said, awesome to talk to, like hes known you forever. He will get anything I cant do and all my parts orders, just for being cool and doing great work!

 

[tbrooks]

^^^ Yep and he has good prices. Piston clearances are measured in thousandths of inches, .006 inches off and your no good, best left to a reputable pro

 

[nick20555]

I ended up finding a very reputable shop that will take my piston and bore it to that piston. I think I will save the other work for the future. When I bought the blaster he actually sold me 2 for $200. One is an 03+ (still need to run the VIN to verify year) and the other a 02 or less but the older one needs a little more work and a few body parts. I decided that I'll get the 03 one looking good and running so I have one to ride and the other one will be my build project for my free time. He gave me a +3 crank that he ordered and never got around to installing so I think I might try to use the other to build and tune a stroked 240. Once I'm satisfied with the work (or far enough to ride) I'll swap it over to the 03 and sell the older one with the lesser engine.

 

[Blaaster]

Gave you a +3 crank! What a score!

 

[nick20555]

Gave you a +3 crank! What a score!

Yeah both blasters that for the most part just need rebuilds and a +3 crank for 200 I couldn't pass that up. Plus one was the newer body style and I always wanted the newer one for those nice hydros on them and I like the built in light better. The only problem is that he didn't order any of the bearings or seals for the bottom end and I know that while I'm down there I'll want to swap those out and prevent future rebuilds but those cost almost as much as a rebuild kit. So to keep reliable but stay on a budget, what bearings and seals do I need to replace while I'm down there? Does anyone have them in a cheap kit with just the bearings and seals I need?

 

[nick20555]

I seemed to have overlooked a huge part of the future build. I need my blasters to run off pump gas. Is this going to limit my dream of building a stroked 240?

 

[speedyslyder]

race fuel burns cooler.
soo it depends on your compression/detonation
compression depends alot on the cylinder head

 

[nick20555]

race fuel burns cooler.
soo it depends on your compression/detonation
compression depends alot on the cylinder head

So I just need to let whoever does my head work know that I want it to run on like 93 octane at the most.

Another question. If I was going to stroke a big bore, do I need to sleeve the stock and have it ported for the stroke or can a big bore cylinder be ported to match the stroke? I ask this because I can get my hands on a big bore cylinder pretty cheap from a friend.

 

[Awk08]

I seemed to have overlooked a huge part of the future build. I need my blasters to run off pump gas. Is this going to limit my dream of building a stroked 240?

no, a reputable shop.... KOR , can set up your head for whatever fuel you ask it to be set for.
I would definately ask for the 165psi-ish head for 93 octane.

Another question. If I was going to stroke a big bore, do I need to sleeve the stock and have it ported for the stroke or can a big bore cylinder be ported to match the stroke? I ask this because I can get my hands on a big bore cylinder pretty cheap from a friend.

if the cylinder was already ported for a stock stroke crank ?, chances are it won't be compatible with a +3/4 stroke.
best to start fresh and match the porting to the + crank.

 

[nick20555]

Okay, I'm kind of in a big delima. I found out that one of the spare cylinders that was given to me with these blasters is a stock cylinder resleaved for a big bore because I measured it today and it measured 72mm. The only issue with that cylinder is that it has sat for a while so it has slight surface rust on it in places. I would think that a .010 over bore would do the trick and wossner makes pistons up to 73mm I believe.

So I now have 2 blasters that need rebuilt, an extra stock cylinder with a 240 sleeve that needs a bore, a +3 stroker crank, and no idea what I should do with it all. Do I pick one or the other with the stroke or big bore to keep it reliable? Try to see if I can find a way to get KOR to do the machining cheap for both to be put in? I can do rebuilds but not the machining involved. I am on a budget like everyone else in the world so I don't want to be blowing cash like its nothing. I can get my hands on a 40mm carb if that helps. I only have left bend pipes right now but may be willing to go for a right bend if the engine build didn't break my bank. Oh and to make things more complicated, I'd like to stay on 93 octane like stated above. Any thoughts would be appreciated.

 

[nick20555]

Ok just in case there are some people kind of following this thread I started in hopes of seeing me build a 240 stroker, I'll give a little update.

I talked to Ken today and we had a much appreciated and very long and informative conversation. He was kind enough to give his complete attention and answer and breakdown everything I needed to know.

We talked about putting that +3 crank in and how he can bore and port my 240 cylinder and machine the head to run a half race fuel mixture. I am very excited to work on this blaster now. I can't wait to order some parts so I can work on it and send it to him for the work. I'll run it with the Vito's pipe I have and I'll be in search of a carb for it so if anyone has one for sale let me know. Ken advised I run the Keihin (or however its spelled) 35mm air striker.

 

[Blaaster]

Now that is what I call customer Pre Service,. Ken is the Man!