How much power can be squeezed out of a stock 88 cylinder?

[flynbyu]

Hey Guys...I have a completely stock 88 cylinder and head that I am going to have ported and re-worked. What kind of Hp can one obtain from this project. Couple things to consider and kind of a deal killer... 93 octane fuel is all we have access to where we ride. So my guess is I have to stay around 180lbs compression. Also looking for Low/mid power delivery/porting. Thinking about a heavily ported cylinder with the 38mm air striker carb. I am open to pipe suggestions and engine builders. Price is not as much of a concern. Thanks for any input.

[Jerry Hall]

Low to mid power delivery, 38 mm carb, 180 lbs compression, 93 octane fuel..............you are not giving us much to work with.........I am an engine builders not a magician.

You have just described a typical stock 250 moto-cross engine.  Not a very exciting ride or build.

[Deuce]

Could probably liven it up a little more by adding a stroker crank to the equation if you're willing to tap into the bottom end...

[mennis1971]

You sure aren't giving ANY builder much to work with. If they claim otherwise, they are lying!!!!! I'd guess you'll make somewhere around 40-42 AT THE MOST and that is with a good/great builder(with a stroker crank) and my hp guess MIGHT still be to generous. One of your main problems is the lack of race fuel-which will limit your compression and your hp. At least Jerry is being honest with you. I can think of another builder(using that word lightly in this case) that prob wouldn't be honest. He's the one that keeps sending me PM's on the the old site about how he is the only distributor for sabers, mini tooths etc... Watch out for him as he will try to pro flow your wallet:pirate:

[flynbyu]

I know this is not an exciting build, its simply a spare cylinder for my son and I to use when our primary cylinder is down. I appreciate everyone's input.

[SARON81]

You could always go with the 310 sleeve in the stock cylinder. That's probably going to give you the most hp out of a stock cylinder. I have one, and it rips.

[flynbyu]

Now that's an option I would consider Saron81...I was not sure if you could go much bigger than a 265cc on a 88 cylinder. Who could re sleeve the stock cylinder to a 310 bore and port it for Low/Mid and slightly bump up the compression?

[Bowtie316]

Now that's an option I would consider Saron81...I was not sure if you could go much bigger than a 265cc on a 88 cylinder. Who could re sleeve the stock cylinder to a 310 bore and port it for Low/Mid and slightly bump up the compression?

I know LED can do it, but it's more expensive than an ESR 310.  Seems like it was $1000 last I heard.

[Jerry Hall]

You could always go with the 310 sleeve in the stock cylinder. That's probably going to give you the most hp out of a stock cylinder. I have one, and it rips.

Putting a 310 sleeve in a stock cylinder puts the studs too close to the bore to be a 100% reliable setup.  The stock casting becomes too flexible as a result of all of the material that has to be removed to accommodate the 310 sleeve.  We can go through an expensive process to try to keep the head gasket sealing but I have not seen a 100% success rate with our set up or anyone elses remedy to this basic design flaw with this type of build.  

The failure rate on keeping the head gasket sealing has been about 1 out of ten builds on a new build and each time the head is removed the sealing rate failure goes up.  The studs being too close to the bore also causes distortion in the bore even when using torque plates when boring and honing the cylinder.

[SARON81]

It did take several attempts to seal up my headgasket.

[flynbyu]

Not sure I want to sacrifice reliability for this type of build as we regularly go on 80+ mile trail rides. Hate to lose the head seal 40 miles from the truck. I guess this just does not make sense.  I should just buy another cylinder ported for low/mid range porting set up with 175-180 lbs compression. Maybe I could just put my completely stock 88 cylinder in a museum.

Opinions on best place to buy a non PV cylinder ported for Low/Mid power and what pipe to accommodate aggressive cross country type riding that would be reliable. Something that hits hard and doesn't  sign off right away.  All opinions appreciated!

[JesseA420]

http://www.eddie-sanders-racing.com/product_p/310-kit-4.htm

[mennis1971]

Since you can't bump up the compression(to race gas levels) and are considering a pipe too, I'd say that ESR kit is the route I'd go. It'll still be reliable, yet make more hp. Shouldn't be a gas guzzler either for those long trail rides. I like oem cylinders. They can be made to run great with the right mods, but do require a lot of work to run great(ported, stroked and up the compression). It's usually cheaper(and easier) these days to just go to a big bore aftermarket cylinder. That kit has a great price. I also have a 05 yz250 and the 325 kit for it is the same price or more, yet doesn't include the pipe/silencer. Eddie has always been a 250r guy. If you don't wanna add compression, then add displacement!

[jadleybray]

IMO, if your considering buying a cylinder, with the build you have described, I would go with a 350cc cylinder.  The added cylinder cost is not much more, and your going to be able to run the same pipe/carb combo most likely as the smaller cylinder being the build is so mild.  I think this would give you some more grunt with the added cc.