Like I said, your piston skirt is your valve which opens and closes the ports. On the stock cylinder there isn't much room to lower the ports, and the piston is just barley closing it off. 1mm can and WILL destory your cylinder if it's in the wrong place..fact.

 

Easily fixed by running double base gaskets or how I prefer to do blaster cylinders with a spacer plate.

 

They should run a spacer plate anyway, they sit too low to begine with, I had to run a spacer plate on my 240, now because of the longrod it's obvousily a bit thicker.

 

try ebay, and ANY year blaster cylinder will work

 

first of all i'm not an idiot, and i work in a machine shop so i have experience on doing things like this, and i know alot about 2 strokes too, that's all i ever dealt with, so before anyone starts saying that any idiot can clean up the intake, you're wrong, because i've been through schooling for this and i'm sure after learning how it's done i would know, so don't try to call me an idiot when i know how to do engine work on these things

 

Im not going to bash anyone [img]i/expressions/face-icon-small-smile.gif[/img]. I am actually thinking of getting my Raptor ported and polished. The machine shop in town operates at $45/hr, and he said 2 hours max. But why did you have to re-sleeve the blaster? How thick is the original sleeve on a blaster? And why could you not have bored it out? How did you get the original sleeve out? And what process is needed to install a new sleeve. Do you guys do Nikasil plating at our shop? Also when you did the porting and polishing on the blaster did you do cylinder mapping? I am not insulting your intelligence, just trying to learn what goes into boring out a cylinder. Thanks for any advice.

John

 

Did I ever say you were a idiot? What I ment was that it dosn't take a genious to figure out how to clean up the intake, all you need to do is remove any ruff spots left by the factory. If you need to go to school to learn how to use a dremel then fill your boots. Don't talk to me about experience, your 17 dude.

 

People usually re-sleve for two main reasons. The first being that it has been bored out to its limit. Each cylinder only has a certian amount of room on the cylinder walls that can be shaved away. Once you reach the limit and still need to go further, because of a bad scratch or imperfection, then the only other option is to install a new sleeve and go back to standard bore or to replace the whole cylinder. Another reason people re-sleve is to go big bore. On the blaster cylinder for example you can only bore it out .080 tho over before the cylinder walls start to get too thin. In order to have a 240 kit (72mm top end) you need to remove the sleeve, cut a larger hole in the cylinder and then install a bigger sleeve back in, you follow? Removing a sleeve is actually quite tricky, you need to be able to remove it without damaging the cylinder walls to make sure that the new sleeve will fit back in tightly and in the right position.

Nikasil is short for Nickle/Silicon, it is a hard coating that is applied to the inner surface of an aluminum cylinder, all new dirtbikes that are liquid cooled now come factory this way, the advantage to it is it will never wear out of round and you can stay the stock size for the life of the bike, occasionally the Nikasil does need honed, but rarely, and if it does, it has to be honed with a diamond stone hone, now the disavantages:
If a piece of piston of ring is let loose in the cylinder it WILL destroy the Nikasil coating, it will then need to be resleeved with an aluminum sleeve and recoated, which is quite expensive, and the Nikasil can also start to flake around the ports like chrome does off a bumper, I personally would much rather have a steel sleeve, they claim that the Nikasil runs cooler, but nothing that will gain noticable power.

 

Shav0 thanks for the reply. That cleared up alot. I was asking about the nikasil because one of my newer dirtbikes have a nikasil finish.

 

I am not a big fan of resleeving with cast iron and personally I prefer the nicasil coated cylinders. I guess I've rarely seen rings cut loose and tear up sleeves bad enough that they must be replaced. Aluminum cylinders typically have the plating striped, and are bored to a larger size if need be (to clean up the marks) or they will weld the cylinder (fill cracks) up and then re-bore it. The cost to replate is usually around $175 (extra for weld and/or bore) and is not much more than the labor alone for a resleeve at most shops. Nicasil offers increased cooling, reduced friction, and good wear resistance. Putting an iron liner in a normally nicasiled cylinders reduces the heat tranfer capabilities making it run hotter (this loses power in big in 2 strokes). Some of the faster blasters in mx classes run a stock cylinder, resleeved with aluminum and nicasiled to run cooler and maintain HP through out the race.