I am rebuilding....Help please

[redhatman]

2002 yamaha blaster

I have not been too happy with this atv so far being I bought it used, but now I came to the conclusion that I will have to rebuild the top end. Compression wasnt even 90psi

Okay, so i took it all apart, and you could actually wiggle the piston inside of the cylinder...I am surprised it didnt blow but thankful at the same time.

Either way, I took the head and base off, and will bring it to NAPA tomororow. I measured the piston that was loose and it was about 67mm, so I am unsure of what to do. The highest piston I saw was .060 over, 67.5mm. Where can I find a .080 or .1 if I need it? What brands and stores should I order from?

As far as reeds, are the boyeson superstock reeds good? I need new reeds too. Are the carbon fiber ones going to pose and advantage? (I do not race, just ride)

Jetting, jetting, jetting... I think I should rejet, but do not know where to start. I have a full DG exhaust kit which is probably the only difference from stock, and then the stock foam air filter for now. I do have the motion pro twist throttle with idle kit.

32:1 premix oil block off.

[Mert]

wiseco piston, check out www.rjatv.com, great prices and service, plus he's a member on here. He has .80 and .90

[redhatman]

Brought it to Napa today...turns out its been bored out several times. Its already sitting at .060 over....He said he will see what he can do for me tomorrow when he gets a chance to work on it.

Also went to the local atv shop, jets are $3.95 a piece... my neighbor told me they are usually no more than a buck. How much do you pay?

[socket17]

$3 a peace for jets around here.
just think of it this way you only have to buy them once.. and be thankfull its not a banshee pilot jet you need... sucks to find them at a local shop.

[redhatman]

Well for $3 a piece its fairly spendy to just throw them around if you are only going to need the one and never the others. I guess I should call DG and see what they think. If I go .070 or .080 over, will that make the quad run more hot?

[socket17]

umm yeah but not really noticeable.. and if you live anywhere it gets cold.. which minesota it does then you will need more then 1 jet.. richin in the winter.

[redhatman]

As for now, I have the summer ahead of me. I want a reliable quad that is fun to ride. I do not want to dump ~$200 into the engine and have it blow or run it lean. Back in the RC days we tuned by temp. How do you tune these? (What do you judge on?)

[socket17]

well ever 20 or so degress you may have to rejet your bike.. i mean thats if you want it runnin prefect.... im not to certain what blaster with a pipe jetting should be at.. but i do know that if you put a new pipe on a banshee you have to go up atleast 7-10 sizes on the main jet. (not always) so i figure it should be the same for a blaster.

take your stock jet any go up.. its better to go rich then lean..

[redhatman]

What is the stock Jet Size? For the main jet.

[socket17]

well im gonna take a stab at this but my guess is its prolly like a stock banshee 19-220 dependin on dealer locations..