I am rebuilding....

[redhatman]

Please help...

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.

 

[blasterfreek30]

u can find a larger piston on ebay, i would go w wiseco piston, and also the boyeson reeds will make it a little more snappy, good choice, u can also get the v force reeds, or the boyeson rad valve but there a little pricey! and like u said, u could prob start with a 270 or 280 main jet w ur mods

 

[Darrell]

sounds like its time for that 240 kit to me!!! lol

 

[ron89]

hey, i got my .090 piston from rjatv ...Yamaha Blaster Wiseco Piston Kit 1988-2006

 

[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?

 

[ron89]

yeah that seems about right for a dealer price, my dealer wants like 5bucks for them and they half to order them ,,,

 

[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?)

 

[redhatman]

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

 

[ron89]

yeah rc tuning is kinda easy is u no what u are doing lol .. umm u just take it for a run and check the plug that what i do ,, the stock is 230.. i have a 260 in mine and i have the mods below in my sig ..and mine runs great ..