i have recently traded for a 2000 yamaha blaster! i was told by the guy that i got it from that the carb on it came off a 03 yz85 and i was wonderin if i needed to jet it the carb any? cause it has been bored to 67.75mm? i actually have to put a piston in it now is why i am askin before i put it back together and try to run it? thanks in advance?
carb question?
- Thread starter perry1990
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I would ask why you needed a new piston, was it destroyed by improper jetting with the YZ85 carb?
If is was running well with the YZ80 carb and confirmed by a plug chop, there is no need to re jet for just a small increase in swept volume.
What exactly is the carb and its size, it will help in advising what jets to use.
It too will help if you tell all the mods done to the motor, pipe, filter, lid on/off, pre mix ratio, ect.
If is was running well with the YZ80 carb and confirmed by a plug chop, there is no need to re jet for just a small increase in swept volume.
What exactly is the carb and its size, it will help in advising what jets to use.
It too will help if you tell all the mods done to the motor, pipe, filter, lid on/off, pre mix ratio, ect.
If that's a stock yz85, why would someone put it on something twice it's size? That's why it blew up
not sure on the size of the carb! he said he forgot to shake up the gas and oil in the can so it was stright gas that went in the tank!!! and the condition of the piston it burnt a hole in the middle of it about the size of a nickel! and the yz85 carb want connect to the stock blaster air pipe so at this point no filter! the motor is bored to 67.75mm which is 0.70 over. stock exhaust!
Sheer case of detonation caused by incorrect jetting in an unsuitable carb, and extra leanness caused by no air filter.
No need to shake fuel using modern day pre mix oil, it disperses pretty well.
You are in the realm of the unknown using other than a stock carby.
If you can tell what size, model and make of carby, some one may be able to put you in the ballpark.
You are going to have to fit an air filter before you attempt any jetting.
You are able to mix your own fuel 93 octane with a ratio of 32:1 oil, I prefer to mix at 25:1 as I strive for maximum power with ultimate protection.
Any good quality 2 stroke is fine provided it is designed for air cooled motorcycles, not for weed eaters or chainsaws.
My choice of oil is either Maxima 927 or Castrol R30, but there are other superb oils to be found.
If you can tell what size, model and make of carby, some one may be able to put you in the ballpark.
You are going to have to fit an air filter before you attempt any jetting.
You are able to mix your own fuel 93 octane with a ratio of 32:1 oil, I prefer to mix at 25:1 as I strive for maximum power with ultimate protection.
Any good quality 2 stroke is fine provided it is designed for air cooled motorcycles, not for weed eaters or chainsaws.
My choice of oil is either Maxima 927 or Castrol R30, but there are other superb oils to be found.
One can buy a foam pod filter to fit directly on the carby throat, that is where mine is fitted.
Be warned it requires some trial and error jetting, but usually 3 - 4 sizes bigger main than a stock setup.
You must plug chop to confirm jetting.
Be warned it requires some trial and error jetting, but usually 3 - 4 sizes bigger main than a stock setup.
You must plug chop to confirm jetting.
The YZ85 came with a keihin PWK 28 mm. I would start jetting at 50 pilot, CEL needle, and 160 main. That will get you close.
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Here's a link to a thread that will expain how to perform a plug chopI:I
http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
No problem! also, remember to perform a leak down test after you rebuild and reassemble your top end. Here's a link on how to perform a leak down test. If you need any more help don't hesitate to askI:I
http://www.blasterforum.com/do-yourself-20/how-perform-leak-down-test-44653/
http://www.blasterforum.com/do-yourself-20/how-perform-leak-down-test-44653/
Read post# 11. I have recommended jetting for you. Do not buy a kit. Buy the ones I told you two and a couple bigger ans smaller ones.
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