I have a 1998 yamaha blaster has fmf pipe boysen power reeds and 180 jet and no lid on air box heres the problem after i run it for like 10 minutes of 15 minutes the power band quits working then it stalls and wont start again any ideas??

 

your main jet sounds small stock is 230 when i had a stock setup with the fmf pipe i ran a 250 an had no problems unless it was over 100 degrees out i would say try about a 260 main an see how that does you can check your jetting by looking at the white part of the spark plug you want it to have a cardboard colored smoke ring up by the base of the ceramic heres a better explination on checking the plug http://www.dfn.com/benkaren/plugchop.html

 

i always thought that atv or dirtbikes owners manuals should have made a section explaining how to do plug chops.

 

sorry its a 280 main jet but i found the problem by commpressions only 15 psi whats a good rebuild kit or would you reccomend borring it out

 

if the cylinder walls still look good you can just buy a piston kit an be good but if theres any nicks or scratches that are deep enough that you can feel them if you lightly run your finger across them i would get it bored to the next size i bought my piston kit from rjatv on ebay hes a great guy an ships fast

 

if i bore it out what would be the next size bigger than 200 and will it overheat easier i live in pa and what would be the life span on it

 

the bore goes in 1/4 mm increments the stock bore is 66.00mm next is 66.25mm then 66.50 an so on an you can go up to 8 or 9 bores you shouldnt have any over heating issues due to boreing unless the carb is not adjusted properly an you run lean mine is 4 times over stock bore with a 67.00mm piston an runs great and before i tore the motor down this last summer i was still on the stock piston so the life span all depends on how its tuned an thats kinda tough to keep up with since the jetting can be off just because the temp dropped 10 degrees meaning it might run great today but horible tomorow

 

Can i just turn the mixture screw instead of jetting

 

the mixture screw is for fine adjustments it changes the air fuel mixture if you have to turn it more than 2 1/2 turns out than you need a diffrent jet size

 

heres a link to a guide that explains how to tune the carb i read this an understood the whole process alot better Yellow Dog Racing - Technical Info For Your Ride