1989 yamaha blaster will idle but won't rev

[dstoner25]

hey guys i got a stock 89' blaster only mod it has is a fmf pipe/exhaust. I can start it up and idle but i can't get it to rev it just bogs really bad. I took the carb apart and cleaned it. Its got a mikuni carb but i noticed it has a 120 main jet and a 32.5 pilot. Any suggestions will help.

 

[BlasterPat]

If it were a newer year I'd say the parking break but idk if them older ones do that if the p break is engaged.

 

[dstoner25]

If it were a newer year I'd say the parking break but idk if them older ones do that if the p break is engaged.

Yeah there is no parking brake sensor I do have the tors system unplugged from the switch, brain and carb.

 

[blasDa]

220 main jet is stock. It would need to be bigger for a Fmf exhaust. 120 does not sound right.

 

[dstoner25]

So what u think a 230 or 240 main? Also story is he was in the beach riding and the quad got hit by a small wave. So maybe something in the electrical system. It's got a new stator.

 

[blasDa]

I'm by no means an expert on jetting, but I'm sure someone will chime in. They will need more info, temp. , elevation. I do believe an Fmf exhaust will require something in the 260-270 area, but again not positive and would have to be confirmed with plug chop.

 

[Larry's Shee]

Go to FMF website, will give specs for stock engine @ sealevel and 70* F adjust accordingly to your specific conditions, porting, temps, elev. IIRC seems like it was more like 280-290.
Always best to error on the rich side.

 

[dstoner25]

hey guys just tried a 240 it started to get a lil better im going to throw in a 250 see what happens. Ill have to go back to the dealer for more. I did pull the plug looked a lil brown around it.

 

[dstoner25]

hey guys just tried a 240 it started to get a lil better im going to throw in a 250 see what happens. Ill have to go back to the dealer for more. I did pull the plug looked a lil brown around it.

ok i tried the 250 it helped a lil bit but it still bogs....

 

[dirtysquared]

Fmf is calling for a a 260 alone. Any other mods that effect air flow in or out of the motor will influence jet sizing. Temps and elevation also come into play as well.

 

[dirtysquared]

What all have you done to the bike? Premix, airbox lid on or off? Uni filter? Elevation? How warm is it where your at?

 

[dstoner25]

What all have you done to the bike? Premix, airbox lid on or off? Uni filter? Elevation? How warm is it where your at?

pre mix, air box on, 230 feet above sea level about 75 degrees. Chico,ca.

 

[82cutty]

Put a 280-290 in there...take the lid off . And make sure the washer is under the main jet . Needle clip in the middle . Start with the air screw at 1.5 turns out . Plug chops to confirm

 

[dirtysquared]

/\ sounds like good advice based on your stuff.

 

[dstoner25]

ok guys i got the needle in the middle just got some new jets ill try it out and see what happens if not ill keep you posted.

 

[230blaster]

If it bogs when it's given gas, I would try taking off the air of lid and see if that helps any, does it flood after the bog?

 

[dstoner25]

If it bogs when it's given gas, I would try taking off the air of lid and see if that helps any, does it flood after the bog?

so i tried all the jets and no luck...yeah kinda seems like its flooded. i did have the lid off still bogged. On the stator what should the mark be at or the degree.

 

[dstoner25]

any one know the ohm readings for the stator maybe a bad stator.....

 

[Larry's Shee]

Specs should be in mànual, ohm coil and plug cap separately.
Have you checked fuel flow from petcock?

 

[82cutty]

Is the brass washer under the main jet ? It will run like crap if it's not there and be impossible to jet right