Recently bought a Blaster. The only modifications that I have done to it are Boyesen Reeds,reed spacer, and removed oil injection( run at 32:1). I would like to run with the air cleaner lid off because I notice a big power increase, but I can't get the jetting right. Have tried 270,280,300, and 330 and it's still lean(white residue on plug)!!! Is this way too big a main jet or do I have to go bigger? Thanks
P.S. With the lid on it is so rich it runs like crap.

[This message has been edited by RVD (edited 12-24-1999).]

 

Where is it running bad, or rich?
You need to set the pilot (idle) circuit first. I did the same mods on my wifes Blaster and the stock jet was fine. I just had to adjust the pilot screw a half turn in, and move the needle clip from the center to up one from center.
Hope this helps...


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[This message has been edited by atvbbs (edited 12-24-1999).]

 

Oh sorry almost forgot, running Yamalube R 40:1 also.

 

RVD.
It sound to me like you have a serious air leak. Whe you rejetted did you remove the boot (s) from your carb or loosen the clamps. Check all the connections on either end of the carb, making certain that the boots are on all the way around & tighten the hose clamps. If the only change you made was just omitting the lid, you shouldn't need more than one size fatter on your main.
I don't recall what the stock size jet is so I can't give you a specific size for the next fatter one.
!!!! If plug electrode is white, I wouldn't run it till you find & fix the problem..You could have some major engine damage if you do
If you don't find an air leak at your carb & want to email me maybe you can give me more specific info & we can look elsewhere.

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THE AZ HARD PACKER, calmiller@kachina.net

save the public land FOR you, not FROM you..join the Blue Ribbon Coalition online @ www.sharetrails.org



[This message has been edited by hot_shoe_cv (edited 12-24-1999).]

 

Thanks for the help guys. Don't worry I won't run it when it is lean. I don't THINK I have an air leak. All the boot connections are tight, maybe the reed spacer is where air is getting in. I'll put the stock 230 or 1 bigger and see if there is an air leak. At least now I know that something else was wrong. Thanks again.

 

My friend bought a '97 blaster last year that had a few upgrades, including a K&N filter and outerwear with the airbox lid removed. The bike has a trinity pipe. It originally was jetted at 330 and the jet needle set at position 2. It ran pretty fat in the desert (sea level) so he took it in to the local Yamaha dealer who recommended he keep it fat but changed the jet to 290. It ran a lot better but in a few months siezed up on a guest rider. We since have bored it out .020 and run it in the desert. It seems ok, buy I think it may require a jet size up or two.

Another experience I have with the airbox removed is on my '96 blaster with a Turner pipe and fatboy, also bored .010 oversize, main jet 260, jet needle at pos 2. I went to the mountains in the summer 6000 ft, and it wouldn't run 10 feet. Rather than change the jet I took off the airbox cover and it ran just great. I think that 6000 ft is like three jet sizes. So the airbox cover off should be equal to three jet sizes, not one like the other post.

 

When you installed the oil injection block-off kit, did you plug up the hole on the side off your carb ??????? Also, take the snorkel off the air box lid and run w/ it on.

[This message has been edited by MrBlonde (edited 12-30-1999).]