I recently got my blaster running after a 2 month "rest" and I need help with jetting. I already know the basics, but I need some advice. It runs like crazy low to mid-throttle but it drops power real quick when I peg the throttle. Does this mean it is running rich on top or does it have something to do with the reed spacers. I've heard they add bottom end but take away from the top, is this true? I haven't really had time to do a plug reading yet but I figured I'd see what you guys could come up with. Also, it is missing the clamp that holds the air box boot to the carb, would this affect anything?

Thanks

 

To answer you first question first, YES! It does make a difference! You are allowing unfiltered air to enter your cylinder along with any dust, dirt, or small flying animals. The other result, and probably the root of your performance problem is the large increase in air intake is causing a big lean condition which will cause you much expense if continued. Unless you have an uncontrollable urge to enhance your mechanic's income, replace the boot clamp now.

 

Howdy...sounds to me like your running lean at WOT...fix the boot clamp and test drive...if it's running the same go one size larger on your main jet..is it cutting out when trying to run at WOT?
hope that helps..
BB

 

I agree that the loose clamp will make it run leaner. Fix the clamp and test ride. Other than the loose boot clamp, have you made any mods to the bike since it was last runnig correctly? If not I would guess that the jetting is correct but that one of the jets is plugged in the carb. If you haven't done anything to the bike the jetting will not change (except for temp and alt affects).

 

what happens is it runs real good below about 3/4 throttle but it seems to almost want to bog down at full throttle. Also, last time I rode before this was 2 months ago and since then the temp has dropped alot. It ran fine in the end of october until the base gasket blew and the compression dropped. I rebuilt the top end and had it bored from .020 to .040. Then I found out the stator was shot and had to find a replacement. I know that the jets are clean I rebuilt the carb when I rebuilt the engine. Today I leaned the needle 1 clip and that really smoothed out the midrange. I havn't changed the main because -like I said- it's COLD outside and it is hard to work with frozen fingers. Right now I have a 245 main instead of the stock 230. I'm going to work on it this weekend and try to fix it. Right now the bottom end through mid is REAL strong. It gets hard to hold on and keep the front wheels down until about 4th but when it gets to full throttle it gets flat. Strange thing is it runs right all over if you rev it in neutral.

 

Howdy...thats good to hear all that you need to do then is go one size bigger on your main jet and it should run fine...just don't forget to check your plug after changing the main jet and test driving..hope that helps..
BB

 

Thanks for all your help regardless of how useless it was. Everyone told richen the main jet-wrong! I did a plug chop and it was running too rich on top. Put in a 240 and what a differance! Ran real strong and didn't sputter. Read the plug for all the throttle positions and each time the plug was a carmel color. Either way-Thanks