02 blaster misfires at high rpm

[Zechy22]

Hi, i'm kinda new here but i need a little bit of help as i have a problem with my blaster.

About a couple of weeks ago i noticed my blaster misfiring more and more and now it is at its worse spot (at least i see it as).

I have checked in the retard mechanism (timing) to check if it moved at all but nothing moved, i also swapped spark plugs and seemed to fix it a little bit.

i just need suggestions on where to look soon as i race a lot and the races are coming in soon. Thanks!

 

[jbuckster07]

Which spark plugs are you using? Oil ratio? Compression?

 

[Zechy22]

Which spark plugs are you using? Oil ratio? Compression?

i probably sound really stupid asking this but is there a way i can tell?

 

[jbuckster07]

well spark plugs will say on the plug.
Oil ratio depends on if you are mixing the oil in the gas or using the oil injection that came on the blaster
and getting a compression tester to test the compression....

 

[Zechy22]

well spark plugs will say on the plug.
Oil ratio depends on if you are mixing the oil in the gas or using the oil injection that came on the blaster
and getting a compression tester to test the compression....

ok than i am oil ratio as i mix gas and oil

 

[Zechy22]

i also am about to thoroughly clean the carb and switch my jets.

 

[jbuckster07]

ok than i am oil ratio as i mix gas and oil

ok whats the ratio? 32/1, 40/1, 16/1, 25/1, 60/1? lol

A good carb clean is a great idea! Check your floats and adjust them accordingly!

do you have any engine mods done? pipe/ port job/ head machined? reeds? reed cage? airbox? list the mods and we can help dial in your jets. Cant just randomly put jets in all willy nilly. will blow that thing up if your wrong in the wrong direction lol.

 

[Larry's Shee]

Hhmmmm, switching jets ?? Why do you think you need to do this ??
List ALL of your known mods, temps, elev, and current jetting. We'll get you close(er)
Did you use a new plug, or a "looks better than the other one" plug ??
While cleaning the carb, do the air filter, petcock, maybe tank also.
Ohm the plug cap separately, should be about 5K (IIRC)
Trim 1/4" off plug wire, install plug cap with bit of dielectric grease.

 

[Zechy22]

mods: vforce 4 reeds with cage, fmf fatty, jetted 350 right now.

I am having a problem though as soon as i turn my gas on it flows out of the overflow.

 

[Zechy22]

i have looked through the booklet of my jetting kit and found the jet that works along side all of my mods also forgot to mention the cover to airbox is off.

 

[jbuckster07]

mods: vforce 4 reeds with cage, fmf fatty, jetted 350 right now.

I am having a problem though as soon as i turn my gas on it flows out of the overflow.

350 JESUS! You are going to def be on the rich side!!!! Im going to guess you should be around 300-310, maybe even 320.

If your flowing out of the overflow, your floats need adjusted! Check in the carb section for a great guide by awk08 on how to do it.

 

[Zechy22]

350 JESUS! You are going to def be on the rich side!!!! Im going to guess you should be around 300-310, maybe even 320.

If your flowing out of the overflow, your floats need adjusted! Check in the carb section for a great guide by awk08 on how to do it.

Thank you! easy to follow guide was awesome. My floats are adjusted accordingly now and am now putting the carb back on will update if all goes well.

 

[Zechy22]

blaster runs but still has a slight show of it missing im going to be picking up a new spark plug and i have also rejetted to 320. Any other suggestions will be great as i have all day tomorrow to work on my machine.

 

[blasterboy91]

Not sure if I missed it, but where is it 'missing'?

1/4 throttle?
1/2 throttle?
Wide open?

Or am I off base completely and is when it's idle?

 

[Zechy22]

Not sure if I missed it, but where is it 'missing'?

1/4 throttle?
1/2 throttle?
Wide open?

Or am I off base completely and is when it's idle?

wide open. sorry should have said that

 

[jbuckster07]

blaster runs but still has a slight show of it missing im going to be picking up a new spark plug and i have also rejetted to 320. Any other suggestions will be great as i have all day tomorrow to work on my machine.

I am having trouble understanding what you mean by "missing". Is it litterally a misfire? Is it a bog?

Also 320 was a suggestion, you need to perform plug chops to confirm this jet. When you buy plugs these bikes like NGK B8es plugs.

A video might help more!!!!!

 

[Zechy22]

I am having trouble understanding what you mean by "missing". Is it litterally a misfire? Is it a bog?

Also 320 was a suggestion, you need to perform plug chops to confirm this jet. When you buy plugs these bikes like NGK B8es plugs.

A video might help more!!!!!

i will try to record a video for you tomorrow but we have kind of come to kind of a conclusion of what is wrong. we believe i may have burned the rings out of the piston. basically blown up (but still runs) i do not if this is true but will be looking into this more tomorrow to see if the rings are burned out.

 

[bummer981]

320 is way too big for your mods, I would suggest 270-280

 

[Larry's Shee]

No clue why there would have been a 350 in there, other than trying to compensate for an air leak !!
BEFORE you tear it down, do a compression and leakdown test !! Plus high speed miss isn't a indication of bad rings, hard starting and lack of power through whole rpm range is.

 

[blasterboy91]

Good point Larry. I'm guessing there is an air leak being compensated for with jets. Throw a compression/Leakdown test at it today and see what you come up with.