Here's the problem. This is my buddies blaster, and he's not real mechannically inclined and I do all my own work so I told him i'd look at it for him. He has a problem with keeping it running. He'll fire it up, it'll run good...for about 5 minutes, then it'll start bogging little by little. Eventually it will just bog down and quit. It wont fire and wont fire but if we let it sit for a while (15 minutes) then kick it, it'll fire right up, but then start bogging again. The first thing I thought was jetting. So I plan on rejetting somewhere around a 170 with 3rd needle clip. He has FMF SST pipe and silencer, Boyesen Reeds, Mild Porting and Polishing, Uni Filter. I don't know what he is jetted at right now, and it wouldn't surprize me if he didn't rejet. I'll be tearing it down tonight. Just wanted to know what you Yamaha guys thought on what might be the problem, am I somewhere in the ballpark here? Another thing to consider is that it's starting to get cold here, so I should probably go richer.

BTW, Blaster8, I searched the past posts and it sounds like what happened to you, did you fix your problem? Thanks

~Team440ex

 

That might be the problem as thats whats happened to mine before i got it jetted right.But a 170 is WAAYYYYY to small,youll probably going for more like a 300 310 or somewhere around there!

 

LOL, dam 2 strokes and all their funny little differences!! So you think that it would be somewhere around a 300? Ill check it out tonight

~Team440ex

 

sounds like its runnin outa gas, check fuel line and float bowl for probs.

later

ryan

 

its not runnin out, gotta be the jetting. 300? i run a 240 in mine.

 

Your problem sounds fuel related to me. Runs well for 5 Min, then bogs and dies... sits and then will re-starts. Sounds like it's consuming all of the fuel in the carb bowl and none or not enough is being replished. Once it sits for a while the fuel runs/trickles back in and fills the carb bowl. Check the float assy to see if it's sticking. Also check the petcock for slow flow, clogs/debris. If you find crud at either area I'd clean both the carb and tank out thoroughly. You might also check the gas gap to make sure it is venting okay. If it isn't venting it will cause a vacuum and once it builds up the gas will cease to flow from the petcock. If it had small jets, would it consume the fuel faster than the fuel system could replish it??? Probably so, but enought to cause this problem?? I wouldn't think so. With the small jets, I would think that you'd just be running lean (getting more air than fuel) and it would just burn it up. Based on the mods you noted, if his carb were jetted stock it should be running pretty darn hot (lean). It might even be running hot enough for the first portion of the pipe to be glowing. Just my 2 cents.

Rude Dog

 

Rudedog

I never thought of that, running out of fuel. It makes sense. Bogging out then starting up later. Ill check it out. Thanks man!

~Team440ex

 

a 300 jet may be too rich. a stock blaster is 230. we put a vitos superstock piston, milled head .020. fatty pipe, fmf power core silencer and k & n filter. vitos sent us a 290 and 300 and said to run without the airbox lid. if its stock i think a 300 would be too rich.

 

oh could be the coil heating up and breaking down. check your spark when its cold and then run it till it quits and check the spark again. should be getting the same amount both times.

 

JMHO but it sounds to me like you are runing out of gas. [someone else already mentioned this]
last wkend, i opened the cap, looked in, hmmm bout half full, cappd it took off it went about 100feet and quit.
it restarted after a couple mins but kept doing it! I finally got fed up and loadd it up.
LESSON: I am used to estimating the fuel in a 3.5 gal Raptor tank, not a 2 gal Blaster tank.
when a raptor is half full, a blaster is EMPTY!
the plug changing, swearing etc didnt help a bit. had i put it on reserve, it would have run fine.
OH, on that jet.....the toomey pipe comes with a 310. thats a big step up from a stock 230, but it works! mine's a little "burbly" is that a word or a sound? and have checked everything else out. considering going to about a 290 or maybe a 300. Plus we are at ALTITUDE, so thats another variable to consider. And i talked with MR TOOMEY about this, and he said to remove the air cleaner cover completely. after i drilled all those holes!!!
Hope this helps you...keep a close eye on that plug or you'll be buying engine parts dude!

######always start with the obvious, simple things, then go from there.##########