I have a y2k blaster.back in September while out riding it died it would start but as soon as you touched the throttle it would bog and stall.I towed it back to my truck and took it home and tore the carb apart thinking I had some type of dirt in the jets well after several hours of tinkering it still did the bog and stall act.Well a friend of mine said to trace all the electrical wires that come out of the carb and make sure nothing was pinched or broken.Well I traced the one wire back to the thumb throttle took the cover off and inside was something like a contact point that disengaged when you were on the throttle my frind said cut the wires and wire them together so I did and it took care of the bog and stall condition the motor sounded fine.But the next time I rode after about half an hour the motor started to nock and ping when trying to accelerate similar to what a car does when you use cheap gas.I've allways run 93 or 94 octane gas so I know that was not the case.So I changed the plug thinking maybe I had a bad plug but it still nocks and pings especially when under a load like when your trying to accelerate through a mud pit or when hill climbing.so i thought maybe it was running lean and went up one jet size but the problem of detonation persists.Now when I cut the wires and bypassed the contact point in the thumb throttle I checked with the local Yamaha mechanic and was told that it would be ok without it because it was just a rev limiter and as long as you don't rev the motor to the moon I'd be fine.I would like to know if this was bogus info and I do in fact need that point for running the quad any help on this would be great and I'd like to thank you all in advance.

 

might be something in your stator

 

My friend had a Blaster and he always had problems with it running good until he took off the oil injection system and started pre-mixing his fuel. Then it ran great. That oil injection always runs rich and fouls plugs. It sounds to me that the contacts had something to do with your oil injection and now its getting hot from lack of oil and pinging.

 

The wires you cut where just like the tors system on the shee. The deal with that is when the bike is on its top or side and the throttle is pinned open it kills the engine with making breaking that contact, thats of course in a perfect world. Most of the time that design doesn't work thats why they cut the wires and splice them together, it eliminates the whole thing. Now the pinging isn't involved with this at all.

That pinging that you hear could be the oil mixture but I doubt it. I have noticed on alot of blasters that they make that pinging noise. The first thing I thought of was pre-detonation. But I think its a combonation of a few things. I noticed when you hop a blaster up the noises seem to go away. The exhaust system on those bikes are very restrictive. To get some good power out of that small engine Put a Vehto piston in it and v-force reeds with a good pipe and silencer take of the injector and mix it 32:1 just for precaution because those injector systems do fail after awhile.

 

I have not modified the engine in any way other than drilling 2 holes in the air box lid and covering the holes with foam to keep gunk out and going up one jet size but these minor mods have all been done after the problem started.while I was cleaning the carb out at the very begining I watched through the back of the carb and could see the 2 cycle oil being injected into the carb so I don't think it is a problem with the injection system.I don't think it is a problem in the carb ,I have not had a problem fouling plugs or with baking them.I have tried hotter plugs and cooler plugs,and I still have the problem.I think it is with the delivery of the spark but I do not know enough about the mechanics of this thing to be able to fix it and cringe at the thought of what a dealer would charge to fix it.

 

is the bike hesitating at all. does the pinging happen only underload or if you rev it and it pings coming down from the high rev. That is common for them. I have had people tell me its the Cooling fins on the head. Thats why they put the rubber pieces between them to help keep this noise down.

 

it only does it when you are on the throttle in gear and in need of rpms such as crossing a mud pit or climbing a hill.In neutral you can rev it up and the engine sounds just fine no knocking no loss of power.does anyone know how to retard or advance the timeing on this thing if it was a car motor I'd twist the distributer around and test drive it till I got the timeing right but on this thing I have know idea how to adjust the timeing or if you even can adjust the timeing.

 

Now that you have by-passed "TORS" which is good thing to do. (You can get the same protection by running a "tether" to the coil. This is required if you want to do any racing.) A good $40.00 investment would be to get rid of the rest of "TORS" that is sitting on the top of your carburetor. Any good Yamaha dealer will know the part numbers for a new carb top, new cable, carb top adjuster , and a new air mixture screw that needs to be drilled into an existing boss on the side of the Carb. The biggest benefits to this is you will no long need to remove the seat and tank to remove the carb and you can change the main jet by simply twisting the carb side ways and removing the float bowl. This sounds like more work than it actually is. My Yamaha dealer loaned me the drill and tap to install the new air mixture screw that simply goes in under the slide and raises or lowers the slide to control the idle.
Also...in regard to your bog..Feel around the base of the barrel for any leaking. I have had a cracked base gasket and was told that it is not uncommon on Blasters. This leaking will give you an extremey lean mixture. Hope this helps..

 

The bog and stall problem was solved when I elminated the tors system.the current problem is the knocking and pinging when on the throttle.I do not think the problem is in the carb it is not leaking gas and I've gone up one jet size so I do not think it is running lean.I believe the problem is in the timing of the spark.Its running like a car on cheap gas .

 

Are you running a BR8ES or a B8ES plug??