Is my top end blown? Need opinions.

Jammies

New Member
Jun 23, 2011
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New York
So here's the story.

I started my Blaster up and rode it around for 20 minutes to warm it up. I stopped riding and filled it up before I hit the trails. I remembered I had some octane booster, so I put some in my tank. I started it up, and went out to the trails. I rode for 3 hours. The Blasty ran awesome. Then I came home, and as soon I was in my driveway, it bogged down and died. I kicked it over for about 10 minutes, but could not start it for the life of me. I then pulled the choke out halfway, and it started. When it started though, it revved really high then died. I let it cool for 2 hours then tried to start it. Choke or no choke, it would not start.

So my theories are:

A) The higher octane fuel freed up a piece of dirt and the carb is now plugged.

B) The higher octane fuel blew my top end.

The fact that it started once with the choke on leads me to believe my top end isn't blown, but I'm unsure. The kickstarter feels the same to push down, which also disproves theory B. This I the first time I've used octane booster in my Blaster. I didn't use much, no more than 4oz. I have the oil injector taken off, so I run 32:1, and I know the injector didn't fail, leaving me running lean. It ran fine before this so I'm pretty sure the jetting is correct. Tomorrow I will go through the basics; airfilter, plug, compression. I would do a leakdown test if I knew what it was... Sorry about the length of this post, I tried to include as many relevant details as possible so that I'll get an answer not more questions..
 
Well That octane booster could have made you had a take pre detonation. did you hear any unusual noises like ticking or clanks? I would just check the basics compression spark fuel and air. It possibly couldnt be the octane booster just a chance of luck that it happened the time you put it in. here is a link to a leak down test on a yamaha blaster. There is a member on here Slickerthanyou that sells them(mine is in the mail from him).

also do you have you tors removed? if not what year is your blaster and i can get you a link on how to remove/unhook it.
 
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I highly doubt your top end is blown, but to check just simply take off your exhaust and look in your exhaust port amd see how the piston looks. It most likely is the octane booster causing your problem, i would drain gas, clean carb, put a new spark plug in and see what it does. Check your reeds too.

Good luck
 
Cheap octane booster or octane booster period usually makes these kind of motors run like crap. I tried octane booster in my cr 250 sand drag bike and it revd to the moon and died, i have no clue why, but just try what
I said and see what happens afterwards.
 
Ok, here's the update.

Airfilter has been washed and re-oiled. Spark plug has been cleaned to new condition. Compression test gave me 120 psi, which is definitely enough to run on. The TORS hasn't been touched yet, but I'm doubting that's the problem for reasons I'm about to say.

Once I determined I have spark(shocked myself, so I'm positive it's there) and compression, my next assumption was a fuel problem.

So I started at the top of the fuel system. I checked to make sure I have gas, and I do. Next I turned the petcock ON and unplugged the hose to the carb... No gas came out. If no fuel leaves the tank I think I'll have quite a hard time starting it :P

So my new question is... Is there a filter between the tank and carb? Something there is blocking the line. I'm going to check my manual right now, but I like to listen to what you guys have to say. Thanks in advance Blaster bros.
 
Take your petcock out of your tank it has two filters clean and re install its easy two screws to take out also i twisted my breather hose coming out of the gas lid it will stop gas flow lmk
 
one filter is for your reserve one is for normal use, i dont see them both clogging, make sure your breather line is free, easy to clean petcock either way it wont hurt
 
It was the petcock filters. They were gunked up pretty bad. I cleaned them with carb cleaner and reinstalled everything. Started 3rd kick.