Problems with my blaster

Dang

Member
Jan 12, 2021
25
1
34
24
I have a 2003 Yamaha blaster, and about 5 years ago I cracked the crankcase left by the shift lever. Now that I find myself with more time and money I have decided to try to fix it back up. I got the bike working and I got everything right (except I need to adjust the clutch because it keeps sticking) but it was running well until I realized that when I took it for a little test drive that I forgot the lock screw on the cap of the carb... FYI I recommend nobody on here do that because it ultimately led to the bike running at full rev while in neutral. I pulled the key and the kill switch and yet nothing happened until luckily it ran out of the little gas that was in the tank. Now since that has happened I had to get the crankshaft rebuilt, and a new head. But ever since then the blaster hasn't been running the same, it will kick over on one kick but it does not rev anymore and it dies out when you try to rev it. I believe it may be something with the tors system on the blaster but I am unsure what is wrong with the bike. If anyone can help, please do
 
Last edited:
Did you do a leak down test?
Retorque head and cylinder after heat cycles?
Was it the head or cylinder that was replaced?
What did the cylinder and piston look like?
What is your compression test say?
 
  • Like
Reactions: Cheese98
Did you do a leak down test?
Retorque head and cylinder after heat cycles?
Was it the head or cylinder that was replaced?
What did the cylinder and piston look like?
What is your compression test say?


there is good compression on the bike, the head was remanufactured, and the head had some chinks taken out of it and those were melted on the piston head. The cylinder was fine tho, with no scratches or anything
 
FYI for you, and anybody else that gets a runaway engine. HOLD brake, shift into gear (preferably 2nd) , drop the clutch to stall it. A hot spot created a glow plug effect and it went into auto-ignition.

What do you call “good “ compression?
PSI? Have you cleaned the carb?
Did you bore it for the new piston?
 
can you do a leak down test with the right side case cover off?


Yes, you actually have to remove the clutch and stator covers to spray around the crank seals for a suspected leak, if no other exposed leaks are found
 
What are you using to seal it?
Are you cleaning the crank and collar with brake cleaner first? You allowing enough time for sealer to set up?