[eheine20]

My 89 Yamaha XLV 540 was running great all last weekend. Did a few laps around the yard last night and just died on me. It’s getting spark it’s getting fuel. Won’t even pop on starter fluid. Did a compression check, each side is at 75. Safe to say I need a rebuild? Anything else that would cause it not to run? Was hoping to do the rebuild during the summer.

 

[kccats]

Test again with throttle wide open
I have had pistons with Holes read 80psi

 

[eheine20]

I will check the compression again later when I get home. Anything else to check if the compression is good?

 

[kccats]

If compression comes back over 100
Then it is in carbs

 

[eheine20]

If it’s in the carb, why wouldn’t it at least pop with starter fluid down the plugs?

 

[eheine20]

Did the compression test again with the throttle wide-open. 85 pounds on the fan side, 100 on. The clutch side. Still have plenty of spark, and does nothing with starter fluid.

 

[Coolhand]

Stop using starting fluid for one unless it has oil in it and use gas mixed with oil instead. Starting fluid was made for diesel engines not 2 strokes. Also with compression that low then yeah it might not start. Clean the carburetors as hinted at as well.

 

[eheine20]

I guess I’ll start here…..

 

[Coolhand]

Yeeeeeeep not shocking always clean carburetors and airboxes every preseason because of that very issue! Good thing it didn't start on fire!

 

[BC_Dan]

Fievel action at it's best!

I have found that those pesky rodents don't like brake clean much... it helps to keep them at bay if you spray things down with it once in a while.

 

[kccats]

AGAIN!
If you do Not clean your carbs EVERY preseason, You WONT find the mouse house!
Now you get to pull the motor apart too!
Just put my 540 back together
Let me know if your air box screws strip out I have a fix!

 

[Yamaha440]

Pull the engine air shroud off and check there for mouse houses too! They love to block the cooling fins of air cooled sleds, and you won't know it until the engine melts down!

 

[kccats]

Have an aftermarket air box om my 98 ZR600 and it ALWAYS had a mouse house!