Is my apex motor blown?

[nytrocirus]

my apex has no compression in three cylinders and 150 in one! This is after a great day on the trails! What have i done wrong?

 

[sherlock29]

um.... what happened... there's a reason why you needed to check compression!!!???

 

[APEX 06]

um.... what happened... there's a reason why you needed to check compression!!!???

X2

 

[nytrocirus]

Well lastnight me and my wife came back for a good run the sled worked great.Got up today , went to leave our camp so i turned the key and it wound over really fast not even sounding right!i talked to some guys at the dealer and now were looking at either a broken cam or timming chain! What do you guys think?This is not heard of!!

 

[teamyamaha]

Is it flooded. Washed cylinders? Does the oil smell like fuel?

 

[nytrocirus]

its not flooded and oil smells fine.Still only one cylinder has compression.

 

[Master of Faster]

I once had my RX-1 let loose of a bunch of carbon, and hang the valves open. Ran perfect one day, shut it off, the next day it was just as you described, no compression, no start.

Pulled the head, found the problem, cleaned and reseated the valves and was good as new.

Had a little over 10,000 miles at the time.

 

[nytrocirus]

hey thanks alot! never though about that!
theres only 5800 miles on this one.

 

[APEX 06]

Im thinking its the chain. The motor is going to need to be open up.

 

[Crewchief47]

Which cylinder has 150?

 

[sgilbert]

Which cylinder has 150?

x2, if its the flywheel end, got to be a broken crank and not a cam as thats the far end I think. cant be timing or you would have nothing. only other thing I can think of is stuck valves from really bad gas ( have seen it happen ) or ice. I would pull valve cover to check things out.

 

[marketparkit]

I have 2007 Apex RTX around 6200 miles and had similar issues this season with loss of engine power and starting of engine & didn't sound right. It was carbon build around engine valves and resulting in loss of compression in my second cylinder. Once carbon was removed engine compression was good and problem fixed. To help avoid carbon build-up in the future I'm using Yamaha Ring Free Fuel Additive to keep it clean. Good luck!

 

[kinger]

If you normally run 91 fuel that would cause high carbon build up when the engine is designed for 87. Otherwise I have never heard of that much carbon build up?

 

[nytrocirus]

thanks guys! im going too open up the engine tonight! I will keep everyone posted just for everyones piece of mind.

 

[marketparkit]

Majority of the time I run 87 octane fuel and got carbon build-up in only one cylinder. Good to know the reason not use higher octane fuel if carbon build and engine performance issues is the end result. Thanks!