Cracked piston

[kevinperry]

Hi guys

Happened a while back .Came to a corner and the 630 stalled, started, stalled started again while adding throttle and got home . The bike cooled off ..then no start , just puffing through airbox. here are a couple of pics of the piston. No other damage to the engine...new piston&tings ,head gasket base gasket . My 630 had 36,000k's when the piston failed . It's running great again thanks to Lang's offroad.

KP

 

[robertaccio]

all metals have a life cycle---wow 36k-k is long life cycle on a single!! interesting , glad it did not come apart.

 

[Fast1]

Would have to examine that piston crown close but could be symptom of detonation from low octane fuel.

Did the engine building determine the cause?

How was the rod end bushing and piston pin? valve guides and seats?

Did you ever replace the timing chain?

What exhaust system and fuel metering? Just power up kit?

You have put some miles on it... 36K's or 24,000 miles..

 

[Big Timmy]

You are lucky my friend. That is a trophy for the fireplace mantle of good luck if I ever saw one. What a keeper.

I would also say that was probably a result of Pre-ignition which would cause detonation.

Detonation does not cause preignition.

Pre-ignition could have been from running poor quality or low octane fuel. Or even just hot spots from carbon build up on the piston dome itself. Or even carbon build up in the combustion chamber.

Either way you are lucky it didn't cause a catastrophic event.

Amazing!

 

[kevinperry]

Hi guys

The engine had the timing chain replaced at 27000k's . The head , valve guides seats are all in good form. The rod had no damage. here is my engine setup since fall of 2011 . power up air box mod FMF pipe JD power for fuel. I do check the plug to make sure the bike is not running lean. Gas...this is the big problem , I always look for gas that's just gas ... no ethanol and always look for 91 . The bike really suffers when I have to run 87 when there is no other choice . It is back to running great again ...I just dumped the oil and the screens are clean . The piston had no discoloring or signs of heat stress....just the giant crack . Got another 1000k on her now....loving it again!

KP

 

[RDTCU]

In the long run you're better running 93 with ethanol than 87 straight gas. It might not give you quite the same mileage but it's safer for the motor.

High-boost guys even prefer E85 for it's anti-knock properties.

 

[Fast1]

If you are forced to run 87 octane.. do all possible to minimize how much you twist the throttle and get high octane ASAP... drain the low octane out before adding appropriate fuel.

If you are into the throttle enough to know that bike is suffering with low octane .. that is too much throttle.

 

[Borgschulze]

Makes no difference in my 610 if I run 87 or 91...

Maybe next time I'll try that fancy Shell V-Power stuff my buddy with a CBR600RR swears by.

 

[DYNOBOB]

If you are forced to run 87 octane.. do all possible to minimize how much you twist the throttle and get high octane ASAP... drain the low octane out before adding appropriate fuel.

If you are into the throttle enough to know that bike is suffering with low octane .. that is too much throttle.

+1 ^

If you have to run low octane you can also richen up the fuel mixture. On the dyno I couldn't hear pinging but you could see it on the graphs. http://www.cafehusky.com/threads/te630-dyno-results-and-thoughts.24763/


.

 

[RDTCU]

Makes no difference in my 610 if I run 87 or 91...

Maybe next time I'll try that fancy Shell V-Power stuff my buddy with a CBR600RR swears by.

You might not feel or hear it, but you are doing more damage to your internals than you have to....