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Unusually high number of motor failures


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I talked with Tin at EES today and asked his opinion on why we have had a rash of motor failures.

 

We were thinking we may need to open them up and check the tightness of the rod bolts. He indicated that if we were using his rod bolts and installed them with a few drops of lock tight, that they should not cone loose. He torques them to 16 foot pounds.

 

If you are using the stock honda rod bolts , he stated that they are designed to strech and at the high RPM's we are turning these motors, combined with the vibration they produce, they will come loose. So for those of you who are running stock Honda rod bolts, checking the tightness would be helpful.

 

When the 8 Karts motor came apart, it was because of a broken rod. The rod bolts did not come loose. Steve Pepper was running a gear that ran the motor up to 6600 RPM and was to much for the rod and it broke. The rod on the # 8 was almost a year old. EES suggests replacing the Rod yearly. Because we run these motors a lot more than on race night, I think it would be a good idea to change the rods around mid season.

 

Hopfully this information will be helpful .

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Fellas, all race motors have expiration dates. BAR NONE.

 

Ya'll are starting to figure out what kind of hours you can get out of one motor. If you can determine "50 hours" or "30 hours" and do a short block rebuild, you can save parts and motors.

 

We do 80cc shifters at 20 hours, 125cc shifters at 80 hours and rotax is at 90 hours.

 

Coming up with a service time is probably ya'll best bet. Last week I ALMOST mentioned to mike about freshening his. I wish I would have, but now he is looking for a block.

 

With the added compression and performance, treating these things like RACE motors is going to be the key to success. They no longer last forever with just an oil change.

 

Just my thoughts anyways..

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Robert

I think you hit the nail on the head. I was with Mike when you suggested keeping track of the hours on these motors. We loose track because of all the practice we do on Tuesdays and Thursdays at Iron Rock on their road course and now we are going to Friday practice at Thunder Hill. It is no telling how many hours we have logged on these motors.

Smitty

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My motor will be a year old in September. I am going to freshen it up with a new rod and rings. Also the valve springs get weak. I had my head freshned up and the valve spring showed 27 LB. They started out at 38 lb. A new set is only about 20 bucks.

 

Good idea on the mycron hour meter.

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