mine was not a rod problem per say but a wristpin problem on my 12.5:1 JE last year MLK (with raptorowner)

Dad, Uncle have stock rods in their high comp sparks engines and my sis has the stock rod in her 686 but it is only 11:1...

 

13.5 to 1 0n stock rod. I did bust on rod 2 years ago but it was more the pistons fault than the rod. Probably got a 100 plus hard hours on this built. (stock bore)

 

14 with that info it brings up another question. What bore were you others running? I noticed in Bob's 686 package on his web site he does not have a rod in there. If it is such an issue, shouldn't it be part of the package?

 

Actually, I dont think anyone lists the rod in their package. Its up to the owner of the machine as an option. Sparks says they never replaced a rod in there raptors, unless they break, then its more than the rod that goes.

 

RaptorOwner, what was your bore size when your rod went?

 

Still running a 727 Trinity build on a stock rod with 12:1 JE... Ow yea on NOS as well. Keep my fingers crossed just about every run! LOL *KOCK ON WOOD* Hope I didn't jinx myself!

I am hoping to get through another season before I tear it totaly down and change rod and cut gears...

 

TheRaptorMan, what size bore is your 12:1 JE?

 

Its a 727 so 105mm bore.

This will be the second year of running the bike HARD at the strip. Its actually the third year that I have had the 727 kit, but It was down a good while the first year due to a roll off a climb. So really probably about a year and a half of HARD time on the engine. I am hoping to get this year out of it, but hell if it would go tomorrow I would still be happy with the time it has lasted after hearing some of the horror stories on here!

 

It was on a 102 mm bore. I had the rod break down at the top of the rod in many pieces.

 

I was running the 102mm when it went. My thoughts to long rod life-
1. good oil
2. warm the motor up and don't thrash on a cold one
3. Do not make more than a few passes back to back at the drag strip without a little cool down
4. Do not chop the throttle off at the end of the pass
5. Idle for a minute before shut down
6. lucas oil treatment.

What i have seen on JUST about every stock rod
1. Scoring on 1/2 of the little end where the wrist pin goes thru reguadless of the amount of time on the motor
2. The wrist pin area starts to "egg" shape rather quickly

What i would do if i were someone else
1. Change the rod. The damage done by a busted rod can add up to big $$. At first everyone thought it was a whole lot cheaper to mod the raptor. I am a slow learner, do it right the first time. ( good thing Bob lives around the courner from me). It is not if but when. And for good measure all 01 trannies will fail also.[img]i/expressions/face-icon-small-sad.gif[/img]