ANyone ever have any issue with the head bolts on CFI 800?

[Sled169]

I have had my head off probably 10 times this year trying different heads and pipe combos. The last two times I put it on torque the head bolts to 25, warm up the motor and check the torque again and find that the bolts feel loose but they really are not and twice now I have snaped a bolt off in the cylinder.

So far I have managed to get them out with out a lot of issues and happen to have some extras, what I am wondering is if these bolts are getting strechted out or getting weak from going in and out so many times.

Last night I borke the second one off and it does not feel like I am even pulling on it with the torque wrench. So last night when I got that one out and put it back together again, torque the head bolts to 25 and warmed the motor up I did not check them again. I put a dab of blue loc tite on them and some gasket sealer around the neck of the bolts to seal the head cover well.

Just wondering if anyone else has had any issues with these bolts.

Thanks

 

[skibreeze]

Are you using inch pounds or foot pounds? My guess is this is your problem.

 

[Sled169]

The specs call for 25 Ft lbs, inch pounds would be a lot less. So that is not the issue.

 

[skibreeze]

I've had mine off more times than I can count and never an issue. I forgot that I use an inch pound wrench and have to multiply for the proper torque.

 

[jim9006]

Snaped the bolt at 25lbs? Whoa...something wrong there.

 

[theshadowrider]

I would question your torque wrench. What one are you using? Maybe you should check the calibration on your torque wrench to make sure you are really getting what you think you are. weight x arm = moment
Clamp the socket end in a vise and then hang 25 pound at 1' or 12.5 at 2'....you get the idea. Hang the weight using small rope. Start at 10" and move out to 12" until your torque wrench clicks and see how close you are.

 

[milehighassassin]

I would just replace the bolts now. Constantly tightening and loosening could cause some stretching.

 

[diamonddave]

I would question your torque wrench. What one are you using? Maybe you should check the calibration on your torque wrench to make sure you are really getting what you thing you are. weight x arm = moment
Clamp the socket end in a vise and then hang 25 pound at 1' or 12.5 at 2'....you get the idea. Hang the weight using small rope. Start at 10" and move out to 12" until your torque wrench clicks and see how close you are.

This is very good information. Torque wrenches are a very high precision device. Mishandling, dropping on the floor, not zeroing out after each use, can cause it to not function correctly. the quality of the torque wrench is a big player also. You get what you pay for and this isn't an area that Harbor Freight or tool town should be used for. IME, Snap-On is the only brand of torque wrench i would ever use.


I use loctite on all my head bolts, torque to spec and never worry again. Yes I've checked many (all) but they've never taken anymore torque. anerobic sealant under the head of the bolt will prevent leaks, etc.

Proper prep, proper tools, and proper tech...

Honestly, I'm surprised you're not stripping threads before you're breaking head bolts?