Front Cam Chain Adjuster Thread Size

Brian G · Post by **Brian G** » Fri Jul 17, 2009 2:23 pm

Shoot!! Went to adjust the cam chain tensioners today and noticed the front adjuster had a square-head adjusting bolt. I thought Honda used hex head bolts exclusively. Then was somewhat alarmed when I found the bolt and locknut to be only hand tight. Yup - after loosening it off then trying to retighten it discovered the threads are stripped inside the housing.

I understand its possible to fit a helicoil insert, but the parts manual doesn't say what size the bolt is - only that it's a "Bolt, Tensioner Adjusting". Can someone please advise what size insert I should use?

Thanks,
Brian

daves79x · Post by **daves79x** » Fri Jul 17, 2009 8:45 pm

Brian:
It's an 8mm x 1.25. If it's a '79. The other years have a 10mm bolt. You can helicoil it in place. You need a right angle drill and the helicoli kit. Trim about 2 or 3 coils from the insert and file down the sharp edge. Run the helicoil in until it's a tread deep. The o-ring on the special bolt will shoulder up on the last coil. You really should do this with the cam cover off so you can be sure your tensioner is free to move. Verify this by pushing down on the bottom run of the chain several times.

Dave

Brian G · Post by **Brian G** » Sat Jul 18, 2009 8:03 am

Great! Thanks for the info, Dave. They're forecasting yet another week of rain and clouds so it will be the perfect opportunity to gaze reverently into the innards of the cam case.

Did they put that decal 'Double Overhead Cam 24 Valves' on the tank to impress onlookers or to intimidate DIY mechanics?

Brian

Don #6141 · Post by **Don #6141** » Sat Jul 18, 2009 11:46 am

daves79x wrote:Brian:
It's an 8mm x 1.25. If it's a '79. The other years have a 10mm bolt. You can helicoil it in place

Would just drilling/tapping the existing hole for a new 10 mm bolt be another option? Wouldn't require drilling a hole any larger than the hole required for the Heli-coil . . . . would it?

Don

Brian G · Post by **Brian G** » Sat Jul 18, 2009 3:09 pm

Um....., makes sense to me. I can't get to the hardware store before Monday so if no-one has any concerns about it, I'll go that route. Thanks for both answers!

Brian

daves79x · Post by **daves79x** » Sun Jul 19, 2009 6:42 am

Problem with drilling the complete hole to 10mm is - you can't unless you remove the cams and tensioner. With the heli-coil for the 8mm - just run the drill as far as you can until it just hits the tensioner arm. Then tap the same way. You won't have the tapped hole all the way through the tower (because of the taper on the tap). That's why you shorten the insert by a couple of coils. You don't want the coils getting squeezed near the top. Anyway, your 8mm bolt will then run free to the tensioner since the original 8mm hole is still there the whole way. The 10mm would have to be drilled the whole way through.

Dave

Brian G · Post by **Brian G** » Sun Jul 19, 2009 8:12 am

(sound of palm slapping forehead...)

Thanks,
Brian