Camshaft holder bolts - Triumph675.Net Forums
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post #1 of 7 Old 11-02-12, 23:48 Thread Starter
rubenastley
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Camshaft holder bolts

Hey guys, I attempted to tighten the camshaft holder bolts back up. I followed the haynes manual which suggested lubing the threads with oil and tightening them finger tight before torquing it down. However when I tightened them it felt like some of the bolts had different resistance levels and started torquing them down at different starting levels. Some bolts hit the torque setting before others (the bolts towards the camshaft guide hit the torque settings before starting middle line etc). What's the chances I have bent the camshaft? Will it be obvious on startup? Can you tell by if its bent visually? What if remove them and do it again properly?

Cheers Wil
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post #2 of 7 Old 11-03-12, 00:29
Polystigma
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If you do not bolt down or remove the cam holder in a specified order, you can mess it up for good.
Worst part is, once messed up, it cannot be readily replaced!
It is matched to the head. So you have to buy a whole new head if you mess it up!

Tightening sequence...

11 3 7 15

9 1 5 13

10 2 6 14

12 4 8 16

Good luck


Last edited by Polystigma; 11-03-12 at 00:34.
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post #3 of 7 Old 11-03-12, 00:55
MacBandit
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If you go down a little bit with each bolt at a time(1/4-1/2 turn) you'll never have an issue and you don't need a tightening order. That said unless you threaded each one down a bunch one by one then it's highly unlikely you screwed anything up. The the cams typically break before they bend. The carrier would bend first but even if it did get a slight bend I think it would sit pretty straight once tightened down.
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post #4 of 7 Old 11-03-12, 01:52 Thread Starter
rubenastley
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Quote:
Originally Posted by MacBandit View Post
If you go down a little bit with each bolt at a time(1/4-1/2 turn) you'll never have an issue and you don't need a tightening order. That said unless you threaded each one down a bunch one by one then it's highly unlikely you screwed anything up. The the cams typically break before they bend. The carrier would bend first but even if it did get a slight bend I think it would sit pretty straight once tightened down.
i threaded each one down one by one with my finger until i felt resistance, so it was finger tight.

=(

Last edited by rubenastley; 11-03-12 at 02:13.
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post #5 of 7 Old 11-03-12, 02:13
MacBandit
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That part can not damage anything. It's the next step where start tightening with a ratchet or torque wrench. You have to compress the valve springs somehow and you can't do that with your fingers.
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post #6 of 7 Old 11-03-12, 05:55
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Quote:
Originally Posted by MacBandit View Post
That part can not damage anything. It's the next step where start tightening with a ratchet or torque wrench. You have to compress the valve springs somehow and you can't do that with your fingers.

Mac, I often imagine you as a two headed monster with one head as a Haynes manual and the other head is a kick ass craftsman tool box with medusa like hair made out of socket wrenches, throttle cables, and zip ties........This forum is without a doubt extremely lucky to have someone as knolwedgable as yourself.......

2013 Triumph Daytona 675R
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post #7 of 7 Old 11-03-12, 14:19
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Cam Installation for any OHC motor

Wow well I don't know what to think about that. Thanks I guess.


Since I'm at my computer now and not typing on my phone I want to describe how to do this properly on any OHC motor even when you don't know the tightening pattern.

So when you're going back together after you align your timing marks so your cams are in position and you have set the carrier in place, yes you go finger tight. But.... You don't go finger tight on all the bolts. If you do you will pull the carrier down further on some cylinders then others. This is because some of the cam lobes are loading the valves and some are not. You don't want to do this. You want to bring the carrier down level or square with the head. So you begin by finger tightening the carrier on the cylinders that have the cam lobes pressing on the valves.

Here there is a difference on triples and fours.

On a four the cams are balanced with 2 sets of lobes on each cam bracing each other kind of like chair legs so the cam will stay in place during this entire procedure. So you can tighten the cams down with out any need to worry about jumping time.

On a triple there is one set of lobes pointing straight down. This makes it extremely difficult to start the proper carrier bolts and equally as difficult to tighten the carrier without jumping time. I would be interested in hearing input from some of the other experienced techs on here on how they do this but this is how I do it. Once I set the cams in place I put the chain around the sprockets to initially hold the cams in place. Then I place the carrier in place and physically press (with my weight) down on the carrier over the offending cam lobes until I can finger start the carrier bolts in that location.

Back to the procedure for all OHC motors.

Once those cylinders are finger tight you start tightening with a ratchet or wrench a 1/4 to 1/2 a turn at a time all while eyeing the gap between the carrier and the head keeping it square the whole time.

On the triple once you've gotten a full turn or two you need to worry about jumping time again. So at this point you put the cam chain tensioner in place and just start the bolts a few turns (the tensioner should still be fully retracted) at this point.

Now you can proceed to tighten again a 1/4-1/2 turn at a time the bolts under tension on the carrier (the ones pressing lobes into the valves) keeping the carrier square the entire time until the carrier is fully seated. Now spin in all the other carrier bolts and proceed and torque all the bolts. Don't forget to seat the tensioner and reinstall the spring, etc..


Also cam removal is just the opposite of this but you don't have to worry about jumping time coming apart.

Just to clarify what I am saying is that the only bolts that matter when going together or coming apart are those that under load.
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