Change cam chain tensioners?

[jeffrozar]

My '83 VF750F makes noise somewhere in/around the cam chain. When I last adjusted the valves, the chain didn't seem streched. Someone told me after 25yrs that the springs have most probably weakened that are part of the cam chain tensioner.

How involved is it to change the springs in the tensioners? I think the shop manual says the camshafts need pulled....any ideas appreciated!

[masonv45]

Basically, there have been several upgrades to the tensioners - better design - strong springs etc . . .

The chain can get stretched. And if stretched too far - the chain can jump a tooth (however, it is unlikely). Masterlink Cam Chains can be purchased from Dave Dodge - along with updated tensioners.

The camshafts do need to be pulled and the tensioner assembly replaced. Then the camshafts are re-installed and and the sprockets lined up.

Based on the fact that you've done your valves yourself, you've already done about 2/3rds of the job.

The two sticking issues are:
- Getting the slipper in it's slot in the block.
- Getting the index marks on the sprockets lined up with the top of the head. You never know if it's lined up or not until you release the tensioner.

Just re-installed the camshafts on my front head about 18 times, so I have some non-endorsed shortcuts. (Don't worry, it's not this hard, my manual was incorrect)

There is a write up here: http://v4hondabbs.com/index.php?topic=4517.0
It's for a V65 Magna, but the steps are basically all the same.

My personal opinion: If you have no pitting or scoring on the cams and the chain noise is not excessive - ride it . . .

An Oil Mod is good insurance.

[5891Jonathan]

If the chain skipped a tooth, what woul be the symptoms? What kind of compression readings would I be seeing for the affected cylinders?

[masonv45]

Symptoms could be a little as low power - to as big as the pistons hitting the valves. And the cylinders affected would be either the two front - or the two back.

A simple compression test may not show anything. A leakdown test would.

A better solution would be to take off the valve covers, put the crank as the appropriate mark, and see if the index marks on the sprockets lined up with the edges of the head. But first, take off the valve covers and see how loose the cam chain throughout it's length.

(Tip: put the bike in highest gear and have someone turn the rear wheel while you feel the tension on the cam chain)

[jeffrozar]

Can a cam chain stretched after just 30k miles? I thought it'd be more likely the weak tensioner springs - and it does make quite a noise.

mason - I tried the link, but it won't come up. Other links come up except that one. And it seems their registration is disabled at the moment. Have it in another source?

[masonv45]

You are correct - it's probably the weak tensioner springs.

Sorry, I don't have another link to the procedure - and I don't know why the registration is down - I guess keep trying.

Speaking of noise, if you adjust the valves too loose, the engine will sound like a "sowing machine". Due to the heads not being line-bored, the cams can rock in their mounts - making valves difficult to adjust.

Either use the special Honda cam tool to remove the cam slop, or use two feeler guages per rocker arm - one under each adjustment screw at the same time and adjust.

[jeffrozar]

I adjust them a bit on the wee tight side, with two feeler gauges and the special tool by Honda that "lifts" the cam up, plus that long wrench to tighten the nuts. It made a differenece, but it sounds like there's "slop" going on.

This Dave Dodge can sell me the tensioners?

[masonv45]

Yes he can . . .

(I am in no way affiliated with him - but he is the foremost expert on the 1st gen V4's)

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