Timing Belt adjustment

5580 Views 29 Replies 10 Participants Last post by Hobie1, Jun 12, 2011

mag

Discussion Starter · May 25, 2005

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Just had the timing belt tension checked at the mechanic, as the belts were whining a bit at 4,000rpm. They said the pulley needs replacing. I had only ridden the bike about 1,000km since re-fitting the current belts (to check on previous owner's work).

Can these pulleys be ruined that quickly from too much belt tension? How serious is the need to replace it?

thanks
78 Gl1000
60,000 km

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mag

Discussion Starter · #2 · May 25, 2005

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i think they mean the tension adjuster pulley, not the cam pulley, right? I can't see how the cam pulley would have been worn?

exavid

· #3 · May 25, 2005

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If it's the tensioner pulley it's pretty easy to check, if it feels rough when hand spinning it or there's any free play other than a tiny bit of endplay (both my new ones had a little bit) they should be good. You shouldn't be able to hear them spin either. These little gems cost about $80 per from Honda so check the old ones carefully. I replaced mine because one had a bit more play than the other, but probably could have run them for a few more years, they had 87,000 miles. If they are bad enough to whine it should be obvious when you check them by hand. If they feel okay it's possible the belts are just a bit on the tight side and slacking them just a bit might get rid of the noise.

mag

Discussion Starter · #4 · May 25, 2005

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unfortunately, i had the mechanic check, so didn't see them. I was told the belts being too tight formed a belt groove on the pulleys. What i don't understand is: if they made noise right from when i adjusted them a month ago, then the noise wouldn't be from adjusters 'wearing' out, unless they originally whined from being too tight, and they still whine because the belt doesn't ride evenly on them anymore?

mag

Discussion Starter · #5 · May 25, 2005

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ok, just spoke with the shop again. They figure the previous owner, who had changed the belts, had overtensioned the pulleys (as they were worn) to compensate for noise. Then, when i re-seated the belts and tensioned very close to spec, because they were worn, the proper tension caused the whine again. Makes sense. He says i could tighten them, as previously done, to avoid noise, but i will stretch the belts and wear pulleys even more. I was pretty careful to just let the tensioner spring into place and not push on the belts. They said it was very close to spec.

GSMacLean

· #6 · May 26, 2005

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I'm about to attempt this on my 82 GL1100A. What is the proper method to re-tension the idler pulleys? I see there are bolts to undo the pulleys to remove the belts, what is the proper method to determine where the pulleys should be fastened when installing new belts?

mag

Discussion Starter · #7 · May 26, 2005

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The manual says: Once the belts are in place, let the tensioner springs apply tension to the rollers, then tighten tensioner bolts. In other words, slide on the belts (you have to push on the tensioner pulleys/springs to get them out of the way) then let them spring back into place on their own, don't apply extra pressure against the tensioners/springs or the belts.

Before buttoning it all up, make sure your cam pulleys are lined up with the marks on each respective side of the timing case, with crankshaft stil at TDC 1.

Look for any wear on the tensioner pulleys. They should spin freely, without any belt mark/groove deforming the surface.

mag

Discussion Starter · #8 · May 26, 2005

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PS...

The center pulley, the crankshaft, is the 'idler' pulley. The ones you are referring to are the 'adjusters' or 'tensioners.'

exavid

· #9 · May 26, 2005

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mag wrote:

PS...

The center pulley, the crankshaft, is the 'idler' pulley. The ones you are referring to are the 'adjusters' or 'tensioners.'

Noope, the tensioners are idlers. The cam pulleys are driven pulleys and the crank pulley is the driving pulley! Idlers are for controlling tension or guiding belts.

mag

Discussion Starter · #10 · May 27, 2005

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Yes. In fact, Honda doesn't refer to the tensioners as pulleys at all, but only as "adjusters."

exavid

· #11 · May 27, 2005

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Just gotta get the semantics straight here. The 'tensioners' or 'adjusters' are in fact in normal English, 'idlers', i.e. a pulley or wheel used to guide or adjust tension on a belt. Now Honda can call them anything they want, probably something a lot different in Japanese, but in general mechanical use in applications as varied as Helicopter drive systems, conveyor belts, and automotive uses idlers are what they are. In Honda specific terminology they are indeed called tensioners or adjusters depending on the manual or parts call out. (End of rant)

There, I feel a lot better.

mag

Discussion Starter · #12 · May 27, 2005

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Oh, you are entirely correct sir.

bmoore106

· #13 · May 27, 2005

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Can someone show me what is what? I am planning on changing the belts in the near future.

Thanks, Billy

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twisty

· #14 · May 27, 2005

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Not sure how Honda refers to their belt tensioner parts but in the automotive world an idler pulleyis a fixed (non movable) belt routing or positioning pulley & an adjuster or tensioner pulley has a spring load or slotted attachment so it's either movable or adjustable

Twisty

mag

Discussion Starter · #15 · May 27, 2005

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the pulleys on the far left and right are the camshaft pulleys, where the belts fit on,groove to groove. The middle pulley is the drive pulley, which is connected to the engine crankshaft, which turns the belts, and in turn the outer pulleys. The smaller pulleys to the inside of each camshaft pulley are the tensioner/adjusters, which are spring loaded and apply slight tension to the belts, which straddle them.

Make sense?

exavid

· #16 · May 28, 2005

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You got it right mag, except the tensioners (adjusters) aren't quite spring loaded since both ends of the mounting brackets of the tensioners and bolted down. I'm not all that sure what the purpose of the springs are since by themselves they don't provide the tension called for in the Honda or Clymer manual. If you just let the tensioners set the belt tension by themselves at least on my 1200 and my 1500 the belts end up a bit too loose.

bmoore106

· #17 · May 28, 2005

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Sounds good to me. Thanks.

GSMacLean

· #18 · May 28, 2005

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I just did this yesterday. You've already got the covers off, so this should be easy.

On the left side of the engine, similar to the position of the oil fill plug on the right side, but a bit farther in, you'll find a round blank with a slot in it for a screwdriver. Remove this, so you can view the flywheel timing marks.

Remove the spark plugs so that you can rotate the engine without having to fight against the compression strokes.

Rotate the engine so that the two timing marks one the cam pulleys are lined up withe marks at the edge of the casing, and the wheels are facing "up". The mark on the flywheel should show "T1" with a line that lines up with the mark on the casing. If not, rotate it around again.

Loosen the four bolts holding the two tensioners. Move the tensioners away from the belts to loosen them as much as possible, then temporarily tighten one bolt on each one to hold them in the loose position.

Pull the right belt off, then the left belt.

Making sure the flywheel is still at the T1 mark, and the left cam pulley is still lined up with its mark, slip the new left belt on both pulleys, and OVER the tensioner, making sure the belt is tight on the bottom. Check the pulley and flywheel marks again, then slip the belt over the tensioner so that it runs UNDER it. Loosen the tensioner bolt you tightened temporarily and let the spring tension the belt. Tighten both tensioner bolts.

Making sure the flywheel is still at the T1 mark, and the right cam pulley is still lined up with its mark, slip the new right belt on both pulleys, and UNDER the tensioner, making sure the belt is tight on the top. Check the pulley and flywheel marks again, then slip the belt over the tensioner so that it runs OVER it. Loosen the tensioner bolt you tightened temporarily and let the spring tension the belt. Tighten both tensioner bolts.

Check the pulley marks and the T1 marks again to make sure everything is right, then start it up and make sure it runs right!

Good luck!

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mag

Discussion Starter · #19 · May 28, 2005

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Remove the spark plugs...YES! Great tip, wow. Do you rotate the engine with alternator bolt, or back wheel?

Also, do you remove the rad to make life easier?

GSMacLean

· #20 · May 28, 2005

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I just left it in 5th gear and used the back wheel to rotate the engine, quick and easier than getting to the alternator bolt. Once the belts were off, it was actually quite easy to rotate the engine using the main crank belt pulley.

I left the radiator on, which is why it took me 2 hours instead of 45 minutes - but I'm glad I did, I really didn't want the mess of dripping coolant everywhere, then have to refill it again.

Another tip: If you are going to leave the radiator on, and plan to change your oil anytime soon, do it at the same time. If you take the oil filter housing off, it makes it quite a bit easier to get at the lower (right) tensioner pulley bolts.

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