Author Topic: Centauri belt tension (Read 1705 times)

steven c · « **on:** August 21, 2019, 06:30:09 PM »

I have the new belts on, bike ran with starter spray, and nothing broke but the right side belt seems to loose on the bottom side. Moving the adjuster which is a pain didn’t seem to make any difference.

pete roper · « **Reply #1 on:** August 21, 2019, 06:37:30 PM »

It looks far too loose to me! Are you sure the belt is the correct length?

steven c · « **Reply #2 on:** August 21, 2019, 06:40:07 PM »

Bought from MG Cycle matched up to the old one, left side is tighter.

Chuck in Indiana · « **Reply #3 on:** August 21, 2019, 06:51:08 PM »

How about a good picture from the front?

Wildguzzi.com · « **Reply #3 on:** August 21, 2019, 06:51:08 PM »

steven c · « **Reply #4 on:** August 21, 2019, 07:23:53 PM »

what is the formula of aluminum sulfide

Chuck in Indiana · « **Reply #5 on:** August 21, 2019, 07:39:44 PM »

Are you tensioning them on the right stroke?
From memory.. Tension the S cylinder on the compression ready to fire TDC, then bring it to the D cylinder compression and tension that one. Look it up to be sure..

dxhall · « **Reply #6 on:** August 21, 2019, 08:09:18 PM »

Too loose. Looks to me as though you’ve got it one tooth off.

rschrum · « **Reply #7 on:** August 21, 2019, 10:10:57 PM »

Yes one tooth off. You will need to slip it one tooth to take that slack out, but which way? Hope you marked everything well before removing old belts. TDC on that side and then get your mark on the cam pulley to line up, when the belt is tight between the crank pulley and the cam pulley. You need all the slack on the tensioner side.

pete roper · « **Reply #8 on:** August 22, 2019, 12:40:19 AM »

Being a tooth out shouldn't make any difference to the tension. The Center to Center distance is still the same.

Kiwi_Roy · « **Reply #9 on:** August 22, 2019, 02:49:42 AM »

Does the tensioner pivot about the plain rod?
If that's the case the hex head bolt is at the wrong end of the slotted hole.
Is the other side a mirror image
One side swings CW the other side goes CCW

A quick and dirty way to tell if it's on the right tooth, looking at the rockers the Inlet & exhaust valve should both be open about the same at TDC

Old Jock · « **Reply #10 on:** August 22, 2019, 03:19:21 AM »

How can you tell it's a tooth out, I can't see any alignment marks on the crank pulley?

As other have stated it looks loose to me too

Huzo · « **Reply #11 on:** August 22, 2019, 03:30:50 AM »

I know NOTHING about these things..
But.
Does the tensioner mechanism move clockwise to increase tension ?
ie
Does it pivot on the 8mm (ish) pin ?
You are up against the left hand end of the adjusting slot, so does that correspond to max tension ?

steven c · « **Reply #12 on:** August 22, 2019, 07:02:58 AM »

One tooth off seems to make sense, even when I was putting it on but i just couldn't get it to go one more tooth though. It will have to wait for a week till I can get back to it.

Chuck in Indiana · « **Reply #13 on:** August 22, 2019, 07:37:28 AM »

It pivots around the pin. Here's the "belt stretching" tool, to help visualize what happens.

There is a nut behind the casting the needs to be loosened a little so the whole assembly can pivot.
In the picture you posted, the adjustment is as loose as it gets.
The tool fits over the pin, and the tension is held with a torque wrench (I used 35-40 inch pounds) while the three fasteners are tightened.
Here's the pertinent info from the shop manual..

Edit: In case you don't know.. this is an interference engine, and several parts are NLA. You *don't* want to guess at what you are doing.. :)

steven c · « **Reply #14 on:** August 22, 2019, 12:33:57 PM »

Is the belt stretcher needed to tighten the belt or something that is done with a new belt?

dxhall · « **Reply #15 on:** August 22, 2019, 01:05:00 PM »

The belt must be retensioned each time it’s installed, new or old. It’s roughly correct if you can twist it 90d by hand. Better to measure, though. As you can tell from this section of the manual, it’s important:

With the engine without the rocker arms, fit a feeler
gauge on the left (Induction Control ducket) cylinder
discharge command points using the tool cod. 69
90 78 50 as indicated in the Fig. 11-47.
The upper timing command pulleys must be without
the inner drive gears as indicated in the Fig. 11-47.
The drive belts must be stretched correctly.

Have you found the ducket yet?

dxhall · « **Reply #16 on:** August 22, 2019, 01:54:46 PM »

It may not be quite that simple. Be sure that, when you tension the belt by moving the tensioner wheel, the cam does not move. It often does.

As you can see from this thread, belt replacements on Centauro/Daytonas are not as easy as first appears.

flangeman_70 · « **Reply #17 on:** August 22, 2019, 02:05:05 PM »

Simply put, I can see by the slot in the tensioner plate that this is loosened off to minimum tension.
Lefty loosey, Righty tighty

Clockwise my friend and you will be good.

Adam

Wayne Orwig · « **Reply #18 on:** August 22, 2019, 04:18:49 PM »

Quote from: steven c on August 21, 2019, 07:23:53 PM

what is the formula of aluminum sulfide

I can see that the belt is sagging. It is WAY too loose. And the slot in the plate under the tensioner is in the 'loose' direction. If that belt slips and you break a valve, that would be a sad thing.

Huzo · « **Reply #19 on:** August 22, 2019, 04:22:55 PM »

Responses #9 & #11 mentioned a possible cause.
Hasn’t he just got the mechanism at the wrong end of it’s range ?

Chuck in Indiana · « **Reply #20 on:** August 22, 2019, 04:37:50 PM »

Uhh, yeah. When I posted how to do it, I said

Quote

In the picture you posted, the adjustment is as loose as it gets.

Huzo · « **Reply #21 on:** August 22, 2019, 05:11:05 PM »

It’s just that quite a few people saw the photo Chuck and I wondered why it looked obvious ...
Thought I must have missed something ?

Huzo · « **Reply #22 on:** August 22, 2019, 05:13:07 PM »

Quote from: steven c on August 21, 2019, 06:30:09 PM

I have the new belts on, bike ran with starter spray, and nothing broke but the right side belt seems to loose on the bottom side. Moving the adjuster which is a pain didn’t seem to make any difference.

Something would have broke if that belt jumped enough teeth...!

Chuck in Indiana · « **Reply #23 on:** August 22, 2019, 07:18:39 PM »

Quote from: Huzo on August 22, 2019, 05:11:05 PM

It’s just that quite a few people saw the photo Chuck and I wondered why it looked obvious ...
Thought I must have missed something ?

I think you have it figured out..

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Author Topic: Centauri belt tension (Read 1705 times)

pete roper

Wildguzzi.com

pete roper