Author Topic: Cam installation (Read 776 times)

rell · « **on:** May 08, 2022, 08:18:35 AM »

I just cleaned up the top end of my 1975 CB550. When reinstalling the cam, I attempted to position the slot in the right end of the cam straight forward. However, in order to bolt up the timing chain gear, the cam ends up angled upward slightly, as shown below. Moving the chain to the next tooth on the gear moves the cam well beyond straight forward. Other than piston rings and a hone, I did not change anything. I will say it took a little bit of force to seat the timing gear on the cam, even with the timing chain tensioner loose, but I don't recall how easily it came off. Is this angle OK? The second photo shows where the timing would be if the cam was positioned straight ahead.

Thanks,
Chris

Don R · « **Reply #1 on:** May 08, 2022, 08:31:14 AM »

In this case close enough isn't. Be sure the chain is properly meshed on the crank gear, you will have to slide the gear off to the notch and walk the chain over the gear one link at a time.

rell · « **Reply #2 on:** May 08, 2022, 08:55:22 AM »

Thanks Don, I will confirm. With the tensioner loose, should it take a bit of force to slide the cam gear onto the cam with the chain in place?

bryanj · « **Reply #3 on:** May 08, 2022, 09:15:23 AM »

That cam chain is worn, i have always seen them a bit off but usually only 1/4 slot not half like that.
You should undo the tensioner nut then with a finger down the tunnel push the rubber blade towards the rear and whilst holding it there nip up the nut.
With new chain it feels almost impossible to get sprocket onto cam

Jerry Rxman Griffin aka MuthaF'er · « **Reply #4 on:** May 08, 2022, 09:16:22 AM »

On the 750's the cam gear has a bevel on one side of the opening which should be positioned inward

Tracksnblades1 · « **Reply #5 on:** May 08, 2022, 09:23:58 AM »

Can a 550 camshaft sprocket be installed 180 off…?
Could you swap sprocket bolt hole with camshaft hole?

I can’t see the teeth and holes index being perfect both ways…

Obviously if there is a recession. it can’t be on backwards, but it “may” be able to bolted on in two positions. Unless Honda
Used a technique to prevent this.

How many miles are on the cam chain?

bryanj · « **Reply #6 on:** May 08, 2022, 09:27:07 AM »

Cam fits all 4 possible ways with no difference, i done loads of these

rell · « **Reply #7 on:** May 08, 2022, 09:49:22 AM »

I just reversed the gear and the slot now angles downward slightly. The top of the slot is aligned with the top of the head. The chain is tight so I don't think the chain is worn. I assume the middle of the slot in the cam should align with the top of the head?

bryanj · « **Reply #8 on:** May 08, 2022, 10:33:58 AM »

Yes it should

rell · « **Reply #9 on:** May 08, 2022, 11:19:08 AM »

I checked TDC and it does look like the timing mark is correct but the cam slot is off.

bryanj · « **Reply #10 on:** May 08, 2022, 11:32:24 AM »

The slot will only be perfectly correct with a new chain, as the chain rollers wear(Chaind DO NOT stretch) the cam will rotate a bit in relation to the crank

BomberMann650 · « **Reply #11 on:** May 09, 2022, 02:04:28 PM »

Just by looking at your advancer mechanism photo.

It might help to have the cylinder at a true Top Dead Center.

rell · « **Reply #12 on:** May 09, 2022, 04:13:01 PM »

That photo shows where the crank would be if the slot was pointed straight ahead. When the crank is at the correct TDC mark, the piston is at TDC but the slot is not straight forward.

BomberMann650 · « **Reply #13 on:** May 09, 2022, 06:55:57 PM »

Quote from: rell on May 09, 2022, 04:13:01 PM

That photo shows where the crank would be if the slot was pointed straight ahead. When the crank is at the correct TDC mark, the piston is at TDC but the slot is not straight forward.

Then advance the cam by 1 sprocket tooth. Should fall in line there.

rell · « **Reply #14 on:** May 09, 2022, 06:59:58 PM »

I tried that. it moves too much

Little_Phil · « **Reply #15 on:** May 10, 2022, 01:51:26 AM »

Looking at the picture and using an adjustable square I estimate that it is not far off 10 deg out. There are 34 teeth on cam sprocket, 10.6 deg per tooth. Rotate after adjusting and only rotate clockwise before observing.

BomberMann650 · « **Reply #16 on:** May 10, 2022, 10:32:41 AM »

Quote from: rell on May 09, 2022, 06:59:58 PM

I tried that. it moves too much

It takes a feel for moving the sprocket 1 tooth. I used to do this caterpillar like move with the chain, and often disappointed myself.

A couple of dabs with a sharpie/paint pen will help see where the next changes end up.

On a side note, I kinda wish more cam chain sprocket setups were like the v-rod. They made it easy!

rell · « **Reply #17 on:** May 10, 2022, 02:18:27 PM »

Thanks Bomber. I know I tried/did to move it one tooth many many times but I'll give it another shot.

newday777 · « **Reply #18 on:** May 11, 2022, 05:09:54 AM »

Quote from: rell on May 10, 2022, 02:18:27 PM

Thanks Bomber. I know I tried/did to move it one tooth many many times but I'll give it another shot.

Did you verify the chain is properly on the bottom sprocket? If you let the chain go slack at any point while the cam was off you need to do this...

bryanj · « **Reply #19 on:** May 11, 2022, 05:19:15 AM »

I have said it twice, the slot WILL NOT be perfect with a used chain.
Advancer on T 1-4 and slot as horizontal as possible the put it together, not forgeting the warning about rockers, and run it!

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Author Topic: Cam installation (Read 776 times)