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SOHC.co.uk Forums => CB500/550 => Topic started by: JM550 on October 14, 2022, 06:35:41 PM

Title: Cam Sprocket to Cam Shaft
Post by: JM550 on October 14, 2022, 06:35:41 PM
Hi guys,

Hoping someone can help me with this one as I surely can't be the only one to have this trouble, unless I'm missing something really obvious.

I've got a very stubborn Cam Sprocket that won't meet with the Cam Shaft correctly.
Any tips or tricks for just getting that extra bit of play out of the Timing chain so I can marry the two up together properly?

I've played around with the Chain adjuster but it just does not want to budge.

Any help appreciated.

Thanks
Title: Re: Cam Sprocket to Cam Shaft
Post by: Oddjob on October 14, 2022, 07:15:13 PM
Are you 100% sure the camchain tensioner is located in the bottom slot in the crankcase?

Are you sure the cam goes behind the guide and not in front of it?

I've never personally had any problems getting a sprocket on, even with a brand new chain.
Title: Re: Cam Sprocket to Cam Shaft
Post by: McCabe-Thiele (Ted) on October 14, 2022, 07:26:24 PM
Not quite the same but it was a heck of a job to remove my sprocket from the camshaft when I was dismantling my 500. I had undone the tapet adjusters. I had to move the tensioner until it was as free as possible then with the sprocket bolts removed I inserted a pointed tapered tool into one of the bolt holes to enable me to lift it a tad so it wriggled off the boss.

Of course assuming the tensioner blades are fitted correctly but you're pushing against the blade iirc.
Title: Re: Cam Sprocket to Cam Shaft
Post by: Oddjob on October 14, 2022, 07:58:38 PM
Just hit it sideways Ted. Hit away from the boss on the shaft and it will just fall off. Small hammer or the handle of a screwdriver works.
Title: Re: Cam Sprocket to Cam Shaft
Post by: mickwinf on October 14, 2022, 08:03:08 PM
I have just done this on my 500 Lazarus. It has a new camchain and i agree sometimes they are a bit tricky. Check the things mentioned, and i found once you get things lined up you may need to lever with a screwdriver and i had to tap it on with a rubber mallet.
Title: Re: Cam Sprocket to Cam Shaft
Post by: Oddjob on October 14, 2022, 08:05:11 PM
Yes you do need to lever it on, it won't go on by hand.
Title: Re: Cam Sprocket to Cam Shaft
Post by: JM550 on October 14, 2022, 10:40:36 PM
Thanks everyone, I'm hoping to spend a bit of time on it over the weekend, so I'll give your suggestions a go.

I did try prying it up onto the boss with a screwdriver but i was probably being too cautious with it. I'll give it a bit more force and see if it budges.

Will let you know how I get on.

Thanks
Title: Re: Cam Sprocket to Cam Shaft
Post by: McCabe-Thiele (Ted) on October 15, 2022, 03:24:56 AM
If the tensioner is fully slack you are effectively pulling against the bow shape of the tensioner with only the chain being pulled up to push sideways against the bow tension - naff all leverage so fingers alone can't pull it up hard enough to push the bow sideways.
Title: Re: Cam Sprocket to Cam Shaft
Post by: Seabeowner on October 15, 2022, 10:01:38 PM
I've done this about half a dozen times including a couple with all new parts. Every time I have trouble remembering the technique and couldn't explain it now! But when I get it right, after puzzling that it is impossible, it actually goes together with a very minimal amount of force and never reverted to anything except bare hands.
Title: Re: Cam Sprocket to Cam Shaft
Post by: Sesman on October 16, 2022, 08:46:15 AM
I’ve done it three times now with new chains and guides. It’s tough, but I’ve never had to use a lever. The trick is the initial set up….observe the manual carefully for the chain and sprocket relative positions.
Title: Re: Cam Sprocket to Cam Shaft
Post by: McCabe-Thiele (Ted) on October 16, 2022, 09:06:17 AM
That will be  the benefits of youth, gym workouts or the Spinach diet lads.
Title: Re: Cam Sprocket to Cam Shaft
Post by: Sesman on October 16, 2022, 12:41:05 PM
He, he. 👍😁
Title: Re: Cam Sprocket to Cam Shaft
Post by: paulbaker1954 on October 17, 2022, 08:26:38 AM
Make sure you have the front tensioner the right way round. I had mine the wrong way and exactly the same problem. Also make sure you are inserting the cam from the rights hand side
Title: Re: Cam Sprocket to Cam Shaft
Post by: McCabe-Thiele (Ted) on October 17, 2022, 03:32:12 PM
Quote from: paulbaker1954  Also make sure you are inserting the cam from the rights hand side
[/quote
Are you sure it's not from left side feeding the cam through the gear as you go until the cam sits in place?
Pretty sure that's the way mine came out - maybe it works from either side?
Title: Re: Cam Sprocket to Cam Shaft
Post by: Bryanj on October 17, 2022, 05:51:36 PM
The most common reason the chain wont fit is having the front cushion on the wrong side of the chain as said above
Title: Re: Cam Sprocket to Cam Shaft
Post by: Sesman on October 17, 2022, 06:31:47 PM
Just get a bigger hammer.🫣 The manual is quite clear on the cam, chain sprocket arrangement. Worked for me.
Title: Re: Cam Sprocket to Cam Shaft
Post by: JM550 on October 19, 2022, 10:31:56 AM
Thanks for all the suggestions,

I had a sticky Tensioner!
The CAM Chain Tensioner wasn't flexing at all. Yesterday, I whipped it back out, free'd it up (the mechanism appeared to have got stuck in place), oiled it up so that it's moving freely again and it's allowed me to pull the chain up just enough to meet the CAM nicely.

Thanks again.
Title: Re: Cam Sprocket to Cam Shaft
Post by: heli_madken on October 19, 2022, 12:03:15 PM
Well done.

Ken mentioned earlier in the thread about getting the bottom of the tensioner sitting correctly in the pocket at the bottom of the crankcase. I made the mistake of fitting the barrels first on my rebuild then found I could not get the tensioner in place correctly.

Just make sure it is in place, only really way you see this is by looking up from the bottom with the sump removed.

Title: Re: Cam Sprocket to Cam Shaft
Post by: Bryanj on October 19, 2022, 02:35:25 PM
If the mechanism itself was sticky the only thing i can think of is the gear out of mesh with the rack and that normaly only happens if the gear is forced with a screwdriver in the slot, that also "springs" the bunt over tabs on the sides alowing the rack to move and you need to bend them back carefully
Title: Re: Cam Sprocket to Cam Shaft
Post by: Oddjob on October 19, 2022, 04:27:09 PM
Also happens when the primary chain hits the bottom of it Bryan, I've got around 6 tensioners ATM and most show some damage that causes the tensioner to stick to some extent. Some I've had to dismantle completely and reshape the metal body to get them to work correctly.
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