HD Cam Chain

[Seabeowner]

Been putting a 500 engine together with the best bits of two engines and a some new items. Re-bored cylinders (thanks Bryan), clutch plates. some new bearing shells and a DID HD cam chain (courtesy of oddjob).
Affixed the head today and all went well. And got the cam chain on the sprocket OK. But to lift the sprocket onto its location on the cam I had to lever it and bang into place. The chain is now so VERY VERY tight.
Is this OK? Will it loosen up/damage bearing surfaces/snap? Afraid to continue.

[taysidedragon]

It sounds like it's not seated on both sprockets properly. If not on the bottom sprocket properly it could be sitting on top of the sprocket teeth making it tight. Shouldn't lever or bang it into position, something not right.
Otherwise the tensioner is pressing on the chain run or the chain is too short. 🤔

[Bryanj]

Are you sure the front cam chain guide is fitted correctly, it goes INSIDE the chain

[Seabeowner]

Definitely sitting on both upper and lower sprockets correctly and I have "timed" the cam position. Rotates smoothly off the kickstart and keeps position.
Double checked the forward slipper and checked its upper and lower location in the crankcase and block. May check for a third time. Have done this operation OK maybe 10 times in the past. I know its inside the chain as I rest the chain on it. as it stops it falling in before you put the head on.

[K2-K6]

Recently bought a borescope to look into places like this, relatively cheap @ £25.00 with front and side facing camera.

Surprisingly good, with light source too and straight into phone with easy app to use in Android. Just a generic product, nothing fancy.

We had car problem with in tank fuel pump and associated hardware, with out a real way of checking internally for which is was very good.

Since used it to check bores through spark plug access and with very good results too.

Then another with son's friend's engine, with a number of faults. Clear inspection and analysis of bore again to confirm head gasket failure and where it was compromised. Bit of a saga prior to this as old car in which original engine suffered from cooling system failure, bought salvage replacement to find it compromised when started, then this very easy inspection to pinpoint further action.

A bit long winded, but emphasise it's easy to use and detailed images are ideal for this type of access to inspect thoroughly. Very good to look inside something rather than dismantling initially.

[Murf]

You say you have done quite a few of these in the past, which I guess you were happy with and they worked ok. So if you think this one is not right it probably isn’t. Cam chains are tight when they are all tensioned up but not so tight when the tensioner is backed off.

[McCabe-Thiele (Ted)]

I would follow my gut instinct, if you feel it's too tight it probably is.

I recall having trouble fitting my chain on my 500 initially.

Page 40 on my 500 project refers to my problem, getting the chain on the sprocket.

[Oddjob]

A new chain is always tight, doesn’t matter if it’s a heavy duty or the normal one, I’ve fitted loads in the past and all of them needed to be levered into position on the cam. It’s normally made worse because it’s very hard to get the tensioner to sit back as far as it should. Also if the tensioner isn’t in its slot in the lower crankcase the misalignment will make it even worse.

[Seabeowner]

Took the cam off and peered down with a borescope that connect with my son's phone. All looked ok. But in the end took the head back of and damaged the new gasket a bit. Doh! Also lifted the block a little to release the tensioner. I did notice that even when held fully retracted there was still a fair amount of bow in the blade that would bear against the chain. And also it was a little bent. So made it look a bit more like the spare tensioner I have.
Put it back together sans the gasket to try and did a little more bending and I think it's better. We'll see tomorrow.
The other thing I noticed is that the chain is a much tighter fit on the sprockets than the standard chain with no movement at all.

[Oddjob]

Tighter fit on the sprockets is no bad thing. The side links are thicker and a different shape so that’s to be expected. Is the blade a genuine Honda one or one of Silvers copies. Wasn’t a big fan of the copy tbh when I compared it to a genuine one, had a slightly different shape to it and wasn’t as strong.

Most tensioners are bent tbh, especially on the lower part, it’s caused by being fitted badly by a PO. I always mount mine in the barrels when the barrels are about 1” above the base gasket, you can really crush the blade back and lock it off with the locknut and it normally fits the slot in the lower case without needing to be moved at all.

The metal part of the tensioner should be perfectly straight with no bends.