Topic: Cb550 primary chain damage!!

[jimbo550]

Just split the cases as I knew the primary chain needed replacing and I was aware of damage to the casing so its no surprise. Should I get the casing welded as I fear the oil way has a thin wall? 

[bryanj]

Post a picture as the 550 is more robust than the 500 and it may just be OK, are you on the UK forum by the way?  http://www.sohc.co.uk

[jimbo550]

Ooo didn't know about the uk forum. Tried posting a pic but something went wrong. Technology isn't my strong point!!

[dave500]

is it worse than this,this is ok.

[Killer Canary]

Where do you buy your primary chains Dave?

[jimbo550]

Yes it's worse than the pics you have shown.

[dave500]

i use david silvers for most of my new stuff killer,ill post another photo of a worse casing that will still be ok to use.
here it is,also a clear shot of the well the bottom of the cam chain tensioner sits into,i got these as bare cases you can see where someone has had the cam chain tensioner miscued and its been pressed against the outside of the well and between the primary hub,,its a common easily done mistake,i also got two tensioners with these cases and both have a wear mark from the hub!

if yours are obviously worse than these theyll be getting thin in the oil passage.

[Killer Canary]

But I've heard 550 primaries don't have tensioners, or are you talking about 750s? My primary has tremendous slack; this winter I'm going to replace it, so I'm trolling for info.

[dave500]

ill edit that post killer,,seeing it was a clear shot of the cam chain tensioner well i thought id point it out,your correct the 500/550 dont have a tensioner on the primary chain and its a hyvo type chain,the 750 use twin roller type chains.

[singedebile]

arg. I really wouldnt like to have to replace the primary this winter... but with over 40k on my 550, it sounds like it may be a good thing to do. Already was going to replace the cam chain... trying to get some alloy wheels together... spokes... fresh tires... adds up quick.

[bryanj]

If you are splitting the cases to fit a cam chain the primary is a no brainer easy job.

The 550 was more robust in this area as the crankcases were cast slightly different and the primary is a touch father away from the oil ways. Even the deep groove in the second of Daves pictures would be OK

[dave500]

just looking again at the first pictures i posted in reply #3,,you can see again there the rub mark on the cam chain tensioner well where its been wrongly installed and fouled,,its a too common assembly error with 500/550s!!!drop the pan and check its gone into its position correctly if you pull one out!heres a photo ive used before,,this is how it looks when wrong,this pertains to this thread as youll be this deep into your cases.

think twice the next time your told the po replaced the cam chain tensioner,,or even if it was done at a proper shop!!

[74750k4]

Hi,

Anyone ever do the 70mm check on a 750 primary chain tensioner per the workshop manual?  If so, what did you find? I will be doing this in a few hours from now. I really, really ,  really!                  don't want to split the case. I 've already put new APE main studs in.


Martin

[74750k4]

Ok...


Here are the results. Mine measured out at 67.65mm. Seems like it would take a lot of hard miles to stretch it out another 2.35mm to 70mm.

But, anyone ever check a new chain for that distance?

Thanks!

Martin