Need help - Cam reassembly

After some head work, I'm trying to put the cams back in the head, but I'm having trouble getting the cams all the way down while also keeping the timing correct.

I'm at the point where the chain is placed on the sprockets, but the sprockets aren't on their ledges yet. The crank is at TDC. I'm in the process of bolting down the cams, and I tried to align the timing marks as best I could.

The timing marks aren't in perfect alignment, so now that I've got the cams bolted down, I'm trying to use a wrench to turn the cams so that the timing marks are perfect. However - I can't seem to fit a wrench around the cam nut w/o impacting the sides of the cam tunnel.

Can anyone offer tips on how you install your cams - particularly how you turn them to get the timing aligned once they're bolted in?

 

You are all at sea there. Unbolt the cam sprockets, bolt down the cam shafts first, then turn the mill to TDC & line up the dots, THEN you bolt up the sprockets.

 

Oh, the cam sprockets are not bolted on yet, though the cam is bolted down.

My main problem is I can't fit a wrench around the cam. The wrench won't fit between the cam hex and the side of the head. Its the smallest wrench I could find too. Here are some pics:

 

Use mole grips.

 

I just went through this with my 550. A 17mm wrench works pretty well, and when it runs out of room, channel locks will work until you have room for the wrench again. If you keep being off on the arrow-dot alignment, and you've taken pains to get it perfect, set it up so the alignment is off that amount in the opposite direction. Then when the cam-chain tension is taken up, it will be in perfect alignment. Don't put those channel-locks on any part except the flats where the wrench goes.

Clint

 

I WISH A 17 MM WRENCH WORKED! This cam is more like 22mm!

 

I use a "Chain Wrench"

I definitely wouldn't risk fracturing the Head with the Biggest Adjustable Wrench I could find.

What does it say in the 550 WorkShop Manual?

 

Its definitely a 21 or 22mm. iirc, the 22 fit, but was just a smidge big.

 

I've done this several times...an adjustable wrench is too big and bulky for the job.

I use (from memory) something like a 22mm open wrench for turning the cams. You can't go very far in either direction but enough to get it to the right location if you start the process in alignment anyway.

And, hopefully you'll have the cam gear in place with the chain but not bolted in place.

It's a tricky process having to mount and align the cam gear with teh bolt holes with the chain and with the ends of the cams lining up with the markers/holes in the caps. Kinda like you need 3 hands for the process; with only 2 it makes for an interesting learning experience. But after a few goes, easily managed.

 

OK, I just said f*ck it and went at it with vice grips. Scored the cam hex pretty good but it's aligned - had to squeeze them until my palms hurt. There were some metal shavings to clean up too.

I'll remember the "chain wrench" for next time. Thanks for the tips.

 

Bah, new problem:

The cams are bolted down and set to the correct timing. However if I mount the naked cam sprocket onto its ledge on the exhaust cam, there is literally about >I I< this much clearance between the sprocket and the front tensioner.

If I put the chain on the sprocket, I can only just BARELY wedge the sprocket onto the cam ledge. However, the chain & sprocket are now digging into the front tensioner and they won't turn without a lot of force. This can't be right. My hunch is that the head is a little warped and the tensioner is now a little closer to the sprocket than it should be. I'm thinking of carefully grinding down the area of the front tensioner where it touches the chained sprocket with a round file or dremel :?

 

Eeek!
Sounds like the front cam-chain guide is out of its slot at the bottom or even at the top.

 

+1


There is a slot at the BOTTOM as well as the top for that front guide.
I would definitely exhaust all other options before you went at it modding the head.

A piece of aluminum doesn't just warp with no outside forces. If you didn't drop it / heat it / stick it in under the tire of your 4x4 i'd (almost) be willing to bet my maxim it is something else.

 

Don't do that!!!

Back Track and GET IT RIGHT.
There NOTHING in the Instructions that say GRIND anything!!!

Go back to Square One and lets do this the RIGHT Way!

Who has a 550 Book that can contribute what it says about the Front Guide Installation on a 550.
The Exploded View shows: Pt.#-27 & 28/28 Special Washer ...
that looks like it Locks the Front Chain Guide.
http://www.yamaha-motor.com/sport/parts/home.aspx

 

Don't grind anything, take a deep breath, stand back, walk around the block & start again. Everything fits together easy on these bikes, like the guys said, one of the guides is out of place, the cam chain tentioner is out, isn't it? Slack everything off again, make sure the cam chain is on the bottom sprocket properly. Don't do anything rash untill you report back to HQ. Wiz.

 

The cam tensioner is out.

I looked at the head-to-cylinders mating edge on the front of the engine and it seems to match up fine there, so probably not warped.

I've tried removing and reinserting the front guide many times. I'm 90% sure its in the right slot. I can feel it tense a little as I push it forward to lock into place. The only possible problem I can see is the height of the guide - dunno if it should be jutting up a few mm like in this picture:

 

Hi,
Compared to the XJ750 front guide it is too high (or the angle of the pic is making it look too high) BUT... this head is not on the engine and i've just dropped the guide into the front to take the pic...

If this is right it looks like the locator pins on the sides are flush with the top of the head and the actual guide pokes up a bit probably touching the bottom of the valve cover.
Maybe something dropped into the slot at the bottom *cringe* under the guide or hopefully a bit of a wiggle and a tap to make it drop in.
See below pic,

 

After another round of fiddling, it turns out I had the guide stuck on a notch just above the bottom. It felt like a slot so I kept thinking it was the right place.

 

blargh. Two steps forward, one step back. Got the timing done and the tensioner set, but checked the shims and they're grossly out of spec.

To be expected since I had the valves lapped I, suppose.