Stupid question - Lining up cams

Hullo there

Situation:

Whipped the cams out to change all the shims on my curvy and now I'll have to put the cams in the correct position. I didn't 'bother' or think to mark the position on the sprocket/cam chain so will have to align it via Haynes manuals methods. However, with all cam shafts off (and spark plugs out) the bikes crank won't turn completely. No cam chain is caught round anything it shouldn't be. Can anyone tell me why this is?

I'm trying to get it to the 'F' mark by moving the actual bike instead of turning the crank via the 17mm nut method (reason being is that the cover for said nut on the engine casing was made of cheese and completely rounded off and I can't even hammer in a bigger size allen key now to get it to turn)

Why is the engine 'locking' in position? Feel like a n00b asking this but I'm a bit....confused really. Spark plugs are off and since the cams are off, I'm assuming all valves are closed. The cam chain tensioners have been taken off etc. I've tried it in 1st gear and 6th gear and it will move round so far then stop and won't budge.



What am I missing here?

(Also to get both cams in place with the cam chain around them is it 100% necessary to break and join the chain? I can't see how it's got enough play to stretch round both cam sprockets. Is there something to do with the cam chain followers?

With the spark plugs out the engine will turn very easily. Wiggle it and pull on the cam chain at the same time in case it has fallen down a bit. Do not force it or you will break something *very* expensive.

That 17mm allen headed grub screw can get a bit corroded on so it is best to give it the ol' wd40 dose the day before (doesn't help you now). However it shouldn't have rounded off so easily. I found that the correct size allen key (allen key socket in fact) had to be gently hammered in because the of the tight clearance. I almost used one size down which would have rounded it off for sure.

You have removed the cam chain adjusters completely I take it.

Getting the cams back in is a little fiddly, but can be done. You have to tilt them both, put the chain on, them gently push them down into position. A picture would be worth a thousand words right now... I'll take one if you don't know what I mean.

Originally Posted by sdusk

With the spark plugs out the engine will turn very easily. Wiggle it and pull on the cam chain at the same time in case it has fallen down a bit. Do not force it or you will break something *very* expensive.

That 17mm allen headed grub screw can get a bit corroded on so it is best to give it the ol' wd40 dose the day before (doesn't help you now). However it shouldn't have rounded off so easily. I found that the correct size allen key (allen key socket in fact) had to be gently hammered in because the of the tight clearance. I almost used one size down which would have rounded it off for sure.

You have removed the cam chain adjusters completely I take it.

Getting the cams back in is a little fiddly, but can be done. You have to tilt them both, put the chain on, them gently push them down into position. A picture would be worth a thousand words right now... I'll take one if you don't know what I mean.

No, I follow you there mate, cheers. (cct's are off, yes )

The 17mm allen headed grub screw did round off very easily and that is with a good quality allen key set (I've learnt my lesson buying cheap tools before!) I'll replace it when one comes up on ebay.

No idea why it's not budging, it'll go so far then stop. Both cam chains lifted and 'taut' as the haynes manual says but not having a lot of luck. I'll give it another go tonight.

[northwind]

That does not sound too good, really. Though i don't know what could cause it. I think I have a spare casing plug though, to replace the one you've mungled...

Sorted. The cam chain on the rear cylinder wasn't FULLY straight and must have got snagged on the lower sprocket so when I really pulled on it and wheeled the bike forward, it released and could move the crank about now.

All fully alligned and placed in but bike isn't starting. And when it did, bit of a clatter really. Knew I should have checked the clearances before peicing it back together. But I'll do that tomorrow. Took absolutely forever to get the cam chain tensioners in place. Think next time, the engine will be dropped as it'd be quicker.

[northwind]

Did you make a wee tensioner tool? It'd be horrendous to do with a screwdriver...

I wish I did. I did on my very 1st sv. I'll make another tomorrow. Wire coat hanger, bash it with a hammer at one end to make a flat screwdriver and bend the other end around so you have a handle.

Okay.

Latest update. Can't remember where I left off last time but I started the bike up once it was back together and it wasn't catching well at all, and when it did it was making a rather loud clatter. I noticed that with the spark plugs out, I could only push the bike (in 6th gear) so far before the wheel locked.

So, today, took it all apart. Had both chains 'taut' and wheeled the bike forward and back and finally one of the chains loosened more so my thoughts are that it must have been snagged (how???)

So, now that they were both free, careful so that not to allow them to snag again, I put in the cams in the front (on F, compression stroke) and rear (on R, compression stroke - I think). I made sure the cams were lined up properly and with correct parts of the cam chain. Then put it all back together again.

Tried to start it. Won't catch unless I give it throttle and the engine starts along with the loud, low end clatter. I then noticed it was again, locking the back wheel after being wheeled about a certain distance. WHAT ON EARTH IS CAUSING THIS? It seems to lock when the intake cam lobes on the rear cylinder are on or touching the bucket/follower I can push the bike backwards (in gear) and once the cams have turned round to the buckets, it locks again. Not in the exact same position but still, when they are on the buckets/followers. I checked the valve clearances at the correct position and they were fine, certainly not too tight. I am lost on this one. When putting the cam shafts back on, I looked down the engine and saw that the chain wasn't snagged at all so how could it do it by itself?

I was trying to avoid draining the bike of it's oil but looks like I will have to do that tomorrow to get a proper look at the other end of the cam chain and it's sprocket. Can you, northwind or sdusk, suggest anything that is causing this??

---- EDIT ----

One problem I have with the haynes manual is getting the F & R markings to correspond with the directions the lobes point in. For the Front and rear cylinder, it states that the lobes should not be pointing towards one another. This if fine, the front cylinder works with this theory and both point in opposite directions. However, the rear cam lobes, when set-up so that they aren't pointing towards one another, point...well....not exactly 'away' from one another either. One points upwards, slightly to the right, the exhaust cam lobes point towards the intake. That is correct for lining up the cams with the cam chain when putting the cams back in so surely thats right..?

I'm confused and I'm sure this post is too.

Also, this time round, I got a mate to wind the cct right out so that there was enough play in the chain to take the cams out and put them back in again. An awful lot easier than doing it by yourself and having to remove the whole thing!!!!

But is it 'okay' to do it like that?

P.S Cam chains still ahev a very slight bit of play when it's fully tensioned up but I'm sure that is normal. Just informing you.

[northwind]

Yeah, I'd want to fully back the tensioners out when changing cams, always done it that way. it's probably easier to remove them entirely in fact.