engine is very very hard to turn over.

[Guest]

I completely overhauled my 1983 katana motor but when I put on the cams the motor is very very hard to turn over, the motor turns over fine if the cams are in the lobes but the cam caps are not torqued to 8lb, but as soon as I tork all the cam caps to 8lb than I can't turn the motor over. I'm not sure what the problem could be, I heard that cams can bend but the cams were never droped when out of the motor and the motor ran fine before with the cams. I also checked all the cam caps and seat and all looks good. Any help would be great on this.

[Big T]

Your cam timing is most likely off and the valves are hitting the pistons

So, to confirm

1. The motor turns over easily with no cams
2. The motor turns over with the cams loosely in place, but not torqued down
3. After you torque down the cams, the motor is:

a. Hard to turn over
b. Won't turn very far

The cams won't bend at 8 pounds of torque

[mustangflyr]

I completely overhauled my 1983 katana motor but when I put on the cams the motor is very very hard to turn over, the motor turns over fine if the cams are in the lobes but the cam caps are not torqued to 8lb, but as soon as I tork all the cam caps to 8lb than I can't turn the motor over. I'm not sure what the problem could be, I heard that cams can bend but the cams were never droped when out of the motor and the motor ran fine before with the cams. I also checked all the cam caps and seat and all looks good. Any help would be great on this.

When the engine was overhauled was the cylinder head resurfaced because it had warped and if so how much? If this was done on a head that was too out of true the combustion chamber side will be good but the cam side is now still warped. We used to see this on Datsun inline six engines where the head was bent and we had to resurface both sides of the head to fix it. But no can do on a GS engine, so see if the cam bores are still straight chances are that's it.

[rapidray]

But no can do on a GS engine, so see if the cam bores are still straight chances are that's it.

Actually, chances are HIGHLY unlikely that is it. I have NEVER had a GS head that far out, even with all I've ever done. The heads are just too short. My money is on the cam timing being wrong. It makes a difference if you have 1 & 4 up on the compression stroke, or exhaust stroke. Make sure you get ALL the slack out of the cam chain when you are putting the cams in & that you get the pin count correct & in the right places. It is EASY to get the cam timing off enough to cause issues with pistons to valves. You can bend the valves if you try forcing it to turn. They will take quite a bit of abuse but will still bend if done wrong. Ray.

[00.]

I fairly sure the timming is dead on, here is a picture of the cams at top dead center on 1-4 cylinder. See here is the thing, the engine turns over fine completely, I can spin the engine all day long if all the cam caps are snug to about 2lb of torque but as soon as I torque them down to 8lb of torque the engine will spin but I really have to put a lot of mussle into turning the engine over it will rotate for day but its so so so hard to rotate when I torque the cams down. I do have a cheap torque tool so I will buy one today that goes to low torque. But I have an other engine that I just overhauled and that one rotates very easily. I don't know can some engines just be more stiffer than others because it does spin a bit tight even with out the cams in.

[tkent02]

Any chance the caps have been swapped from another engine?

[TheCafeKid]

20 pins between mark 2 and 3? And yes on what Ray said about the slack in the chain. Often times trying to do this by yourself will result in the chain binding a link on the crank, even if the timing is right. I usually have rose or someone use two fingers to represent the cam sprockets, pull the chain taught and spin the engine a couple times to assure you're all good on the crank sprocket. Then install the cams. I don't think I've ever gotten the cam timing right on the first try, I usually have to adjust it once after I've bolted the caps down. Heh. I'd do what everyone suggests and double check everything. And pull the spark plugs if you have them in. Makes it much easier to spin

[00.]

[QUOTE=TheCafeKid;1566606. And pull the spark plugs if you have them in. Makes it much easier to spin [/QUOTE]

LOL, Thanks I did pull the spark plugs; I'm not that bad yet. But I did screw up in many ways basically thes engines were all apart and a lot of the parts got mixed up the cam caps could be all mixed up between the 2 engines I know this is not good to do but I didn't think cam caps would cause this much racket, I will try to double check the crank gear, I will pull them of and keep the chain tight but I did this earler; how can the crank sprcket bind on the chain?

[chef1366]

Did you put the cam caps in A thru D correctly?

[tkent02]

I did screw up in many ways basically thes engines were all apart and a lot of the parts got mixed up the cam caps could be all mixed up between the 2 engines I know this is not good to do but I didn't think cam caps would cause this much racket,

At the factory the caps are bolted down to the head, then bored together to make the bores round. With caps off another engine bolted to your head the bores would not be round, the diameter of the hole may be less than the diameter of the cam, so once it is bolted down tight the cam can't turn anymore.

Don't know if this is your problem, but it could be. Can you determine if it is any one particular cap which makes it hard to turn?
You do have each cap in it's correct position, don't you?

[chef1366]

Mixing cam caps is bad and is probably your problem.

[rapidray]

If you mixed up 2 sets of cam caps, THAT is your problem! Try to give us ALL the information in the future, it makes a huge difference when trying to help you. Ray.

[GS1100GK]

Unevenly tightening the caps can cause problems, too. IE if you tighten one down all the way before working them all down evenly on each cam, you can bind it, too.

Use a little assembly lube on the caps before assembly for a little lubrication.

Also be sure to tighten each cap evenly, too. Don't tighten one bolt too far ahead of the other.

Are you following the tightening order in the manual?

You may know all this, but I'm posting it, hoping it's not worn/mixed up caps

If it is mixed up caps, maybe you can determine which one(s) are NOT okay by tightening a bit at a time on each one (the last bit after all are down mostly and evenly). Hopefully, you'll find the one that binds....

Good luck.

- JC

[duaneage]

Buy some plasti-gauge and measure the cam to cam clearance when torqued down. Do all 4. Clean oil off before using. Then you will know for sure.

[00.]

I got the engine running right today, I had the camp caps from the the two engines switched, once I swaped all the cam caps the engine was easy to spin again...