79 kz1000 st no compression on all 4 cylinders

kz1k wrote:

you ganna do the whole head, or just the bad valves? whats it ganna set ya back?

Already had the head done. Took it to my machinest and checked things over. Guides and seats were ok, just needed the new valves. Valves are running me $125 total, and the reassembly will be around $20-25.

I don't think the marks on the exhaust cam are very clear (that's my excuse and I'm sticking to it!), but the way to determine if you're correct is to compare the cam lobes on #4....they should be close to 180 deg difference when positioned correctly.

Yes... Ron is correct. Both cams are way off. Those lines on the sprockets are for checking lash, not timing the cams.

Any damage has already been done so you may as well check lash next. If any valve has excessive lash, it's probably bent.

If by some miracle the lash is within reason do this.

Pull the cams, pressurize each cylinder with 50LBS of air with piston at TDC.... see if it the air pours past the valves... If so, yank the head. If not, set cams to correct timing & recheck compression.

If compression at least 100 lbs. See if the bike will run.

Larry C

Thanks larry, I will re-check the manual..
Too pull the Cams off , I need to remove the Chain, Do i need to lock the Chain Tensioner? the manual says to do this? but how do i do this with a Automatic tensioner?

You don't remove the chain to remove the cams. What manual are you using? Ed

morhaven wrote:

Thanks larry, I will re-check the manual..
Too pull the Cams off , I need to remove the Chain, Do i need to lock the Chain Tensioner? the manual says to do this? but how do i do this with a Automatic tensioner?

If you have the stock tensioner all you do to lock it is remove the short 10mm head bolt on the side of the tensioner, then thread a long bolt in there that is long enough to contact the tensioner rod and hold it. When you're done just reinstall the short bolt to return to automatic operation. You're in for a lot of work on this engine. I have made this same mistake as have many others, and for sure you have bent valves, so head will have to come off.

Ok so this is my first time taking the head off..

Should I be able to move the vavles with my fingers?

To see if they are bent I assume i have to take them appart?

All I see now is the Top "shims" and on the bottom i see the valve closed

Did you check your valve clearances before removing the head? This will quickly reveal any bent valves. No you can't open the valves with your fingers unless you have 300psi finger pressure. Once the head is off if you suspect bent valves, turn the head upside down and fill the combustion chambers with gas. If gas leaks past the valves they are bent. The way the cams were in there you most likely have 4 valves bent at a minimum.

I removed the head without checking the clearance.

since I cannot push on the valves without 300psi,

since this bike was sittin for 20 years how do I know if they are stuck?sticking?

I will pour gas into the chambers to see if they leek as well.

Ron, I pored gas into the Intake ports, and I see 3 of the intake valves leaked gas.

I will have to replace them.
The exhaust ones did not leak.

This will be my fist time replacing valves , i really appreciate All your help, I will most likely be back here asking more questions.


Any tips or website you recommend for cheap valves.

Also Tools I will need to get, any links for good ones that won't burn up the wallet?

morhaven wrote:

Ron, I pored gas into the Intake ports, and I see 3 of the intake valves leaked gas.

I will have to replace them.
The exhaust ones did not leak.

This will be my fist time replacing valves , i really appreciate All your help, I will most likely be back here asking more questions.


Any tips or website you recommend for cheap valves.

Also Tools I will need to get, any links for good ones that won't burn up the wallet?

Check the guides.

First,

see if the valves are actually bent. Measure them or just roll them around and look for wobbling on the shafts

It's possible that they never got adjusted and got burnt

Post up some pictures of your valves

If they're bent, repair is done by a competent machinist.

Cut new seats, replace bad guides, new valve stem seals, maybe deck the head

You just don't know what level of abuse this poor bike has suffered until you check

GPZPDX wrote:

First,

see if the valves are actually bent. Measure them or just roll them around and look for wobbling on the shafts

It's possible that they never got adjusted and got burnt

Post up some pictures of your valves

If they're bent, repair is done by a competent machinist.

Cut new seats, replace bad guides, new valve stem seals, maybe deck the head

You just don't know what level of abuse this poor bike has suffered until you check

You could have the valves cut and can tell if they are bent while cutting. If they have any kind of pitting they need cut anyway. It's pretty hard to tell by rolling them.