75 kz400d Cam sprocket bolts

Hi kzr. Firstly thanks for everything so far. I started riding in march, a 1975 kz400d is my first bike and the manual and this forum have helped keep it running. That and extreme patience in googling parts for it.

The oil leaking from the top end has motivated me to look inside. Got the breather cover and the cylinder head cover off. Next step is "remove cam sprocket bolts." Proving difficult. Just turning one turns the whole sprocket and chain. Jamming a ratchet on one so it can't rotate too far while going to town on the other one sends the ratchet down anyway. Smacking the end of a wrench has sheared a corner off a bolt. Putting a flame on it seems kinda dumb with all the oil everywhere. Pb blaster seems like it wouldn't do much (though I haven't tried that).

I like my bike and don't want to destroy it inadvertently. How do I keep the chain from moving or how do i loosen the bolts to remove em. If its so obvious you can only say it condescending I'm fine with that. Regards all.

Top speed 55 (I got work cut out)

Why are you trying to remove the cam sprockets? I'm not specifically familiar with the 400 engine but the other KZ engines don't need the sprockets removed to service the engine.

PatC78KZ wrote: Pb blaster seems like it wouldn't do much (though I haven't tried that).
...
I like my bike and don't want to destroy it inadvertently.

Your bike uses a wet clutch, meaning (basically) that the clutch is in the same oil as the bottom end and transmission. It is best not to introduce other chemicals or solvents into the engine oil as this may cause issues. If you spray PB Blaster on the cam bolts, the PB can run down the cam chain channel into the crankcase.

Also what Nessism said. If you want to disassemble the engine you should be able to break (i.e. disconnect) the cam chain to remove the cam, rather than removing the bolts. Do not drop the cam chain down into the crankcase.

When you "sheared a corner off a bolt", did you track down the sheared-off piece? You do not want metal fragments wandering around the inside of the engine.

Edit: PS Do not "[smack] the end of a wrench". This is a bad practice and can lead to more serious breakages. Apply steady pressure to the wrench.

PatC78KZ wrote:
................"Next step is "remove cam sprocket bolts." .....................

I like my bike and don't want to destroy it inadvertently..........

Egads - Why are you trying to remove the cam sprocket bolts, and who told you that was a smart thing to do? You state "I like my bike and don't want to destroy it inadvertently", but to me tearing the cams apart can only lead to trouble, unless your statement really means you want to destroy the bike advertently rather than inadvertently. :whistle: Ed

Thanks for the replies and concern.

I failed to mention: my intent is to remove the cylinder head, which is exposed right now, to check the valves.

The clymer manual sez (1983, page 66) under "cylinder head removal" to remove the bolts before trying to work the chain off. The chain (which is of course holding on the cam) is fairly taut even with the tensioner removed - I imagine bending even slightly the chain trying to shimmy it off now.

Shear might be strong. More accurate to say maybe that I stripped or bent a corner - very small damage to the bolt but still get grip with a ratchet. Enough damage that I don't want to attempt the "whacking" method again. Pretty sure I smashed the bolt and didn't send metal into the engine.

Pb blaster has not and now will not be used.

The manual doesn't mention breaking the chain, only removing the bolts and then "slide can sprocket along camshaft until chain can be removed from sprocket." I'll look for a break in the chain.

I'm proceeding slow and except for damaging the bolt haven't made cam damaging errors. Learn by doing. In April the bike was idling real high and I guessed correctly it was carb issues. Turns out the end bolt/jets were completely off the starter jets and sitting in the bottom of the bowls. Concerned I tightened everything, including so-called "pilot jets" which seemed loose to me. After a few weeks of opening the throttle stop to get it started I had one of those 'while you're riding' epiphanies and then I knew what pilot jets were. Backed the jets off a bit and the bike starts right up. I try to not make errors but they've taught me so much..

Got a few more days PTO. Back out to the bike. Its my ride to work. I will get this done. Looking for a break in the chain. Thanks for the interest and responses!

The plot thickens... Just spun the cam (using main bolt by the points) around a few times, pretty sure I've seen the whole chain a few times and no lead or break link. The thing seems continuous, which seems counter intuitive but I'm pretty sure of what I'm seeing. Update, anyway.

The culprits. Pic attached.

Do NOT remove the sprocket from the cam.
Remove the cam chain tensioner on the front of the block.
Why do you want to look at the valves?
Did you ever check and adjust valve lash?
Have you done a compression test?
Do you have a complete gasket set with all the O-rings?


.

Nebr, thanks. I adjusted the valve clearance twice, first not well (drove on a very open exhaust on one side for a while - again, teaching myself as I go so expecting to do a certain amount of hopefully minimum damage as I make mistakes) then got it right.

The tensioner plunger is out - I figured the tensioner seat could stay in assuming the plunger provided the tension. Now thinking I'll remove the whole mechanism tomorrow morning and see if that does the trick.

I do have a complete set of gaskets and all the orings needed (very tedious eBay/ dime city/mikexs/etc shopping in the last few weeks in preparation for my days off and this attempt).

I have not, however, done a compression test assuming from a top speed of 55 that, with carb and ignition in good enough shape (again, might be wrong) I figured looking inside the worst that could happen is I install a better set of seals than before (this bike has not had the warranty oil fix done to it). Didn't have a compression gauge before I started because I'm a rookie. Bought one AFTER I started this work. Don't laugh.

I really won't be able to sleep well in a week if I have to put the bike back together (to get to work) without being able to figure this stuff out. And this is my only vehicle - so I'm moving slow so I don't break something big. All the same, i want to tinker. I can't resist.

Will remove entire tensioner mechanism tomorrow. Thanks Nebr. And will check compression first next time.

The factory chain, and most aftermarket ones, are endless. There is no master link. For many roller chain engines, which I think yours is, an aftermarket chain with a master link can be installed. This avoids having to disassemble the entire engine, but some folks think the master link introduces a potentially catastrophic weakness. To remove the endless factory style chain without removing the crankshaft, you would need to use a chain breaker, which is what the previous post referred to.

The service manual i have say that the cam sprocket have to removed







Turn the crank so that the sprocket bolt is on the top ( 12:00 position )
Put a piece of hardwood or plastic bar that fit between the sprocket and the cylinder head bolts long enough to the edge
of the cylinder head. Made so high that you can access the bolt with the ratchet.
The bar will support the ratchet and prevent rotating the cam sprocket when you loosen the bolts.
I hope you understand my description..

Get the full manual here for your bike

www.manualedereparatie.info/manuale/Kawa...dereparatie.info.zip

Thanks, Scirocco, for contributing and posting your manual. I was assuming from the responses before yours that my manual (which has the same steps as yours) was leaving something out. Good new, though. I had success this morning getting the sprocket removed. For the record, while there may be another maybe smarter way to get the cam chain off, on a 1975 KZ400D removing the sprocket bolts IS a legit way to get the chain out of the way.

I ended up getting the first bolt off with a strap wrench from home depot. Wrapped it around the outer most cam lobe on the side furthest from the bolt head, put a 2 foot long but thin steel pipe (I used to use to extend the lug nut wrench on my now junked Subaru Forester) on the end of a 1/4 socket on the first bolt and holding the end of the pipe rocked pulled real light and gentle a bunch of times to get the bolt moving. The second one was more stubborn - the strap wrench kept slipped - so I put an allen wrench in the hole where the first bolt had been and very very gently (not trying to destroy the threads) let it push against the body of the cylinder head while I pulled gently to get the next bolt moving. (beautiful illustration attached). I gotta say the bolts seemed to have been installed with a torque way higher than the 11 ft/pound the manual recommends.

Scirocco as far as the hardwood or plastic idea - I couldn't figure it out and ran out of data on my phone in the process of downloading the manual! So I couldn't ask for clarification. So I slept on it. My data resets on the 18th at midnight. So my impatience had me go another way. Thanks for throwing an idea my way. If you hadn't spoke up I'd try to be doing it without removing the sprocket and pretty sure that would have required breaking the chain, which I'm glad I didn't do.

Check out the mess I found when I got the head off. Glad I did this. I was thinking about thinking of giving up! I felt stupid for paying $24 for two oval o-rings a week ago. I look inside and the ones I've been riding on are destroyed.