KZ1000 engine wont turn over when warm

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[brettbolt]

I have an '82 KZ1000 and just replaced the cylinder head with one that 'chance' sent me.

When cold, the engine will turn over slowly and then it will start. But after running even for just a minute, if I try to restart it, it either barely turns over or not at all. After trying to start it this morning, the starter wire got very hot and started smoking.

The battery is a few months old and I charged it overnight.

When I replaced the cylinder head, I didn't do anything with the pistons, rings, or cylinder block.

I am certain that the cam timing is correct. I checked it several times after the tensioner was installed and the engine turned over several times.

My guesses are:
1) camshafts too tight? (I am not sure if the cam bearings are the correct size or if the camshafts are the same ones that were on it before).
2) Bad starter? (But it worked fine before I replaced the cylinder head, so it seems unlikely but is possible).
3) Pistons or crankshaft seizing up? (The #4 piston and the intake valve in the previous cylinder head collided and bent the valve. Could that have damaged the #4 rod bearing?)

I'd welcome any help if anyone can help me figure this out.

Brett

 

[wiredgeorge]

Did you replace the piston/rings? Also, I think the starter grounds via its mount and there is no separate ground wire. You could pull out the starter and clean the mount points but seems unlikely that the ground would be bad.  Can't see the solenoid making the short but it is possible and could affect the wire to the starter.

It make sense that the problem is mechanical because the engine is warming and stuff expands. That is the question about the pistons and rings.  Cam bearings ain't all that fussy, in my experience. Could you be binding one? (the bearing isn't seated correctly)... that would do it as well.

[brettbolt]

No, I didn't replace the pistons/rings -- the cylinder block stayed on the whole time because the engine had good compression.

I'll check the cam bearings to make sure they are seated.

This evening I discovered that the ignition advance mechanism was stuck in the advanced position, which tends to fight the starter motor at low RPM. I cleaned and lubed it and now it doesnt stick.

But it still has problems starting hot. I measured the torque required to turn the engine over manually and its 15-20 ft/lbs. Is that normal?

[chance]

The cams and bering are the ones that were on it and it spun over correct. Then I layed the cams in the head I jut layed them in there I didn't look to see if the cams were swapped you know intake cam and exhaust cam. Hope you checked that ? The motor ran and never was tight .In fact it started faster when hot..Oh well thought I was helping you . Did you torque the cam bearing caps ?

[wiredgeorge]

My thought was that the piston or rings may have sustained a bit of damaged when they knocked a hole in the cylinder head. The J chain doesn't have a lot of places where it can bind... the other thing I though about was loosening the cam caps and reseating the cams and retorquing the caps again to ensure no binding. Really hard to say about the amount of force needed to turn the engine. This is with the plugs out I suppose but I have never measured? I generally use a small 3/8" drive socket wrench to turn the engine over and would guess I used that much force but might have.

[brettbolt]

The cams and bering are the ones that were on it and it spun over correct. Then I layed the cams in the head I jut layed them in there I didn't look to see if the cams were swapped you know intake cam and exhaust cam. Hope you checked that ? The motor ran and never was tight .In fact it started faster when hot..Oh well thought I was helping you . Did you torque the cam bearing caps ?

I went by the sprockets to tell which one was intake and which was exhaust. When the cams and sprockets arrived, they weren't bolted together, but I could see signs of where the bolts were previously and that told me which was which. I did torque the cam cap bolts to 12 ft/lbs. But I'm going to double check that. Also, I changed 6 of the valve shims to get the right clearance (0.05 to 0.15 mm). But one valve is 0.17mm right now and the shim to correct that is in the mail.

My thought was that the piston or rings may have sustained a bit of damaged when they knocked a hole in the cylinder head. The J chain doesn't have a lot of places where it can bind... the other thing I though about was loosening the cam caps and reseating the cams and retorquing the caps again to ensure no binding. Really hard to say about the amount of force needed to turn the engine. This is with the plugs out I suppose but I have never measured? I generally use a small 3/8" drive socket wrench to turn the engine over and would guess I used that much force but might have.

The #4 piston had a barely noticeable scratch on it where it hit the intake valve. None of the debris from the shattered valve shim got into the cylinder.

The 15-20 ft/lbs to turn the engine is with the plugs in. That doesn't seem excessive to me so I think I'm going to inspect the starter motor. Are the starter rebuild kits any good?

[wiredgeorge]

I have never tried to turn an engine over with the plugs in... it would seem to me that it would be pretty difficult. I have never rebuilt a starter... just used a replacement from a pile of them I have. I just check the replacement with a battery.

[Texpin]

One thing....

 Did you release/reset the cam chain tensioner BEFORE
installing the valve cover?  This must be done because
of the chain guide on the top of the cover.

 It will be in a bind if you didn't

Fred
TX

I have an '82 KZ1000 and just replaced the cylinder head with one that 'chance' sent me.

[brettbolt]

I took the starter motor apart today and discovered that one of the armature windings had broken and partially wrapped around the rotor! It was making partial contact with the motor frame (ground) and that cant be good.

[brettbolt]

I tried fixing the starter tonight. Seemed to work better for a short while, but now its not cranking when hot.

I'm ordering a new starter.

[MFolks]

Try these three websites for parts:

A. http://www.mawonline.com/newsite/rick_s_motorsport_electric-starter_brushes.htm

 B. http://www.cyclewareables.com/pages/street_startermotor_repair_kits/startmtrkit.htm (not sure if the website is still viable)

C. http://www.psep.biz/store/mitsuba_starter_motors_page_2.htm

[brettbolt]

Try these three websites for parts:
...

Thanks, but it was a broken wire in the armature -- so ordering a rebuild kit would not help.

I soldered in a replacement section of wire and then used JB Weld so it would stay in place. I think it helped. However, I noticed other places where the armature windings had exposed sections where the resin coating cracked off.

A replacement starter from Z1 Enterprises is on its way.

[kopcicle]

http://www.customrewind.com/
Even though you have one on the way get yours done up as a spare .

very good people .

~kop