Repair Diagnosis/Top-End Rebuild?

if u are interested in learning more about your bike this is a good opertunity. Buy a compression tester and a manual. There is a lot of help here at this site. U cant go wrong.

Rather than a compression test, do a leakdown test. Then if it needs it, take the head and block off and send it to us. We will send it back as a 1075 with a fresh head.

Jay

onanysunday wrote:

Deciding a good place to start was to actually "read" the plugs, I found 3 plugs with an acceptable light grey color but cylinder 2 had wet, gas residue?! My guess would be a worn intake valve causing a poor valve seal.

I wouldn't do anything until I checked carb float levels and other normal items associated with "gassy" smelling plugs - including switching to a new plug and possibly a new plug wire / cap. To minimize cost, you could swap the plug and wire to another cylinder to see if the problem follows the plug/wire combo. If so, then it might just be a bad plug or wire. If the problem is still with the same cylinder, check the carb next.

These things don't take a lot of money to check. If you don't find the problem, then spend the money on compression check/leakdown test etc.

My 82 ltd 1000 went over 50k miles before burning an exhaust valve on cylinder number 3 and needing the head reworked. I think I was having some other problems that led to this - namely that there were "dirt dobber" nests in the holes through the cylinder fins that I couldn't see which led to continual overheating. Dirt dobbers (if you don't have them) are wasp-like creatures that poke mud into any hole they can find and lay their eggs (and some spiders for the offspring to eat) in the hole. Then poke some more mud in the hole. Not good for an air cooled engine...

Thanks for all the advice. The carbs are being disassembled and professionally cleaned as we speak. After the results of that are in, maybe I'll be good to go, maybe not. At least I'll have a better idea.

However, part of the problem is that it is also burning more oil recently but plugs are not fouled in any way. This only started a few months ago. I am not sure that can be a carb problem..what do you think?

So, after the carbs are cleaned, then it looks like a leakdown test and/or a compression test if it's needed. I do have a question..how do you check resistance of spark plug caps while keeping the caps connected to spark plug wire? I had to pull back insulation around the cap to find a metal contact point and by the time I had done that, the cap fell off the wire and it didn't seem electrical testing was possible. Am I missing something? Ideas on how to do this in the future? I have the shop manual but it didn't give any specifics on HOW to do this-it only showed the contact points and gave specs..Also, I cut the spark plug wire back 1/4" and re-attached spark plug wire by screwing its rubber wire back into the cap, problem is it doesn't seem like a secure fit and the new connection feels a bit looser than all the others. It seems like a weak design for an electrical connection because all you have to do is pull with slight pressure to remove the cap from the wire..

When you get the bike running again you might try this: Swap the 2 coils around to see if the wet plug problem moves from the number 2 cylinder to whichever cylinder that plug wire goes to after the swap. That will tell you if the problem is related to the plug cap, wire, or possibly the coil itself where the spark plug wire connects to the coil. Ed

More than one guy has done the "Wired George" relay modification to their older KZ. www.wgcarbs.com lists parts needed and how to wire a relay bypassing the aged wiring(and voltage drop) in these bikes

try a tune up!:laugh:

If you have the hard plastic spark plug caps they normally just unscrew from the plug wires.

Ok, I may try the coil swap or relay modification if I'm still looking for answers. The plugs have only 2 hours of use, brand new battery, Rotella oil changes every 1k (some carbon sludge internally when first purchased=new oil w/ filter still becomes dark brown-black after only 4-5 hours of use) K&N pods are clean, and I'm pretty meticulous about doing the easier general maintenance when needed. The engine had a lot of stored sludge/blackness. However, the bike has been in a very reasonable state of tune. Aside from the oil issue and what appear to be original NGK spark plug wires, these problems have only been around for a few months, with any luck I should be able to figure it out thanks to everyone's help. And with the resistor caps-do I measure resistance with caps on or off the wire, I tried taking a measurement while the plug and cap were attached but it didn't seem possible to be able to get past the insulation with the wire inserted into the cap.. I measured resistance within the cap after it fell off the wire and there was no reading on voltmeter. As far as the spark plug wires, should I be looking for 7mm resistor type, or what? Thanks.

S. will try to be brief. Ohm-ing coils is quick. primary (little wires) should be 3-8ohms.secondary,(plug wires w/out caps, read from 1 to the other) @ 20-30K ohms. plug caps read disconnected 3-7 k ohms each. plug wires are intregal portions of stock coils, and while can be spliced aren't worth the effort. plug caps of the 'Plastic/ceramic/phenolic' type, are basicly a housing, which hold a sheetmetal screw (hopefully making contact w/the copper/other core of plug wire) a conduit, a spring, a resistor. (for radio suppression) and a contact to plug. with rubber boots at either end to keep water out. all can fail. Plugs have additional loads and are no#1 culpret. caps are #2,. either opening up. or becoming porus and leaking to ground (IE sparking to head fins instead of plug anode). 3rd is actual coil failure. coils which either are open, or open after coming to temp. hope this helps, G

bountyhunter wrote:

... check valve clearance. If you have low comp on only one hole, it's likely a valve.

Ma Kaw's routine maintenance schedule for 1979 KZ1000 specifies checking valve clearances every 5000 kilometers (or 3,000 miles).

Good Luck!

After getting the bike back from the mechanic it is running better than ever. The carbs were cleaned and synced for the 1st time since I've had the bike. It's a thrill to finally get the carbs tuned! It turns out there was some arching going on in one of the caps and there were some small particulates blocking carb passages.

One question on these carbs..Is it normal to have a sound like birds "twittering" in synchrony lightly emanating from newly synced carbs? This new noise has coincided with getting them synced-the noise wasn't there before..I think it may be the sound each carb makes as it gulps air? Doesn't sound terrible but it does sound like light repetitive twittering (and can only be heard at idle) The noise goes away as soon as I give it a little gas.

Although I've never checked valve clearance in the 6xxx miles I've put on the bike, it is running incredibly smoothly right now (and of course new plugs never hurt either) I don't notice as much smoke any more so I am going to leave it at that and not try to mess around w/ anything any more. My experience has shown that sometimes the best thing can be to leave it alone, because the more I tinker, the likelihood something can go wrong can be increased. However for the future I may consider a leakdown test or checking valve clearance. Thanks all!