Virtually zero power below 3000 rpm when cold

Tune up.

My kz650 is very similar you can't just start it up, hop on it, and ride away. I start it up, let it idle high choked for a couple min, and it's still a little grumpy until I get out of my subdivision. I thought something was wrong, but that's just kinda how they are. Even when new, cold starting was always a complaint. Check out these articles:
articles.kz650.info/documents/RR-Aug1980-12-161.pdf
articles.kz650.info/documents/MotorcycleSport1.pdf
(more here: articles.kz650.info/index.php )
They both mention cold running problems. Two things to try are the coil wire mod to make sure your coils are getting as much juice as possible, and the other is to clean the contacts in the voltage regulator if you still have a mechanical one. These helped my bike warm up faster and be ridable sooner, but it didn't completely solve the problem.

Edit, another article that mentions cold running problems:
articles.kz650.info/documents/RR-Jul1978-12-15A.pdf

650ed wrote: What spark plugs are you using? Ed

Oft overlooked inquiry.

clean the boots too, Q-tip whatever- same goes coil side.
I have seen carbon build up, or bugs, or gawd knows what crud in there

And lots of high performance air cooled engines that were forced by that twat Carter to go lean need to warm up. So far the WORSE one I've had yet was this KZ1100. Full choke to start, half choke till the idle finally climbs to 2000 then..and only then..maybe it will let me take off and not have to sound like some squid racing the engine if I get caught in traffic.
The companies didn't redesign anything, just leaned the crap outta the jets- cheapest fix first- modern bikes different.
Imagine your boss suddenly showing up and saying...guess what? Today you make these run 10% cleaner or find a new job.

Well, I went to work today, removing the spark plugs first. They are all one heat range hotter than stock - 7 vs the stock 8. Manual said to use 9 under extreme conditions for cooler running spark plugs. Every one is very clean with just a hint of tan colouration on the insulator here and there. No trace of overheating. All perfectly gapped.

Then did a compression test, values in kg; 4.5, 9.5, 5.0, 5.5. Not good.

Valve cover had a 3 bolts that felt like the threads were bad because it took a lot of effort to get them out, yet they felt a bit "buttery". But all was good with the bolts and tracing threads on bolts and in the head fixed all nicely. Access was good and big bonus for making all bolts the same length.

Other than a tiny spot in one corner, the gasket let go perectly. Bit miffed that I had to remove the coils, but then again it's only 4 nuts.

With the cover off it was time to measure clearances, all in mm:
Exhaust; 0.20, 0.10, less than 0.05, 0.10
Inlet; less than 0.05, less than 0.00, 0.05, less than 0.00

You do not get below 0 IMO unless the were fitted that way. I could not turn the shim buckets under these two valves. Luckily, they're on the intake side so I have hopes of them not being burned.

Next post: Ignition

Before taking off the camshafts, I decided to swap ignition plates. Only the backplate from the parts bike wobbled a bit, enough to upset timing and gap. The outer ring above the upper slot were banged in a bit. Managed to bend it out again with a big flat-blade screwdriver.

However, I ran into issues when trying to set the timing. I must be missing something. You see, the moment I hook up the wire going to the ignition coils, the darn thing short. That is, if I measure resistance over the points I get zero whether they're gapped or not. The condenser doesn't cause anything, whether hooked up or not. Wasn't like that with the other plate, despite identical connections.

Ed, is that why you unhook the green and black wire at the coils?

One more thing about the cams... When I turn the engine and two pistons are about TDC, the inlet cam seems to rush and the chain gets pretty slack between the two sprockets. Is this normal? There are zero chain slop to hear when the engine is running, it is very silent.

Also, the manual tells me the cam chain tensioner is automatic, but mine looks very manual. How do I adjust it, does anybody know and can help me on this?

Can you post a picture of it?

It may be automatic after all - I assumed it was a B1 engine and the presumably B2 engine in my spare bike have the same type. However, it suddenly dawned on my that my cam chain was Hy-Vo.


Not right. So I checked the engine number, and it's a late F1 unit from 1980!

faffi wrote: Well, I went to work today, removing the spark plugs first. They are all one heat range hotter than stock - 7 vs the stock 8. Manual said to use 9 under extreme conditions for cooler running spark plugs.....

ND W22ES-U or NGK B7ES are stock. You are using the standard, correct heat range. It sounds like you are using a first edition manual or an aftermarket (I hope not) manual that is quoting the error from the first edition manual. Ed

Looks like an auto tensioner to me, on my 900 you just loosen the locknut, then the bolt. Turn the engine over a time or two by hand, and retighten bolts.emphasis on by hand.

650ed wrote:

faffi wrote: Well, I went to work today, removing the spark plugs first. They are all one heat range hotter than stock - 7 vs the stock 8. Manual said to use 9 under extreme conditions for cooler running spark plugs.....

ND W22ES-U or NGK B7ES are stock. You are using the standard, correct heat range. It sounds like you are using a first edition manual or an aftermarket (I hope not) manual that is quoting the error from the first edition manual. Ed

I bought a Haynes manual for the 76-78 models (sorry), which must be their worst effort to date. Very few pages, no structure, hardly any torque figures etc. Still, the cleanliness of the spark plugs suggest I shouldn't run any hotter, me thinks.

DOES THIS SEEM RIGHT?


Crank is set to TDC, but the rear line angles down slightly and is also a little below the cylinder head.

Exhaust is even more off, one full tooth.


When I count the pins between the EX mark on the inlet cam and the IN mark on the exhaust cam - including the pins above the marks - I get 32. But my manual is for the old cam chain system, so I'm not sure if I use the correct marks.