Is my KH100 possessed by an evil spirit?

Did I miss the part where you check the look of the spark plug? What color, wet or dry? It sounds like a crank seal, is the trans oil level dropping at all? If the exhaust is that clogged it could be because of a crank seal or using incorrect oil for a period of time. What kind of oil are you putting in the injector tank? Describe what the motor is doing when it feels as though it is "seizing". Nice looking 100, hope you get her going.

Hi there. I perhaps forgot to mention the spark plug. I can't call it a true 'plug chop' but I've checked the plug after riding a couple of times and I'm getting a very dark almost black on the top 2 or so thread rows, and dark dark brown (which I thought was rich) on both electrode and insulator. Wet on threads, dry on sparky bits.

While de-coking the exhaust a while back I also emptied the trans oil only to find there was too much in there. This made made me think this was adding to the overheating by the engine lugging. I emptied it and measure 750ml or so. The manual says it should be 600ml and I found when replacing the oil it spilled out the oil level hole at 550ml. I thought this, along with the exhaust decoking, that it might solve it. It didn't. As far as I can tell the trans oil level is stable. I think the pipe was partially clogged, but I'm told clogged up baffles on 2 strokes were more common on the old bikes with the old oil. Performance is much better now post caustic soda and coat hanger attack.

I am running Castrol Activ 2T, which I bought because it was readily available and was in the tank when I did the top end so I figured I'd stick with it. It's mineral and ok for injector systems. I'd like to find something else though.

The feeling is this: the bike flies for 25-30 minutes, less if the weather is hot, more if it is cool. I think I can feel a small loss in power in acceleration, but only very slight, and then while accelerating I will feel a jolt or what feels like a stutter in the engine. A jerk. Then I might feel a couple or more in a row, along with loss in power and struggle accelerating. Before I did the top end I figured this was a seize but I used to ride it til it stopped. Now, I just shut it off before it shuts itself off

My experience with a seize is either an abrupt stop of the piston or a tightening up of the motor. If you know someone with a 2 stroke pressure tester, it would be worth the time. Are you getting any extra spooge out of the exhaust or at the headpipe? After it cuts of what do you have to do to get it running again? You could try this, if you haven't already, take a new plug with you and replace it when the bike shuts off. If it starts right up you know something is causing your plug to foul. If it doesn't start right up then the whole crank seal leak may be the wrong way to go. It really depends on the restart circumstances.

When you say abrupt stop do you mean lock up? In the past the bike has simply stopped running, but the lead up to this is the stuttering/and staggering, what seems like misfiring or something. It goes from smooth to rough in acceleration, and this is usually the precursor to the inevitable engine shut off.

Is a tightening up of the motor the feeling of jerking as opposed to smoothness?

I could find someone to compression test it. I aim to do compression and bottom end testing asap.

In terms of spooge, there is only ever one drip or two hanging from the end of the pipe.

Now that I shut it off before it stalls I find it kick starts immediately after stopping. The bike turns over almost first time every time, hot or cold. Post top end rebuild I haven't let it get to the point during a ride of it stalling/shutting, so I can't say for sure how it starts after that.

What are the chances of this problem being electrical? As far as I know it has all the original ignition parts.

Typically a seize will not turn over right away or at all. So it acts up, stuttering and stalls, and then starts right up? How does it run afterward? Absolutely you could have a coil heating up and failing, but normally the coil must cool before it sparks again. You have points on that bike? If so, how about the condenser? My experience with seizures is the piston sticks in the bore, suddenly. There have been times when a motor has tightened up and seized, It feels like someone is dragging you backward as you try to accelerate, You can tell by both the feel and sound that the motor is seizing. It doesn't sound like what you are describing to me. Definitely check electrical, if it has a condenser replace it unless it's new. It sounds like the plug is fouling but if that where the case it most likely would not restart so easily or at all. Did you float assembly have any liquid in them? If they are leaking it could effect the float level and richen it up, Just throwing stuff out there, hope something helps.

Bottom pressure test will all but eliminate the crank seal. Compression test won't hurt but if it starts up easily and has a good feel in the kicker it most likely is OK.

Hang tight here folks, I feel like I MIGHT have found it.

I just found this thread from a Kawasaki singles forum.
http://kawasakikhregister.myfastforum.org/A_VERY_COMMON_FAULT_about2595.html

Now, look at my carb. It is the same hole as this photo, yes? The thread states it as a very common fault, and for a bike that "will not run when hot" and "air gets into the cylinder". This could be the leak I've been looking for?



*I'm sorry I bit my nails. It's the Kawasaki's fault.

1. You should have side to side play (horizontal), but none vertical on the rod. No up/down play if you hold down on the crank with your other hand. You should have NO crank play vertically or horizontally.

2. An engine can partially seize and not lock all the way up solid if you catch it fast enough. Early Bultaco Astro owners know this feeling well. You get pretty sensitive to how this feels....sort of like running with a back brake on. Is that your feel?

3. That choke issue could introduce air into the mixture and will increase with venturi effect considering where it is. Question is, can you get another one?

4. If the exhaust were your only problem then the bike would run badly hot or cold.

5. The problem is not the needle. Put in pos 3. Check all your jet #s to make sure they are to factory spec. That bike ran great in 1965 and probably with those jets. Are they clean? Can you see daylight through them?They tell you not to do this but flip a wire brush over and run the jets through with a bristle of the brush. You may get crud out of them.

6. The top end removal is the only way to tell if it is seizing. Light emery cloth on any scuff marks, re-oil the bore. Check ring end gap or re-ring and put it back together again.

1. OK, had my wires crossed on that one for sure. It was months ago now. The play was only side to side (less than 1mm or so at top of the rod, if I recall) on the rod. I remember reading widely about side to side play at the time and being relieved that it was the case with my con rod.

2. It doesn't feel like a back brake dragging when it does it. But maybe a back brake stomped on at random moments? Does that make sense? More of shuddering and hesitation through the rev range, gradually getting worse.

3. The guys on that forum say a washer and liquid metal would do the trick to block that hole. Apparently originally it would have had a plug in it as per construction but it seems maybe over time it comes loose. I'm going to do this ASAP because all other things considered, and like I've said, it runs pretty great until this problem happens.

4. Roger that. I'll put that in the brain bank. Thanks Buls!

5. It was a tad rich on 4 so I'll put it on 3. I can see daylight through both the jets. No apparent obstructions there. Will spray some carb cleaner around and blow it out anyway, along with the float bowl. Do I need to remove floats for cleaning? I'll start with chemicals and air. All else fails, wire it is!

6. I will see how it runs after this carb fix and take it from there. If the problem persists I will take the head off and have a look down the bore. If I see scuff marks then it is rings off to check ring end gap. If that's not it I will have a mental breakdown. Nah, I'll go bottom end then. Though I think this might be close with this carb problem. Perhaps even if this carb thing works I will look down the barrel just to get certainty.

I can't thank you guys enough so far. Update to come in the next few days! I've been here before and I can say I'm optimistic but incredibly cautious too.

My bike kicks up immediately. However, it will start right up but continue the sluggish/hiccup symptons until cool. If I let it cool it will run great again until it gets, presumably, hot again.

Points as far as I know, haven't been in that side very much at all.

I'd describe the symptoms as loss of a bit of power and then hiccups. One here and there or a couple in a row.

The floats themselves or the bowl? The bowl had gas in it but the floats seemed without gas. I presume, being floats, they aren't to have gas in them.

Any ideas will help. Thanks. It's all for the experience and knowledge.

Keep us posted Kay.....

Definitely sounds like coil or condenser breaking down with heat causing the engine hiccups. I've seen that many times with autos too. As for carb cleaning, the Pine-sol treatment (50/50 with hot water) works very well. Used that trick on my old Evinrude outboard with ancient 2t fuel in the bowl. Not necessary to remove the jets. Just rinse and blow dry after soaking overnight or 24hrs.

See http://advrider.com/forums/showthread.php?t=560117

Hope all the advice helps. You've got a neat bike there.

You might even be able to get a condenser at an auto parts store. Take it in with you and try to match up the parts and numbers and mounting. I seem to remember some early Chevy distributors used those condensers.

I too have considered the condensor electrical idea only because I have read about other KH100s with similar symptoms to mine being fixed with a new condensor. Now, I know what the condensor does theoretically BUT where exactly is it, somewhere in the left side with the magneto?

There is no Pine-sol in Australia I'm afraid. I wonder what else I could use.

I can get a condensor for $25 tomorrow. Is it hard to install? I have the Clymer and Kawasaki manual so I'll have a read.

I thought I would look into the left side/timing cover to see if I could spot it. I couldn't see it but I did note a little bit of grease or oil (not sure) in the bottom of the case. Bad sign? Is this my leak?



The clear smudge is where I ran my finger. There is a bit of grime in there for sure.

So this is where I am at:

1. Clean carb and put back together.

2. New condensor to be purchased and installed. Should I look at doing the coil and points too? This is as new to me as the carb. Should be interesting.

3. To find out if that hole is supposed to be in the choke plunger side of the carb body or not and if not, plug it up with a washer and some epoxy.

4. Check magneto side for leak. I might already have my answer there.

:huh Lots to do.

So my best guess after seeing the mag.... A bad crank seal is very possible. The points are EZ enuf to replace but are behind that flywheel. So...

1. Outer case off

2. Soak down flywheel center thoroughly with a substance like PB Blaster if you have that there.

3. You will need a center pull flywheel puller that threads into those big dia threads after your remove the flywheel nut.DO NOT TRY TO USE AN EXTERNAL PULLER..... USE THE RIGHT ONE!

4. The flywheel is probably really on there. Put pressure on the puller by holding with one wrench and torquing with another. It may help to put a turn or 2 on the puller then let it sit for a while to get penetrating fluid into the taper. Some guys tap on them. I don't like to do this as it may damage the crank end or puller threads. After it sits a bit then try again and usually off comes the flywheel.

5. Let me say I don't trust your re-build guy. Nothing was cleaned up in there. There should be a keyed, tapered shaft that you need to clean off, but first look right at that rubber seal around the crank! Bet that drool trail can be traced right to it. That seal was likely NOT REPLACED.

6. Replace the crank seal. I think you should be able to use a small lady finger like pick to get it out. A seal shop can get you another from the numbers on it. At this point have someone hold the bike down firmly (a fat friend helps here), and see if that crank play is evident. should be no up/down at all.

7. Your condenser is right with the points plate. It is an alum cylinder about 1/2 in by 1 1/2 in long with 1 wire off from it. If you can get points or if yours look bad.....well now is the time to replace those 2.

8. Crankseals must be put on proper direction and I usually use a little Vaseline to put them over that cleaned shaft. Carefully and uniformly press back into the case. Key back in shaft and lightly tap to seat it. Points and cond in? All wire nuts tight? Time to put flywheel carefully back on. It should go most of the way back on and feel snug BEFORE you try to tighten the nut. Torque to spec. Usually hardest part is devising a way to hold the twisting flywheel here. There is a proper clamping tool to use and you might borrow one. It goes around the outside of the flywheel dia and lodges up against the case to hold it still.

Yup, some more work to do................

Magneto side crank seal would suck air, making it lean, high revs. Not exactly what you described.

I would bet good money, that this is the condenser or coil from the symptoms OP has described.
I would buy new points at the same time as the condenser and coil, but not install them yet. OP's skill level is limited, so why add timing to the learning curve until it is needed.

BUT I would try blocking the hole in the carb first, if that is known to be a fix on this model bike.

Limit the repairs to one system at a time, until you find the cause. There is plenty of time to learn the rest of the systems.