Coughing, knocking or backfiring

Hey guys, love the site - hate the search. Sorry to ask whats such a basic question.

79 KZ1000E
26mm Mikunis, Pods, 4into1, unknown jets
Recent top end rebuild
Good compression
New intake boots
NG8's gapped to spec, blue spark
Valve clearance to spec
Cam chain inspected seems good.

Just got this thing back together. Before it wouldn't run on #3 and had an intake leak. I replaced the boots and reshimmed #3 and now it's running on all 4.

It starts fine with no choke (its very warm out.) Idles at 2k. I evidently need a new idle adjustment screw cause its not where it's shown in clymers. After about a minute it starts coughing out of one or more pods. I can tell for sure that 4 is coughing but not sure about the others. Then it starts banging. Cant tell if its predetonation knock or backfiring. It's fairly loud. I can hear it thru the pipe.

So now what? Timing? I thought these 79s with electronic timing didn't need adjustment. I'm not that familiar with these bikes and honestly wouldn't know if the engine sounded right or not.

I'm about fed up. Thought I was buying a rider. I have 3 months before I deploy and have already spent a month troubleshooting a bike I haven't even ridden yet. I normally don't mind doing this stuff but damn! I have no patience for this shit right now. Paid more then the bike is worth so I could get a runner I could enjoy. If I'd wanted a project I could have saved alot of money.

Sorry for the mid thread vent. Does it sound like a timing or advance issue?
Thanks.

If all 4 cylinders are firing then I would look at carburation. Make sure the timing is right the check the carbs. JMO

Thanks. Guess I'll buy a timing light today. And order a new idle adjuster so I can wait till next week to get it. Hopefully I have to order a whole bunch of new jets and stuff too so I can get it running before I put the thing in storage.
<Thanks for the reply. The sarcasm is not directed at you, I'm just pissy. I do appreciate the help.>

Life is too short for me to be this frustrated. Somebody please tell me this bike is gonna be awesome and worth the headache.

Keep the shiney side up.

You can use a $3.00 test light to get your timing close without spending the money for a timing light, this will make sure your ignition is working. Then you can troubleshoot other things that could use more attention. Yes when you get finished it will be worth it.

I assume the ignition is working. I mean the bike does run. I don't know what your test light method involves. Guess I need to do more research. Thanks.

A test light will let you know its firing when it is supposed to. Check the cam timing and make sure you all that is good then use a test light on the crank for ignition timing. I would assume it is carburation from what you describe. That is if your cams are right and not off by a tooth or so. If you are sure about the top end pull the carbs and do a thourough cleaning and look hard at #4 carb. You can clean the carbs a hundred times and a little trash in the tank will make it 101 times, make sure the tank is clean and install inline fuel filter if not already done.

You wouldn't happen to know any good threads about checking cam position would you? Is that something that can be done without pulling the valve cover again? Thanks. This bike makes me tired.

Do a search and you will find a wealth of info on the subject. You will have to pull the valve cover. There should be two dots or possibly two arrows on the cam gears that should line up directly across from each other. You should try to download a manual for the bike if you don't have one already. My bike is different so I am not sure of the particulars of your model. You say the topend has been redone, was that from the previous owner? If so pull the valve cover to make sure all is right. You can probably reuse the gasket if you are careful. so that would'nt cost any thing but a little time. This is process of elimination the more things YOU check the more things YOU can eliminate.

pretty much everything your describing sounds carb related to me you will need to get those off and clean them very well with spray carb cleaner and lots of compressed air especalliy in the pilot circuits . the only way you can check cam timing is with the valve cover off. ditto the good inline filter and junk in the tank. your clymer sould have a section in on checking cam timing. relax you still have time and where your going working on this bike will become a fond memory.

Well, I just put the damn thing back together last night. I had the cover off to shim the valve clearances. Ran the crank almost all the way around I think inspecting the chain while I was in there. Tension 'seemed' right and chain and top guide looked really good. Didn't even think to check if the cams were lined up right. I assumed it wouldn't run at all if the valves arent opening and closing in sequence. I have a clymer manual at home. I'm sure it has a description.

I just put the carbs back on from changing the boots. I had #3 carb open before when the cylinder wasn't firing. Hit the bottom end with cleaner. Checked float height with tube. Did a visual inspection in needle jet and pilot.

I've already replaced the inline fuel filter with a new one. When I had carbs off all the bowls were full so don't think its starvation.

I figured a new way to re-seat the carb group into the intakes. The new intakes were 'virginal.' Try as I might I couldn't get the carbs to seat. Used a ratchet strap and some shop rags all the way around the engine and the carbs and cinched em down. Worked real smooth. Still a PIA.

So here's my plan of attack if I feel up to it:
1) Borrowed a friends timing light. I'll check that first since its the least invasive.
2) Re-open valve cover and make sure cams are lined up.
3) If not better, pull the carbs and do the lemon bath.

If that doesn't work, to hell with it, it's going in storage. I've got better things to do right now then sweating in the garage.

Thanks for the help guys. Can anybody think of anything else to check while I'm in there?

Howdy all, hope resurrecting an older thread is allowed.

I pulled the valve cover. Turned the crank to the T mark. The timing plate looks a little different then the book.

Kinda like:
T \ ... / F (imagine straight lines in next to letters)

Lined it up on the line next to the T. Locked the tensioner. Pulled the upper chain guide. The number 1 cam lobes are pointed away from each other and horizontal. The number 4 are pointed towards each other with the exhaust a little bit lower (eyeball gauge maybe 20deg or less.)

The exhaust gear bolt pattern doesn't look exactly like the diagram in the book but there is a very small arrow pointed horizontal and forward. It lines up almost exactly with the top of the valve gasket. I believe this is the mark described in the book. If I count the chain pin directly in line with this mark as number 1, the 28th pin lines up directly with the 28 mark on the intake gear.

I'm fairly confident this is correct but it's the first time I've done this. Couple questions.

1) From what I describe is it TDC on 1 and 4?
2) Number 4 cams arent exactly pointed at each other. wrong?
3) The chain pin is directly inline with the mark on exhaust gear. This is number 1 correct? The book mentions going to the pin a little above the mark but if I did that it would be and entire link above.

I'll think about it tonight, if I'm confident I'll put it back together tommorrow and check timing next. Then do the carb breakdown. Thanks all.
Keep the shiney side up.

As can be reviewed in the attached image, the lobe centering on the left is off (high)... This was due to my incorrect lobe centering with adjustable cam sprockets... My bad... :blush:

If using OEM sprockets (non adjustable) and with your exhaust sprocket dimple aligned with the head decking, count 1 pin up then 28 over as depicted in the diagram.

AT 1/4 TDC, your cam lobes should be facing each other, parallel with the head decking as corrected and depicted in the right image.

NOTE: This image is from the right side of the bike, cylinder 4!

There are several versions of the timing advancer unit...

OMR