Topic: I want to burn my K3 750!/ How to check Dyna ignition?

[zoo mob]

This thing has been both nightmare, and learning experience. Learning experience in that I've learned how it comes apart and goes together, and nightmare in that its been apart waaay more than its been ridden this season. Early on, I had a problem with #3 not firing, first I thought it was electrical, so in hindsight, I jumped the gun and bought dyna coils and ignition, installed them, and it still wasn't running on all four. Checked compression, and #3 was indeed low, blah, blah, blah. Suddenly, it decided to run on all four, had the carbs synced, mechanic set the timing (but didn't do the static method as suggested by dyna) and I rode it for a couple hundred miles, and bang, no #3 again.

Took it back to the mechanic, and it turns out it was just the #3 float level the whole time. Guess I spent a bit more than I needed on the dyna stuff. Well, about that time I picked up a 750 K0 and while tinkering with it I had been switching the air filter and battery back and forth between the bikes. The last time I switched it, the K3 didn't want to start, finally it did, but ran like crap. Took the air filter out, and it smelled of gas and was pretty dirty, also the plugs were fouled. Well I put new plugs in, and sliced the air filter up a bit to try and make it flow a bit better, and it still ran like crap. All four are firing, but it runs really lumpy until you get to about 4,000rpm, and runs good until about 5,000.

The bike had always been jetted a bit rich (but I was able to get several hundred miles before plus fouled) so I figured I'd get a better flowing K&N and it might take care of the problem. Got it today, cleaned the plugs, put the filter in, and its still running like crap. One last thing, got a Hondaman resistor but have yet to install it. What the hell is going on with this bike? Is my ignition fried or something? What should I be checking? I'm about ready to take the new ignition stuff out, and sell this turd so I can focus on my K0.

I'm supposed to go on my first overnight trip next weekend with my buddies next weekend, they're going to have my ass if I don't make it, I've missed all the others due to all of the b.s. problems with this bike. Somebody point me in the right direction please.

Thanks for reading all of that.

[Hush]

Welcome to the Hell that is Honda carburation.
99 times out of 100 it's the flaming carbs on these bikes, not that they are easily accessible either oh no that would make a difficult job bareable!
Maybe you are putting too much effort into two bikes when the K0 seems the better bet for a reliable ride.
How about parking the Frankenstein bike up and ignoring it for the rest of the riding season, you know it's just gonna drive you nuts?

[Shenanigans]

I will take it off your hands. Might as well save the trouble and give me the KO to .



Start with a NEW air filter and work your way back from there. Then clean and re-clean the carbs and make sure they are set right. Then make sure your timing and valves are correct. Then check your electronics and so forth. Does the bike have any modifications from stock?

It seems like a lot to do but if you start doing these one by one ( and don't make assumption of the cause of the problems) even if you don't know the problem you will eventually eliminate everything else.

[zoo mob]

Everthing's been done, brand new K&N, jets have ben cleaned several times this season, inline fuel filters installed, bike was timed, valves have been done, cam chain tightened, carbs synced etc. How do I check the electronic ignition?

[jtb]

ZM,  Do a search on carb rubbers.  while the bike is idling, spray some wd40 around each of the rubbers.  If you notice a change in idle speed, you have a leak.  They can make a big difference.  I bought a new set 2 years ago, and it made a different bike.  Uncrash just posted his results with new rubbers. 

[greenjeans]

Hate to beat a dead horse, but.....I know that you've cleaned your jets, but when's the last time the whole rack has come off and
been cleaned.  When I finally got mine going, I "thought" that I had cleaned them enough.  I finally ended up taking them off again
and boiling them lightly in some carb cleaner.   Ran the tiny wire throught the passages and ran endless amounts of carb cleaner &
compressed air through every passage repeatedly.   It was day and night.  Thing is, they really loooked clean the first time.  I also
had trouble with the float levels...Take the time to REALLY set them accurately.

[zoo mob]

The whole rack has been off a bunch of times in the last couple of months, and all the passages cleaned etc. This feels really different than when a jet or passage has been clogged. I tried the wd40 on the carb boots, and no noticeable effect. Bike is very rideable, but is horrible under any kind of acceleration up to 4k. Its obviously getting spark since all 4 are firing. Could this be the ignition, or is that unlikely? I thought that with the electronics, they remained in time permanently. Also, there is some minor backfiring at idle that was not previously present.

[Tower]

Since there are no gremlins and magic anti-SOHC4 spells, its got to be in the mechanics  (Sometimes, I have my doubts about the gremlins though)
Kind-of in order of likelihood:
1 - Carb settings, levels
2 - Dirty jets, worn seals, leaks
3 - Timing, advance, capacitors, points
4 - Air flow
5 - Valves, lash, chain tension
6 - Gasoline supply, worn jets, wrong jetting
7 - Plugs and wires, poor connections
8 - Compression, rings, valves and seats, exhaust leak
9 - Coils, wiring, battery
10 - Esoteric, your-guess-is-as-good-as-mine stuff

Sounds like you've worked your way through much of this.  If not go back and check them off your list.  No sense in skipping around because then its just random guessing.  

Here's my guess: You mentioned compression - what tests did you do - wet/dry, leak down test, and what were the results?  Are the cylinders within 10% of each other and within 20% of the optimal?   Any exhaust blow-by or discoloured pipes?

Fix any problems, then move on to the esoteric causes, like wrong plugs, warped valves, stuck tensioners, frayed wires, hidden broken wires in harness, etc., etc  or tear apart the entire bike and rebuild from scratch

[martino1972]

first off,it should faul the plugs that fast,so it seems your really rich...
running like crap seems to confirm that too...
a wet airfilter from fuel is not good either...here's some thoughts.....

-are the needles in the slide worn out?(causes the same symthoms,below 4k running weird,fauling plugs)
-is there a intake valve leak,blowing back compression into the carb/carb's??
-is the float hight set right,not to high.?

my best bet would be worn needles though.......

[greenjeans]

Have you checked your spark advancer ?  Maybe it's its gummed up or sticking.  I would definitely check the points and timing if you haven't already.

[Artfrombama]

When you remove the fouled plugs, what do they look like?
Black and sooty or puffy grey/black deposits?

I've never had much luck cleaning fouled plugs, new set will run better.

[m00ntan]

I rode it for a couple hundred miles, and bang, no #3 again.

I would take real close look at that cap and wire if it goes off like a light bulb.

[zoo mob]

Well, I was talking through this with my mechanic and I may have found the culprit. As I mentioned before, #3 was giving me trouble until he adjusted the float, well I had the idea that I should adjust the others to spec as well since he'd just looked at the float from the cylinder giving me trouble. I probably should have left well enough alone, but why be easy. So, I'm going to go out and try to back them off a bit, will the carbs need to synced again after messing with them again? Thanks so much for all of your input.

[zoo mob]

OK, looked at my floats, and if anything, they're riding lower in the bowls, not too high. I don't think they are the culprit here, all of the above stuff such as air flow, gas supply, etc. seems good. How do I go about determining if anything is wrong with my Dyna ignition?

[UnCrash]

I just had a failure on 1 and 4 with my K6.  I have an old Martek electronic ignition that turned out to be the culprit.

I posted a thanks to TwoTired who wrote up a great diagnostic for testing the ignition system from the plug all the way back to the ignition unit (Dyna in your case).

Read up on it here (and follow the link in the thread).

http://forums.sohc4.net/index.php?topic=40075.0

[Tower]

How you making out with the K3?  Is it in flames yet, or have you located and fixed the problem?