Ever feel like you met your match??

[DCII]

Cracked Coil?

Don if that coil has a crack in it I think I would change that out with one of the units off the old bike if you still have them. If you need a coil let me know I am pretty sure I have a couple spare sets in the office. Have you ruled out any possible issue with intake boot or a vacuum line?

[bikerphil]

Don... Didn't you do a coil mod of some kind, with Honda coils or something? Maybe one is weak and not firing properly, you did say the colortune wouldn't fire properly? JAT

[DGXSER]

I have a set of the Honda VF1000 coils, but the ones on the bike are stock. I needed new wires for the Honda coils. The colortune looked like it was sparking well, but only got combustion every so often and that looked bright yellow.

I am going to try swapping out pick-up coils tomorrow. I have the ones from the wrecked bike which were working fine. After that, I will get new wires for the Honda coils and try those.

[TopCatGr58]

I'm with Greg on this one. It's firing, but has nothing to fire. Carbs are clean, no obstruction to fuel flow as far as you can see/determine. Pilot circuit open, new pilot screw, pilot jet clear, so it's down to vacuum being able to pull fuel into carb. The valve clearances are okay, compression a little low, but same across all, and the other 3 work, so #1 should.

Intake boot has external cracks, but has been checked and is intact internally. You're able to synch the carbs but that's been done before WITH a vacuum leak. Other sources are mating surface of boot to engine, the synch port cap/tube, the carb's butterfly shaft seals, I think I remember something about the seals of the choke/enrichener plunger even!

I've been surprised at the comments about the combustability of carb cleaner? When I've used it years ago on a carbed car, it would cause the car to NOT run well, I would even have to rev the engine while spraying it into the carb throat and such and even then it could kill the engine if I sprayed too heavily. I was using GUMOUT brand back then. SO..I'm just curious about the comments about it "helping" to diagnose a lack of fuel flow by firing the non-firing cylinder when sprayed. Perhaps the carb cleaner formulas have been changed, don't know? Guess I'll get out my can of cleaner and test it on my bike to see if it actually causes it to REV vs. bog?

T.C.

[ddragon63]

TC,

A good carb cleaner ie Gum-out, Berrymans, and seafoam will bog the motor when fogged. they're are flammable, but when saturated in a concentrated area they are very heavy and burn slow. this is why people fog they're motors with them. cleans out all the unwanted carbon as the motor works to try and burn it all out of the combustion area.

[natemoen]

Also it is like with any combustable material, you need the proper fuel/air ratio to burn. If you cram a buck of highly combustable carb cleaner into a cylinder and it doesn't have enough air, it won't burn.

[DGXSER]

OK, so it almost HAS to be some type of vacuum leak.

So far today, I put it all back together starting with the valve cover. That "Right Stuff" gasket in a can stuff is the wrong stuff for me. I found it hard to control the size of the bead, and also hard to control period. I much prefer the tube of RTV.

Anyway, after that I checked float heights, right on spec all across the board. Loaded the carbs back in, got the air box put back together, fired it up on full choke it sounds almost good, part choke still sounds better, no choke it sputters. Granted the engine is cold still, so I put it back at half choke, synch again just to be sure. No change.

Now, I am thinking it must be electrical, so I check no 1 again with the colortune, very intermittent combustion, but spark is there. So I check number four, fires well all the time, good combustion. So, I swap plug wires from 1 - 4. Problem stays on no 1. So, not electrical.

Carb was working great, been cleaned like it has never been cleaned before, yet, has to be a fuel related issue. Gets marginally better with half choke. Staring at no 1 and I see a sign. There is a crack in no 1 carb boot, right where the boot meets up with the head flange of the boot. And the crack looks a little wet. Sooo..it almost has to be a vacuum leak right there. Now the interesting part is that I intentionally sprayed this with carb cleaner and got no improvement. I pulled the boot off the head, look inside, no sign what-so-ever of this crack. Maybe , just maybe a sign of the area around the vacuum tube being a little overly mushroomed where it penetrates the boot. So I now have the crack gooped up and over with RTV. Will install the carbs again and see if this helps it at all. If so, new boots will be on order.

[DGXSER]

So, it appears that it is a vacuum leak at the carb boot. It is better, not gone, but better substantially since the RTV on the boot.

So, now to get soem good boots or new ones. Then I will address the cracked coil. Got new wires for my Honda coils.

Then I can figure out the rear wheel/tire issue. The fun never ends when you own an antique.

[petejw]

Stole soem time this morning. I can confirm the valve clearances are all within spec. Most are on the loose side of spec. I do need to check the battery, but I had 14.5 volts at the coils red/white with key on bike not running.

it might not be a problem, but the wires going to the coil
run thru a relay and it should read around 12 volts, if ur
getting 14.5 volts at the coil that could be causing a problem
especially if the coils are getting to hot or overheating,
maybe steve or randy can chime in they know more about
electrics than i do.

[skids]

OK. So if it was leaking a little when it was originally synched, and then it got worse, and then you fixed the vacuum leak, you need to synch again... or you can just wait for your boots, install them and resynch then.

[DGXSER]

OK, so this seems to become the never ending saga.

To date, I have removed and cleaned the carbs several times, never finding any real improvement. Also replaced the carb boots, seemed better when I had the one sealed, but once I got it our for a good run after replacing them, In fact, it only has gotten worse, now seems to be running on two cylinders.

But, here is the confusing part, all four header pipes sizzle water. Adding choke seems to help it run a little faster, but still feels like two cylinders.

Next, replace the pick-up coils, had the ones form my wrecked SH, checked the gaps. right at .7 mm. No joy.

So, I went to replace coils, well, I bought a set of plug wires to replace the ones on the coils. Check ohms on terminals of coils, get 15k. Low side 3 ohms. Add wires, I get nothing on high side. Ok, now what, look at the wires I can not see any copper. WTF??!! Remove wires, check resistance, none. Cut a piece off, open it up length wise, no wire inside, the core is just white cottony stuff. Really??!! Is this possible!!!???

So, now I decide to reinstall the old coils. Start the bike up, running on two cylinders. Now, my exhaust does not have a crossover. So I feel and listen to each side. It appears that only the right side is firing, left side I can feel puffs of air, but no real sound of combustion. So now I am wondering if I got something come loose in that muffler that has it partially blocked. But I get some and consistant compression on all four. If the exhaust were blocked would it effect compression?? Seams it would.

Any thoughts appreciated.

[petejw]

hey don, did u fix the high voltage going to the coils?
ive seen green powdery stuff in old copper leads, lol
a partially blocked exhaust wouldnt affect the engine
so much at idle or cranking to check compression pressures.

[bikerphil]

Don. I bought a cheap wire set for my Accel coils that are for a 79 Camaro 3.8 V6, they are the carbon core type and they have the correct ends on them, just need to trim down the 2+3 plug ends. Cost about $20. They have been working fine for me for 5 years now. Hang in there, hopefully you find the problem very soon.

[DGXSER]

I know it has to be something simple and stupid. The only thing I have not yet done is remove the fuel inlets from the carbs. Hate to ruin them trying to get them out. I will try my spare 79 carbs. see What they do for it. Can't hurt I would think.

[DGXSER]

Well, the spare carbs helped some, except I could not get the floats to work, so had gas peeing all over. So, went back to the carbs. Stuck a small wire in all three holes in the throat of the body, the one out to the side seemed like it took a little effort to get the wire in there. Anyway, it seems to run a little better.

On the spark plug wires, I went back to Autozone, they brough out two other sets of Duralast, both had the same wire. It seems the center is some black material that is supposed to be conductive filled with white stranded stuff. That is surrounded by white silicone, which is wrapped in black rubber/silicone. The stuff at the store was conductive, the stuff I have is not. No matter what year of engine you look for all their wires are like this. SO I need ot run to NAPA or Smyth where the folks know something, maybe I can find normal spark plug wires!!