Author Topic: more problems, bigger headache (Read 4045 times)

OApb · « **on:** September 04, 2009, 09:07:27 PM »

Well guys, I though I had her running great but she let me down again. The other night while on my way home from a cruise night she broke down on left me stranded. Not only that but I was in a part of town where i wasnt exactly comfortable standing around in, if you get my drift. So I had come to the conclusion that she had overheated on me. While riding, the motor started sounding like it was missing while accelerating and then just shut off all together and would not start again. The head felt real hot but was not hot enough to sizzle the water i poured on it. after getting it towed (after waiting 2 hours in a not so nice part of town) I tried to start it and she fired right up.
This morning I tried to figure out what had caused it to act strange. I found that the pod filter on the #2 carb was interfering with the choke linkage and caused it to stay open. I pulled all the plugs and found that the plug on cylinder 1 was very white due to running lean . I then decided to adjust the mixture screws to see if that helped. I found that all the mixture screws were screwed all the way in. I was told these carbs were "professionally rebuilt" but i have a gut feeling the professional was not very good. I started with the 1 3/4 turns out as per factory specs and started it up. she ran terrible, no power, very laggy throttle response and would bog down with anything more than 1/8 throttle so I started with the #2 carb and turned it in until the highest rpms were reached and then turned it 1/4 back. I proceeded to do this for all carbs and it started running great. I went on a 10 mile ride and again it started showing the same problems as before. Im losing my marbles with these carbs. I just dont know what else it could be. can running d9ea plugs cause some of these symptoms? Any help and ideas are greatly appreciated and will be put to use. thanks

Spanner 1 · « **Reply #1 on:** September 04, 2009, 09:45:57 PM »

What is the bike

First off the idle/slow mixture screws turned all the way in on the carbs on ' professionally rebuilt ' carbs does not bode well ! Think you need to investigate the float levels and also the main and slow jet sizes ( stock airbox/filter and exhaust / ) also check for air leaks at the rubber manifolds........some stuff to start with ! Looks like #1 cyl. is trying to run very lean, how are the other 3 ? Too lean running will produce an overheat condition, possible seize.

seaweb11 · « **Reply #2 on:** September 05, 2009, 01:56:44 AM »

You have Pods......... your killing squirrel's and small children

You need to check your main jets. OH yeah, what bike are we talking about?
Exhaust?

P.S. See if your neighbors are still breathing.

Johnny5 · « **Reply #3 on:** September 05, 2009, 05:15:45 AM »

Small children should be fine, babies on the other hand....best of luck.

For my bike, 750K7, I had to bend the choke lever and bend a little bit of the pod so the choke lever wouldnt hang up.

Have you checked your plugs to get an indication of how the bike is running (lean or rich)?

OApb · « **Reply #4 on:** September 05, 2009, 06:59:34 AM »

Sorry guys, bike is a 78 750f running pods and a 4-1 exhaust with the baffle taken out. Only #1 cylinder was showing a lean condition, the others were a little bit dark but not fouled. what would be the best way to check for manifold leaks? spraying some starter fluid around them and seeing if the rpms change? The float levels have already been set, they were either brand new or the "pro" didnt adjust them because they were so high that all 4 carbs leaked fuel from the overflow.

OApb · « **Reply #5 on:** September 05, 2009, 05:27:06 PM »

would the carbs being a little out of sync cause lean conditions? what else could cause this? Its seems like its overheating but the head would not sizzle some spit/water so it cant be that hot. Im so confused, Im about ready to just take her off the road and tear her apart and start my projects early but I have atleast another month of riding season left and dont really want to waste it

Retro Rocket · « **Reply #6 on:** September 05, 2009, 05:32:47 PM »

I know you think its carb related but i have seen "bad" coils breakdown when hot only to start again when everything has cooled down..

Mick

Brian G · « **Reply #7 on:** September 05, 2009, 05:45:22 PM »

Quote

what would be the best way to check for manifold leaks? spraying some starter fluid around them and seeing if the rpms change?

Please, Please be careful spraying starter fluid around a running engine

WD-40 is a better bet - same result but not as volatile. And FWIW, if she ran OK

Quote

I thought I had her running great

at the cruise night and just stopped on the way home I'd be looking at a failure in the ignition system rather than a tuning problem. +1 on retro's thoughts on the coils.

Good Luck and Regards,
Brian

OApb · « **Reply #8 on:** September 05, 2009, 05:50:29 PM »

yes she ran fine on the thruway for about 15 miles to the cruise night, fine from there to a hockey rink about 5 miles away and fine for another 5 miles or so and then started to bog down, misfire and then completely stall and not start again. she did it again yesterday, this time it only took about 10 miles to do the same thing. will any test for the coils show if they are going bad even if they are cold or will I have to heat them back up with a short ride? would running d9ea plugs contribute to these problems?

edit: brian, i feel very silly for typing starter fluid. I actually meant wd40 but for some reason that signal got crossed and starter fluid was typed. Ill chalk it up to my ripe old age....of 21

Im a car guy by nature and job so bikes are new to me but im slowly learning

JohnG · « **Reply #9 on:** September 05, 2009, 06:06:53 PM »

First rule of thumb when working on old vehicles: Assume Nothing. Take nothing for granted.

So sit down and carefully clean and gap the points and do static timing. This has to be done no matter what so might as well cross it off the list. (new points would be good but oldies can be rejuventated with 600-800 grit wetsandpaper or a point file)

Next in the dark, crank it over with one plug laying on the head. See what kind of spark quality you have.

A multimeter would be good. Check out the resistance of all 4 plug caps. These can and do fail as they are resistor caps.

Don't quit until you are convinced your ignition system is functioning properly.

Carbs: same advice - take nothing for granted. Forget the "professionally rebuilt" due to evidence to the contrary.

Did the carbs get pushed all the way into the rubber manifolds?? If the manifolds are original and have seen alot of heat, they dont fit well. For the time being you could use some hi temp silicon.

Do you know what jets it has??

Be patient!! It will run well yet!

john

Brian G · « **Reply #10 on:** September 05, 2009, 06:14:49 PM »

I can't see the cooler plugs being the problem. If they were fouled, you wouldn't get her started again so quickly - or at all, for that matter.

An auto-electric place should be able to test your coils, although you'll have to remove them...

Just a thought...., is it possible that your fuel tank vent might be clogged? Are you running an in-line filter? I'm thinking now of a restriction in fuel flow.....

John's right - there is a reason, and it will eventually be found!

Brian

OApb · « **Reply #11 on:** September 05, 2009, 06:44:57 PM »

John~ replaced the entire points plate assembly, static timed as well as dynamic when I found my timing light. Spark quality is good, nice blue spark. Ive replaced the plug caps with new ngk ones but i will check them again. As far as the carbs go, the only thing I have left to do is pull the jets out and see what they are. Ive been planning on buying new carb boots so I guess now is as good a time as any. The carbs are all pushed into the boots but its possible they arent sealing very well since the boots are pretty stiff.

brian~ yes, running an inline filter. one of those small clear ones. it doesnt look clogged. I took a paperclip and cleaned out the vent a while ago so that should not be an issue. The petcock is newer and passed the flow test with ease

Retro Rocket · « **Reply #12 on:** September 06, 2009, 05:02:28 AM »

Quote

The carbs are all pushed into the boots but its possible they arent sealing very well since the boots are pretty stiff.

I would say, based on what you have said that it isn't the carbs, if it was it would run like crap all the time especially if they weren't sealing on the manifolds. I would be looking at coils, condensers and carefully checking plug caps and other heat effected ignition parts.

Mick

edbikerii · « **Reply #13 on:** September 06, 2009, 05:33:34 AM »

The cap on the gas tank has an air vent. Is it clear? If this problem happens again, try opening the gas cap and listen for a "whoosh" as air rushes in. Then see if it runs.

OApb · « **Reply #14 on:** September 06, 2009, 12:23:18 PM »

Ill check out the cap today. It would be great if it was something small like that. would also make me feel pretty silly

KB02 · « **Reply #15 on:** September 06, 2009, 12:33:57 PM »

I had that happen on my wife's bike. There's a door over the gas cap, and the rubber bits that keep it from vibrating were gone. I wadded up a paper towel to keep it from vibrating. The towel was wadded up enough that it actually closed up that vent. I was just about ready to tear the carbs apart when I just threw the stupit rag out and dealt with the vibrations (I have since replaced the rubber bits

).

Let us know what you find.

markjenn · « **Reply #16 on:** September 06, 2009, 12:43:48 PM »

Yes, check that gas cap vent. This is an easy thing to troubleshoot - if you take the cap off and it makes a "whoosh" and the engine starts running better, you've found it. I had a gas tank venting issue on my 1975 750F. They clog if the bike sits.

If it's not the vent, I vote carb troubles rather than ignition for several reasons: 1) its running best with mixture screws all wacky, 2) evidence points to a ham-fisted mechanic working on them; and 3) more often than not, its the carbs rather than ignition on these old bikes. I don't think you're overheating, at least not enough to cause the engine to seize.

- Mark

Retro Rocket · « **Reply #17 on:** September 06, 2009, 06:06:36 PM »

Quote from: edbikerii on September 06, 2009, 05:33:34 AM

The cap on the gas tank has an air vent. Is it clear? If this problem happens again, try opening the gas cap and listen for a "whoosh" as air rushes in. Then see if it runs.

Good one ED, i thought of that last night, based on the distance traveled before the problem starts, this could well be the problem..

Mick

OApb · « **Reply #18 on:** September 06, 2009, 09:44:30 PM »

I checked the cap. It seems to be a little clogged, takes a little bit of pressure to blow through. I would think that a vent should be pretty free flowing and not take a little pressure. whats the best way to unclog these? I have a charger sitting on the bike now, the battery was dead from trying to start it. Ill try it again tomorrow morning. I didnt think of the cap at first but when someone said it, it made alot of sense. figure the vent is to let air in to displace the fuel as its sucked in by the carbs. if no air is let in then it gets fuel locked. Ill try it in the morning and see what we come up with

OApb · « **Reply #19 on:** September 07, 2009, 11:04:21 AM »

Well, came to the conclusion that the coils are bad. neither coil has continuity on the primary (plug wires). The secondary coil is good at 4.5 ohms but theres nothing between the plug wires. Guess its time to find a new one, good thing partsnmore is out of stock :/

edbikerii · « **Reply #20 on:** September 07, 2009, 07:37:05 PM »

Wait a minute. How could that be the problem if the bike runs?

Quote from: OApb on September 07, 2009, 11:04:21 AM

Well, came to the conclusion that the coils are bad. neither coil has continuity on the primary (plug wires). The secondary coil is good at 4.5 ohms but theres nothing between the plug wires. Guess its time to find a new one, good thing partsnmore is out of stock :/

Retro Rocket · « **Reply #21 on:** September 07, 2009, 07:45:53 PM »

As i have said earlier, i have had coils that would run but break down when they got hot, i didn't think that this was too unusual as i have had the same problem with mower coils and condensers for that matter..

Mick

OApb · « **Reply #22 on:** September 07, 2009, 07:47:18 PM »

bike was running, now wont start. Im guessing the coils were on their way out and these few rides pushed them over the edge. props to retro rocket for calling the bad coils when hot. neither coil has continuity between plug wires, according to the service manual there should be 4.5 ohms +/- .1 ohms, im getting nothing, effectively an infinite open. When tested when the coils were cool, i was getting a weak spark but when left in the sun to heat up a bit I got nothing

edbikerii · « **Reply #23 on:** September 07, 2009, 07:49:41 PM »

I could see that (I have seen that), but he said that it ran fine for several miles before it died.

Hey, I guess they finally gave up the ghost when cold, too. Good call!

Quote from: retro rocket on September 07, 2009, 07:45:53 PM

As i have said earlier, i have had coils that would run but break down when they got hot, i didn't think that this was too unusual as i have had the same problem with mower coils and condensers for that matter..

Mick

OApb · « **Reply #24 on:** September 07, 2009, 07:53:46 PM »

yes, good call retro rocket. thanks all for the help. I wish I would have figured it out before I went through the trouble of replacing the plug wires and wasting some money. Could have used that to help pay my credit card bills

oh well, ive got a line on some coils so I should be back up and running soon. hopefully I can get a few more rides in before we get some snow, which could be tomorrow, we nenver know here in buffalo

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Author Topic: more problems, bigger headache (Read 4045 times)