Surging & poor performance -- Need Help

[rdsmith3]

I have run out of ideas and need help.

About 3,000 miles ago I adjusted the valves on my bike and synched the Throttle Bodies with a Morgan Carb Tune. I also replaced the spark plugs and air filter, but not the fuel filter. Ever since then, it has been running worse, not better. I get surging, which I never had before. It is also harder to start when cold, but starts fine when hot.

So I took the time to check the valves again. One of the exhaust valves needed a little adjusting, but I am pretty confident that the valves are all adjusted properly. I used the Wurth feeler gauges. They slide firmly but not too tight; there is enough friction to hold the feelers in place.

The throttle body synch seems OK, but I cannot get the idle much above 1,000.

Any ideas on what to try next?

Clean the brass screws?

Replace fuel filter?

Is air leaking in the system?

Use a Techlusion?

[challey]

rd --

I'm sure others with more technical savvy will chime in on this but it certainly can't hurt to clean the brass screws. Cost is right too. As far as the fuel filter, I don't think that a clogged filter will result in surging - if it's clogged, it's restricting the fuel flow more or less constantly, not intermittantly. Still, if you're close to the 25,000 mile change interval mark, it can't hurt to reolace it (and it's not all that difficult to do either).

You may want to change the vacuum hoses. Not particularly likely culprits but the hose is cheap, it's easy to do and it might help. The other thing you can try is removing the CCP and resetting the Motronic. Again, low probability that this is cause but it's easy to do and doesn't cost anything.

Good luck!

Charlie

[rdsmith3]

Thanks. The CCP has been out since the first year of ownership.

The fuel filter has been changed once during my ownership, and I don't think that is the culprit.

[bikermeow]

Surging only at specific RPMs or generally through the range?

[dgates]

Are you twin spark? If so, consider the stick coils.

[rdsmith3]

single spark

surging is in a range, maybe below 4,000 rpm

[boxermania]

So it appears to run worse after the "service". I would look at what was done first

Valves, you checked twice - dismiss
Air filter - dismiss
Plugs - Correct gap?
TB's - Re-check

Other than that, I can come up with two things

1) Is the TB's throttle cble inside the adjuster? Check both sides.
2) Are the vacuum tubes on the bottom of the TB's disconected/cracked/broken?

[rdsmith3]

I forgot to mention that I checked the throttle body synchronization twice, after checking the valves twice. I will check the cables. thanks.

[bikermeow]

Let me mull over, but in the meantime, a mate of mine lost his surges with Broquet fuel additive, and I lost mine after fixing the Y-Pipe.

[Daryl.Stamp]

Can someone describe what surging is?

DLS

[iowabeakster]

things I would try...

1. You might have gotten a bum spark plug. If you have the old ones still, try putting them back in. If the old ones are already in the dump...another one or two are pretty reasonable.

2. While doing that, I would also check/clean the connection between the plug wire and the plug. Check the wire for possible failure.

3. Pull out the brass screws, clean them, spary carb/choke cleaner in the holes.

4. Try some fuel additive (like seafoam).

5. I would pull the injector nozzles out the throttle body and make sure that they are spraying properly.

[toolinalong]

mileage on the bike?

[Twempie]

What's your spark plug gap? Make sure it's .032.

[CycleRob]

"Ever since then, it has been running worse, not better. I get surging, which I never had before. It is also harder to start when cold, but starts fine when hot."

Resetting the Motronic should be your first step. Two things immediately cause hard cold starts and they were already mentioned.
1-- Sparkplug gap(s) too wide or a weak spark
2-- Vacuum hose leaks.
The vacuum hoses are at the age where leaking cracks just appear. Those cover the "Ever since then" condition. Also possible but way less likely would be a secondary sparkplug wire pulling out of electrical contact with it's connector. If you pulled the tank off, grains of dirt entering the open QD will end up in the fuel line where it can disrupt the fuel pressure regulator's normal function and the injector's normal spray pattern & volume. One last one is the sneakiest one with a good probability . . . . bad gasoline. Possible with the summer formulation changeover or it's 10% Ethanol absorbing 100% of (several?) tank's small water puddle(s).

.

[rdsmith3]

Thanks all for the suggestions.

Regarding the spark plugs and bad gas, I did the "service" over a period of time because of time constraints. So, for example, I replaced the spark plugs one night because that is a quick and easy job. I ran for a while with the new spark plugs before I had a chance to adjust the valves. During that time, it ran great. In fact, I had less knocking with the Autolite plugs I used than with the previous NGK. Therefore, I don't think it is the plugs, but they are easy enough to check.

However, it is quite possible that I damaged a spark plug wire when removing them as part of the valve adj process.

Regarding gas, as I noted above, when I first replaced the plugs, I had less knocking than before. Now that we are in the summer, and ethanol is in the gas, there is more knocking.

I used some Techron earlier this year, but maybe it is time to try some Seafoam.

I did not remove the tank to do the service, but I did tilt it up to replace the air filter.

[lionlady]

My bike had been running like crap for 6 months... Cold starts were tough, but not impossible. Problem: The spark plug wire on the right side cylinder had a broken connector. Replaced the connector and all is well.

I had the advantage of access to a box of wiring "spaghetti" and was able to scavenge the connector. If you need to replace yours, it will cost $104.

P

[rdsmith3]

Lionlady

How did you diagnose that the spark plug wire connector was the problem?

[lionlady]

The plastic connector was broken.

Originally thought that just the housing was cracked. Upon closer inspection, it was possible to see that one of the 3 wires inside was broken as well.

Wouldn't have known what had happened, except that the lovely tech who was working on my bike actually disconnected the wire from the coil before removing the spark plug (which I never do). The connector was cracked where it meets the stick coil.

p

[boxermania]

rd

I think loinlady's bike is a 4 plug as she referred to the "stickcoil connector", you might want to check the resistance of the high tension wires (the one from the coil to the plugs), they should be in the 5K Ohm range..........

[rdsmith3]

boxermania

Thanks. Dumb question -- where is the other end of the spark plug wire? Is it easily accessible?