Bad Running

[BrianDallasTX]

Hey guys I have a couple of Q's.  Last night I wanted to go for a ride.  I haven't ridden in about two weeks b/c of the heat and/or prior obligations etc.  Went to start the bike and it immediately died. Again, Again etc.  I could get her to run with the throttle open and keeping the idle around 2000 rpm.  Then it would start dropping and then revving back up.  After I gave up on the ride and let the bike cool off, I changed the plugs.  Looked to running a bit rich, but not to bad.  I checked the following:

-carb jets are clean and free of obstructions
-checked the gas cap vent hole-clear
-gas is no more than 30 days old, smelled a bit stale but not bad
-good battery and points
-I have a KN filter and it is clean and rechraged I did notice a little oil on the drip guard from the filter (fliter oil)

I only got a few minutes to play after changing the plugs, but it died again.  At that point I simply went inside as I was frustrated.  Here are the carb specs:

-single 389 monobloc
-360 main
-109 needle
-I forgot the pilot but 20 maybe?

What are you guys running?  Any thoughts? I am totally at a loss right now.

TIA,

Brian

[admin]

Sorry for your troubles. Can't be this simple, but y never know: start with eliminating all possibilities of water\condensation in the carb\tank. Then check that the carb for sure gets the right amount of petrol (float\needle). Then check .......

Regards
Erling

[LJ.]

I would not know where to start with recommending, It could be anything. This afternoon while I was out the bike started off and went a treat. Later on it was lumpy with back firing. I went home via town rush hour traffic and had to keep blipping the throttle to keep it running. I notice on my tripo meter that petrol was low, reading 168 miles, normally I will get 200 miles to a UK size tank. I just tried pulling on my reserve tap and what a differnce! Again, stupid little things that cause uneccessary worry. I filled up and came home pleased. Still got to get the polishes out though after yesterdays rain! Duhh

[fido]

Have you checked the magneto pickup brushes?

[trevinoz]

Check magy points also. Sometimes the plate comes loose . Check earth brush.

[63a10r]

hey brian. had the same problem with a triumph once. were you on reserve? turns out there was a little crap in the tank. if so, try fillin up and runnin again on the main circuit.. and have you checked for an intake leak? if thats the case, you may have bowed the carb/intake flange. it dont take much

[BrianDallasTX]

When I got home yesterday, I cleaned the pilot circuit.  There was a tiny bit of crap in the jet from where some gas evaporated(?).  Cleaned it out and went for a quick ride.  Back to normal.  Thanks for the suggestions.

Brian

[admin]

Good to see your problem was easy to fix, when first found! And thanks for having the courtesy of posting the solution. Have always been so frustrating when I read long threads in forums about problems, and there is no solution or explanation in the end!

Regards
Erling

[LJ.]

I quite agree, and I sometimes feel reluctant to help again in future if there is little in the way of a decent conclusion to various threads.

[admin]

yes, sometimes frustrating to see topics stopping in the middle of some "detective work", but it's ok anyway to post, can help someone and good theads with lots of suggestions are always interesting to look up and read, but so more satisfying & useful if one gets the answer to the riddle in the end, and knowing the bike's owner goes from  to 

Have a fine day
E.

[BrianDallasTX]

I completely agree.  Thanks again for the thoughts.

[LJ.]

Might be an idea to keep this thread running because we all suffer bad running from time to time, and here might be a good place to refere back to when one gets desperate!

So here's another tip...

Check the Hight Tension leads where they screw into the magneto pickups, I found mine completely gunged up with dried out oil. This could lead to insulating preventing a good spark especially if the core of the cable is not soldered to the little brass disc and not tight inside the pickup.

Just a thought.