HarleyTechTalk

One thing I forgot to include is that it is way worse when cold and dissipates greatly (but doesn't go away) once it reaches normal operating temp. If I let it sit and warm up before riding it runs much smoother, but if I try to take off after only a couple minutes warm up the idle fluctuates more wildly.

When it fluctuates.. Set up to monitor the system..  What is the TPS line doing..  does the line bounce around.  How does the head temp look.. Could it be more of a local fuel blend change?   Some here have had similar issues and have adjusted the AFR Correction VS Engine Temp.. to correct the problem.. They cut the low temp fuel (ie add less)..

Max

A more pronounced condition when cold would lead me to think the engine is lean. Warm engines atomize fuel more effectively and thus require less of it.
Did you do the carb spray test yet?
Other electrical issues would not usually be temperature sensitive.
You could even add fuel (carb spray) right in the throttle body in modest amounts and see if it runs better. If it does, then you just have to find out if or why there's lack of fuel (injector, ecm, etc.) or unmetered air entry (intake sealing issues, vacuum leaks, etc.)
Good luck
Michael

Quote from: sfmichael on June 09, 2010, 04:27:57 PM
A more pronounced condition when cold would lead me to think the engine is lean. Warm engines atomize fuel more effectively and thus require less of it.
Did you do the carb spray test yet?
Other electrical issues would not usually be temperature sensitive.
You could even add fuel (carb spray) right in the throttle body in modest amounts and see if it runs better. If it does, then you just have to find out if or why there's lack of fuel (injector, ecm, etc.) or unmetered air entry (intake sealing issues, vacuum leaks, etc.)
Good luck
Michael

It's and FI bike so it would have to be either intake seal or injector, I picked up a can of carb cleaner this afternoon I'll check the intake in the morning before work, if that's not it the next step will be an injector change.

A cleaner way to check for a intake leak is to use a plumbers propane torch. Turn the gas on but don't light the torch. It will do the same thing as carb cleaner less the mess.

Quote from: Showdog75 on June 09, 2010, 06:15:13 PM
A cleaner way to check for a intake leak is to use a plumbers propane torch. Turn the gas on but don't light the torch. It will do the same thing as carb cleaner less the mess.

I did that once with no leak detected, but I'm running out of options for what it can be so I figured a re-check can't hurt.

does this bike have a power commander on it? also i have seen many times that an intake leak doesnt show with the spray test and really is the source of the problem. it may not hurt for the price just to pick up a set and put them in

Quote from: hdtech76 on June 09, 2010, 08:06:31 PM
does this bike have a power commander on it? also i have seen many times that an intake leak doesnt show with the spray test and really is the source of the problem. it may not hurt for the price just to pick up a set and put them in

I'm thinking I might order another set from HPI, unfortunately the 1.8 intake ports make it a not off the shelf item as far as I know. I should probably get the injectors from him at the same time, I was gonna call Eric there and ask him his take on the issue anyway. I've always questioned my original choice in injector size and supplier, the 6.25 g.p.s. Morrel's that i chose have always been a question in my mind of did I go to big. They idle at below 4% duty cycle which I've been told can burn them out the same as prolonged operation above 80%, not to mention they are a single port injector instead of an 8 or 25 degree like stock or HPI have.   

i did not read the whole thread but i remember correctly you are running the t-max. that is where i would look first. if you are running the tmax there are guys with big inch motors who ran the tmax who have had similar problems and went back to stock ecm and tts. witha proper dyno their bikes run perfect now way better then the tmax.
something with the cam over lap and the tmax at low rpm could not compensate correctly.

Also, when checking for intake leaks, check the engine both hot and cold. I checked one when it was cold and had no leaks, but as the engine warmed, it opened up.

When I had my shovel, I had a weird electrical problem in the rain: it would cut off. Then it got to the point where it would do it on cool, humid days. I finally got frustrated enough to do something extreme.

I started the bike in the driveway one evening. Let it idle and start getting warm. Then out came the hose. I started at the bottom and worked my way up. When I sprayed the cylinders, it steamed up my glasses pretty good, but didn't cut out. When I got to the dash, where the ignition switch and indicator lights were, it stalled out. Also, I noticed the neutral light wasn't lit.

When I pulled the dash off, there was a rigged bulb socket for the neutral light. I went to the local indy and spent $5 for a replacement socket, problem solved.

So before you set the bike on fire, take it outside, start it up, get the garden hose, and start at the bottom and work your way up. It's best  to do this at night, so you can see any arcing taking place.

Yep that is the way I located a miss on a friends Ultra
shops couldn't duplicate it on the road or dyno..

When he told me it got bad with rain, then I rode it home
got the ol garden hose out and worked my way up, when it hit
the front plug wire it arc'd over to the cyl from the wire.

There was a hairline cut in the front plug wire, right where
the chrome cover was over the plug, it had cut its way through
over time.

Had chrome plug covers on my Heritage at one time, the ones
that slip over the plug base, they have a rubber insert, dang
rubber cracked on the rear one, and every once in a while I'd get
a miss, then it got worse, finally found it would go away after pulling the
plugs and seating the chrome covers, looked closer and found the cracked
rubber insulator in the cover...

Tossed them out better than the miss.

Anyway, point is it could be something not related
to the ecm or injectors.. 

I am leaning towards the other stuff only because it first manifested after a rain ride and wash, the bike has not seen a drop of water in almost 1 month and the miss is still there, after a talk with HPI on the phone they seem to think it is the rear injector, I think that I may throw the stockers back in to test the theory......if i can figure out where I "stored" them.....lol

Quote from: Quick_2s on June 08, 2010, 03:13:27 PM
Picked up a known good coil, switched it with mine, still same miss.

To recapp;
Changed plugs
Changed wires
Changed O2 sensors (runs much stronger but with same miss)
Changed TPS
Cleaned IAC valve
Changed coil
Went over entire wiring harness and all connectors, unplugged, blew out, and dielectric greased all connectors.

Thinking my next step is a bad injector or something inside the charging system.

Any more suggestions??

And now switched out injectors, and a new map per Zippers selection map #499 with a 15% global fuel increase. I'm gonna give it a day or so to make its adjustments and see what happens.

AAAAAGGGGGGHHHHHHHH!!!!!!! Same identical miss still there after 50 miles of curvy back roads to let the auto-tune do it's thing, I guess next on the list is to order new manifold gaskets. I think I'm gonna open up the charging system tomorrow and take a look around since I have been putting off a weeping main seal replacement and tranny sprocket change anyway. It's the last part of the electrical system I haven't handled since this all began. This is really starting to get annoying. 

i have seem lots of problems with the zippers and or maps.. i will have to do somedigging but i seem to remember a very similar problem somewhere i delt with

When I come across issues like this, I put the scoot in the garage and turn the garage lights off w/door down (a really dark place). If the lights on the bike come on when the ignition is turned on, I have a hat that I put over the head light and cover the tail light with a townell. I start it up and use the squirt bottle routine (with rubber gloves) and see if I can see spark arc.
As a side note after doing this on my kid's honda 900 we saw (what you saw) arc from plug wire to hex part of spark plug. We had new plug wire ends and new plugs. The only thing we had not tries (yet) was new plug wires.

I think I may have found the issue, after the injector swap and remap I took it out for a short 6 mile out and back run to check for the miss... it was still there BUT on the return trip I hit the rev limiter in 3rd and blew out all the gauges and the headlight fuses, which has happened before anytime I tach over 7k it usually costs me a headlight bulb at the least. I came home replaced the fuses and realized the headlight fuse that had blown was not connected to the headlight anymore. When I switched to dual lights I routed them on their own fuse block and had stuck a spare 75 amp fuse in the stock headlight location for whatever reason I cant remember. But anyway it was blown along with the instrument power and lights. The long and the short of it was it made me wonder enough to pull the fuse block up and out and I found a lot of corrosion and dried soap on the bottom as well as the pins on the system and starter relay. Pulled them all including fused, sprayed WD-40 down in all the connectors and wallah miss has disappeared. I think this is a classic example of me over-thinking the problem but I have all new sensors plugs wires and a lot of connector maintenance done to show for it......lol

Glad you found it. Often it's all about persistence, and a little guidance doesn't hurt either. Good job.