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2004 Twin Spark Stumbling (Low RPM)


Tominator

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Posted

Has anyone experienced this? Been doing it for a while. Runs great over 2000RPM but when slowing down and at idle every once and a while bike stumbles...Pressure regulator? On my second fuel pump and it’s still the same? HAL sensor? Almost as if its going to die…not safe in stop and go traffic for sure 

 

Tomas

 

ArthurKnowles
Posted

My R1100Rt did this after a complete tune up and TB sync. I changed form the stock BMW (Bosch) plugs to autolight 3923s and gapped them to .035 and the problem went away.

Posted

My bike has started exhibiting this same behavior after I did the 48k service which INCLUDED my first use of AP3923's. It's very prominent from either a cold start, or a hot restart. Double checked everything, but still no joy.

 

Has enyone else had stumbling issues AFTER the install of AP3923's?

Posted

How interesting. My 2004 RT is doing a very similar thing. It's due for it's next 6K service soon, so I've been babying it a bit until it goes into the shop (and riding the Buell more often). I find on my bike it's very sporatic, sometimes it does it, other times it seems to work like a charm. I can't figure out what's going on.

 

Wayne

Urban Surfer
Posted

I have had the same problem with my RT for about 20,000 kilometers.

The bike has been maintained at the dealer.

The last time I took it in the experienced mechanic discovered the problem, a week left ignition coil.

They didn't have one in stock so I did the John day trip as is.

( What a hoot ripping through those twistys riding solo)

The further evidence of a coil problem showed up under heavy load at full throttle. There was pinging in the left cylinder.

They want $ 260 for a new coil! Gotta have it.

Posted

I had the same (or very similar) thing: occasional miss on idle, occasional hard to start, sometimes very rough running when cold, not smooth at lower rpm.

I replaced both stick coils. It now runs like a dream.

 

It's better that you find someone who will allow you to borrow a stick coil for a test. It's a bit too expensive as a trial and error exercise.

Posted

Wow...overwelming response. Sort of what I expected...coil. What is weird is once your cruising no issues runs like a dream.

 

BTW I have 120,000KM on my RT...

 

Tomas

Posted

Mines a twin spark BTW....whichg coil did you replace Keith?

Posted
Mines a twin spark BTW....whichg coil did you replace Keith?
On the twin spark '04 RT, only the upper plugs are coil (stick) on plug. The lowers use/share the original design single conventional coil.
Posted

I know that...just thought I would ask which one Keith replaced...thanks for the reply!

 

Thanks

Tomas

Posted

My bike started running badly last month. One day it was fine. The next day it wasn't. I was commuting daily, so the difference was immediately noticeable--idling rougher, (the dreaded!) surging between 3-5K, and less power starting-off (having to slip the clutch more).

 

I took it in for 12K service early and thought that would cure it (replace fuel filter, resynchronize TB's). But it didn't. Took the bike back in and they told me BOTH coils (sticks) on the upper plug were bad. If they removed the lower plugs, it wouldn't run. Amazing what the bike will do without two out of four plugs working!

 

-Dallas

'04 R1150RT

ProductUser
Posted

I replaced both primary coil sticks and the secondary plug wires after 60k miles; there was some noticble hesitation, too. After doing the primary coil swap, one of the coils was found to be bad. The primary coil packs are in a place where it gets very, very hot.

 

The plug wires, although they didn't show any signs of cracking, were very brittle.

 

After changing the above metioned items, the bike runs much smoother and gas mileage improved somewhat.

 

Tony

Pat St. Jean
Posted
I replaced both primary coil sticks and the secondary plug wires after 60k miles; there was some noticble hesitation, too. After doing the primary coil swap, one of the coils was found to be bad. The primary coil packs are in a place where it gets very, very hot.

 

Hey Tony,

I'm seeing something similar here, and was wondering what you did to confirm the bad coil. Is there something I can do with a meter to see if a coil's potentially dodgy?

 

Pat

ProductUser
Posted
I replaced both primary coil sticks and the secondary plug wires after 60k miles; there was some noticble hesitation, too. After doing the primary coil swap, one of the coils was found to be bad. The primary coil packs are in a place where it gets very, very hot.

 

Hey Tony,

I'm seeing something similar here, and was wondering what you did to confirm the bad coil. Is there something I can do with a meter to see if a coil's potentially dodgy?

 

Pat

 

You can ohm them (I forget the resistance at the moment), but that will not tell you if it will fail when hot, which is where I noticed some issues.

 

After several months, I finally started to notice that one side was running rough. After checking the obvious, I switched the primary coils and the problem migrated to the other side. That was enough evidence for me to replace the stick coil.

 

This process took several weeks once I noticed one side acting up; I wanted to rule out: valve adjustment and throttle body sync; air leaks around the TB...etc. I also performed a compression test to rule out and internal issues; I stopped short of doing a leak-down test, however :grin:

 

You can also check the seconday wires for cracks. I replaced those as a precautionary measure.

 

Good luck.

Tony

 

 

Pat St. Jean
Posted

You can ohm them (I forget the resistance at the moment), but that will not tell you if it will fail when hot, which is where I noticed some issues.

 

After several months, I finally started to notice that one side was running rough. After checking the obvious, I switched the primary coils and the problem migrated to the other side. That was enough evidence for me to replace the stick coil.

 

This process took several weeks once I noticed one side acting up; I wanted to rule out: valve adjustment and throttle body sync; air leaks around the TB...etc. I also performed a compression test to rule out and internal issues; I stopped short of doing a leak-down test, however :grin:

 

You can also check the seconday wires for cracks. I replaced those as a precautionary measure.

 

Thanks Tony,

 

I went over to the local dealer and picked up a coil last night. I replaced the left cylinder's coil and the problem was still there, so then replaced the right and it seemed to smooth out. I then took the old right one and put it in the left cylinder. The problem was back so it's in the trash now.

 

This morning was the first time in a couple weeks that it's started the way it "should" and the flat spots under acceleration are gone. The last test will be to see if my mileage goes back up, the last tank was down to 37 mpg. I suspect it will... :)

 

Thanks for the info!

 

Pat

Posted

Can a dealer check the coil sticks if you bring them in (without the bike)?

Posted

Thanks...I will order one stick and give it a try. On my RT Im sure its ignition related....and I think you guys are on the right track!

 

Thanks for everyones input!

 

Tomas

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