Surging while accelerating in high speed range

[duegi]

2004 R1150R 36K miles, twin spark or 4 plug motor;
I'm feeling some surging under hard acceleration in the higher speed ranges while in the upper revs. Any input on this would be appreciated.

Valves were adjusted a couple of weeks ago which should have little effect. Leaning towards need new spark plugs at this point. I'm not too worried about the stick coils as coils tend to be either good or bad. Maybe a sync of the TB's although I'm not familiar enough with the oilhead motor to know the effect at higher revs. Beyond that I was also wondering about the mapping for the computer.

Nothing wrong with the clutch on through the drive train as I don't see the tach surging with the motor nor hear it revving.

[iowabeakster]

Brett,

Have you replaced the fuel filter yet... or do you know when it was last replaced?

I second your idea to replace spark plugs. A TB sync is never a bad idea...but that would affect lower RPM's more... and the complaint is usually "vibes".

Over the last couple years, I have read so many threads about the coils. There is large range of descriptions of symptoms from people who've had coils go bad. There have been: people who only notice a stumbling idle, or people who only notice a flat spot under heavy acceleration, to people that don't notice anything but a decrease in mileage.

One particular thread was from Taosports (doesn't post very much anymore). He observed problems at certain RPM's and then it got worse over an extended period until all RPM's were symptomatic.

I wouldn't consider the coil failure to be an "all or nothing" failure process, in every case. The coils really could be the problem... but plugs are much cheaper to start with.

If you want to meet up... we could sync the TB's... that'll take a couple minutes... then, we could swap coils and drag race!!!

[taosports]

One particular thread was from Taosports (doesn't post very much anymore). He observed problems at certain RPM's and then it got worse over an extended period until all RPM's were symptomatic.

I wouldn't consider the coil failure to an "all or nothing" failure process, in every case. The coils really could be the problem... but plugs are much cheaper to start with.

If you want to meet up... we could sync the TB's... that'll take a couple minutes... then, we could swap coils and drag race!!!

I'm still around and you are right, I'd definitely check the coils. Btw, I just celebrated 75,000 miles on my 04 without any problems other than the coils and a wire shorting out due to the over-tightened plastic tie wraps. Hoping to squeeze out 25,000 more then it's bike shopping time!

[iowabeakster]

Hey Michael...

Nice job on the puppy videos...

[taosports]

Thanks for checking them out. I do some volunteer work 3 days a week at the local SPCA and saw a need for these videos so I started producing them for free for any local dog rescue organization. It gives me a creative outlet and helps showcase the long term shelter dogs and the volunteers who work with them.

(my apologies for this brief hijack)

[boxermania]

TB's out of sync will not lead to the symptoms being experienced. I go with weak stick coil(s), plugs have never been much of an issue unless they have been exposed to extremely rich mixtures.

[duegi]

Rats, stick coils, I was hoping someone had another Idea or thought that hadn't crossed my mind yet. Have to wait till Spring as I already shot my motorcycle funds for this year on a set of Ohlin's.

[eduardobelmonte]

I've had a bad stick coil and run with it up until it died.
While in the process, placing new spark plugs help the faulty stick coil effect not to be perceived so strongly... so then you believe the spark-plugs were the cause.
Then after, when the spark plugs loose part of their brand new capability, the problem restarts again.
You change spark-plugs again, and again the process loops until the coil finally dies.
I can tell in my case the stick coil had a gradual failure that ranged for something like 1k miles ( I guess). Had to change it at 49k and I have a bike identical to yours.

The best way to check the stick coil is to use a tool that shows a light when spark is available and vice-versa. I bought one at Harbor Freight for like 10$, it's name is "In-Line Spark Checker For Recessed Plugs". (Item # is 97577) It's perfect for the recessed spark-plugs we have on the RRs. It has a long connector that gets to the spark-plug. Be aware though that it has some small fins that you need to cut away in order for it to be introduced into the RRs cylinder head.

The amount of light you see is a measurement of how good the spark is.
If both stick coils generate equal amount of clear light at different rpms, then they are good
and vice versa.

Best wishes my friend.

Eduardo

[Biff's R]

I had similar symptoms about a year or year and a half ago. Replaced the stick coil and all was well. One other thing you can do is disconnect the secondary plug wire. A bad coil will stall the bike.

[duegi]

Thanks for the input folks, looks like a set of stick coils will be added to the Spring tune up shopping list. Let's see: tires, spark plugs, oil/lubricating type fluids, alternator belt, and stick coils. Am I missing anything?

[WVRockster]

I would definitely try new plugs before coils. I just replaced my plugs last night experiencing the same problems. I didn't realize what I had been missing. It was surging under high speed load and wasn't doing it every time. Anyway I replaced the plugs. I didn't realize the throttle response I had lost either. Much more snappy.

[Rider Rick]

IT seems spark plugs get eaten up on these bikes almost more than any other vehicle I've experienced. I haven't changed mine yet, was thinking 9800 miles, how could plugs cause any real problems. But...apparently they are very susceptible to the slightest deviation from the narrow operating conditions called for. Are these sticks so delicate just checking or removing to replace plugs can reduce their lifespan? I'm almost afraid to touch them, lol.

By the way, WVRockster, what specific plug did you use for the secondaries? I know what most people like as primary, but the secondary list ist still at about 3-4 different ngk brands, thanks. Has there been any research on getting rid of these sticks and running wires from a central coil device?

[macx]

I'd definitely replace the plugs, even if they look good.

When I got my 04, it had 25k miles, and I had no idea of previous servicing.

It ran good for maybe 5k miles - of course with nothing to compare it to -
then I noticed surging and hesitation under heavy throttle - starting out just
noticeable but getting progressively worse.

By that time I had learned how to set the valves and synchro the TB's and set
the tps. I did all that to no avail even tho the valves and rockers needed some
adjustment. I looked at the plugs and they looked to be in very good condition.
However, with the other things known to be good, I installed new plugs and the
problem absolutely disappeared. In fact it ran better than it had since I bought it,
probly due in part to the very careful tuneup I had performed before I swapped plugs.

I ran across a (hopefully) good low miles stick coil so snapped it up, but am
prepared for eventual stick coil failure.

I've pondered the possibility of removing those and substituting a conventional
coil and plug wires similar to the setup for the lower plugs - the wiring diagrams
show that voltage is fed directly to both the stick and the conventional lower
coil, and the motronic just triggers them both via simple grounding. Soooo -
I wonder if that might not work as a permanent and inexpensive "fix" for the
expensive stick coil failures. Just about tempted to try it if my stick coil(s) go bad.
I've even purchased a good used setup off of a single spark bike at less than 1/2
of the cost of 1 new stick coil. Hmmmm. I just hate to take any risk of burning up
that godawful expensive motronic unit!

[marius basson]

I own a 2005 R1150R Twin spark and have the exact problem. The bike had it's 40000km service where all plugs and filters where changed. It was fine for aprox 300km and started again. The plug in computer showed no faults. The spark plug leads for the bottom plugs where rerouted and the coils where cleaned. It made the bike go better was did not solve the problem.

[marius basson]

Me again!I Found the problem. I changed the L/H side coil and the problem was solved.

[NoRRmad]

YAY! Good to know.

[eduardobelmonte]

Other thing that has proven to make a difference was that I let go the Champion spark-plugs I was using as secondaries, now I'm using NGKs DCPR6E.... yes exactly that one. I concluded them to be the best match for heat range.

I've been using them now for 1k miles on all kind of rides and they are much better than the Champions. Acceleration deceleration in any rpm is much smother, no empty gaps or roughness. They do make a difference, have no doubt.

[towerworker]

Glad I didn't suggest the antifreeze.

[riceburner]

To be frank - I'd always trust the plugs before the coils. Plugs have been around for the live of the petrol engine - they're a much more reliable and "known" quantity than the poxy stick coils.

I also strongly believe that the stick coils on our bikes (and the 1200s) are NOT designed for the range of temperatures and humid conditions found on an air-cooled motorcycle engine. They're designed to be hidden under a bonnet, a plastic cover, another plastic cover and a rubber sheet, and maintained by water-cooling at a reasonably steady temperature.

I've had plugs that were rusty as f**k but still working fine, and stick coils that appeared almost untouched but were utterly dead.