Surging or balance issue? Rough ride at 3-4k

[JML]

I've had my 2004 R1150R with 3500 miles for a few weeks now and have done some great canyon rides, but I'm having one problem I'd like some advice on. I mostly notice this in 4th gear at 35-40 MPH (2800-3200 RPM or so). The bike jerks forwards and back a bit, as if I were riding over wavy pavement. If I drop into 3rd (4000 RPM) it sometimes goes away, but not always. Is that what's meant when people talk about surging?

The bike seems happiest under acceleration. If I'm into the throttle I don't notice any of that behavior. The problems seems worst if I get the bike hot, then stop for a few minutes (bike off) and then start again.

At 65 in 6th (3000 RPM) I don't have that problem, but the mirrors vibrate a bit (I can tell there's a car behind me, but maybe I can't tell you what kind of car). I've read posts where people have balanced their throttle bodies and then said their mirrors don't vibrate anymore. Could an inbalance be responsible for my low speed problem?

Should I get a TwinMax and do the balancing stuff? How much of a hassle is it? I'm not useless at mechanical stuff, but I don't particularly enjoy wrenching. I tend to do my own work so I know it's done right, but I find the actually doing of it a nuisance. I can also take the bike to a local shop I'm not sure that I trust. I would be delighted if I gave them money and they gave me back a working bike, but my experience with all shops I've been to is that I give them money, and still have to fix the bike myself...

I changed all of the fluids, so the oil is fresh. This problem occurred with the old oil, too.

Thanks for your help.

[Airman]

It certainly sounds like the dreaded surge. My `03 does it. I do most of my riding at freeway speeds, 4000 rpm. At that rpm I don't get the surge. Doing the valve adjust and balancing the throttle bodies will help but probably not cure it. The only real fix I have heard of, (haven't tried it myself) is the Power Commander. With it you can change the fuel mapping and eliminate the lean mixture that causes the surging. Someone else here will tell us.

[JML]

OK, so that is surging. I didn't want to call it "surging" if it was really "tire out of balance."

I think I'll go talk to the shop and if they say, "Oh yeah, a surging R, we know about that and can fix it." I'll probably let them take a shot at it. If they say their happy to look at it, but don't really know about surging, then I'll pass.

So, if order the Twinmax, do I want the 5mm or 6mm adapter plugs?

[markg]

BMW's do not and have never surged. Ask anyone at the factory....Ok now that you've stopped laughing, the problem described sounds like something other than the usual surging, which is typically in the lower gears at light throttle opening, and 3500 rpm or less. Shouldn't do it at speed in a higher gear unless the valve and/or TB adjustment is WAY out. Look there first.

[boxermania]

JML

One of the most beneficial adjustments to the BMW boxer engine is the syncronization of the TB's (throttle bodies). Due to the opposed cylinder design any side to side difference will affect the operation and vibration level of the engine as there will be a leading and a lagging cylinder.

Save your money on the purchase of the aftermarket balancing tools, such as the TwinMax, CarbTune and others. I'm not putting them down, however, you will get the same or better results by fabricating your own device to the tune of ~$4 and have fun doing it.

I have ienclosed a link to one such device and don't forget to sync the idle speed as well.....good luck.

http://www.powerchutes.com/manometer.asp

[mkmd555]

Boxermania:

2002 / R1150R / 62000mi

I synched the throttle with a home made manometer. The bike runs great. I even applied your 'Test" of taking the bike in 4th gear to 90 mph. The bike leapt like a tiger and ran like a champ. I did not notice any problems.

My question now is:

During the synch process both sides of the fluid level ( manometer) are aligned at 1050 rpm. However, when I open the throttle slowly the right side fluid level on the manometer starts rising.

What does this mean and what is the solution?

Thanks
M Khan

[toolinalong]

Hi JML,

So I'm guessing that was you I passed on the red bike in Boulder Canyon a couple of days ago.

The answers are yes and yes and yes, and no.

I got a deal for you. You can borrow my twinmax. But you have to pay your dues and become a paid member of this bulletin board before I will do that.

Then you need to sell me your Red '04 for $2000. (I have lusted after one of those since I saw my first one in summer of '05.)

Also, I was at M-----'s the other day talking to him about the surging issue. Don't go there just yet ok? I have a solution. check out this thread....

viewtopic.php?f=2&t=15046&start=0&st=0&sk=t&sd=a

[JML]

BMW's do not and have never surged. Ask anyone at the factory....Ok now that you've stopped laughing, the problem described sounds like something other than the usual surging, which is typically in the lower gears at light throttle opening, and 3500 rpm or less. Shouldn't do it at speed in a higher gear unless the valve and/or TB adjustment is WAY out. Look there first.

Actually, "lower gears at light throttle opening, and 3500 rpm or less" is exactly where I experience the problem. I get a bit of vibration in high gear at high speed, but it isn't nearly as annoying as the surging.

In four years the bike had less than 3000 miles put on it. It had the 600 mile service, but probably nothing has been done since then. I'm not sure if the engine can detune just sitting, or if it was never properly balanced in the first place.

[JML]

Hi JML,

So I'm guessing that was you I passed on the red bike in Boulder Canyon a couple of days ago.

Unfortunately that wasn't me. I like the red color, too, but the bike I found was silver, so that is what I have. I'm the silver R1150R with either a top box or system cases, depending on how much junk I have to carry around.

The answers are yes and yes and yes, and no.

I got a deal for you. You can borrow my twinmax. But you have to pay your dues and become a paid member of this bulletin board before I will do that.

Then you need to sell me your Red '04 for $2000. (I have lusted after one of those since I saw my first one in summer of '05.)

Also, I was at M-----'s the other day talking to him about the surging issue. Don't go there just yet ok? I have a solution. check out this thread....

viewtopic.php?f=2&t=15046&start=0&st=0&sk=t&sd=a

Thanks for the offer, I'll probably take you up on it.

I think the way to proceed from here is to get my throttle bodies balanced, and if the surging problem persists (it probably will) to get a Techlusion.

[JML]

Toolinalong kindly loaned me his twinmax and sent me the great Throttle Body Syncing for Dummies file. I went ahead and had the valves adjusted at a shop. After the adjustment the engine is much quieter, and the shop owner said that the valves were a bit loose.

This weekend I attached the twinmax to get the balancing done. I found the left brass screw was 1 turn out, and the right screw was 1.5 turns out. I played with both screws until I got the twinmax to center on 0. I'm not sure of the exact adjustment I ended up with. I might have it with the idle too low, though. When warm, the idle appears to be right at 1100-1200. When cold, even with the fast idle on, the idle is closer to 1000. Is this right, or should I readjust so the idle is a bit higher?

I've seen some instructions that say to put both screws at 2.5 turns out, and then adjust from there. That is a different than the Dummies guide, but it would probably end at a similar place. Is it worth readjusting using this other method?

I adjusted the right throttle cable as best I could, and the twinmax is pretty close to 0 at 2500, 3500, and 4500 RPM. All of the adjustment involved turning the right side adjustment nut counterclockwise. Going up and down through the range, the needle bounces to one side or the other a bit, but at a steady RPM it settles on 0.

Unfortunately none of this did much for the surging. When hot there is surging between 2500-4000 RPM. The engine does pull very strong and smooth from 30-70mph in 4th gear.

I guess if the surging bothers me too much, I'll need to invest in a techlusion.

[CycleRob]

I also cast one big vote for the homemade water manometer:
http://i142.photobucket.com/albums/r87/ ... Manom2.jpg
http://i142.photobucket.com/albums/r87/ ... Manom1.jpg

Before you buy a Power Commander or Teclusion, try removing the Cat Code Plug then reset the Motronic.
http://r1150r.smugmug.com/gallery/44666 ... CmzKb-O-LB

.

[gregor]

Maybe I am just an insensitive soul but I have not ever experienced this surging with my early 2002 single plug. Maybe I instinctively adjust the throtle opening to keep a constant speed- or I am always accelerating. I think the latter....