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-   -   Weird Sputtering/Grinding at 80+mph -'00 1150GS (http://www.advrider.com/forums/showthread.php?t=832287)

jdgmntDay 10-06-2012 11:29 PM

Weird Sputtering/Grinding at 80+mph -'00 1150GS
 
The longer I have this bike the more things I find wrong with it. I don't mind fixing them, but sometimes it gets expensive. The latest one I found yesterday cruising (read: "flying") down the highway. In E-gear (overdrive I think?), going up a slight hill at 80-85 I could hear a weird sound coming from the front half the bike - maybe underneath me. It sounded like a mix between an airplane sputtering about to stall and a metallic grinding. I didn't feel a lack of power during this. Confused I let off the throttle and the noise went away. I pulled harder on the throttle and it came back louder til I heard some sort of pop and I could have sworn I felt something fly past my left foot. The pop sounded like a cough and had a bump of power loss, and looking back I didn't see anything fly off the bike. Startled, I let off the throttle immediately. The bike continued to ride fine. Nervous, I didn't test it anymore. Today I was going down the same road and wanted to see if I could get it to do it again. And I got the same results, though I didn't pull hard enough to get the pop-cough. I got the sputtering/grinding and I stopped before it got worse.

My first thought was some sort of engine trouble, but now I'm thinking it's the transmission, since I've never heard it in any other gear and only does it under heavy load (80+mph). I also think maybe the thing flying past my foot with the gear shifter twitching with the transmission spazzing out. Has anyone else had similar problems or know what could cause something like this? What is likely wrong, and is my bike going to detonate anytime soon?

Ben

Zoef zoef 10-07-2012 01:41 AM

Sir,

It sounds like your engine is knocking/pinging. Depending on the hill, next time you might want to try it in 5th gear, see what happens then.

jdgmntDay 04-09-2013 05:42 PM

Revivng an old thread from the graveyard here, but I haven't for sure nailed down my problem and how to fix it yet.

It's not just 6th (Eth) drive, it's any gear in which I ride with high RPM and high load. I have tried switching the ignition cables to the spark plugs - one looked a little cracked or worn and had a touch higher resistance. My thinking was if one wire had just a bit too much resistance that the spark would not reliably ignite the cylinder, then switching the cables should move my problem. That did not fix it.

I tried switching fuel injectors from one side to the other, thinking one might be plugged or spray differently or something wrong with them. Did not move the problem.

I pulled the ignition coil out and measured the resistance across the primary and it was normal at .5 Ohms. The secondary resistance however is a bit perplexing - my measured resistance with a Fluke meter at the coil (not the end of the wires) was 7600 Ohms. My Clymer manual says the secondary resistance on my single spark bike should be 1300 Ohms. That makes it sound defective, however, further down the chart it says the secondary resistance for "secondary spark plugs with traditional ignition coil" is 7500 Ohms. Now I'm thinking this is somehow the wrong ignition coil for my '00 single spark bike. It also says in the book if I pull the spark plug out, ground it to the cylinder head and watch it as I turn the bike over while doing a compression check, I should see a fat blue spark shoot off the plug. I barely see anything, let alone a fat blue spark. This might also be causing the minute surging problem my bike also has.

So I pulled the part number off the ignition coil and looked up the part number on the MAX BMW microfiche of what's supposed to be on my bike, and they're the same. So where is this miracle 1300 Ohm coil coming from, where can I get one, and do you think it would solve my problem?

I've also talked to a dealer about this, but his knee jerk reaction was to pull the heads off and clean out the compression chamber. That sounds like big dollars to pay him to do (I don't have a garage to work on this, and as soon as I pulled the heads off, inevitably a rainstorm and dust storm would break the laws of nature and happen at the same time), and it seems like overkill. I want to try everything I can for free first. Modifying this, switching that, etc so I can really narrow down my problem before having a dealer fix it.

I saw a good deal on EuroMotoElectrics for ignition coil and cables, so I could just buy them and swap them out whether they need it or not, but I could think of better ways to blow close to $150 if it turns out to not help.

mouthfulloflake 04-09-2013 06:08 PM

That sounds like pre-detonation-pinging to me, what octane fuel are you running?

the surging thing is a historically known and celebrated feature of this lineage of bikes.

GS Addict 04-09-2013 06:16 PM

Quote:

Originally Posted by mouthfulloflake (Post 21148875)
that sounds like pre-detonation-pinging to me, what octane fuel are you running?

The surging thing is a historically known and celebrated feature of this lineage of bikes.

+1

Callisto224 04-09-2013 06:20 PM

Like a previous post asked, what octane are you running?

Also, how many miles are on your 2000 1150?

When was the last time you changed the plugs?

If it only happens under heavy load it's probably pinging.

def 04-09-2013 06:41 PM

Secondary coil resistance is ~7.5K ohms cold.

Also, many oilhead boxer owners use Autolite 3923 plugs (the plain ones...no iridium, platinum or gold plated versions...the $2.00 each version...mine are 10 years old and still work like new) and report improved performance.

Perform a compression check to determine if you have excessive carbon. Don't remove the heads just yet until you know the cause of your problem.

Finally, you might try running the valve lash a bit loose, say a couple thousandths of an inch at each valve. This will decrease effective compression and may solve the problem.

BluByU 04-09-2013 07:17 PM

Quote:

Originally Posted by def (Post 21149182)
Secondary coil resistance is ~7.5K ohms cold.


Perform a compression check to determine if you have excessive carbon. Don't remove the heads just yet until you know the cause of your problem.

OK, What is the proper range of a compression check?? I did my 04 R1150GSA last week after valve adj and came up with 240psi in both cylinders (seemed rather high to me but both cylinder were the same) and after reading this thread I have to ask what is the factory spec?

mouthfulloflake 04-09-2013 07:31 PM

that seems high, but I am unsure of the actual spec.

its pretty common for the gauges to read incorrectly, its really only important that they match cylinder to cylinder, the actual number is pretty meaningless to me if the bike runs, and doesnt smoke blue.

maybe this helps.

http://bmwsporttouring.com/ubbthread...&Number=826697

GS Addict 04-09-2013 07:34 PM

Quote:

Originally Posted by def (Post 21149182)
Secondary coil resistance is ~7.5K ohms cold.

Also, many oilhead boxer owners use Autolite 3923 plugs (the plain ones...no iridium, platinum or gold plated versions...the $2.00 each version...mine are 10 years old and still work like new) and report improved performance.

Perform a compression check to determine if you have excessive carbon. Don't remove the heads just yet until you know the cause of your problem.

Finally, you might try running the valve lash a bit loose, say a couple thousandths of an inch at each valve. This will decrease effective compression and may solve the problem.

Autolite 3922 are used on the 1150 engines, the 3923 is for the 1100's

vintagerider 04-10-2013 12:08 AM

metallic grinding
Pre-ignition or pinging is a distinctive clatter. May have u joint/drive shaft issue. If that is the case then repair before it fails. btw 160 is normal compression

roger 04 rt 04-10-2013 04:32 AM

There is a real possibility that your in-tank hoses are cracked and leaking, your fuel filter is clogged or your fuel pump is weak. The noise you describe sounds like pre-ignition. Also your engine may be misfiring which will overheat your cat.

At idle, try measuring the return flow of fuel to the tank. If you get about 2 liters per minute your in tank stuff is okay. Or you can open the tank and inspect.

Jim Moore 04-10-2013 04:45 AM

Your coil is fine. The 13K spec was a misprint in the original manual that no one has ever bothered to fix.

Pinging sounds like you are shaking a bunch of BBs in a coffee can. If it's bad enough you will also feel a slight stumble or power reduction. Your model is susceptible to pinging in hot weather at 4000-6000 rpm at full throttle, especially at high elevation.

People have tried all sorts of things to rid the bike of pinging. I finally cured mine by installing a set of RT intake tubes. You can prbably find a cheap set at bmwsporttouring.com. Lots of RT folks put GS tubes in their RTs, so there are lots of them sitting in garages.

roger 04 rt 04-10-2013 04:57 AM

http://www.streamlineleaders.com/images/fuelfix9.jpg

def 04-10-2013 08:23 AM

Quote:

Originally Posted by GS Addict (Post 21149616)
Autolite 3922 are used on the 1150 engines, the 3923 is for the 1100's

The 3923s are one range hotter than the 3922s. I have used both but now just stick with the 3923s in my 2001 R1150GS.

Plug color is correct and has been for almost a decade with the same 3923s. They cost me $1.00 each back when with a mail-in rebate coupon.


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