Had today second ride after long winter and noticed some problems. My bike (1100GS '99) has noticeable empty spot near 2500 rpm. At least I did not notice suck empty spot last year.

During last month I have done lot of necessary service operations: new spark plugs, I did valves, new oil and all possible filters (air, oil and petrol), synced injection, checked and adjusted all cables.

Only thing what has changed from last year is that I have also installed Remus sump without catalysator.

After three weeks I plan to go for two week tour from Estonia to Germany-Chroatia and back to Estonia.

Any ideas what to do with this empty spot? :-(

Tarmo,

seems to be a typical after market exhaust issue(?) Unless some corroded ignition coil/sparkplug cables or any contacts don't achieve resonance with the engine vibration @2500rpm, which is unlikely.

Have you already done Motronic reset? Before doing that I'd also check the fault code report for any sign of a bad lambda sensor connection. Are you using OEM air filter or any after market (K&N)?


I experimented with a hand made racing exhaust some time back on my 1100 and it then had multiple dead spots over the rpm range, mostly on low and mid revs, and as with any racing exhaust - most of the power was shifted to the high revs. But the main spot was somewhere around 3000rpms, the exhaust was w/o Lambda(O2) sensor, so I thought this could be the cause, since the injection's open->closed loop mapping transition should be around 3000rpms. The bike was almost unrideable since on communiting I mostly use 2000-4000rpms that was the worst with the exhaust. K&N filter "smoothed" some of these spots but it apparently shifted the power even more higher RPMs, so it was a dead end. I put the OEM exhaust back.

Now I bough Leo Vince after market exhaust, with Lambda sensor and the engine seems to work as should all over the RPM range. I'm using OEM paper air filter currently. What I like about it is that it has preserved the low-rpm power, that most of sports/racing exhaust don't do, a feature which I really like about this exhaust. I only did a 300kms ride with it just few days ago, so maybe too early to tell about the details. What I'm certain is that there isn't any that dramatic dead spots as the hand-made racing exhaust had, I'd notice those instantly.

Keep us updated on your case!

Margus

Try removing the cat code plug in the fuse box. It's the square one about 2.5cm square often beige colour in front of the fuses normally in the middle of the fuse box- just take it out (with the ignition off) and try riding without it for a while . The motronic will adjust the fueling and the bike will run smoother and a bit richer but not so that you'd notice any problems with fuel comsumption.
If you haven't done a motronic reset that would be worth doing too as Margus says. In case you don't know how :
Ignition off, pull fuse #5, wait 30 seconds and reinsert fuse. Turn ignition on, fully open and close throttle a few times. Start bike, make a test run. This tells the motronic where the folly open and closed positions are on the throttle bodies. It may help and if it doesn't no harm done but worth a try.
For some visual images to help you along look here: fusebox diagram - ::. UKGS'er.com .::

Cheers
Gecko

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Thank you. I will do some experimenting as you suggested.

BTW my bike does not have lambda sensor. It never had it. And I use OEM air filter.

I let you know about the results. I believe that I do not have to uninstall my Remus as I like the sound. I believe in fairy-tales with happy endings. :-)

Mine doens't have the sensor either and I run a remus Grand Prix exhaust system without the cat code plug - smooth sweet and sounds great too

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Took CCP out. Did Motronic restart. Testride was perfect.
Installed CCP back. Did Motronic restart. Lot of backfireing and empty spot was back.
Took CCP out. Did Motronic restart. Grosse Silver runs again perfectly.
Installed CCP permanently on garage shelf.
Thank you for your help. Life is again perfect. :-)

Excellent - I love a story with a happy ending

Maybe just check your spark plugs after you have ridden for a while. The bike may be running richer without the CCP but the motronic reset should have smoothed that out . Mine were OK - slightly darker than before but certainly no problems and fuel comsumption seemed the same to me .
I'm up in Estonia in August so you can buy me a

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Let me know when you are coming to Estonia.
I know that I owe you not only one .