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Discussion Starter · #1 ·
Been doing some servicing & mods on my 2017 R9T Racer over the winter.

The servicing work is irrelevant as it was nothing to do with the problem.

The mods included, full SS Zard exhaust system, an MWR performance filter (road), flapper valve elimination & a Rapid Bike Evo fuelling module. Last year I was having problems and faults due to a RapidBike Easy on the bike, that I didn't know about until later, being wrongly set and a duff knock sensor into the bargain.

When I went to start the bike the other day it would not run on the RHS cylinder, easy to tell, the bike wouldn't idle on its own and after a few minutes the LH pipe was hot the RH virtually cold. The RH would chime in roughly & intermittently when applying larger throttle openings and higher revs. No fault codes thrown up, tried a few times still the same.

The only thing of note was I was using gas from last year

Removed the plugs, which were slightly wet and black, although I've seen a lot worse, also smell of fuel so it was getting gas. Heated the plugs with a gas torch to burn off any carbon and then cleaned the residual up with some emery cloth. Checked all the coils were properly seated, connectors secure and also tested for a spark on the plugs, all was good.

Tried again no change, still no joy on the RH cylinder

Then I went through all the connectors involved with the EVO to ensure nothing was loose or wrong there, all good.

Checked with the GS911 and it confirmed that the RH cylinder was not pulling its weight, the RH Lambda was zero mV almost the whole time the LH around 350-380mV. Put the Rapid Bike software on and tested, checked the maps, all seemed fine and the EVO software was seeing all the parameters, but the RH cylinder steadfastly refused to co-operate

I went to the local petrol station and bought 5 litres of new gas, put that in, after draining off most, but not all of the old gas I'd been using.

Also wondered about how these bikes control air to the cylinders, I still don't know how it works and would love somebody to chime in or give me a link to the ins and outs of it. I'm thinking it must have a butterfly on the TBs but how it's driven I've no clue.............stepper motor?

Prior to starting I reset the TPS by cycling the throttle 3 times with the ignition on then closing and swtiching the igntion off.

With no real hope I tried again and BINGO!! fired right up on both cylinders and idling like a champ.

It could have been the fuel but I very much doubt it as it fired immediately, any bad gas in the fuel system was still in there. I'm 99% certain this was due to the TPS reset, again some info on it would be useful, is it a single sensor or one on each TB?

I've come across bad TPS calibration causing rough running but never heard of it dropping out a cylinder..............perhaps that's a BMW quirk. :unsure:

Just thought I'd post the problem what I did and ultimately what cured it. :)
 

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Nice one mate, this particular fault hasn't been documented so this is great information. :)
 
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Great to hear your running again, I perform a TPS reset periodically especially with a change of season. Riding habits change and the cpu doesn't know that.
It would be good to know the preferred hand shake BMW expect, as there are a couple of methods.
 

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Discussion Starter · #4 ·
@Fez are there other ways of recalibrating the TPS? I'm sure the GS would be able to, but don't know of the other methods apart from that I've already mentioned.

The problem may well have been self inflicted as adding the toys and playing with them could have resulted in me doing something stupid.

I never knew about the throtte cycling reset until yesterday, so it could well have been "Fat Fingers."

Doing an ocassional reset is a very easy thing to do and it's a good idea as you suggest.

As an aside the Guzzis are a PIA in this respect, involving a multimeter and an overly sensitive TPS.

A weather window has appeared in Jockland, so going to stretch her legs tomorrow and give the EVO a chance to do its thing.

On another note the full Zard which most seem to find "Not too bad", sounds a little lairy to me (baffle in).

It's nowhere near Harley "straight through" loud (which I find excruciating) but will require some finesse on the throttle in built up areas
 

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Yes as you have mentioned there is the 3 rotation method.
I have found with ignition on to take 10 seconds to make a full throttle rotation - hold for 3 then return to stop taking 10 seconds - switch ignition off and leave for 3 minutes.(The 10 seconds doesn't need to be exact and the 3 minutes is a hand shake process for the ECU so it recognizes the new input) Bosch TPS used this process in the past and also works for cars.
Has solved a few head aches without needing cash.
There is another process which I have long forgot for when replacing a throttle body or calibrating the butterfly.
 

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I'm confident the TPS, which is mounted on the l/h throttle body would not be the cause of one cylinder not running. Mr Weegie you ask "how these bikes control air to the cylinders?" Air goes through the throttle bodies regulated by a butterfly valve in each TB which is pulled by a cable to each pulley connected to each butterfly, those two cables run into the "splitter box" where they join to one cable that runs up to the throttle which is where you input comes in. With the info you have given us I would be confident that one of your cables was "hung up" ie not fully returned to idle stop. was hung up somewhat, doesn't take much to stop one cylinder from firing, I don't know how clean your cable end is in the pulley, any manner of grit can play havoc with it. After every wash and dry of the bike I spray silicone lube behind the throttle body in the hope that some gets into the cable end seated in the the pulley lever. Another thing that can easily hang up a throttle cable is the silly little plastic cover you can see inboard of the TB, they easily become loose and can hinder the pulley return, this happened to my R9T only a week ago, admittedly after I had the throttle bodies off for a preventative mod I did to the butterfly pulleys, on start only one cylinder was firing normally so suspected fouling of a cable and sure enough I had not seated the plastic dust cover properly and it got in the way, took all of 2 minutes to figure. The mod I mention is simply gluing a washer with JB Weld epoxy to the throttle pulley, why? because the pulleys are prone to cracking and falling apart, absolute show stopper and you cant fix it on the side of the road. R9T riders don't chalk up the milage that GS Adv riders tend to, and loads of the these pulleys on hex head and cam head motors have failed. Hopefully two pics have uploaded successfully, one a before the mod, the other after the strengthening washer has been bonded on. You can also see the plastic dust cover dangling around, that not being seated on assembly correctly was the culprit on my R9T. Hope this has been of some use to you.:cool:
 

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