R1200GS/A Hidden Filter bypass

Stan H said:
Awesome result and write up, your persistence is amazing :bow :thumby:

Just came across a pretty decent end to end vid on how to backflush the hidden filter 'as another option' (lots of useful tips around assembly and disassembly... etc etc). Makes you wonder how many GS's are rolling around without pulling with all their ponies at the top end :blast

Skip ahead to 29:30 to see the start of the hidden filter backflush process.

Click to expand...
Ah yeah watched that, back flushed mines for ages and no joy. Ran clear

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Well done sir , thought you were going to end up sectioned at the end of this thread


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GeorgeM said:
Well done sir , thought you were going to end up sectioned at the end of this thread


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Almost was, it was driving me nuts as absolutely loved the bike but this was really dampening my experience.

But all good and I like it even more now.

DYING for a longer ride to dartmoor or wales or something.
 
Moonmanzn said:
Almost was, it was driving me nuts as absolutely loved the bike but this was really dampening my experience.

But all good and I like it even more now.

DYING for a longer ride to dartmoor or wales or something.
Click to expand...

Wales is shut and likely to be so for a long time. The Welsh assembly have us "locked down" tighter than the rest of the UK.
 
Moonmanzn said:
Just bike was fuel starved at higher rpm. Try above 80 and slowly creeped up like I was riding in massive headwind or bike was governed.
Click to expand...

Did you experience any sudden cutoffs?
Mine is riding ok, power-wise, but will cutoff at higher speeds/rpm. Generally around 90/100mpg it reaches a point where it cuts and detonates before resuming power.

Mech said it should have been sorted at the last service (tight valve) but sadly this was before lockdown and obviously haven't been able to test the bike yet.
 
er-minio said:
Did you experience any sudden cutoffs?
Mine is riding ok, power-wise, but will cutoff at higher speeds/rpm. Generally around 90/100mpg it reaches a point where it cuts and detonates before resuming power.

Mech said it should have been sorted at the last service (tight valve) but sadly this was before lockdown and obviously haven't been able to test the bike yet.
Click to expand...

No bike ran fine and did t stall etc.
Only the slow acceleration issue for me.

Yours sounds like possibly coils breaking down at high rpm?
 
Yours sounds like possibly coils breaking down at high rpm?
Click to expand...

That was my first guess.
Replaced: niet.

I'll have to test it when possible, I trust the mechanic solved it, I think I was just pre-emptively trying to sort the problem in a different way :) :D
I think I was considering the pump/filter as I installed Hank's vlotter last year and converted my bike from fuel strip to float and assumed I damaged something in the process.

Thanks for the tutorial though: saved just in case.
 
Pukmeister said:
Thanks for the reply, my '08 Hexhead has had intermittent issues for years, only occasionally running silky smooth but mostly a bit rough and strangled. I never knew about this hidden pump housing filter but now I am doubting mine is intact so might get the drill out.
Click to expand...


check for recalls.... it should get a new pump for free "the plastic around the high pressure hose connection fractures causing a fire"
 
Thread Bump to make it easy to find

Just bumping this thread to tie in with the other long thread the OP wrote about this issue, I need easy access to this information for the weekend so I can finally get around to drilling mine and replacing the fuel pump.

For the benefit of Botus, the bike had a recall years ago to crimp a metal reinforcing collar to the fuel housing. Didn't work though as the 3/8"NPT threaded "CPC" quick connect fuel fitting subsequently split its threads and was puddling fuel on top of the tank recess below the FPC. BMW don't sell the CPC coupling as a separate item but Motorworks do two versions, about £18 in plastic and about £34 in metal. (Weird that its a 3/8" NPT thread form on a modern metric German motorcycle). I bought the plastic one but if buying again I would go for metal.
 
Hope all goes well with doing the filter bypass, let us know how you get on as I am also watching this with interest. I have a similar issues that I have had some success in resolving by replacing the seals on the injectors where they enter the throttle bodies. When I get to 80 I get a bit more vibes and a reluctance to accelerate. The bike is 16 years old and with the *rap fuel it’s hardly surprising!!
Following with interest
 
@Pukmeister, Which size fuel clamps did you buy and what type of sealing tape are you going to use when you screw the QD back in, starting to order the parts to do this but think it’s a bit late to get it sorted for the weekend!
 
Will do, my only worry is drilling a touch too deep and wrecking the fuel pump housing but I intend to go slow and steady. A pity I don't have an online photo hosting account anymore otherwise I could post up a few 'after' pics. I need to sort one out eventually so I can post up my gearbox rebuild pics.

It occurred to me yesterday that my bike feels a bit more eager to rev smoothly when the fuel level in the tank is low, fill it up and it is rougher. I suspect that a high fuel level somehow causes more back pressure on the (presumably weak) fuel pump, perhaps it has to work a bit harder to drive the sucking jet pump?

Parts should arrive today courtesy of Amazon prime, the Quantum fuel pump kit was £41 and the Mahle fuel filter was £13, I already have fuel hose and jubilee clips in my garage stock.
 
I was led to believe that the pump works less hard ( fuel pump controller) when the tank is full as it does not need to drive the sucking jet pump. Only when the level drops does it need to transfer from right to left so pump runs at max.?
Could be pish of course.?
 
Kenny Rodkiss said:
I was led to believe that the pump works less hard ( fuel pump controller) when the tank is full as it does not need to drive the sucking jet pump. Only when the level drops does it need to transfer from right to left so pump runs at max.?
Could be pish of course.?
Click to expand...

Kenny, that is something I haven't ever considered but now you mention it, it makes perfect sense. It also ties in with my belief that my fuel pump delivery is weak and the probable cause of my rough running when the tank is high, and smoother running when it is low if the pump rate increases (the proof will be in drilling out the hidden filter, adding an external filter and replacing the fuel pump).

Waggy, I have some high quality marine grade 8-16mm stainless steel jubilee clips already at home and a roll of PTFE plumbing thread tape. PTFE is petrol resistant so is fine for use on the threads of the fuel fitting. If that won't seal it dry, I have an extensive range of Loctite products at work, one of which will be suitable to seal the threads in the presence of petrol.
 
Thank you for that. I have been researching this for a while now but I am yet to purchase the new pump kit. I will get it from fuelperformance at £64 + postage at some point but I am going to fit a fuel pressure gauge first to see how that is running but again the hidden filter will impact that as well but it will give me some pointers
 
I looked on Amazon and there was an enhanced kit for an R1200GS/A at about £64 but further down the page was the basic HFP-382-B kit at £45 which includes everything you need, so with another £13 for the Mahle KL145 filter it was £58 all in (I have Prime so free next day delivery). I did previously make a fitting at work to measure fuel pressure but the threads on the pump housing leaked and I couldn't be bothered to mess around further with it as time is precious.

My suspicion is that BMW upped the fuel delivery pressure on the twin cams to 4 bar from 3.5 due to fuel supply issues at higher RPM (it redlines 500 revs higher). The difference in fuel flow between 8000 and 8500rpm is probably quite a few percent higher. If thats truly the case, it makes sense that the single-cam with its lower fuel pressure at 3.5 Bar might begin to struggle if the pump was worn, filter screen blocked etc.
 
Just for information, as stated fuel pressures are 4 bar twin cam & 3.5 bar pre twin cam.
My twin cam was down to 2 bar under full throttle at speed.
I used a pump from ebay around £25 at the time.
The pressure this pump generated direct ( no regulator in circuit) was 8 bar it is still holding steady at 4 bar at full throttle, the pressure the regulator is set at, it has now done over 30k miles.
There is plenty of capacity in a new pump but I am keeping an eye on this cheap pump as the original BMW pump only lasted approx 42K miles.
 
Mistacat said:
The pressure this pump generated direct ( no regulator in circuit) was 8 bar it is still holding steady at 4 bar at full throttle, the pressure the regulator is set at, it has now done over 30k miles.

There is plenty of capacity in a new pump but I am keeping an eye on this cheap pump as the original BMW pump only lasted approx 42K miles.
Click to expand...

It sounds like a bargain at £25 Chris, I bought a Quantum fuel pump kit as they are supposedly of reputable quality although probably from the same Chinese production line as all the rest. I already have a spare cheap new unknown brand fuel pump in my garage spares in case my Tmax pump dies (a common fault on them) but I only intend to do the job once so I bought the Quantum item for the GSA. I don't fancy being stuck in the south of France this summer with a problem.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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