BMW K bikes (Bricks)

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1Back to top Go down   throttle  Empty throttle Mon Nov 23, 2015 1:23 am

Ken52

Ken52
active member
active member
Hello gentlemen, another quick question.Still getting my 85 k100rt tweaked in and having some issues with the throttle,it seems that my throttle has to be manualy pushed off, I was wondering if it has a throttle return spring somewhere? haven't taken the fairing off yet. it seems that it should have one but I haven't located it yet. Would it be down nearer to the engine? Or is it a matter of lubricating the cable? Any help is appreciated.thanks.. Very Happy

    

2Back to top Go down   throttle  Empty Re: throttle Mon Nov 23, 2015 2:23 am

Chocolate

Chocolate
Life time member
Life time member
Hello down under!
You can put a drop of WD40 on the throttle and on the left side of the engine beneath the airbox. Not to much, otherwise dirt and smale stones will stick on it. Maybe it is dirt or a smale stone that stops the throttle from going back by it self.

On the picture you can see direct under the airbox between intake 2 and 3 is a kind of wheel that moves when you move the throttle and a spring to the left and right.

But it could also be a brocken throttle cable.
Do not put to much WD40.

Wait until somebody else adds a other idea!

Cheers espresso

throttle  35778_2013_1172_Fig2_HTML


__________________________________________________
Only a few activities make me experience my senses in a way motorcycle riding does, it is like swimming in the nude in a river.
K75 BA/1992 ABS, K75 BA/1991 noABS, Ducati, Mobylette M1/1973
    

3Back to top Go down   throttle  Empty Re: throttle Mon Nov 23, 2015 2:28 am

Holister

Holister
Life time member
Life time member
If you have a BMW cable it should not be lubricated as the liner is made from Teflon. The return spring is located on the throttle lever on the TBs in between #2 and #3.
The problem tho is likely to be your grip is pushed on too far bringing it into contact with the switch block causing the throttle to bind... or possibly your throttle mechanism on the handlebar needs grease. Something that's not too sticky.
If all that fails, your cable maybe shot.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
 throttle  Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

4Back to top Go down   throttle  Empty Re: throttle Mon Nov 23, 2015 2:59 am

Rick G

Rick G
admin
admin
I had a non return problem with my wife's K75RT and it turned out to be the OEM heated grip wire inside the handlebar was bunched up right at the end of the handlebar. It felt good to turn without any conection to the gears but when it was assembled but was just enough to prevent the return.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1986 K75 GS.
    

5Back to top Go down   throttle  Empty Re: throttle Mon Nov 23, 2015 6:01 am

Born Again Eccentric

Born Again Eccentric
Life time member
Life time member
Ken 52 - don't know whether throttle friction screws are fitted/legal in USA, but this is another obvious reason why the throttle may not snap back to the shut position on release.

throttle  Thrott10

Screws into underside of throttle/front brake lever assembly (if not fitted - may have a soft plastic bung in it's place). Legal in UK - I have them fitted to both my bikes as a crude but effective cruise control. Screwing in the knurled screw increases the friction of the throttle mechanism and stops it snapping back to shut. Screwed in until just tight enough to be effective but not so tight that it interferes with comfortable throttle operation.


__________________________________________________
throttle  Uk-log10 throttle  Sco-lo15
                              Paul  throttle  905546712

"Heidi" K100LT 1991 (Grey) (VIN 0190172 Engine No. 104EB 2590 2213) - 5th owner. January 2014 (34,000 - 61,000 miles and counting....)
"Gretel" K100LT 1989 (Silver Grey) (VIN 0177324 Engine No. 104EA 2789 2211) - 4th+ owner. September 2015 (58,500miles and counting....). Cat C Insurance write-off rebuild Feb 17
"Donor" K100LT 1990 (Red)  (VIN 0178091 Engine No. 4489 2024) - 6th & final owner (crash write-off now donor bike).   June 2012 (73,000 miles) to November 2013 (89,500 miles)
    

Born Again Eccentric

Born Again Eccentric
Life time member
Life time member
Just subjected Heidi to her annual MoT (vehicle safety inspection) - not my usual garage for the MoT, as he decided to wrap his hand in after another lean winter.Sad

Having ridden into the test station, I was kind of reliant on the bike passing so I could get home again. The tester did the usual poking and prodding, brakes, lights, everything OK....apart from the throttle not snapping back to closed. Allegedly this is a MoT failure. Disaster! I pointed out the throttle friction screw - the sole purpose of which is to stop the throttle snapping closed on release and asked how it could be legal to use if the snapping closed action was a MoT requirement. Doesn't make sense at all! I know in other countries, the friction screw is not legal for that very reason.

He had a quick look at the throttle mechanism and my heart sank when he started saying that he'd never seen an arrangement like that before. Not being able to free it up, he went on to tell me that I could leave the bike and he would look at it sometime in the next couple of weeks and probably change the throttle cable. I don't think he appreciated the effort needed to change the cable - partial fairing off, tank off....none of it difficult, but if you haven't worked on a K - it could prove an expensive exercise (he would probably take all the fairing off for starters).

I decided that I would come back with car & trailer to collect the bike and do the job myself. However, while I was still there, I thought that I might as well have a look to see if I could free the throttle up. I checked the usual suspects - the grip rubber was not tight against the non-rotating surface, so not the culprit; the bar end weight was not impeding movement at the other end either; the heated grip wires were not preventing free movement (although the heated grips have ceased to work and need attention anyway); I removed the throttle friction screw completely - but the throttle still would not snap back to closed. Running out of ideas I disconnected the twist grip from the throttle cable - and ah ha, a clue...there was still some light resistance to twisting. Bar end weight off, heated grip wiring brutally disconnected and I was able to slide the twist grip off the end of the handle bars. Beneath the grip, the bars were horrible and rusty. The paint from 25 years ago had worn away and been replaced by a rough surface layer of rust. It took a few minutes to scrape off the worst of the rust (note to self - need to put some wet & dry paper/emery paper in my tool kit), lube the surface lightly with WD40, pull a rag through the twist grip  and then reassemble. Instant success - the throttle snapped back crisply, exactly as it is supposed to. 

Tools re-stowed, I got the tester to check the throttle operation and MoT failure was turned into MoT pass...and good for another year of riding. I rode home happy Very Happy

Moral of the story - sometimes it is the simplest things that are preventing proper operation. The stiffness of the throttle operation, due to the corrosion of the handle bar beneath the grip, was masked by my use of the throttle friction screw. 

So, if you are experiencing this kind of problem, don't assume it is the cable that is at fault. I narrowly averted a potentially expensive (due to labour hours) repair - a repair that would have been totally unnecessary - and wouldn't have fixed the problem!

Now I'm home, I need to effect the full repair - clean up the bars and re-preserve properly. I was intending to replace the non-functional OEM grips with Oxford heated grips this summer anyway...looks like this is the boot up the back side I needed to just get on with it!


__________________________________________________
throttle  Uk-log10 throttle  Sco-lo15
                              Paul  throttle  905546712

"Heidi" K100LT 1991 (Grey) (VIN 0190172 Engine No. 104EB 2590 2213) - 5th owner. January 2014 (34,000 - 61,000 miles and counting....)
"Gretel" K100LT 1989 (Silver Grey) (VIN 0177324 Engine No. 104EA 2789 2211) - 4th+ owner. September 2015 (58,500miles and counting....). Cat C Insurance write-off rebuild Feb 17
"Donor" K100LT 1990 (Red)  (VIN 0178091 Engine No. 4489 2024) - 6th & final owner (crash write-off now donor bike).   June 2012 (73,000 miles) to November 2013 (89,500 miles)
    

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