BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   Bad misfire Empty Bad misfire Mon Mar 18, 2019 5:04 am

ajsm18

ajsm18
active member
active member
Hi,
I haven't used my bike much this winter but, when I have everything seems to have been fine. I replaced the battery a few weeks ago as it has struggled to start at times and failed completely once when I made a short stop.
The new battery has transformed the starting. This morning, though, it has developed a serious misfire. The symptoms are that it just seems to keep cutting out and then pick up again. This seems to be at all times - when accelerating, on a steady throttle and when slowing down.
It started OK and idled on the choke when I left home but after a mile or so started to misbehave.
The first half of my 20 mile commute is at about 40 mph and the second half at motorway speeds. As far as I could tell, it was bad all the way and when idling as I parked at work.
I'll go out and check it will start when it has cooled down and that nothing has come loose under the seat but any thoughts?
I have to say that, apart from oil, battery, brake and tyre changes, it is pretty neglected so I guess it could be the air filter is clogged and I've never attempted to touch the fuel system but I thought I'd ask for any pointers as I don't really want to strip it down to fix!
Thanks
Mark

    

2Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 6:44 am

duck

duck
Life time member
Life time member
Usual suspects:

1-Fuel level sender connector
2-Ignition switch


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

3Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 7:42 am

ajsm18

ajsm18
active member
active member
@duck wrote:Usual suspects:

1-Fuel level sender connector
2-Ignition switch
Great. Thank you. I wouldn't have thought of either of those. I'll have to see if I can limp home tonight then see if I can check them.
Thanks, again.

    

4Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 7:58 am

Two Wheels Better

Two Wheels Better
Moderator
Moderator
Check that the ECU's multi-pin plug is firmly pressed home, especially since the recent battery change. Things mighta got moved round a bit during the operation.


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100'87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-P  - Beemers owned still or sold.

~We all believe what we want to believe in - Rob Dickinson
    

5Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 8:06 am

ajsm18

ajsm18
active member
active member
@Two Wheels Better wrote:Check that the ECU's multi-pin plug is firmly pressed home, especially since the recent battery change. Things mighta got moved round a bit during the operation.
Thanks. I've just been out to check that everything is still in place and secure. I pushed the multi-pin plug and nothing seemed to move but the bike started up OK and ran nicely so, I hope, things may be OK and I just dislodged something when I fitted the new battery. If not, I'll be trying to find the fuel level sender connector!
Thanks, again
Mark

    

6Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 8:10 am

duck

duck
Life time member
Life time member
@ajsm18 wrote:
@duck wrote:Usual suspects:

1-Fuel level sender connector
2-Ignition switch
Great. Thank you. I wouldn't have thought of either of those. I'll have to see if I can limp home tonight then see if I can check them.
Thanks, again.

Fuel level sender check:  Remove right battery cover.  Shake that connector while idling on the side/center stand to see if that causes issues.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

7Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 8:31 am

Dai

Dai
Life time member
Life time member
It's the four-pin connector: there's two two-pin connectors there as well (speedo and brake).


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

8Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 10:06 am

ajsm18

ajsm18
active member
active member
Thanks, all, for your help. I was feeling a bit fed up this morning and wondering if I should get rid of it and get something else but now feel a bit more confident in it!
Mark

    

9Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 12:31 pm

Arlina

Arlina
Moderator
Moderator
We've got your back Smile
Sounds like a bad connection, connector.
As said, could be tye 4-pin to the pump, or the big one in the EFI under the seat.
Take it off and on several times, plug everything back, and start the bike again.


__________________________________________________
Bad misfire Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

10Back to top Go down   Bad misfire Empty Re: Bad misfire Mon Mar 18, 2019 4:52 pm

tinyspuds

tinyspuds
Life time member
Life time member
The first time I messed with my battery I had mis-firing issues after. It turned out that I hadn’t relocated the EFI connector properly, it has to be hooked into the unit at the front and positively clicked into place over the little plastic ‘speed bump’ at the back (the bit that silly silver thing releases when you take out the underseat tray) If not it will work loose. 
After the second time (yes, yes, I know) I wrapped the connector and unit with a cable tie to make sure it all stayed nice and snug.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

11Back to top Go down   Bad misfire Empty Re: Bad misfire Tue Mar 19, 2019 9:42 am

ajsm18

ajsm18
active member
active member
I thought I'd report back. After fiddling with everything under the seat and, although I didn't feel anything was loose, the bike started and ran well. I got home again safely and all is well in my BMW world so thanks for your help, everyone. If only fixing badly running Brit bikes was as easy...

Once again, thank you all so much for your kind help.

Mark

    

12Back to top Go down   Bad misfire Empty Re: Bad misfire Tue Mar 19, 2019 11:05 am

Two Wheels Better

Two Wheels Better
Moderator
Moderator
cheers  is it fix-ed, a fluke perhaps, or just some crud or a dislodged pin in a connector?

Glad to hear the bad misfire is now a good misfire!

Serious crisis averted.


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100'87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-P  - Beemers owned still or sold.

~We all believe what we want to believe in - Rob Dickinson
    

13Back to top Go down   Bad misfire Empty Re: Bad misfire Tue Mar 19, 2019 11:42 am

ajsm18

ajsm18
active member
active member
@Two Wheels Better wrote:cheers  is it fix-ed, a fluke perhaps, or just some crud or a dislodged pin in a connector?

Glad to hear the bad misfire is now a good misfire!

Serious crisis averted.
I think I must have knocked something when I was using the accessory socket at the weekend.

    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum