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Topic Blown Fuse - Help! By tomlem Date 14.05.19 21:56
Hi all,

I have been having an issue with the bike recently. The C1 starts fine and will drive for a bit but then suddenly cut out and won't start again. This is due to the BMW Engine Management fuse blowing (15A and is the 4th one up from the bottom). I replace the fuse and it is able to drive a bit further but cuts out again with the BMS fuse having blown again. After changing some relays around and fiddling with some wires coming out of the generator/on that side of the engine I was able to get the bike home and ride it without any problems for about a week. However, today the bike broke down again and BMS fuse blew was to blame once more. I was wondering if any you you on the forum had a similar experience of this happening and could point me in the direction of what is causing the fuse to blow? I am assuming that something is shorting somewhere? Looking at the wiring diagram the fuse goes to a BMS relay above (which is the 3rd from the bottom) but I don't know where it goes thereafter.

Any help would be much appreciated!
Topic Coolant Leak - help! By tomlem Date 25.02.18 21:21
Thanks guys - I unscrewed the nipple on the top of the engine for the coolant to try and bleed it after I replaced the water pump and eventually the gasket and there was coolant dripping out - but maybe I didn't do it long enough... what is the correct procedure?
If the bleed which I will do again tomorrow night doesn't work, where is the best place for me to find a new thermostat?

Thanks again for all the help!

Topic Coolant Leak - help! By tomlem Date 25.02.18 18:19
Hi all thanks for your help! It is very much appreciated! Apologies for the length of time to reply to your help/suggestions - I have been travelling with work and waiting for parts to arrive. Here is what has happened:

I replaced the water pump with a new one from BMW (paid £80 for it) but the gasket for the housing broke so had to replace that as well (so another week of taking the tube waiting for the gasket to arrive).
I put the gasket on yesterday and no coolant or oil leak and all seemed fined.
I decided to go out for a ride on the bike and after 20 mins of riding the temperature light came on!!! Very frustrating.
I scoured the forums again and think I might have a broken thermostat - the radiator doesn't seem to get warm at all.
My question should I try the DIY repair job of putting in a small steel bar? And how do you go about doing this? Or just buy a new one? Would my diagnosis of the thermostat be right if the radiator is not warming up?


Topic Coolant Leak - help! By tomlem Date 13.02.18 09:10
Hello all!

Last night my 2001 C1 Exec with c.34,000 miles on the clock made it home after my commute but as I was parking the coolant light came on (oh no!). I decided to investigate the issue and found that the expansion tank had enough coolant in it (at the max level) but the filler/cap radiator level next to the headlight was lacking about 700ml (if not more) of coolant. I topped it up and turned on the bike to then look for leaks. Upon looking under the bike I could see drips hitting the exhaust and steaming - I think it is coming from the run off hole that allows the coolant to come out between the water pump impeller seals. I think this was the case but it was dark and cannot be sure. I took it for a 10 min drive and the coolant light came on again and when I got back the entire sump/bottom part of the enging was covered in coolant/water, I am not sure how much of the coolant I put in leaked out but I assume the majority.

Having scoured the forums for the best part of 3 hours last night I can see that lots has been written about the water pump seals hardening, damaging the impeller shaft and causing this leak to happen. I hope that this is the case... as if it were a head gasket I think the bike would probably end up as scrap :(. Is there a way of diagnosing whether it is indeed a water pump seal failure vs. a head gasket failure? And if so, where is the best place just to buy a new water pump or a water pump kit (including o-ring seals)?

Any help, as ever, would be much appreciated!

All the best,
Topic Engine stalls when passing minor potholes By tomlem Date 21.04.17 14:56
Hi leonm,

Thanks for your quick reply, it is much appreciated. The bike restarts immediately when it does cut out and the instrument cluster is still alive and shows the same time as before.
I will do what you have said when(if!) I get home on the bike tonight and report back immediately.

Thanks again,

Topic Engine stalls when passing minor potholes By tomlem Date 21.04.17 07:58
Hello all,

I have a similar problem with my 125 Executive. I checked the battery terminals yesterday and replaced the injector wire/connector back in january. So was wondering what else it could be!?

The bike loses power over some potholes then i am able to drive as normal. However, this morning it cut out completely. Another feature of my fault is that when I park up (going backwards) as the bike hits the kerb it cuts out completely. It feels to me like it is an electrical fault but where is best to look to diagnose the problem? I am keen to fix it ASAP as not having confidence in the bike being able to accelerate in central London is worrying!!

As ever, any help is much appreciated!

Topic Handlebar/steering squeak By tomlem Date 20.03.17 10:02
Hello all,

Owning a C1 is not without its peaks and troughs!

Everything had been working well (for two whole months!) until last Thursday when the bike started developing a squeak when turning the handlebars. At first the noise was not too loud and would disappear after moving the handlebars rapidly from side to side. This morning though it was much louder and would not go (maybe something to do with the wet weather in London!). It does not squeak when the front wheel is raised - so it only does it when there is weight on the wheel/forks.

I have found one post from 2011 with similar symptoms to mine that identifies 3 different options - polystyrene in the cowling where the handlebars are rubbing against something, a seal that needs to be lubricated due to being perished or a bearing problem. However, there is no conclusion to the post so I was hoping the many combined years of experience on the forum would help me identify what is causing the squeaking so I can try to fix it!

As ever, any help or insight would be greatly appreciated!

Topic Injector wire/plug By tomlem Date 20.01.17 08:48
Thank you! I will check all that you have talked about this weekend as it was a bit dark last night to give the bike a good once over!
Topic Injector wire/plug By tomlem Date 19.01.17 22:46
Hello all!

I hope you are all well - this is now my 3rd/4th post on the forum... these bikes do keep us entertained!

I rode over a ginormous pothole on Piccadilly by mistake (was quite scary and was a rather large shock/shunt on the bike) this evening and after that the bike was shuddering when any throttle was used, it eventually died. I managed to get it going but same shuddery acceleration and engine cutting out meant i only got a few hundred meters further towards home! Post getting it back home after an extortionate lift back home with a recovery vehicle I think i figured out the problem - one of the injector wires had broken completely off the plug. I have two questions:
1. where can i find a new injector plug to wire a new one in? (i have read that vw do an equivalent one you can use but happy to find anything that works!)
2. post the rather large shock to the bike is it likely that this is the only thing that has caused the problems?

Any advice/help greatly appreciated,

All the best,

Topic Alarm problem means I can't get to work! By tomlem Date 25.02.16 11:24
I hope it is as simple as loose battery connections! Will have to check that when I get back home - Thanks alunt!

Still worried (as ever with C1s) that it is something more sinister...
Topic Alarm problem means I can't get to work! By tomlem Date 25.02.16 10:56
Hello all,

Sorry for not posting on here for a while - the bike has been working well and trouble free for the last year... until yesterday and today!

The back story is - on my way to work yesterday I rode over a bump and the C1 cut out and then started again a little distance down the road (whilst still moving). Then for the rest of the journey, at traffic lights, it would turn off when at idle. It would then start up again when ignition was turned off and on. On the way home from work that evening the bike was fine rode like a dream and no cut outs.

This morning however, I came down at around 6am to begin my commute to work, put the key in the ignition and the alarm starts sounding (it is usually turned off and not required and has been this way forever). I tried for the best part of 25 minutes to turn off the alarm to get the bike started (key fob has never really worked) with the induction black stick thing but to no avail. (I tried scratching off the corrosion on the LED next to the ignition and cleaning the pin in the induction stick). So eventually I gave up and took the tube.... :(

I don't know if these two things are related - I assume they are or it is just a case of many problems turning up at once (like london buses!).

Ideally I would like to completely disable the alarm so I never have the shock of it disabling the bike from starting. I have looked on the forum and found that people have done this but with no instructions available anywhere.

Any help would be incredibly well received!

Thanks very much in advance,


(P.S. it is a 2000 125cc exec)
Topic I am an idiot... broke a bit of the fin whist trying to... By tomlem Date 09.03.15 13:23
Hi C1live - I live in Fulham and definitely still the need the variator tool! It would be great to potentially borrow it off you!
Topic I am an idiot... broke a bit of the fin whist trying to... By tomlem Date 08.03.15 18:15
Hello all,

I tried removing the cover plate with fins on of the driving variator today so that I could change the old belt for a new bando belt (bought for the princely sum of c£60 from J&G - is this too much?). The guys there told me that the tool was not necessary if I had an impact gun and the nut would whizz right off! So I borrowed my neighbours impact wrench and gave it a go... wouldn't budge. I then tried to lock the plate by sticking a metal extender for my ratchet in between 2 fins and using my other ratchet to unscrew the nut. Unfortunately,  this resulted in part of one fin (about 1 cm) snapping off!!! I should've know better hence the title of the post!

Does anyone know if it is bad to run the C1 with one fin that has had a bit broken off it? I definitely want to replace it but just until I can get the replacement. Which leads me to my second question... where can I buy the replacement finned cover plate? If anybody has one on the forum for sale I would gladly buy it off them.

My third question is are there any C1ers that live in SW london (or work in the city of London) that could lend me the tool needed to apply the counter pressure on plate so that I can remove it?

Any help at all/hearing about your experiences with changing the belt/checking the variator would be hugely appreciated!


Topic Worried about my C1 - Idle judder & needs a service? By tomlem Date 05.03.15 12:45
I'm afraid the tool kit no longer exists. The previous owner of the bike didn't give it over with the bike itself!
Topic Worried about my C1 - Idle judder & needs a service? By tomlem Date 05.03.15 11:05
Thanks for your reply Gerard. I will go out at lunch time today during work and try pressing on the injector to see if it has any effect. If this is the issue how is it fixed?
Topic Worried about my C1 - Idle judder & needs a service? By tomlem Date 05.03.15 11:03
Thanks Texy1. When my dad used to get the bike serviced/fixed he used to take it to Neil and also trusted him. I thought he was no longer around! I would like to give a go at fixing myself if possible rather than spending straight away! Need to find a spark plug tool!
Topic Worried about my C1 - Idle judder & needs a service? By tomlem Date 05.03.15 11:01
Thanks for all the advice. I would like to start by changing the spark plug but I dont have the tool to do so (I have spark plug sockets but they do not fit). I called up Jap & German to see if I could buy one off them or to see if they could quickly do it over lunchtime. Their immediate reaction was that it needed to be plugged in and checked after I told them what was wrong and they said it definitely wasn't the spark plug... I felt like they were trying to up-sell me immediately on a full service/moditech plug in.

Does anyone have an idea on where I can buy the spark plug tool so that I can change it myself and see whether or not there is any improvement?


Topic Worried about my C1 - Idle judder & needs a service? By tomlem Date 04.03.15 22:03
Hello all!

My lovely C1, after a year of faultless use for commuting after inheriting it from my dad when he moved country, has decided to develop a strange idle. The idle drops and catches itself back up but has never completely cut out on me... it also feels, when travelling at constant speed, like it is accelerating and slowing down immediately afterwards in a constant cycle. Does anyone have any idea what this could be? Does it need a new spark plug? (I dont have the right tool to change it!) HT lead? new air filter? or is it something more sinister?

I also think it is time for a service - I am not too keen to take it to chasbikes/jap & german as I have heard mixed reviews (I live in south west london and work in central). Would anyone be able to help me/tell me where to go? I am handy with a spanner (mechanical engineering graduate) and have done a basic service on it myself last year but have never looked at the variator and more complicated parts.

As a side note - it is also sometimes quite juddery when pulling away and then fine above a certain speed.

I would appreciate any help at all and would love it if someone could come down and help me out/show me how to service bits properly!


Topic Failed MOT - Help Needed! By tomlem Date 06.02.14 22:22
Hi Bob. That is a great price considering BMW charge £14 pounds for each of them and they are made out of aluminium... so will last much less time than your stainless ones.
Topic Failed MOT - Help Needed! By tomlem Date 06.02.14 22:21
Hi Thanks for this! Massively useful! I will see if they let me into the workshop tomorrow to make them! Shouldn't take too long. Thanks once again!
Topic Failed MOT - Help Needed! By tomlem Date 06.02.14 15:59
Would anyone happen to have the dimensions of both engine spacers? So the inner diameters, outer diameters and lengths? I have just realised that the right side one is missing on my C1 which is why it is 'distorted' and I would like to make them myself in the university workshop I used to go to. I called up BMW and they don't have them in stock and are an absolute rip off!
Topic Failed MOT - Help Needed! By tomlem Date 06.02.14 14:53
Hi Leonm. Thanks for the advice. I managed to get the screws out this morning by drilling them out. I have now replaced them with allen head screws and should be easier to get in and out when brake fluid service happens. Lets hope I can get the front caliper to stop sticking and stopping the wheel from turning freely.
Topic Failed MOT - Help Needed! By tomlem Date 06.02.14 14:50
Hi Bob,

Thanks for the advice and help.

I have ordered a new disc and pads through the club and they should be arriving tomorrow and I will be tackling that then. They are EBC and should do the job! I am not sure whether new bolts come with the new disc? I also received a new pair of Hagon shocks today which will be fitted soon.

On the "excessive distortion" of the rear of the bike. The bearings and spacers seem fine. However, I think whoever changed the spacers last may have put them in the wrong way round. The shocks that are on there at the moment seem to look like a backslash ( \ ). At the moment when you look at the rear of the bike the longer spacer is fitted to the left slide. Is this correct? Or should they be the other way round (i.e the shorter spacer on the left side of the bike as you look at it from the back)?

Any help with this would be great!


Topic Failed MOT - Help Needed! By tomlem Date 04.02.14 16:01
Hi there.

I have just been given my dad's C1 which he has owned and used to commute since 2004. He had to move from the UK to overseas in 2011 and so it has been standing in our driveway since then (last MOT was in 2010). I have just got a job in central London and rather than take the dreary tube everyday I would rather commute on the C1. So I took it to get an MOT after doing some work on it myself to get it running again. It has failed on the following:
- Front brake disc excessively worn (relatively easily replaced)
- Nearside and Offside shock absorber seals failed and leaking oil (also relatively easily replaced although quite expensive!)... Worth getting new Hagons or 2nd hand off ebay?
- Rear motorcycle structure excessively distorted (???)

The last point of failure is where I am a bit confused. We have owned it a long time and it has never been crashed (but it has taken a few tumbles as would be expected with a C1!). The tester told me to check the engine mounts. Is it possible that in the near 3 years it has been standing still that these would fail (it was not an issue at its last MOT)? I am hoping that by fitting new shock absorbers this will right itself as I am absolutely convinced that it is not the C1's structure that is at fault here. As a side note I recently took the rear wheel off (what a job!) to replace the rear tyre. Could this of had any effect on this?

Other sore points about the bike but that have had no effect on the MOT are:
- Stand cable has snapped and needs replacing. Is it worth buying a Bowden cable with a solderless nipple and repairing it that way? (I have read that this is a common problem and that there are modifications you can make)
- Front wheel does not spin freely. I think this is due to brake caliper and pads sticking to the disk. I would love to rejuvenate the calliper, however, the screws in both the brake fluid pots have stripped heads and are impossible to get out. So I can't even do a brake fluid service! Should I drill them out and try and find new screws?

Any help or suggestions would be hugely appreciated and thank you to anyone who replies in advance.


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