Not logged inThe UK C1 Forum
Forum Home Help Search Register Login OpenID
Up Topic C1 Information / Repairs - Faults & Fixes / Thumping at 50
1 2 3 Previous Next  
- - By Spck111 Date 20.11.17 00:30 Edited 20.11.17 00:33
I’m still getting this thump thump thump of varying frequency when I get to 50-60 and it’s varies in strength and speed. It stops but I can slightly feel it if I shut off the throttle which makes me think its something to do with the drive train . I’ve changed all the motor mounts and bearings, front and rear wheel bearings, the rear in the rearbrake mounting bracket.Both of the mounting  spacers ( by the main engine mounting bearing) balanced both wheels, changed the variator to a Malossi , changed the clutch and drive belt.  But it’s still there,  the only thing I haven’t changed is the clutch cover. Mine seemed a bit worn and had surface rust in places on the inner lining which I’ve sanded off. Ive ordered a new one as it’s the only thing I can think of that I haven’t done. Andy ideas?
Parent - - By V2k Date 20.11.17 17:29
the rear wheel tophat spacer has been replaced the correct way round as well when you put the rear wheel back on I presume
Parent - By Spck111 Date 21.11.17 14:02 Edited 21.11.17 14:05
Yes In the right way
Parent - - By leonm Date 20.11.17 20:21
I would test all three shocks for proper operation. wheel hop can cause some bad vibrations and oscillations.
Parent - - By Spck111 Date 21.11.17 14:04 Edited 21.11.17 14:10
Brand new rear Hagon shocks and the front works fine.  It’s not a hopping feeling it’s a spinning up and down thumping, whoop whoop whoop. It also spins so fast it becomes a constant vibration. If I nail the throttle from pull away and keep it wide open up to 60-70 I don’t really get the feeling until I ease back on the throttle   Starting to bloody annoy me now. 
Parent - - By p.gill Date 21.11.17 15:53
Is your tyre ok? Has it gone out of round? Is it de laminating causing a blister?
Have encountered both of these problems, very rare but worth checking out!
Parent - By Spck111 Date 21.11.17 18:52
Two new tyres and wheels balanced. You can see why I’m stratching my head. :)
Parent - By V2k Date 22.11.17 09:31
well unless something is failing in the engine,which I doubt,the only obvious thing,without having actually seen your bike would be to take all covers off and re check all variator work done to date.
Parent - - By alunt Date 22.11.17 13:40
It sounds like a problem with the drive belt from your description. Is it a BMW spec drive belt? Are all the dimensions correct? Could it be a more or less stretchy type of belt in there? Does it work properly with the Malossi variator ? Maybe the variator is tending to grab the belt instead of letting it slide up and down the surfaces smoothly. Just a few ideas to consider.
Parent - By leonm Date 22.11.17 15:34
I had a case of a loose nut on the primary variator (Loctite  not used on threads).   the bike was still rideable but suffered from noise , vibration and low power.
the splines in the front disc were worn away (shaft splines and nut thread were 100%).   new disc, dish washer and nut cured problem.
Parent - - By Spck111 Date 22.11.17 22:27 Edited 22.11.17 22:38
OK. So since I’ve done the oil change it’s got much better but it’s still there.  I found a bottle of oil I got with the bike when I bought it and it was 5w 40 not 15w 40 so I think the previous owner might have had 5w40 in the Bike.  Not sure but this was in the top box when I got it so I’m hoping he just used it to top up but the oil was runny like water when I changed it. The engine is also much quieter on tickover and riding . Changed the clutch cover this evening so will see how it all works on the ride to work at 0400 :).  Checked and cleaned the variator again. The belt I’m using is a Kevlar type. Not sure of the make but all in good order with no obvious signs of chunks missing or dodgy wear. I’ve also changed then outer finned part of the variator as two of the fins were broken on mine I would imagine by someone using the wrong variator tool. Second hand part but in new condition from Germany.
Parent - - By Spck111 Date 23.11.17 05:55 Edited 23.11.17 06:04
Bloody things still doing it. Definitely more of an oscillating vibration thou getting faster as you roll the throttle on but then slowing down again . Stronger on uphills where the engine has to work harder. Smooth as silk up to this point thou :)
Parent - - By alunt Date 23.11.17 10:12
The general feeling on here seems to be that Bando belts are the ones to have and that Malossi belts don’t work well with the BMW variator. You have a Malossi variator so I’m not sure if a Bando belt will work properly with it. So it’s worth finding out what make belt you have. The symptoms you describe still seem to point to a variator / belt problem, they might be incompatible. Have a search on here to see if anyone has tried that combination.
Variobob has plenty of experience and can supply parts if you need them. Also Pat50 found : for a Bando belt, not sure if they do Malossi. BMW belts prices are eye watering.
Parent - By Spck111 Date 23.11.17 11:36 Edited 23.11.17 11:45
Ok thanks. What belt is recommended for a Malossi variator ? Malossi belt I would think. Lol  I’ll  get a new one and try that out. I’m sure mine was a dayco? 
Parent - - By Spck111 Date 23.11.17 12:05
Right Ive ordered a Malossi belt nearly £50!!  Lol.  The teeth look a lot shorter that the one I’ve currently got on the bike.  ?
Parent - - By leonm Date 23.11.17 15:45
hi spck
by this time you must be ready to set fire to the bike!
if problem still persists, do a swop-out of the driven variator clutch unit with another c1 (125 or 200). easy to remove from bike.
     if problem is cured,  you  could have a worn or broken  takeup gadget inside your  driven  variator which assists in ratio change.
as a first test,   apply counter clockwise torque to the two drive dishes (requires strong hands) and the two halves should rotate about 10 degrees and slightly separate.

belt teeth length of no importance. energy is transmitted via the edges of the belt, hence importance of belt width
Parent - By leonm Date 23.11.17 15:48
the name of dick turpin springs to mind when I hear £50 for a belt
Parent - - By Spck111 Date 23.11.17 16:05 Edited 23.11.17 17:23
So I the bike home from work today and it’s it was bloody awful.  Felt like the bloody thing was going to explode. Now it was very windy but with a lot of headwind but even so. The Bike was really struggling and “thumping” like an elephants on LSD.  Where’s the poxy matches. 

I don’t have anyone else near me who has a C1 that I know of (Sussex) so I don’t really have the option to swap parts out.  :(. The variator seems fine I put a new one on and it was the same thump. I checked it yesterday. Cleaned and no play or anything worn or missing and no flat spots etc. The clutch variator was completely replaced with  new New yellow spring at the same time
Parent - - By leonm Date 23.11.17 16:27
did you replace whole clutch unit or only clutch shoes and springs?
Parent - - By Spck111 Date 23.11.17 17:16 Edited 23.11.17 17:29
Shoes an springs only. As I seem to have no life trying to sort this out I took the whole clutch assembly off  and apart tonight and it was a little sticky when you twisted the two faces apart so I VERY lightly put some acf50 on the central part  and it freed it up nicely. Loose and smooth.  As the bishop said to the actress. Greased the needle bearings which didn’t seem notchy or rough and greased the central drive shaft. Also, The belt? Does it matter what way round it goes.  I put it in so you could read the text markings the  right way up from the right hand side of the Bike as this is the way the one is in the manual.

I’m taking it there shouldnt be anything wrong inside the engine as it words great st low speed and I’d have thought if something was wrong  in there  it would be noticeable at any speed

This is the belt I bought. Bit pricey I know. But it’s only money. :)

Parent - - By Spck111 Date 24.11.17 00:55 Edited 24.11.17 01:05
Right, I have no idea how i missed this but if you look at the attached picture The parts numbered 4 5 and 7 are missing from my variator.  now i can't confirm this until i take it off yet again tomorrow but I'm sure I've never taken these off when i stripped it down before.   would this be causing my vibration  ? I’m thinking there’s a good chance it has as this seems to hold the whole lot together. If it’s not there as I suspect then it never has been from day one . FFS!!!   ps  if anyone has these parts lying around I have cash waiting :)  BMW has had enough of my money this month.   However. Looking at the parts Fische these parts as listed as deleted so I don’t know if I need them or not not.

Parent - By V2k Date 24.11.17 07:05 Edited 24.11.17 07:10
just a hint,dont grease the rollers,a common error,that only serves to attract muck and dust and gum them up over time,instead after cleaning  just lightly spraylube before reassembly.I cant upload that photobucket thing,what parts are missing? Also when you refit the variator holding nuts,they are torqued to 60nm,s as per specs.
Parent - By alunt Date 24.11.17 07:54
I think there are variators without the bits you list. I seem to recall talk of greased variators and dry variators , one with the shield and one without, so don’t pin your hopes on that being the problem.
Parent - - By leonm Date 24.11.17 12:12
attached picture?
Parent - - By Spck111 Date 24.11.17 12:15 Edited 24.11.17 12:35
Oh bugger. Sorry about the picture. Was there when I posted it  it’s the round mounting bracket that sits on the back of the variator with  screws  and a large round rubber seal
Parent - - By leonm Date 24.11.17 12:19
are you now referring to the primary (drive) variator?
Parent - - By Spck111 Date 24.11.17 12:35
Yes.  The front one
Parent - - By leonm Date 24.11.17 16:04
I was referring to item 11 in the driven variator. see attachment
Attachment: drivenvariator.pdf (99k)
Parent - By Spck111 Date 25.11.17 00:51 Edited 25.11.17 00:57
No. Not that one. On the back of the front variator. The one with the rollers.
Parent - - By Spck111 Date 26.11.17 23:21 Edited 26.11.17 23:59
This is the pic I posted earlier but photobucket removed it. :(

parts 4 5 and 7

btw  how do you post attachments in posts as in jpegs pdfs etc?
Parent - - By Clunkfish Date 27.11.17 08:26

>how do you post attachments in posts as in jpegs pdfs etc?

From the very useful Help section at the top of the page ;-):

"First submit your post without the attachment, after that you can click the post's Attach button to go to the upload page. Posting and uploading is separated this way because uploads can fail for various reasons, and you probably don't want to lose your post text when that happens."
Parent - By Spck111 Date 27.11.17 23:27
Bugger I didn’t see that in the help section. Ok thanks for the info. You’d never know I had a computer science degree would you.  Lol
Parent - By Spck111 Date 25.11.17 00:56
So I rode the bike to work this afternoon and the Same Old vibration.  But, when I went to go home about 11pm. I started the bike up and left it tick over for about 5 Mins to get it warmed up while I got suited and booted. It was almost zero degrees.  The ride home was vibration free. Nothing at all. All the way up to 65mph. All the way home. Was lovely!!!  Bike was humming away nicely. Also noticeably more drive when opening the throttle at lower town speeds .  First time since I got the bike.  Maybe the cold weather made something shrink and tighten up. Dunno.  Was a lovely ride thou. Can’t work it out at all. Very strange.
Parent - - By Spck111 Date 29.11.17 00:52
New molossi belt on today and the bike is so much smoother up to 50mph and great around town and then guess what.....different type of feeling. Not really vibration but now feels like a spluttering.  Open the throttle wide open and no adverse effect , nice and smooth up to
About 60 and then a little spluttering as I’m now calling it. Back throttle off and slow to 55 ish and there it is again. Ease and squeeze on the throttle creates the spluttering mainly. Full throttle and it almost disappears. Letting the Bike tick over for 5-10 mins before a ride massively reduces the effect.  Do you think the fuel injector may be the problem ?   Just a thought.  I have a spare that came in a box of bits when I bought the bike so I’m going to change it over tomorrow and see if there’s a difference
Parent - - By Spck111 Date 29.11.17 15:54
Took injectors out and the top rubber o ring seal had split. Replaced injector and New seals. Will take for a run tomorrow and see what happens.
Parent - By Spck111 Date 04.12.17 09:02
Nope.  No difference. :(
Parent - By Spck111 Date 30.01.18 11:32
So a bit of an update. Just checking out front brake pads today and whipped out the front wheel and checked the wheel bearings while I was at it. The near side bearing was very notchy. Now I put these in New so I don’t know if it was a dodgy bearing but I’m hoping if I replace the wheel bearings this may cure my problem.  It’s manly vibration now and much less when it’s really cold, We shall see. :)
Parent - - By Spck111 Date 12.02.18 02:32 Edited 12.02.18 02:36
Nope.  Still the same.  Seems worse if I’m riding into headwind.   If I wind open the throttle to full tilt I don’t get anything at all to top speed but when I ease the throttle off it goes back to thumping/vibrating again.  I really don’t know anymore. Lost now. Don’t know what to check next.  Putting a new spark plug in tomorrow as it’s the only thing I haven’t done so why not.  I think it’s insured for fire.  Lol

On another note. The other night I left work and it was riding fine no vibration was riding exactly as it should. Rode for about 10 miles with no issues when I had to stop at a red traffic light. After that and I pulled away it was vibrating again for the rest of the ride home over 50mph .   Doing my bloody head in
Parent - By aware Date 18.02.18 18:37
I had a similar issue of thumping while accelerating and especially up a hill and the problem was with the clucth.
But still the transmission just after the clucth can be part ot the problem itself.
My 2 cents.
Parent - - By leonm Date 19.02.18 17:03
swop out the entire drive comprising primary and secondary drives as well as belt from your bike to donor bike and vice versa, and see what happens
Parent - - By Spck111 Date 25.02.18 14:01 Edited 25.02.18 14:30
If only I had the parts!!! Or a doner Bike.   I rode home on it last night at -1.   No vibration whatsoever. It never vibrates when it’s this cold.  Maybe I’ll move to Sweden :) Got up to 70mph. For the 12 mile ride home.  Town, dual carriageway rural roads various speeds and it worked as it should.  I think the cold must be shrinking something and making a tighter fit somewhere. I see there are two bearings behind the driven wariator so I think I’ll swap these out and see what happens.  Didn’t appear to be any play when I checked then previously but they’re cheap enough so I reckon so why not. Maybe they have a bit of play when the driver variator moves out at speed.
Parent - - By leonm Date 26.02.18 09:13
the bearing only rotate with bike at standstill so would first check them out carefully, particularly the needle bearing which is rather expensive and difficult to fit
Parent - - By Spck111 Date 16.03.18 12:07
So. Eventually got around to taking the driven Variator off and noticed slight play in the needle bearing which is located inside the variator.. put some grease in there to take up the play and took the bike out for a spin.  No vibration whatsoever.  Think I’ve the problem at long last. New bearing ordered.  Happy bunny. :)
Parent - - By Spck111 Date 16.03.18 12:18
So I was going to change the roller bearing as well but the price from BMW is ridiculous. Is this only available from BMW or does anyone know where I can get the same bearing elsewhere. Almost £70. For a bloody bearing!!!
Parent - By aware Date 17.03.18 05:42
A bit confused now, which bearing do you mean?
Some realoem link would help
Parent - - By Spck111 Date 19.03.18 00:26
Brilliant.  Thank you :)
Parent - - By Spck111 Date 19.03.18 17:59
Just trying to preempt any problems.   Is there a specific way to remove the lock ring that holds the grooved bearing?
Parent - By Spck111 Date 19.03.18 21:37
Dont worry. Sorted it :)
Parent - - By Spck111 Date 20.03.18 21:52
Well I took the driven variator completely apart today and removed both bearings. The needle bearing was buggered, very loose on shaft and the rollers very very stiff.  The grooved bearing seemed ok but if I put any sideways pressure on it with my finger it became very notchy so I think I’m on to a winner. New bearings ordered and variator waiting for fitment. :)
Up Topic C1 Information / Repairs - Faults & Fixes / Thumping at 50
1 2 3 Previous Next  

Powered by mwForum 2.29.3 © 1999-2013 Markus Wichitill