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Advice on SB6 dragging clutch
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Sat Mar 09, 2019 12:48 pm    Post subject: Advice on SB6 dragging clutch Reply with quote

Hello all,
I did a search of the forum for advice on bleeding the slave. (I thought I had solved my starting issues over the winter and was ready to MOT the bike, but as soon as I popped her in gear she was off...eek)
I'm not so gifted a mechanic but I've bled a slave on my Duc 851 many times, foolishly I thought I was in for a 15 minute job...but this is a bimota. Imagine my surprise at the inaccessible bleed nipple on the slave cylinder, behind the frame spar. I just shook my head in disbelief.
Please tell me I don't have to swing the engine forwatrd to do this and there is some nifty way of doing this without a massive amount of work?

While we are at it, what spanner size fits, my 8mm and 10mm dont, nor a 7/16ths.

thanks in advance, I'm very grateful

Greg
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brian



Joined: 22 Aug 2011
Posts: 3129
Location: Australia

PostPosted: Sun Mar 10, 2019 12:13 am    Post subject: Reply with quote

Hi Greg,

If your bike had been sitting for a long period, the clutch drag is probably just due to the clutch plates/ discs sticking together.

My SB6 had been sitting in the previous owners lounge room for a few years before I bought it. When I first got the bike, the clutch was dragging really bad. I did manage to to bleed the slave cylinder, but yes, it was a very fiddly job. It can be done without moving the engine. I just canít remember now if I had to modify a spanner to do it Rolling Eyes. It is definitely metric, so if 8 and 10 donít fit it may be 9mm. Bleeding my slave cylinder did not make any difference.

I rode it for a while and then dropped the engine oil. I flushed the crankcase out with an engine flush product and filled with new semi synthetic oil. The clutch drag was better after the flush and refill. With use the clutch came back to normal and now operates perfectly. I planned on dropping the engine to strip, check, clean the clutch, but I still havenít done it.
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Current motorcycles - '99 Bimota DB4 #104, '96 Bimota SB6 #1165, Ď94 Bimota DB2 J #652, '99 Bimota DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, Ď94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, Ď61 BSA A10 650
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 427
Location: NE London

PostPosted: Sun Mar 10, 2019 8:11 am    Post subject: SB6 clutch slave Reply with quote

It can be bled relatively easily in-situ with a pneumatic bleeder on a compressor and a 90 degree 8mm ring spanner. If the bike's not had much TLC to date, you'll want to replace the slave seal, when next you pivot the motor for valve clearances/engine sprocket replacement. If you have a sleaved slave, you'll have to replace the whole cylinder, because you won't find the seal for the smaller piston. So you'll replace the cylinder with a standard Suzuki one, and then you'll want a bigger master cylinder, because the ratio will be wrong.

So, as you can see, the relative inaccessibility of the bleed nipple is the least of your problems Laughing
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Mon Mar 11, 2019 3:16 pm    Post subject: Reply with quote

I bled the fluid, there was no air in there that I could see. So its still dragging a lot. I put it on the paddock stand and knocked it into gear and revved it to get the rear wheel moving a fair bit and applied the break to see if I could free things up...no joy. Although I only did it for a few minutes.

I'm concerned to try and ride like this, basically because you can't stop at a junction without some drama or start again either. Just how much riding are you talking about? Did you thrash it a bit and were you slipping the clutch?

Of course I'm MOT free, so the consequences if I had a spill trying to sort this would be grim.



brian wrote:
Hi Greg,

If your bike had been sitting for a long period, the clutch drag is probably just due to the clutch plates/ discs sticking together.

My SB6 had been sitting in the previous owners lounge room for a few years before I bought it. When I first got the bike, the clutch was dragging really bad. I did manage to to bleed the slave cylinder, but yes, it was a very fiddly job. It can be done without moving the engine. I just canít remember now if I had to modify a spanner to do it Rolling Eyes. It is definitely metric, so if 8 and 10 donít fit it may be 9mm. Bleeding my slave cylinder did not make any difference.

I rode it for a while and then dropped the engine oil. I flushed the crankcase out with an engine flush product and filled with new semi synthetic oil. The clutch drag was better after the flush and refill. With use the clutch came back to normal and now operates perfectly. I planned on dropping the engine to strip, check, clean the clutch, but I still havenít done it.

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Evilchicken0



Joined: 12 May 2010
Posts: 2887
Location: London

PostPosted: Mon Mar 11, 2019 10:13 pm    Post subject: Reply with quote

Ok - is the slave flexing ? Check its bolts are tight and next check the sproket cover hasnt split where its cut around the frame spar.

To replace the cover is a part engine drop. If the cover is ok and you don't want to ride it like that drop the engine and fit new steel and friction plates - It's better to do it as a full kit and have it done than revisit it a year down the line
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sb8rs



Joined: 05 Aug 2011
Posts: 147
Location: London

PostPosted: Thu Mar 14, 2019 1:04 pm    Post subject: Reply with quote

Uprate the master cylinder and it will be fine, costly mind.
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brian



Joined: 22 Aug 2011
Posts: 3129
Location: Australia

PostPosted: Thu Mar 14, 2019 1:21 pm    Post subject: Reply with quote

hippotech wrote:
I put it on the paddock stand and knocked it into gear and revved it to get the rear wheel moving a fair bit and applied the break to see if I could free things up...no joy. Although I only did it for a few minutes.




brian wrote:
Hi Greg,

If your bike had been sitting for a long period, the clutch drag is probably just due to the clutch plates/ discs sticking together.

My SB6 had been sitting in the previous owners lounge room for a few years before I bought it. When I first got the bike, the clutch was dragging really bad. I did manage to to bleed the slave cylinder, but yes, it was a very fiddly job. It can be done without moving the engine. I just canít remember now if I had to modify a spanner to do it Rolling Eyes. It is definitely metric, so if 8 and 10 donít fit it may be 9mm. Bleeding my slave cylinder did not make any difference.

I rode it for a while and then dropped the engine oil. I flushed the crankcase out with an engine flush product and filled with new semi synthetic oil. The clutch drag was better after the flush and refill. With use the clutch came back to normal and now operates perfectly. I planned on dropping the engine to strip, check, clean the clutch, but I still havenít done it.



You first need to determine that the clutch actuation is doing what it's meant to do. If you are confident that the slave cylinder IS pushing the rod sufficiently, then it's most likely stuck clutch plates. The method that I would use is to leave the bike on the ground and apply the rear brake. With the engine idling and clutch lever pulled in, put it into 2nd gear. The engine may stall a few times but eventually the plates should break free. Oce the plates have broken free, ride the bike and flush the engine oil as I described above.


.
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Fri Mar 15, 2019 1:55 pm    Post subject: Advice on SB6 dragging clutch Reply with quote

So I decided to bite the bullet and try and take her for a spin.

What a handfull, this bike is going to take some getting used to. The handling feels strange, probably tires are old and crap (recommendations on replacements?). Not getting a feeling of confidence tipping into the corners and she is running wide, could be my body position too though. Probably just the feel of a different bike and I need to get used to it on a longer than 5 minute ride.
Clutch seems to have sorted itself out, although hard to get into neutral. So I dropped it off for MOT and we will see what they say...
Adrenalin still pumping hard long after I got off, just nerves because it doesn't go anything like as hard as my TL1000R.
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Fri Mar 15, 2019 3:35 pm    Post subject: Reply with quote

...update

She passed her MOT! Minor advisory to fix the indicator switch gear which is not secure

Feel like I breathed a ton of exhaust gas or something, actually feel a bit high!
Opened her up a bit on the way home, power comes in a bit of a 2 stroke wave, but seems to get a bit starved on fully open throttle. Its got flat slide carbs on it. Perhaps thats a characteristic?
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brian



Joined: 22 Aug 2011
Posts: 3129
Location: Australia

PostPosted: Fri Mar 15, 2019 5:53 pm    Post subject: Reply with quote

hippotech wrote:
Its got flat slide carbs on it. Perhaps thats a characteristic?


They're difficult to tune with flatslides by all accounts. Has it also got pod filters? Are they Keihin's or Mikuni's? I'm not sure about the Mikuni's but the Keihin FCR's definitely don't fit without cutting/ modifying the frame
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Current motorcycles - '99 Bimota DB4 #104, '96 Bimota SB6 #1165, Ď94 Bimota DB2 J #652, '99 Bimota DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, Ď94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, Ď61 BSA A10 650
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Evilchicken0



Joined: 12 May 2010
Posts: 2887
Location: London

PostPosted: Fri Mar 15, 2019 6:16 pm    Post subject: Reply with quote

The power delivery on mine is really linea Ö it's quite deceptive but there's a point at about 80-90 in top where the engine smooths out.
I remember once wondering why it seemed to be vibrating a bit Ö turned out I was doing 130
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Sun Mar 17, 2019 3:23 pm    Post subject: Reply with quote

They're difficult to tune with flatslides by all accounts. Has it also got pod filters? Are they Keihin's or Mikuni's? I'm not sure about the Mikuni's but the Keihin FCR's definitely don't fit without cutting/ modifying the frame[/quote]



Seems I have the Keihin's with pod filters. I wonder who up north could tune her up for me, any recommendations?

Thanks for all the helpful advice

Greg
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brian



Joined: 22 Aug 2011
Posts: 3129
Location: Australia

PostPosted: Sun Mar 17, 2019 7:25 pm    Post subject: Reply with quote

hippotech wrote:
They're difficult to tune with flatslides by all accounts. Has it also got pod filters? Are they Keihin's or Mikuni's? I'm not sure about the Mikuni's but the Keihin FCR's definitely don't fit without cutting/ modifying the frame




Seems I have the Keihin's with pod filters. I wonder who up north could tune her up for me, any recommendations?

Thanks for all the helpful advice

Greg[/quote]

Nope sorry.... I'm down south, way down south Wink
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Current motorcycles - '99 Bimota DB4 #104, '96 Bimota SB6 #1165, Ď94 Bimota DB2 J #652, '99 Bimota DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, Ď94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, Ď61 BSA A10 650
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hippotech



Joined: 14 Aug 2018
Posts: 18
Location: Cumbria, UK

PostPosted: Sun Mar 24, 2019 11:14 pm    Post subject: First proper ride on the SB6, 1st impressions Reply with quote

Well today I really opened her up and gave he a good run out.

A quick action throttle would be a good addition, travel is a bit far for my liking. There were some sublime moments but you really have to work for them in the 'power band'. Breaks are absolutely superb, 1 finger and raising the tail. Bike is a little cramped for my 6ft, or I'm just getting old and less bendy. Seems smaller than my old NC30. Lots of feedback to the point of feeling the rear tyre squirming under power. Clip-on's were pretty buzzy and I found I was quite tired in my hands after the ride. For a bike with a fair amount of power it didn't want to pick up the front wheel in 2nd. Tendency to under-steer still, even with quite a lot of body movement. Absolutely feral howl at the top end. Seems to me it would benefit from a very smooth track rather than bumpy B roads. Used up a heck of a lot of fuel on full throttle riding and seems to be running a bit rich, so will get her tuned.
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Evilchicken0



Joined: 12 May 2010
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PostPosted: Mon Mar 25, 2019 9:12 am    Post subject: Reply with quote

Have you had the suspension set up on it yet ???
I dropped the bars on the forks a bit - 25mm made it easier to get close to the tank and feels a bit better
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