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NOS bike issue

 
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Wed Feb 16, 2022 10:27 am    Post subject: NOS bike issue Reply with quote

Salutary lesson here. The perils of buying a "new" bike that has stood for a long time are well known. But here's one that I've not heard before. I bought an SB6R in 2008, which was registered for the first time for me. It had purportedly been in somebody's collection since first coming to the UK in 1998, albeit it was sold to me by a dealer. I believe it was only first introduced to fluids when I bought it.

The only issue I had, that I was aware of from early in my ownership, was the the two steel coolant pipes that go into the back of the head had rusted, which was evident from the brown colour of the coolant. I replaced the pipes a while back and the coolant has long since stayed a nice shade of green.

When I needed to strip the bike down, to do the valve clearances, at around 7500 miles, I decided to put some flat slides on, to see what they would do to an already torquey motor. I don't have torque figures, but the original motor in the GSXR was producing around 125bhp, as the airbox didn't allow it to breathe at its best. Whilst induction on the SB6 was very similar to the GSXR, it was completely different on the 6R and peak power went up to around 140bhp. I believe that the flatslides have added in the region of 10% to that and torque feels stronger as well. However, the clutch started slipping, so I decided that I would replace one of the original diaphragm springs with a heavy duty item. Strip the bike down again, as one of the many "benefits" of Bimota's straight line technology, that took the frame beam from the steering head to the swingarm pivot, is that you can't get the clutch cover off with the engine in situ.

Once the clutch cover was off, I thought I would take a look at the plates, before installing the stiffer spring, expecting them to be in a condition that would reflect 7000 miles of relatively careful use. Well, it was carnage in there. All of the friction plates had several blocks of friction material torn off the plate - not worn, torn off! One plate had all of its friction blocks torn off. I assume that the friction plates, which would have had a small amount of lube on them when they were installed, effectively bonded themselves to the steels and when the clutch was first disengaged ten years later, friction blocks were torn from the friction plates. Once I got all the displaced friction blocks cleaned out, the basket and hub showed no signs of wear.

So, the salutary lesson is: if you buy a nos Bimota, or any other nos bike for that matter, budget for a replacement clutch. At the very least, get in there early doors and see what shape it's in.
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stockcar



Joined: 07 Apr 2011
Posts: 836
Location: in the shadow of the "angel"

PostPosted: Wed Feb 16, 2022 1:42 pm    Post subject: Reply with quote

intriguing...........

good to see its sussed
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Evilchicken0



Joined: 12 May 2010
Posts: 2996
Location: London

PostPosted: Sat Feb 19, 2022 9:41 pm    Post subject: Reply with quote

I had heard of this with one of Oily's SB6 waaaay back in the day. One of the bikes he bought had been standing and had the same thing with the friction plates sheared off.

Hopefully it was easy to drop the engine Wink Wink Wink
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Sun Feb 20, 2022 3:56 pm    Post subject: NOS SB6R Reply with quote

Good to know I’m not the only one to have suffered this phenomenon Chuckie. But it has knocked my confidence in the widely held view that OEM is invariably the right way to go when replacing a clutch pack. Although I guess that wisdom is more about getting a pack of reliable thickness, rather than withstanding the abuse of being left standing for years.

I’ve put one heavy duty spring in, to cope with the extra torque from the flat slides. I don’t know that it definitely needs it, but it doesn’t add much to the pull needed at the lever and I’ve no desire to get in there again any time soon!

I know what you mean about dropping the engine Chuckie Wink but I’ve found that I can get the cam cover off by pivotting the motor off the rear lower pin and get the clutch cover off by pivotting off the front pins. But I’d still like to build something like a certain stand for when I do have to drop the motor. I think I need to learn how to weld!
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Evilchicken0



Joined: 12 May 2010
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PostPosted: Wed Feb 23, 2022 8:56 am    Post subject: Reply with quote

Maybe you can drill and bolt together ?
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2bims



Joined: 03 Apr 2010
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PostPosted: Wed Feb 23, 2022 9:30 am    Post subject: Reply with quote

They do say with both cars and bikes...if the vehicle is to be laid up for several years...to depress and keep held down...the clutch...to stop the plates bonding to each other over time
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Jonny B Bad



Joined: 05 Dec 2009
Posts: 555
Location: NE London

PostPosted: Wed Feb 23, 2022 9:39 am    Post subject: NOS SB6R Reply with quote

I want to build one that’s sufficiently low profile that I can get a scissor stand under it, to lower it out of the frame to the ground and then just wheel it out. I’m probably being too ambitious, but that lump doesn’t half have some weight in it and I’m future-proofing to when I can barely pick up a mug of tea Sad
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Evilchicken0



Joined: 12 May 2010
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PostPosted: Sat Mar 05, 2022 11:46 pm    Post subject: Re: NOS SB6R Reply with quote

Jonny B Bad wrote:
I want to build one that’s sufficiently low profile that I can get a scissor stand under it, to lower it out of the frame to the ground and then just wheel it out. I’m probably being too ambitious, but that lump doesn’t half have some weight in it and I’m future-proofing to when I can barely pick up a mug of tea Sad


Yes - the one you borrowed is about 30mm to low to get my jack under using an Abba stand ... but I put a bit of wood under the front wheel
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