M750 project - Page 2

25-11-2011, 12:38 PM

Saturday came early,grinding belts did not arrive for a job I am doing so some "me time" on a roll now.

26-11-2011, 12:37 PM

S4 belly pan fitted a treat without any modifying.

26-11-2011, 02:03 PM

Looking good so far mate.

27-11-2011, 11:12 AM

Wow looking good!
On your downtime why not build the micro brewery in the shed for those moments when things don't turn up or don't go as planned?

Win win situation!

Mind you those tanks are not small!

27-11-2011, 11:28 AM

Too busy making sloe Gin to get involved with the ale at the moment, have enough room tho! Managed 18 bottles this year bring on the snow!

gary tompkins · 27-11-2011, 12:24 PM

Looks like you are making great progress on the bike.. and the gin

27-11-2011, 06:52 PM

Started on the exhaust system today going for a two into one reverse cone thingy, will make some sort of baffle using a 4" carbon tube on the end 3" perf tube and wadding.

This is just a mock up final position not determined yet," but ye will git ma drift"

27-11-2011, 07:54 PM

when "they" say 2 in to 1 on parallel twins work but on V / L twins it doesn't improve power the only thing I can see that is majorly different is the length and frictional losses on the rear cylinder.
Just a thought for you;
If you look at the losses on the rear/ shorter link pipe you could add a plate valve (washer with a hole) to get the pressures/ and fluid movement of the exhaust gasses equal on both cylinders.
Or just build it and see how it works.

27-11-2011, 08:19 PM

Quote:

Originally Posted by Lima071

when "they" say 2 in to 1 on parallel twins work but on V / L twins it doesn't improve power the only thing I can see that is majorly different is the length and frictional losses on the rear cylinder.
Just a thought for you;
If you look at the losses on the rear/ shorter link pipe you could add a plate valve (washer with a hole) to get the pressures/ and fluid movement of the exhaust gasses equal on both cylinders.
Or just build it and see how it works.

Both headers will be 21" long or very close to, the main cone is 24" long tapering to 4" with a 1" long reverse cone down to 3" this will improve mid range it has all be calculated tried and tested but not on this particular motor.Two separate exhausts will be better for top end. Look at the grand fathers of the belt drive 2v twins TT1 750 AND TT2 600 they worked well for four world titles using a two into one system. I dont see the washer being a good idea would be too much of a restriction I would rather do the head scratching and if need be double back using bends to get the correct length.I can reduce the cone dia at the end to gain more back pressure if needed. Well that's my interpretation of it anyway.

I ran my Pantah with a works exhaust not only did it go well it sounded braw!
I would not say the std exhaust collector is the most advanced design when I first saw it I thought to myself what the feck is that supposed to be and was the first thing to be junked.

13-12-2011, 09:47 AM

Electrics done, brake and clutch lines also just need to chase up the painter for my tank now and set about the exhaust.

utopia · 13-12-2011, 12:54 PM

The 2-1 system will be interesting. Looks like you're planning a system like the one I was planning for my 750 (until I happened across some ridiculously cheap hi-level ti Termis).
Its always seemed to me that there's little point in carrying around two cans when one will do the job.
I like the look of the single can system too.
One thing that concerned me slightly was the fact that, in the std system, each cylinder exhausts through both silencers simultaneously, hence the pressure pulses will be much higher in the single can and I was concerned that this might tend to blow the can apart.
I guess there may also be a problem of getting enough silencing out of just the one can, though many would not see that as too much of a problem.
Stuart runs a 2-1 on his 750 though, and I don't think he has any problems with it.
There's something pure, natural and clean about a single can system.
Personally, I would say that, in your mock-up, the can looks a little long and might look better with a longer collector section and correspondingly shorter can.....just to mess up your calculations.
It might be easier to get maximum ground clearance that way too.
Looking forward to seeing the finished result.

13-12-2011, 02:43 PM

Had been with the idea of two stubby cans the last week or so dont like the long cone either, going to mock a shortie up and see what it looks like both sides was thinking of a 2" link after the header length to make up for the reduced cone length.I can use the long cone for my TT2 project.

gary tompkins · 13-12-2011, 03:09 PM

Something like this maybe?

http://www.bikeexif.com/hypermotard-ducati

13-12-2011, 04:10 PM

Stubby reverse cone! not keen on the oval can.

utopia · 14-12-2011, 03:31 AM

Dunno.
Can't look at it long enough to make my mind up cos its got open belts and they make me whince.
But probably not...I think Sam's pics look about right in general, but needs the early part of the taper replacing with straight pipe, and just possibly an inch losing from the overall length too.....maybe.
Don't like the stubby fat can on the black bike, and the system is too low slung and doesn't follow the lines of the bike very well.......all imho.

My current guess at the mysteries of exhaust design suggests that a longer system gives better mid and low range performance, and for that reason, coupled with my aforementioned reluctance to lug two cans around, my thinking is moving towards a single, hi-level can, 2-1 system.
My 750 certainly seemed more tractable when I put the hi-level cans and extension pipes on.
If your plans aren't set in stone yet, there's another option to conjure with, maybe.
But the mid slung, single tapered can look is classic.

I also wonder whether a narrow, tapered single can could provide enough silencing capacity, if it has to do the work of two cans....and any retrofitted baffles to quieten it would further increase the pressure loading on the can.

But a single can system must surely be a great way of losing a big chunk of weight.....not only do you lose one complete can, but you only have to buy one can too, so you can justify spending out for a really lightweight one, with ti internals etc.

I need to buy a welder, and learn to use it, don't I....?
.....and thus, I'm very interested to see what you come up with.

Nice job, so far.

27-11-2011, 12:24 PM	#21
gary tompkins 1/2 man - 1/2 pogo-stick Join Date: Aug 2002 Location: Dartford, Kent Bike: M900ie Posts: 7,241	Looks like you are making great progress on the bike.. and the gin __________________ GT Fully paid up member of the S.A.S. (Scottoiler Appreciation Society) 27,000 miles on original chain - and still going strong!

13-12-2011, 03:09 PM	#28
gary tompkins 1/2 man - 1/2 pogo-stick Join Date: Aug 2002 Location: Dartford, Kent Bike: M900ie Posts: 7,241	Something like this maybe? http://www.bikeexif.com/hypermotard-ducati __________________ GT Fully paid up member of the S.A.S. (Scottoiler Appreciation Society) 27,000 miles on original chain - and still going strong!

26-11-2011, 02:03 PM	#18
Lima071 Guest Posts: n/a	Looking good so far mate.

27-11-2011, 11:12 AM	#19
He11cat Guest Posts: n/a	Wow looking good! On your downtime why not build the micro brewery in the shed for those moments when things don't turn up or don't go as planned? Win win situation! Mind you those tanks are not small!

27-11-2011, 07:54 PM	#23
Lima071 Guest Posts: n/a	when "they" say 2 in to 1 on parallel twins work but on V / L twins it doesn't improve power the only thing I can see that is majorly different is the length and frictional losses on the rear cylinder. Just a thought for you; If you look at the losses on the rear/ shorter link pipe you could add a plate valve (washer with a hole) to get the pressures/ and fluid movement of the exhaust gasses equal on both cylinders. Or just build it and see how it works.

13-12-2011, 12:54 PM	#26
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,559	The 2-1 system will be interesting. Looks like you're planning a system like the one I was planning for my 750 (until I happened across some ridiculously cheap hi-level ti Termis). Its always seemed to me that there's little point in carrying around two cans when one will do the job. I like the look of the single can system too. One thing that concerned me slightly was the fact that, in the std system, each cylinder exhausts through both silencers simultaneously, hence the pressure pulses will be much higher in the single can and I was concerned that this might tend to blow the can apart. I guess there may also be a problem of getting enough silencing out of just the one can, though many would not see that as too much of a problem. Stuart runs a 2-1 on his 750 though, and I don't think he has any problems with it. There's something pure, natural and clean about a single can system. Personally, I would say that, in your mock-up, the can looks a little long and might look better with a longer collector section and correspondingly shorter can.....just to mess up your calculations. It might be easier to get maximum ground clearance that way too. Looking forward to seeing the finished result.

13-12-2011, 02:43 PM	#27
Sam69 Guest Posts: n/a	Had been with the idea of two stubby cans the last week or so dont like the long cone either, going to mock a shortie up and see what it looks like both sides was thinking of a 2" link after the header length to make up for the reduced cone length.I can use the long cone for my TT2 project.

13-12-2011, 04:10 PM	#29
Sam69 Guest Posts: n/a	Stubby reverse cone! not keen on the oval can.

14-12-2011, 03:31 AM	#30
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,559	Dunno. Can't look at it long enough to make my mind up cos its got open belts and they make me whince. But probably not...I think Sam's pics look about right in general, but needs the early part of the taper replacing with straight pipe, and just possibly an inch losing from the overall length too.....maybe. Don't like the stubby fat can on the black bike, and the system is too low slung and doesn't follow the lines of the bike very well.......all imho. My current guess at the mysteries of exhaust design suggests that a longer system gives better mid and low range performance, and for that reason, coupled with my aforementioned reluctance to lug two cans around, my thinking is moving towards a single, hi-level can, 2-1 system. My 750 certainly seemed more tractable when I put the hi-level cans and extension pipes on. If your plans aren't set in stone yet, there's another option to conjure with, maybe. But the mid slung, single tapered can look is classic. I also wonder whether a narrow, tapered single can could provide enough silencing capacity, if it has to do the work of two cans....and any retrofitted baffles to quieten it would further increase the pressure loading on the can. But a single can system must surely be a great way of losing a big chunk of weight.....not only do you lose one complete can, but you only have to buy one can too, so you can justify spending out for a really lightweight one, with ti internals etc. I need to buy a welder, and learn to use it, don't I....? .....and thus, I'm very interested to see what you come up with. Nice job, so far.