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 Post subject: Re: Back into my 89 900 Supersport
PostPosted: Thu Jan 02, 2014 10:41 pm 
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Joined: Tue Dec 03, 2013 7:41 am
Posts: 66
Location: Gympie Qld Australia
model: 900 SS
year: 1989
Thanks Phil, didn't think about whether there is enough space to recess under the seat but need to check that out as my fuse block has broken off it's mounts. The plastic has crumbled. Haven't pulled the tail off yet to look at that.

Trying to avoid elbows in the inlet tract too if I can help it, would prefer a straight entry. I have mocked up with some plumbing elbows I have lying around and they do not clear the brace either so any elbow would need a hump in the front edge to miss the brace. Given that I would prefer the extra effort to move the brace forward so might just bite the bullet and do it. It looks like with the brace moved forward a fairly decent K & N will fit. Ca Cycleworks supply an RU1750 with their kit that has a 2" rubber flange/neck with a 20 degree kick then a 4" long by 3.5" body which would be a good fit. Ultimately I would prefer a decent bellmouth adaptor with a short flange (5/8) K & N. There are some guys working on good bellmouth designs but unless the flange of the filter is flush or below the bell I see no benefit.


Instead of buggering around with some angled Unifilters that will still be compromised by pressing hard into the brace Ii may just have to get keen and move it now.


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 Post subject: Re: Back into my 89 900 Supersport
PostPosted: Fri Jan 03, 2014 4:50 am 
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paso grand pooh-bah
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Joined: Sat Sep 03, 2005 12:00 am
Posts: 1309
Location: SF Bay Area
model: 750 Sport
year: 1990
Yeah, well, if you cut and weld, then moving that cross brace forward looks to be a reasonable course of action. I think the only reason that brace is not further forward, was the original size of the battery needed, and you have downsized that quite a bit. if you need some CrMo tubing, and old bicycle frame offers plenty.

The SS has the battery near the top of the rear cylinder, which might work for you. Plenty of room under that tank with the air filters up front. Heck, you might be able to fit an SS air box.

Cheers, Phil

_________________
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.


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 Post subject: Re: Back into my 89 900 Supersport
PostPosted: Fri Jan 03, 2014 12:58 pm 
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Joined: Tue Dec 03, 2013 7:41 am
Posts: 66
Location: Gympie Qld Australia
model: 900 SS
year: 1989
ducinthebay wrote:
Yeah, well, if you cut and weld, then moving that cross brace forward looks to be a reasonable course of action. I think the only reason that brace is not further forward, was the original size of the battery needed, and you have downsized that quite a bit. if you need some CrMo tubing, and old bicycle frame offers plenty.

The SS has the battery near the top of the rear cylinder, which might work for you. Plenty of room under that tank with the air filters up front. Heck, you might be able to fit an SS air box.

Cheers, Phil


Bit the bullet and moved the brace forward. Perfect solution. Clears the existing K & N filters fairly easily and I should be able to get the larger cylindrical ones in with a few mm to spare when I upgrade. The ones I have now do not have a lot of internal volume so the longer ones should be better. I could even squeeze the battery back up the front as it looks like you could just get it out from below if it was mounted hard to one side but I think the space behind the headstock will be better served with putting the coils back in behind the reg/rec. I had moved them and cable tied them to the frame back near the rear cylinder to allow access to adjust the Minunis. I think I can make a bracket to hold them and the starter solenoid which will get the solenoid closer to the starter also. This will allow a bit more room and the battery should fit in the tray under the seat with the Digiplex. My tank leaks a little at the front too so it's probably better to not have the battery under there, another thing to fix.

The battery just fits very tightly under the seat where the solenoid was so I might cut the bottom out of the tray at that spot and fold up an light ally tray that drops down say another 10mm for clearance. I can silicon it into the tray to seal it.

Anyone know how close the swingarm/shock/tyre get to the tray on full compression. I see the tray does have a bit of a clearance hump in it.

I had been thinking the later airbox for some time but it will not fit with the brace. I tried it briefly with the brace out and I'm still not sure it would be an easy fit in the Sport frame although I didn't get too involved with it. The brace is the subject of much discussion with the later bikes and their frame cracking so I'm not sure it's worth leaving out for the sake of the airbox anyway. I have seen the airbox modded to miss a brace and I have seen a bolt in brace from the UK neither of which look all that professional for my liking so I am happy to stick with the K & N's. It would not be that hard to make up a fibreglass airbox at some stage using the adaptors out of the later airbox but again I'm not sure it is worth the effort.

Pic tomorrow, only just finished in time tonight to clean up and go out for dinner so not so popular.


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 Post subject: Re: Back into my 89 900 Supersport
PostPosted: Fri Jan 03, 2014 5:20 pm 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5090
Location: southern Germany
model: 750 Paso
year: 1987
Quote:
The SS has the battery near the top of the rear cylinder, which might work for you. Plenty of room under that tank with the air filters up front.

found these pictures on a german Duc forum. It was about a FCR conversion of a 900SS
http://imageshack.us/f/687/p1012448.jpg/
http://imageshack.us/f/811/p1012445.jpg/
http://imageshack.us/f/713/p1012442.jpg/

G.


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 Post subject: Re: Back into my 89 900 Supersport
PostPosted: Fri Jan 03, 2014 10:24 pm 
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Joined: Sun Feb 24, 2013 11:14 pm
Posts: 70
Location: Melbourne Australia
model: other
year: 1995
fester wrote:
ducinthebay wrote:
Yeah, well, if you cut and weld, then moving that cross brace forward looks to be a reasonable course of action. I think the only reason that brace is not further forward, was the original size of the battery needed, and you have downsized that quite a bit. if you need some CrMo tubing, and old bicycle frame offers plenty.

The SS has the battery near the top of the rear cylinder, which might work for you. Plenty of room under that tank with the air filters up front. Heck, you might be able to fit an SS air box.

Cheers, Phil


Bit the bullet and moved the brace forward. Perfect solution. Clears the existing K & N filters fairly easily and I should be able to get the larger cylindrical ones in with a few mm to spare when I upgrade. The ones I have now do not have a lot of internal volume so the longer ones should be better. I could even squeeze the battery back up the front as it looks like you could just get it out from below if it was mounted hard to one side but I think the space behind the headstock will be better served with putting the coils back in behind the reg/rec. I had moved them and cable tied them to the frame back near the rear cylinder to allow access to adjust the Minunis. I think I can make a bracket to hold them and the starter solenoid which will get the solenoid closer to the starter also. This will allow a bit more room and the battery should fit in the tray under the seat with the Digiplex. My tank leaks a little at the front too so it's probably better to not have the battery under there, another thing to fix.

The battery just fits very tightly under the seat where the solenoid was so I might cut the bottom out of the tray at that spot and fold up an light ally tray that drops down say another 10mm for clearance. I can silicon it into the tray to seal it.

Anyone know how close the swingarm/shock/tyre get to the tray on full compression. I see the tray does have a bit of a clearance hump in it.

I had been thinking the later airbox for some time but it will not fit with the brace. I tried it briefly with the brace out and I'm still not sure it would be an easy fit in the Sport frame although I didn't get too involved with it. The brace is the subject of much discussion with the later bikes and their frame cracking so I'm not sure it's worth leaving out for the sake of the airbox anyway. I have seen the airbox modded to miss a brace and I have seen a bolt in brace from the UK neither of which look all that professional for my liking so I am happy to stick with the K & N's. It would not be that hard to make up a fibreglass airbox at some stage using the adaptors out of the later airbox but again I'm not sure it is worth the effort.

Pic tomorrow, only just finished in time tonight to clean up and go out for dinner so not so popular.


Don't sweat too much on not being able to use a later carbed 900SS/M900 airbox. I have dyno tested an open airbox with K&N filter Vs the K&N RU1750 pods. There was only a couple of hp and ft/lbs in it with the airbox flowing better at high rpm. That was on the dyno so I cant account for turbulence and cross wind at speed with the pods. The airbox was more forgiving jetting wise and the pods wanted less fuel at high rpm but a little right more down low.
With the jetting adjusted they would be very close. The pods were incredibly loud however (or I'm just getting old)!
My tests were on a M900 with hi comp, porting and FCR41s.

Now an enlarged/modified M900/900SS airbox is another matter. My modified airbox with about a litre more capacity and short trumpets really helped power from 5000 rpm. I gained around 5 hp from5-8000 rpm. Torque at 5000 rpm increased significantly. The ported motor wanted more air, but I note that further testing showed the bigger airbox didn't give much increase at all on an unported motor with similar mods which stands to reason. The larger airbox will be even harder to fit I suppose.

So in the end, don't worry about it, just jet carefully. Whatever you lose with pods you will more than gain with the FCRs!

_________________
1995 M900
2004 GSXR750


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