another incarnation

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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the finn
Posts: 22
Joined: Tue Feb 24, 2009 11:28 pm
model: 750 Sport
year: 1990
Location: USA

another incarnation

Post by the finn »

so you may remember this bike from a couple years ago. last winter i decided to bite the bullet and do all the things i'd always thought of doing to it. here's a summary:

- modified frame (rear section cut off, shock mount relocated).
- wheels, forks, brakes, shock from '01 900ss.
- dellorto phf 36's.
- new tank from fuelcel (i built my own tank previously, which i think looked really awesome, but eventually it started leaking - don't think i'll try building tanks again, too much trouble).
- 916 oil cooler.
- hid bixenon headlights
- led 916 taillight
- bespoke front fairing/gauge subframe.
- bespoke fiberglass fairing and tail (i started with a 916 windscreen and nose, but it ended up being very different).
- koso tnt-01 multifunction gauge.
- dynotune o2 sensor
- completely rewired everything using a pdm60 (http://pdm60.com/). all high current wiring was removed from handlebar switches and controls. i didn't realize when i bought this thing, however, that circuits are not individually switchable, so i ended up with several relays anyway.
- slime fighter oil separator at case breather (http://www.aircraftspruce.com/catalog/e ... imeftr.php).

i still haven't weighed it, but my guess is i'm now around 360-370lbs. now getting dellortos dialed, and lemme tell you, they're wonderful. to say nothing of the new rollers. as some people have mentioned on this site, the 17" conversion is totally worth it. i can't stress enough how well this thing handles now. absolute bliss. it turns in without you even thinking about it, and holds a line effortlessly. absolute bliss. i don't know how i ever put with with 16's before. easily the finest handling machine i've ever ridden (though i haven't ridden anything newer than say, 2005).

anyway, enough gushing. it's still pretty rough, and lots to do, but it's summer in the rocky mountains which means i ride.

peace - ian.
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900streetfighter
Posts: 364
Joined: Wed Oct 27, 2010 5:52 pm
model: 907 I.E.
year: 1992
Location: Essex UK

Re: another incarnation

Post by 900streetfighter »

Thats looking really pretty mate and the seat looks comfy. The tank looks like a reworked SSie with the bollock pad recess and centre crease filled in. Like the front and rear lights, very subtle. The front end looks a bit high, have you tried dropping the yokes down the legs a bit.
Are you going to put a front guard on it? A SSie or monster will fit direct with the oe nylon clips. Can I suggest a monster with about 75mm chopped off the front, I did that to my naked SSie and it looks well and also protects the motor better with the longer tail.
the finn
Posts: 22
Joined: Tue Feb 24, 2009 11:28 pm
model: 750 Sport
year: 1990
Location: USA

Re: another incarnation

Post by the finn »

thanks for the compliments. you called it on the fuel tank. fuelcel makes a streamlined version of the 99+ 900ss tank: http://eti-fuelcel.com/Ducati900SSpost.html

forgot to actually post a pic of the tail. it's one of these: http://www.motodynamic.com/94-04-ducati ... smoke.html

i haven't played with the fork height yet. i'm a little worried about contact between front tire and the oil cooler at full compression, and it handles so well. i do have a front fender with the nylon clamps, but i just haven't put it on yet.

yet to do...

- finish bodywork. i'll probably just rattle can it for the summer, then strip it all down and repaint everything professionally this winter.
- upholster saddle. still a little fiberglass to do there too.
- actually attach the saddle and taillight somehow. they're being held in place with velcro.
- build a little cowling for the headlights.
- add an oil temp gauge
- find some nice little front turn signals to put somewhere.

that's about it. actually i'm not sure i even like the bodywork i've done. maybe this winter i'll completely redo it. i learned a lot about composites and i know i can do it way better.

ian.
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paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: another incarnation

Post by paso750 »

I honestly can`t say it`s nice but it looks like fun to ride and like a nice handling bike. Riding w/o front fender and w/o belt covers. Not sure that`s the best idea. Curious to see it when it`s finished.
What does that pdm60 exactly do?

G.
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ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: another incarnation

Post by ducinthebay »

Interesting build. That front end and 17"s surely made a big difference.
What did you do to the rear shock mount? I can't see any difference.

Two recomendations
- 2" (50mm) rubber elbows on back of the carbs. It will improve the drivability, and make it easier to tune the carbs.
- big fat clear hose from the crankcase breather tube, to the back of the bike, like the old singles and bevel drives.

Oh, and the last thing. Ride it lots. Keeps the smile on your face and your blood pressure low. Fun bike. Light, simple, and enough horsepower to keep up with the locals.

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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paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: another incarnation

Post by paso750 »

about that oil sight glas. Keep an eye on it. I had the same. There are comments on the web that these fully plastic oil sight windows don`t withstand the engine heat very well and start to leak or loosen.
I had some drops of oil on the floor once but couldn`t make out the reason. When the bike was fired up it started smoking from below the engine as oil had accumulated in the header cross. It did come from the oil sight window and it didn`t feel well tightening it stronger. I had gotten mine from a Duc dealer and paid about €30. Recently I noticed I have about the same one on my air compressor and that you find these things really cheap in all kinds of sizes and threads. http://www.ebay.de/itm/1-Olschauglas-Ho ... 43a91fa6e0 (and they are sold half the price directly from China).
I replaced it with an aftermarket machined part which has quite a different quality.
the finn
Posts: 22
Joined: Tue Feb 24, 2009 11:28 pm
model: 750 Sport
year: 1990
Location: USA

Re: another incarnation

Post by the finn »

pdm60 basically replaces your fusebox with 60 amps worth of electronic breakers. a single internal relay switches everything, which i found a little disappointing. i think each circuit should be independently switchable. instead, i ended up with three other relays (ign, hi-, lo-beam).

most 900ss shocks are shorter than the unit that came stock on our bikes, so i cut off the old shock mount tabs on the frame and welded on new ones. this moves the whole shock down to put unloaded swingarm sag where i wanted it. also has the effect of steepening steering head angle and quickening handling somewhat. i'm not exactly a suspension guru, so i'll likely spend the rest of the summer trying to dial rates and damping.

crankcase breather now talks to a dedicated air/oil separator as you can see in the pic above. engine oil drains back to the case. there should be zero oil coming out of the filter, but i'll be watching it for a long time til i'm sure.

thanks for the tip on the sight glass. i've always been a little leery of these plastic ones, though i now have 500 miles on it.

peace.
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ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: another incarnation

Post by ducinthebay »

the finn wrote: most 900ss shocks are shorter than the unit that came stock on our bikes, so i cut off the old shock mount tabs on the frame and welded on new ones. this moves the whole shock down to put unloaded swingarm sag where i wanted it. also has the effect of steepening steering head angle and quickening handling somewhat. i'm not exactly a suspension guru, so i'll likely spend the rest of the summer trying to dial rates and damping.
.
Actually, the Sport shock was the same length and mounting as the later 900ss, which I think is 13" or something like that. (at least that's what came on my 750 Sport. Hard to tell what Ducati did on the 1990 900SS) The 750 SS (1991 - on) had a shorter shock by 6mm, which slows the steering a bit. If you are buying a used shock, make sure you measure the eye to eye length. If you get an aftermarket shock, some have adjustable length, so you can set your ride height where you want it. Otherwise, just make sure you are buying a shock that came on the 900ss. I found one that had been rebuild, revalved, and respringed for my weight and it was only $100 on ebay. Seller had gone to an Ohlins. Anything that fits the 1991 and on SS series will fit the Sport chassis, but the increased spring size will interfere with the oil seperator/breather 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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