1990 750 Sport for sale

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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paso750
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Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: 1990 750 Sport for sale

Post by paso750 »

I would agree with you on the ST2 cams if this was about a 900 not a 750 Sport. Also I have 'street use' in my mind. Not to forget that ST2 cams have become really rare and therefore expensive. 900 carb cam specs are more comparable with the 750 cams (except to the higher lift) than ST2 cams are. They will work on an original engine. There's actually an article about it somewhere on Brads site. The cams were not advanced in his test tho.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

I currently have the head at a machine shop to try to fix my blunder, I have a new valve and a new valve guide on the way, I may also order a new re-tractor rocker arm as that may be bent as well. On a side note, I did find a complete engine from a Paso 906 for sale........would there be any fitment issues installing it in the 750 sport? 900cc could be fun in the light weight sport frame.
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Derek
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Re: 1990 750 Sport for sale

Post by Derek »

Challenger392 wrote:I currently have the head at a machine shop to try to fix my blunder, I have a new valve and a new valve guide on the way, I may also order a new re-tractor rocker arm as that may be bent as well. On a side note, I did find a complete engine from a Paso 906 for sale........would there be any fitment issues installing it in the 750 sport? 900cc could be fun in the light weight sport frame.
The 906 engine is water cooled!
1994 907ie
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Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

Dang it!!!
Bluey
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model: 907 I.E.
year: 1991
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Re: 1990 750 Sport for sale

Post by Bluey »

Challenger392 wrote:Dang it!!!
Fit a radiator? that wouldn't be too hard...
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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: 1990 750 Sport for sale

Post by paso750 »

Fit a radiator? that wouldn't be too hard...
not to forget the Marelli Digiplex and its wiring. However with a different flywheel & pick ups a 906 motor can be converted to the existing Kokusan ignition.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

Finally got the bike back together yesterday. A I had to order a valve guide from the Netherlands and a valve from California :-D. I reassembled it and checked the valve lash. I only had to adjust the opener cup amazingly. She runs as well as she did before. Its good to finally know the bike is going to work again.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

I am having one small issue with carb tuning. The RPM's hang up at around 4-5k if you rev it in neutral and are very slow to come down. While riding it is sometimes slow to decelerate off throttle. A small blip of the throttle sometimes helps it to come back down. Any suggestions would be great.
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higgy
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Re: 1990 750 Sport for sale

Post by higgy »

Sounds like either a cable or throttle shaft hanging up or an air leak
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Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

Ill have to check for air leaks first. Cable seems fine I can hear the carb slides click shut if I go off throttle quickly.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

I just got my new tires mounted ab balanced today!! Ill hopefully get them put back on soon. I still have stock rims so I am running the 130/60-16 front and 160/60-16 rear. The only tire currently available comes from Shinko, which luckily makes it affordable, Ill report back on how it rides.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

I rode the bike for 60 miles yesterday and she ran like a charm. No throttle hanging, idles well at 950-1050 rpm, pulls strong, runs nice and smooth (a lot smoother than my brothers 2011 Monster 796). The power seems to drop off at higher RPM but that's probably just the nature of the beast. The only problem now is that the battery light started coming on at anything below 1500RPM. It used to flash a little if it idled down to low (800RPM), now it slowly starts to glow around 1500-1600 RPM's and is on steady below that.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

Video I posted to facebook of her running, let me know if you can't access it.
https://m.facebook.com/story.php?story_ ... 1560360090
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

As far as the throttle hanging goes, I did change out 1 carb boot that had a tear in it. That really didn't make much of a change. There were two vacuum lines coming off of the intake manifolds that Tee together and went somewhere up under the seat, not really sure what those were for... I capped them off and that really didn't do much either. I finally broke down and richened the idle mixture screws out 1/4 turn. Now it idles quite nicely and has much less tendency to hang. I probably changed the air fuel characteristics when I added intake track length over its previous config.
Last edited by Challenger392 on Sun Aug 19, 2018 12:15 pm, edited 1 time in total.
Challenger392
Posts: 36
Joined: Sun Mar 25, 2018 6:39 pm
model: 750 Sport
year: 1990
Location: Vermont,USA

Re: 1990 750 Sport for sale

Post by Challenger392 »

I figured out where the mystery vacuum hose went!!!! Turns out this bike was converted to marelli digiplex ignition. Isn't that a pretty involved process? What would be the benefit of doing this? I suppose I should hook that hose back up and see how it runs.
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