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Re: 1990 750 Sport for sale

Posted: Sun Jun 17, 2018 10:47 am
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.

Re: 1990 750 Sport for sale

Posted: Sun Jul 15, 2018 3:16 pm
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.

Re: 1990 750 Sport for sale

Posted: Mon Jul 16, 2018 8:51 am
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!

Re: 1990 750 Sport for sale

Posted: Wed Jul 18, 2018 8:39 pm
by Challenger392
Dang it!!!

Re: 1990 750 Sport for sale

Posted: Fri Jul 20, 2018 2:18 am
by Bluey
Challenger392 wrote:Dang it!!!
Fit a radiator? that wouldn't be too hard...

Re: 1990 750 Sport for sale

Posted: Fri Jul 20, 2018 2:09 pm
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.

Re: 1990 750 Sport for sale

Posted: Fri Aug 03, 2018 9:36 pm
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.

Re: 1990 750 Sport for sale

Posted: Fri Aug 03, 2018 9:40 pm
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.

Re: 1990 750 Sport for sale

Posted: Fri Aug 03, 2018 11:16 pm
by higgy
Sounds like either a cable or throttle shaft hanging up or an air leak

Re: 1990 750 Sport for sale

Posted: Sat Aug 04, 2018 9:08 pm
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.

Re: 1990 750 Sport for sale

Posted: Fri Aug 10, 2018 9:17 pm
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.

Re: 1990 750 Sport for sale

Posted: Sat Aug 18, 2018 2:18 pm
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.

Re: 1990 750 Sport for sale

Posted: Sat Aug 18, 2018 2:19 pm
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

Re: 1990 750 Sport for sale

Posted: Sat Aug 18, 2018 2:29 pm
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.

Re: 1990 750 Sport for sale

Posted: Sun Aug 19, 2018 12:04 pm
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.