1988 Paso 750 finally running with the Weber

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murphus
Posts: 73
Joined: Wed Jun 24, 2020 6:27 pm
model: 750 Paso
year: 1988
Location: USA

1988 Paso 750 finally running with the Weber

Post by murphus »

To my great surprise my 1988 Paso is running on the Weber. I've posted about wanting to get it back to stock and my subsequent failure at getting it sorted in other threads, but apparently I finally did something right because it's up and running, and quite nicely at that. Keep in mind I haven't actually ridden it yet with the Weber. It's winter here in the Midwest in the U.S. of A, so the weather's not really amenable to riding, even if I am something of a wimp these days. Regardless, it seems to be running very nicely. I've balanced the throats to each other with the air screws and I'm getting a nice, even, maybe just mildly lumpy, idle. Throttle response is really crisp and with the air box in place there's almost no induction noise, which is actually slightly disappointing.

The turning point(s) in getting it sorted appears to center around discovering the throttle shaft was slightly bent and that somehow I hadn't quite gotten all the crud out of the various circuits, despite a good soaking and an ultrasonic bath. Also, in my earlier attempts I hadn't bothered to install the air box onto the carb, which is apparently critical for proper setup and tuning. The carb I'm using is a used one I picked up as the original is damaged. I swapped the throttle shaft from the original into the used unit after yet another soak and ultrasonic bath. I'm using sealed bearings for the throttle shaft.

I set it up with 150 mains, F27 emulsion tubes, 60 idle jets and 4.5 auxiliary venturis. Float set to 43mm and running the stock fuel pump. I'm pretty stoked. Here's a link to a quick video I did of a cold start earlier tonight:

https://www.youtube.com/watch?v=l-c-cb2bcbI
1973 BMW R75/5
1976 Suzuki GT185
1983 Lavarda RGS 1000
1988 Ducati Paso 750
1995 BMW K75
Mc tool
paso grand pooh-bah
Posts: 1811
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: 1988 Paso 750 finally running with the Weber

Post by Mc tool »

Sounds good . I found with my 906 that even removing the air box cover made it spit and fart and backfire . I guess you could "jet " your way around that if you wanted that intake howl , and lets face it , thats something no petrol head should ever grow out of :D . Fortunately mine has a pair of stainless mufflers ( not ) that you could drop a golf ball thru so noise aint a problem
ducati%20004.jpg
ducati%20004.jpg (142.93 KiB) Viewed 397 times
, specially when I had voltage issues and it would backfire in time with the blinkers......big blue flames too ........ha ha , caused no small amount of panic when it decided to play up at an intersection outside a bank in Christchurch while I was waiting for the lights to change
I wish I was young again............Id be heaps smarter than last time
murphus
Posts: 73
Joined: Wed Jun 24, 2020 6:27 pm
model: 750 Paso
year: 1988
Location: USA

Re: 1988 Paso 750 finally running with the Weber

Post by murphus »

Yeah, kinda funny, it's so damn quiet now with Silentium mufflers and the stock air box and all. I might have to put the SuperTrap mufflers it came with back on just to give it a little more aural personality. That'll have to wait a bit. First I want to replace the timing belt layshaft seal and then get a few miles on it and see how I like now that it's set up the way I wanted. I'm just a little stoked to think I might have it running right, although I could be getting ahead of myself, like I usually do. I'll report back. Love the image of back-firing in front of a bank ...
1973 BMW R75/5
1976 Suzuki GT185
1983 Lavarda RGS 1000
1988 Ducati Paso 750
1995 BMW K75
murphus
Posts: 73
Joined: Wed Jun 24, 2020 6:27 pm
model: 750 Paso
year: 1988
Location: USA

Re: 1988 Paso 750 finally running with the Weber

Post by murphus »

The weather's finally been nice enough to get out and ride the now Weber-ized Paso. Haven't quite figured out cold-starting protocol, seems to want a fair bit of gas. Temps are in the 50s-60s F. Full choke and 3 twists of the throttle seems to give the quickest start. On the move it's great, with immediate throttle response and so far no hunting at lower rpms and no lag anywhere in the rev range. It'll be interesting to see how it performs in warmer temps.
1973 BMW R75/5
1976 Suzuki GT185
1983 Lavarda RGS 1000
1988 Ducati Paso 750
1995 BMW K75
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randtcastell
Posts: 329
Joined: Fri Nov 13, 2009 4:33 pm
model: 750 Paso
year: 1987
Location: San Francisco Bay, California USA
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Re: 1988 Paso 750 finally running with the Weber

Post by randtcastell »

Congratulations! Wow, no stumbling @ 4-5K. How you do that?

For my PHM40 Dellortos its choke on, no gas, start up.

Best sound is when the throttle pump circuit opens, but that requires a bit of road for that kind of acceleration. :^)
1987 Paso 750
1973 Honda CB450
2017 Kawasaki Ninja300 track bike
murphus
Posts: 73
Joined: Wed Jun 24, 2020 6:27 pm
model: 750 Paso
year: 1988
Location: USA

Re: 1988 Paso 750 finally running with the Weber

Post by murphus »

It's probably yet a little too early to declare victory, if only because I haven't ridden it enough and in enough varied conditions, but yeah, no stumbling so far at any rev range. It pulls very cleanly. I need to put a little more slack in the throttle cable - it's a bit of a light switch the way I have it now. Unfortunately, I neglected to leave room for adjustment at the throttle end and I don't think I can reach the cable adjustment at the carb without pulling the gas tank. Might be able to finesse it from below ...
1973 BMW R75/5
1976 Suzuki GT185
1983 Lavarda RGS 1000
1988 Ducati Paso 750
1995 BMW K75
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