Full Adjustment for your M1BB forks!!

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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Mustang505
Posts: 134
Joined: Wed Jan 28, 2009 9:27 pm
model: 750 Sport
year: 1988
Location: Auckland, New Zealand

Full Adjustment for your M1BB forks!!

Post by Mustang505 »

I have raced my 750 sport in post classic for approx 5 years in NZ with just the standard forks and finally found a system that makes them fully adjustable!!! At my last meeting I meet Glyn Robinson who runs Sports Motorcycles now here in NZ. he showed me his creation of valves and components for M1BB and M1R forks that makes them finally work as a proper fork should and fully adjustable for rebound and compression damping. Glyn is part of the Steve Wynn heritage that provided Mike Hailwood the Ducati to win on his return to the IOM TT.
website http://sportsvalve.com/
Glyn has really done his homework and makes a damper rod for the leg that has the useless compression stuff in it. So both forks end up the same with internals and work together. all the parts fit perfect with no problem. i was going to put some pics here but his website has all the detail.

I have bought the kit and fitted to the 750 so really looking for to getting it back on track in 3 weeks time. i will post an update on how it goes.
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Cheers
Clive
HIGHWAY89
paso grand pooh-bah
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Joined: Sat Jul 16, 2016 6:35 am
model: 900 SS
year: 1989
Location: Australia

Re: Full Adjustment for your M1BB forks!!

Post by HIGHWAY89 »

That sounds like a great mod for the M1BB fork but right now i'm having trouble just locating the little cup/washer that sits directly on your taper
roller bearings on the headstem of my 89/900/ss, i presume they are the same on the 750 sport, any ideas ther, cheers Rob.
HIGHWAY89
paso grand pooh-bah
Posts: 637
Joined: Sat Jul 16, 2016 6:35 am
model: 900 SS
year: 1989
Location: Australia

Re: Full Adjustment for your M1BB forks!!

Post by HIGHWAY89 »

Hi Clive, another fork question mate, i have rebuilt my standard m1bb's as standard and now have done all the measurements to
refill with new oil, using a 4mm rod to check level and nearly impossible to see oil level on rod , do you know a better way or is there a
actual fluid amount i can go off, cheers Rob.
HIGHWAY89
paso grand pooh-bah
Posts: 637
Joined: Sat Jul 16, 2016 6:35 am
model: 900 SS
year: 1989
Location: Australia

Re: Full Adjustment for your M1BB forks!!

Post by HIGHWAY89 »

ps; your bike looks awesome, must be a load of fun on track
Mc tool
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Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: Full Adjustment for your M1BB forks!!

Post by Mc tool »

Easiest way is to get a large syringe ( or similar ) and a piece of tube , place tube a measured distance down the fork and suck fluid out till you get bubbles ..... fluid is now at the measured distance from the top . Pays to work the forks up and down a bit after refilling so as to get any air bubbles out of internal passages before setting the correct level :)
I wish I was young again............Id be heaps smarter than last time
HIGHWAY89
paso grand pooh-bah
Posts: 637
Joined: Sat Jul 16, 2016 6:35 am
model: 900 SS
year: 1989
Location: Australia

Re: Full Adjustment for your M1BB forks!!

Post by HIGHWAY89 »

thanks for that ,. sounds a lot better than my method, cheers i'll give that a shot, basicly overfill a little and suck till she stops.
Mc tool
paso grand pooh-bah
Posts: 1874
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: Full Adjustment for your M1BB forks!!

Post by Mc tool »

Yeah , its more the volume of air left in the fork once it has its oil that's the important part as this compresses with fork action , which is why checking the level of oil in compressed forks ( springs out ) is better than measuring the amount of oil going in ( unless you know the exact amount AND can be sure there is no residual oil in there ), specially with forks such as the M1R's which have different internals in each side. By adding more oil you reduce the air volume which effectively increases the overall ( spring and compressed air ) spring rate and the fork will firm up quicker ( and more overall) as its compressed :)
I wish I was young again............Id be heaps smarter than last time
HIGHWAY89
paso grand pooh-bah
Posts: 637
Joined: Sat Jul 16, 2016 6:35 am
model: 900 SS
year: 1989
Location: Australia

Re: Full Adjustment for your M1BB forks!!

Post by HIGHWAY89 »

that went pretty well, oil in and all buttoned up thanks very much, the cup/washer i was saying i cant find to buy i believe were not an original part of the steering head assembly anyway, atleast thats how it seems in any diagrams i can find, ie steinedinse and my parts bookso im hoping to have that all back together soon,thanks ,Rob.
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ducinthebay
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Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: Full Adjustment for your M1BB forks!!

Post by ducinthebay »

The kit looks really nice. Just can't quite justify the cost right now. But, if you are racing, or doing trackdays, its all well worth it.

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.
Vincent1
Posts: 2
Joined: Wed Oct 26, 2016 3:03 pm
model: 750 Sport
year: 1989
Location: UK

Re: Full Adjustment for your M1BB forks!!

Post by Vincent1 »

After fork bushes for marzocchi M1BB 40mm forks 750 sport. Help!! Uk.
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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: Full Adjustment for your M1BB forks!!

Post by paso750 »

have you tried to check your local Duc dealer asking for the availability of #34910061A?
This shop http://www.duc-store.de/epages/15495490 ... Categories (at least last year when I had asked) claimed they could get them within a week. If that`s so a Duc dealer should be able to order them as well.
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