Front end setup and other bits of info needed

discussions specific to the 750 Paso

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ahdoman
Posts: 107
Joined: Sat Mar 19, 2005 12:00 am
model: 750 Paso
year: 1988
Location: Santa Clarita, Ca.

Front end setup and other bits of info needed

Post by ahdoman »

First let me say - So good to have the site back! Just in time for my front end rebuild. I've got a leaking fork seal so I need to tear everything down and install new seals (which sucks because I just installed new seals about two years ago (6k miles). But, since I'm there, I have a couple of other things I need advice on...

1) Most of the riding I do is sport touring. No racing or on the edge stuff. One of the things that bother me with my bike is that the front end tends to "skip" if I'm in a corner and hit a small road imperfection. I also tend to readily feel those same imperfections on the straights. I would like to solve this. How can I get a smoother performance out of my front end? Progressive springs? Lighter weight oil? Any suggestions would be appreciated. The current setup is stock. Also - I thought I remember seeing a "how to rebuild" front forks thread on this site. Now I can't find anything.

2) The bike has 18k miles on it. I get a bit of steering head shake if I loosen my grip on the handle bars (ok, if I let go completely). It's not immediate and it's not an extreme situation where the handlebars start immediately swapping sides but it's enough that I'd like it to eliminate it. I'm thinking this could be my steering bearings going bad? Is there a way to tell if my steering head bearings are starting to go without having to take everything apart?

3) I need to replace my brake pads since the left side got soaked with the fork oil. I'd like your opinion on what pads you prefer and why.

That's it for now and thanks in advance for the replies.
1988 Red Ducati Paso 750
1999 BMW R1100S
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ducinthebay
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Re: Front end setup and other bits of info needed

Post by ducinthebay »

Yeah, there is certainly something wrong there.
- Check to see that the rim is not bent.
- check that the tire is still round.
- Check the steering head bearings. Most of the time it just needs grease and adjustment.
- Check your wheel bearings.
- When you take it all apart, confirm that everything is tight.

Here's a nice guide from GuzziTech on the M1R forks.
http://archive.guzzitech.com/M1R.html

For videos, search youtube for Delboys Garage. He's usually right on.

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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bmw851
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Re: Front end setup and other bits of info needed

Post by bmw851 »

On top of what Phil has suggested, also some simple KISS principle type things to check are tyre pressures, and is the back tyre going square, make sure there is no swingarm side play, and are the front and rear wheels aligned properly, I'd suggest string lining the wheels to check, which may sound like a moron thing to write, but is often the reason for a bike that was alright to start with misbehaving, doesn't take much to knock out of alignment when adjusting a chain regardless of the alignment marks being the same, and you may not even realise it.

By skip, if you mean the bars try to flick out of your hands, then that is either as Phil writes steering head or to firm front suspension, and/or both, my every day ride is a Triumph 675 R Street Triple and it is a shocker (Pun intended :D ) for over firm suspension, had to fit a steering damper it was that bad on rough roads, can't get the compression and rebound damping backed off enough to make it rideable.

Just my 2 Bob's worth

Cheers

Peter
So long, and thanks for all the fish...............

https://www.facebook.com/PDBCustomGuitars
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paso750
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Re: Front end setup and other bits of info needed

Post by paso750 »

- check that the tire is still round.
a longer storage without increasing the tire pressure and w/o moving the bike a bit once in a while can lead to a flat spot on the tire. Therefore it`s always recommendable to store it on bike stands.
Another reason for vibration could be the age of the tires. Do you still have old Michelins on your bike ?

The M1R manual can be found in the downloads and the workshop manual should also show how to rebuild the fork.
Just remember driving a screw in the old oil seal and warming up the upper part of the fork leg will get the seal out effortlessly and with no damage to the forkleg other than when trying to lever it out.
Also slide on the oiled oil seal on the stanchion tube when rebuilding the fork. I`ve seen guys replace the oil seal in the fork leg and then push the stanchion tube through it. It`s no wonder that these oil seals won`t last long.
If the stanchion tubes have play in the forklegs you will have to check the guide bushes.

If the bike is stored dive in the front end a few times once in a while to prevent the rubber seals sticking to the chromed stanchion tubes.
Also there`s a grease that can be used to decrease the break loose torque of the seals.

I do have progressive fork springs from Hyperpro and like them a lot.

G.
ahdoman
Posts: 107
Joined: Sat Mar 19, 2005 12:00 am
model: 750 Paso
year: 1988
Location: Santa Clarita, Ca.

Re: Front end setup and other bits of info needed

Post by ahdoman »

Thanks for all of the input. I've ordered the Hyperpro progressive springs so those will get installed. FYI - They also have a kit that includes the spring for the rear shock as well. I passed on that for now due to budget.

The front tire is a Conti Sport Attack 130/70 ZR16. I had to go that route because when my front Michelin finally gave up the tires from Golden Tyre were not yet availble. I spaced the fender up and lightly shaved the sides of the tire so it would fit. Tire was balanced after I did that. Now that the front of the bike is apart I may also cut a left and right slot in the fender where it passes behind the forks for additional clearance. I know the wheel is round because I had that checked prior to installing the new tire. The tires (front and rear) only have about 3k on them. The rear is a Shinko SE-890 180/60. Again, since the GoldenTyre options were not available at the time this seemed like the best replacement. I had to shave the sidewall a little and spaced the rear sprocket 10mm as well as doing a 10mm mod on the front sprocket as well. Chain is straight. But, when I get it back together I'll check tracking front to rear.

The bike doesn't sit too long and it's always on the center stand. I try to ride it at least once every week. Even if it's a short ride around town.

Any suggestions on brake pads?
1988 Red Ducati Paso 750
1999 BMW R1100S
Mc tool
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Re: Front end setup and other bits of info needed

Post by Mc tool »

The easiest way to check the steering head bearings . Bike on center stand ... front wheel off the ground ./ Try to pull forks back and forth to check for loose ness ( adjustment ) and turn bars from side to side feeling for any notchy ness in the straight ahead position , this indicates wear and will tend to cause the bars to want to stay a within few degrees of straight ahead , this will usually show up as a weave . If your not sure if you can feel it or not , and it can be hard to determine , try tightening up the bearings and retest . When you get the bearings out the wear is easy to see , I don't have an image to show you .... someone else might
I wish I was young again............Id be heaps smarter than last time
ahdoman
Posts: 107
Joined: Sat Mar 19, 2005 12:00 am
model: 750 Paso
year: 1988
Location: Santa Clarita, Ca.

Re: Front end setup and other bits of info needed

Post by ahdoman »

Thanks McTool. I'll go put "the feel" on my forks.

Also - Just posted this in the for sale section (http://forums.ducatipaso.org/viewtopic.php?f=4&t=6459). I bought the Hyperpro Progressive springs and when I got the invoice there was a 15% discount applied?! I called them back and asked what was differnt from what I was quoted and they said it was a holiday promo until January 30th. Reduced cost of the kit; $135.15. :choo:
1988 Red Ducati Paso 750
1999 BMW R1100S
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Fraser
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Re: Front end setup and other bits of info needed

Post by Fraser »

Ahdoman,

Try 5wt fork oil. Have used that for some years and works well.

Cheers,

Fraser.
750 Paso
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paso750
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Re: Front end setup and other bits of info needed

Post by paso750 »

Any suggestions on brake pads?
get organic pads not sintered as they wear the cast iron discs a lot more.

The Hyperpro kits usually come with the matching oil.
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Re: Front end setup and other bits of info needed

Post by jcslocum »

Without a standard size tire, your setup will be all guesswork and only apply to your bike. The hopping or jumping of the front could just be the strange sized tire. Who knows?
ahdoman
Posts: 107
Joined: Sat Mar 19, 2005 12:00 am
model: 750 Paso
year: 1988
Location: Santa Clarita, Ca.

Re: Front end setup and other bits of info needed

Post by ahdoman »

Thanks "ducinthebay" and "Paso750" for the links and info. I keep forgetting that you need to dig around in that documents section to find the treasures.

Any idea why Marzocchi released the service bulletin showing the holes being drilled? What does that do? Also. I assume the measurements they give are from the bottom of the fork tube? I assume the hole can be anywhere around the circumfirence of the tube as long as it's the right height?
1988 Red Ducati Paso 750
1999 BMW R1100S
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ducinthebay
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Re: Front end setup and other bits of info needed

Post by ducinthebay »

The holes allow the fork oil to return to the bath quicker. If you hit a quick series of bumps, you will pump all of the fluid into the center of the fork tube, and it won't have any oil left to dampen properly It also makes the fork action very stiff until the oil is allowed to return to the fork bottom. Basically, it keeps your fork action the same all the time by keeping the oil levels proper more of the time.

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.
ahdoman
Posts: 107
Joined: Sat Mar 19, 2005 12:00 am
model: 750 Paso
year: 1988
Location: Santa Clarita, Ca.

Re: Front end setup and other bits of info needed

Post by ahdoman »

Sounds like a worthwhile operation. That perfectly describes what has happening over small quick consistent bumps. I assume they are measuring from the bottom of the fork tube and not the external slider?
1988 Red Ducati Paso 750
1999 BMW R1100S
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Re: Front end setup and other bits of info needed

Post by paso750 »

there`s a pm you didn`t read
jfiore
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Re: Front end setup and other bits of info needed

Post by jfiore »

One thing to remember about the M1R - the left fork tube controls compression damping, the right fork tube controls rebound damping.

Try 5 wt fork oil in the left tube, and 10 wt in the right, I like the results that I got for both compression and rebound with the rebound control set to position 2.
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