M1R fork oil
- Thread starter andre
- Start date
Tippie
Hero member
- Location
- Dr?bak, Norway
There are others here with experience on M1R but 5 wt sounds like very thin oil for old style forks like these. Check your specs. How was it before you changed the oil, and was there a problem that was the reason for changing it?
If you encounter problems with suspension it would be wise to study the setup guides from e.g Racetech for checking of spring weight and static sag etc. It is quick to check and gives you a good picture of where you are starting from.
If you encounter problems with suspension it would be wise to study the setup guides from e.g Racetech for checking of spring weight and static sag etc. It is quick to check and gives you a good picture of where you are starting from.
Laverdalothar
Hero member
- Location
- Germany
Hi Andre,
5 is the recommended oil for the M1R, which gives a very sensitive fork travel. If you experience bottoming out, I would recommend to check the air-gap above the oil-level when forks are compressed and the springs are out. Factory setting is 170mm, you can reduce that to 140 in steps. (make sure that the bike does not hop off its centerstand when you take out the fork springs and compress the fork! happens easily!!!).
Other way would be to apply some pressure via the top valves. This will make the forks a bit more "wooden" though.
changing the oil-quality would be only necessary on the compression damping side of the fork, if rebound is OK, so please only do that on the compression leg. Have you tried changing the setting at the right lower leg? is this adjuster moving freely?
5 is the recommended oil for the M1R, which gives a very sensitive fork travel. If you experience bottoming out, I would recommend to check the air-gap above the oil-level when forks are compressed and the springs are out. Factory setting is 170mm, you can reduce that to 140 in steps. (make sure that the bike does not hop off its centerstand when you take out the fork springs and compress the fork! happens easily!!!).
Other way would be to apply some pressure via the top valves. This will make the forks a bit more "wooden" though.
changing the oil-quality would be only necessary on the compression damping side of the fork, if rebound is OK, so please only do that on the compression leg. Have you tried changing the setting at the right lower leg? is this adjuster moving freely?
jotacorsa
Hero member
- Location
- between Santa Fe and Taos
i can count the M1R's i've serviced on one hand so my tuning is limited
this was posted on another forum for other brands with M1R fitment:
Marzocchi M1R Specifications
The following information supplied by Marzocchi in Feb.1986
and should be use for the 1989-90 Ducati 851 and SP versions,
Bimota DB1, S, SR series motorcycles.
This what I have found and what actually worked well for me (170 lbs)
And my son (120lbs).
GENERAL INFORMATION
The right fork assembly controls rebound (knob at the bottom of the fork slider) and the left fork assembly controls compression (no control anywhere).
Different levels and different viscosities of oils can be used to suit conditions. This is the beauty of these forks. Adjustments on each leg will not effect the other. Only fork springs and oil levels need to remain the same. Oil viscosity can be varied on each leg if you are competent enough to judge and appreciate the differences.
Fork Springs
There seems to be misleading and inconsistant information on the springs for the M1R forks. There are 2 springs, one in each leg. Some parts breakdowns will only show one and even Marzocchi literature is misleading when it actually shows NO SPRING in the crossection of left fork tube. Trust me.......there ARE 2 springs.
Marzocchi has different fork springs for the 42mm M1R forks which are:
Light Spring-------30 inch/lbs---------Part # 18.0071
Medium Spring ---40 inch/lbs---------Part # 18.0072 (standard)
Heavy Spring-----50 inch/lbs---------Part # 18.0073 (standard)
Progressive Suspension has springs (Part # PS 1130). They work extremely well especially with the adjustable preload caps (no Part #) on pg. 7 of the Pro Italia, June 1994 catalog. These adjustable caps were made for the Ducati 750 Paso and the 907 Paso.
FORK TUBES
It appears that the right and left fork tubes are of different lengths as supplied on a motorcycle and there are different lengths available.
YOKES (Triple Trees)
Different offsets and stem diameters are available.
OIL LEVEL(s)
The oil level is measured from the top of the open fork tube (cap off) to the centerline (repeat: centerline) top of the oil inside the upper fork tube. Take the springs(s) out and compress the fork completely to
Make this measurement.
38mm tube models should have 160 mm of air distance from top
42mm tube models take 170mm of air distance from top.
I recommend you buy one of the many availble fork oil measuring tools that look like a very large medial syringe with a long tube where the needle would be. On that tube there is a sliding disc that will rest on the top of your fork tube. The idea is to put a large amount of oil in the tube and then(with the tool) you suck off the unwanted oil and then repeat for the second tube. Simple and very accurate.....IFthe forks are vertical.
Use 5 weight oil for temps 10-15 centigrade (30-50 F)
Use 10 weight oil for temps above 15c (50 degrees F )
Adjust the oil viscosity to suit temps. There is 2 wt oil for colder temps and you can "play" with mixtures as you desire and learn.
The right fork leg with the knob down on the bottom is for REBOUND and has 4 (yes only 4) positions. You can rotate past 4 and will go back to 1 after you get the oil and spring(s) installed you should be able to tell the 1 position from the 4 position.There are different springs in the REBOUND adjustment (knob area) to adjust the range of rebound dampening rates (not to mention you can play with oils).
Light rebound: Spring # 71.0050
Medium rebound: Spring # 71.0051 (nromal)
Heavy rebound: Spring # 71.0052 (normal)
Use no air in these forks. From time to time you will need to bleed off unwanted air that gets trapped in the forks.
MODIFICATIONS TO FORK LEGS (Tubes)
In March 1986 a Marzocchi service bulletin recommended:
Left tube: drilling a 6mm hole, 65mm from the bottom of the fork tube
Right tube: drilling a 6mm hole, 35mm from the bottom of the fork tube.
BE CERTAIN TO "DEBUR" THIS HOLE AND SMOOTH EDGES OF
DRILLED HOLE AS BEST POSSIBLE.
ricambi.spa@marzocchi.it has the Marzocchi service manual & parts book (one book) and spares.
this was posted on another forum for other brands with M1R fitment:
Marzocchi M1R Specifications
The following information supplied by Marzocchi in Feb.1986
and should be use for the 1989-90 Ducati 851 and SP versions,
Bimota DB1, S, SR series motorcycles.
This what I have found and what actually worked well for me (170 lbs)
And my son (120lbs).
GENERAL INFORMATION
The right fork assembly controls rebound (knob at the bottom of the fork slider) and the left fork assembly controls compression (no control anywhere).
Different levels and different viscosities of oils can be used to suit conditions. This is the beauty of these forks. Adjustments on each leg will not effect the other. Only fork springs and oil levels need to remain the same. Oil viscosity can be varied on each leg if you are competent enough to judge and appreciate the differences.
Fork Springs
There seems to be misleading and inconsistant information on the springs for the M1R forks. There are 2 springs, one in each leg. Some parts breakdowns will only show one and even Marzocchi literature is misleading when it actually shows NO SPRING in the crossection of left fork tube. Trust me.......there ARE 2 springs.
Marzocchi has different fork springs for the 42mm M1R forks which are:
Light Spring-------30 inch/lbs---------Part # 18.0071
Medium Spring ---40 inch/lbs---------Part # 18.0072 (standard)
Heavy Spring-----50 inch/lbs---------Part # 18.0073 (standard)
Progressive Suspension has springs (Part # PS 1130). They work extremely well especially with the adjustable preload caps (no Part #) on pg. 7 of the Pro Italia, June 1994 catalog. These adjustable caps were made for the Ducati 750 Paso and the 907 Paso.
FORK TUBES
It appears that the right and left fork tubes are of different lengths as supplied on a motorcycle and there are different lengths available.
YOKES (Triple Trees)
Different offsets and stem diameters are available.
OIL LEVEL(s)
The oil level is measured from the top of the open fork tube (cap off) to the centerline (repeat: centerline) top of the oil inside the upper fork tube. Take the springs(s) out and compress the fork completely to
Make this measurement.
38mm tube models should have 160 mm of air distance from top
42mm tube models take 170mm of air distance from top.
I recommend you buy one of the many availble fork oil measuring tools that look like a very large medial syringe with a long tube where the needle would be. On that tube there is a sliding disc that will rest on the top of your fork tube. The idea is to put a large amount of oil in the tube and then(with the tool) you suck off the unwanted oil and then repeat for the second tube. Simple and very accurate.....IFthe forks are vertical.
Use 5 weight oil for temps 10-15 centigrade (30-50 F)
Use 10 weight oil for temps above 15c (50 degrees F )
Adjust the oil viscosity to suit temps. There is 2 wt oil for colder temps and you can "play" with mixtures as you desire and learn.
The right fork leg with the knob down on the bottom is for REBOUND and has 4 (yes only 4) positions. You can rotate past 4 and will go back to 1 after you get the oil and spring(s) installed you should be able to tell the 1 position from the 4 position.There are different springs in the REBOUND adjustment (knob area) to adjust the range of rebound dampening rates (not to mention you can play with oils).
Light rebound: Spring # 71.0050
Medium rebound: Spring # 71.0051 (nromal)
Heavy rebound: Spring # 71.0052 (normal)
Use no air in these forks. From time to time you will need to bleed off unwanted air that gets trapped in the forks.
MODIFICATIONS TO FORK LEGS (Tubes)
In March 1986 a Marzocchi service bulletin recommended:
Left tube: drilling a 6mm hole, 65mm from the bottom of the fork tube
Right tube: drilling a 6mm hole, 35mm from the bottom of the fork tube.
BE CERTAIN TO "DEBUR" THIS HOLE AND SMOOTH EDGES OF
DRILLED HOLE AS BEST POSSIBLE.
ricambi.spa@marzocchi.it has the Marzocchi service manual & parts book (one book) and spares.
Laverdalothar
Hero member
- Location
- Germany
andre said:
Well - it depends which documentation you follow...
It was named as Rebound damping or "Anti-Dive", which would be compression damping. I think in reality it is rebound as also Scott confirmed. Just wanted to make sure you don't put it to straight (4) and therefore used the lighter oil in both tubes... 
Andre,
To get my M1R working satisfactorily at Spa last year, I resorted to topping it up with 80W gearbox oil for MZ 2-strokes! Sort of 50:50 mix with 10W fork oil.
A bit firm on the road now, but a treat once the tarmac flattens out...
Stock oil volume is 360cc/leg, more can be added to increase spring progression and avoid bottoming. I ended up with about 420cc/leg. Seems my forks are definitely a bit worn by now, used to get by with 7.5W oil for road use and added a thimbleful of 20W50 for track use. 10W usually makes the compression damping too firm, 5W allows wallowing, rebound is quite mushy.
piet
To get my M1R working satisfactorily at Spa last year, I resorted to topping it up with 80W gearbox oil for MZ 2-strokes! Sort of 50:50 mix with 10W fork oil.
A bit firm on the road now, but a treat once the tarmac flattens out...
Stock oil volume is 360cc/leg, more can be added to increase spring progression and avoid bottoming. I ended up with about 420cc/leg. Seems my forks are definitely a bit worn by now, used to get by with 7.5W oil for road use and added a thimbleful of 20W50 for track use. 10W usually makes the compression damping too firm, 5W allows wallowing, rebound is quite mushy.
piet
piranha-bro2
Hero member
- Location
- Melbourne
Am i wrong in assuming that using the oil level method is totally dependent on the length of the stanchions in use? Surely a Jota stanchion is way longer than a Ducati stanchion, therefore measuring the distance from the oil to the top of the stanchion when fully compressed and making it the same as for a different fork length is completely wayward?
I'd be going with Piet's quantity method (unless you know exactly what it's supposed to be FOR THAT LENGTH FORK).
I'd be going with Piet's quantity method (unless you know exactly what it's supposed to be FOR THAT LENGTH FORK).
Quentin,
The air volume method works for any length stanchion. The idea is to use the volume as a secondary rising-rate spring to afford some progression, especially when the actual steel spring is at its limits. "170mm from the top" affords the same amount of progression in any length of fork.
If the stanchion is open at the top, it wouldn't matter much how much oil is filled, as long as the damper components are always flooded.
piet
The air volume method works for any length stanchion. The idea is to use the volume as a secondary rising-rate spring to afford some progression, especially when the actual steel spring is at its limits. "170mm from the top" affords the same amount of progression in any length of fork.
If the stanchion is open at the top, it wouldn't matter much how much oil is filled, as long as the damper components are always flooded.
piet
Laverdalothar
Hero member
- Location
- Germany
fAndre said:
Andre, if the oil is dirty, you should make sure that the side with the adjuster on the leg, you also pull out the alloy part at the very low end of the lower leg (it is only held in by the O-Ring!). I found a lot of dirt blocking the channels in there. You can push it through with a bit of patience from the under-side of the leg through the hole where the screw sits that holds the damper. Replace if possible the O-Ring and also the one in the rebound-adjuster on the right leg as they might have suffered a bit.
I had the fork reworked by HH-Racetech to damper-elements with one side re-bound, one side compression and both sides with pre-load adjustment. Totally different fork now, but roughly 900? investment... Normal service will give it back most of its glory and if you were fine with it up to now, servicing will make for a good difference already.
piranha-bro2
Hero member
- Location
- Melbourne
sfcpiet said:
Kinda makes sense, as it's travel, not stanchion length you're accounting for. I guess it means in a really long fork you're going to have to use heaps more oil to get the same air gap (cos it'll be way above the damper components c/w a shorter fork)? Sounds a bit extreme to me - rather have the correct spring rate and preload!
Tippie
Hero member
- Location
- Dr?bak, Norway
On a chopper you would have a few gallons of spare oil in your extended forks.
Lothar
I'll take your advice and give it a go to take that leg off. And its not like I dont have time at the moment. Cant be too hard...
The black shite coming out the drain hole is amazing. Someone hasnt been maintaining... These forks are off a 851 Ducati, fitted on my Motodd. They've not had a lot of use since a full rebuild some 15 or more years ago.
And I've decided to check the cam timing for the P1 cams in my SFC1000. Installed new by the NZ dealer, but I have no confidence that timing is correct. I havent noticed anything wrong in the last 32 years, but..
Andre
I'll take your advice and give it a go to take that leg off. And its not like I dont have time at the moment. Cant be too hard...
The black shite coming out the drain hole is amazing. Someone hasnt been maintaining... These forks are off a 851 Ducati, fitted on my Motodd. They've not had a lot of use since a full rebuild some 15 or more years ago.
And I've decided to check the cam timing for the P1 cams in my SFC1000. Installed new by the NZ dealer, but I have no confidence that timing is correct. I havent noticed anything wrong in the last 32 years, but..
Andre
One of my fork experiments was trying 2 different oil levels, no not at the same time. I couldn't feel any difference between 130mm and 170mm, springs and emulators out and fully compressed. Maybe the base settings were too far out when I did this as one setting change affects every other setting. It also didnt notice any effect on suspension travel used or the big one for oil hight bottoming resistance. I didn't notice much change at all. That's 38mm Cer forks, who knows for MR1s