Fork length/ride height...

[Dukedesmo]

So as I'm using 916 forks on my Monster I don't know what the standard ride height at the front should be.

I think that 916 forks maybe a slightly different length? so need to have a starting point for the height in the yokes and whilst I'm not ready to ride it yet it will have an effect on what handlebars I can use (adjusters maybe in the way of the bars) and also the steering damper setup - I'm planning an across-the-frame damper setup like on a 916, the positioning of which depends on the bar height etc.

Can anyone tell me the fork length, distance from yoke to axle, rideheight etc for an M900 or better still anyone using 916 forks that can tell me what line to use on the top yoke as height setting for a standard rideheight?

TIA. :thumbsup:

[bialbero]

Dukedesmo,

can't tell you the distance spindle to top yoke, but aim for 24degree steerinh head angle and 96mm Trail.
Put your bike on a straight and stable platform, zero the spirit level app on your iPhone app on the platform and then hold it to your forklegs and adjust accordingly
if you can't push the legs further in or out compensate for it with your rear ride height bearing groung clearance in mind
hope this was of any help

[gary tompkins]

What year/model 900 monster have you got? I fitted 996 legs to my 900ie and have stock showa legs on the trike for comparison. Can take some measurements if it helps? Bear in mind the springing may need changing for 900 to get the correct handling and sag/ride height. The 1.0kg/m springs on 916 forks are too hard IMO for the lighter aircooled monster. I was told 0.9kg/m or less works better... it's on my things to do list

[Dukedesmo]

Thanks for the replies, to complicate things the frame is actually from a '99 M600 and the rest is 900 and other sources.

The reason I'm looking at fork height at the moment is that I have just 'test assembled' prior to painting the frame and rebuilding the engine (no barells/heads at the moment) to check the front suspension/bars/steering damper and rear wheel/swingarm fitment but because the 916 forks have quite long adjusters on the top they may be an interference with the handlebar fitting? (don't have any bars at the moment) also I heard that the forks are a slightly different length so don't neccessarily fit at the same height in relation to the top yoke?

I've got standard Monster bar risers but unless the fork caps are set flush with the yoke (on a 916 they don't) then I don't think normal bars will fit so if I know what the height/length from yoke to spindle standard setting 'should' be (I appreciate it can be altered to suit riding style etc) then I can see what kind of bars/risers I need and also where/how to fit a steering damper - I have an across-frame damper for which I need to make a new bar mounting bracket but this depends on what type of bar mounts I use.

To give you an idea of what I mean see this pic;

http://www.ducati.ms/gallery/files/9/3/7/0/img_0346a.jpg

[utopia]

Oooh, nice tank paint.
This is gonna be one nice monster when its finished.
Looking forward to seeing it in the metal.

How about clip-on style bars fitted on the fork legs ?
Or even, particularly if you're tall, raise the whole bike by raising the yokes until you have clearance on your chosen bars, and fit rear ride height adjusters to control the overall pitch of the bike....??

[Dukedesmo]

Thanks, I had considered clip-ons but one reason for getting a Monster was for a change of style/riding position from the race-rep bikes I'm used to (probably 'coz I'm getting old :chuckle:) so I was wanting handlebars.

I have got the (Louigi Moto) ride height adjusters at the rear because I know it will be too low without. I don't need to get it setup to ride yet as there's still much to do but wanted to sort out the engineering for the steering damper mount and that is linked to the bar riser height which I'm not sure will work with those forks unless they're some trick bent bars? Of course I could get higher risers and use a flatter bar but this is what I'm trying to establish if I need or not.

A simple measurement from yoke to spindle (with unloaded suspension) of a standard Monster ride height setup would be a useful starting point plus any info from 916/996 forked Monster owners would be helpful.

:thumbsup:

[Dukedesmo]

I fitted 996 legs to my 900ie and have stock showa legs on the trike for comparison. Can take some measurements if it helps?

Yes please, measurements would be great, particularly the length of the Monster forks and the unloaded spindle to yoke measurement for both, also where are the fork tops in relation to your top yoke on the 996 sprung bike?

BTW I've had the 916 forks modified with Ktech internals, 0.95 springs and 5wt oil and they are quite a bit softer/more supple than standard, I think the spring weight should be OK for the lighter weight of the Monster plus my (substantial) weight on it? :thumbsup:

[jerry]

where did you get the bottom fork shims ???? and how much did K tech charge for the revalve and mods as i have a set of 996 forks now for my S4

[Dukedesmo]

where did you get the bottom fork shims ???? and how much did K tech charge for the revalve and mods as i have a set of 996 forks now for my S4

I got the shims made by a local engineer, who also bored out the top yoke;

http://www.ducati.ms/gallery/files/9/3/7/0/p1010664a.jpg

The revalving was done some time ago by Ktech, IIRC the valving was around £250? plus the cost of a service (around £200) but I also had ti-nitride tubes and radial brake mounts fitted at the same time.

http://www.ducati.ms/gallery/files/9/3/7/0/p1010227a.jpg

I originally had them on the 916 and they were a great improvement, if perhaps a little too softly sprung which is why I think they'll be OK on the lighter Monster. But the 916 got a set of Ohlins so these became surplus to requirements, which turned out nicely because my Monster had no forks.

[utopia]

Dunno whether this helps any, but on my M750, spindle centre to lower face of bottom yoke is 425mm.
As far as I know, its still as it came out of the factory.

And shims can be made from flat alloy sheet. The stuff they sell at B&Q as adaptor plates for the back of gas fires is the right thickness, and dead cheap.

[Dukedesmo]

Dunno whether this helps any, but on my M750, spindle centre to lower face of bottom yoke is 425mm.


Is that with the forks fully extended, wheel off the ground? because if so that measurement leaves me with 33mm of fork top above the top yoke (plus the adjusters), these same forks would only have 15-20mm above the yoke when fitted to a 916, I thought that Monster forks were longer?

If that is the correct height I could fit clip-ons above the yoke.

[gary tompkins]

I'll check mine for you tonight. My clip on bars are fitted above the yoke on the 996 legs

The trike has stock risers and renthals

[utopia]

Sorry, I was being slack, or dim witted. That is at rest, wheel on the ground.
I don't really have the kit to measure fully extended (well not without a Heath-Robinson lash up anyway.

[Dukedesmo]

Sorry, I was being slack, or dim witted. That is at rest, wheel on the ground.
I don't really have the kit to measure fully extended (well not without a Heath-Robinson lash up anyway.

OK, I would expect that you have 20-30mm of sag? so probably nearer to 450mm extended?

I would expect to see some variation between bikes due to individual setup but I'm looking for the factory setup point to start with and then possibly drop it a tad to quicken up the steering, as an example the 916 forks in my pic have 4 reference lines at the top (approx 5mm apart) the factory setup for 916 is 3rd line level with top of yoke I dropped them to the 4th, you can't go much lower or the front wheel may hit the radiator under braking.

On the Monster with the forks pushed down so that the top of the tube (but not the red cap) is level with the top yoke I get 460mm bottom yoke to centre spindle and a total length from centre spindle to fork top of 715mm.

As for measuring when fully extended, could you not wheelie while someone runs alongside with a tape measure?... :eek:

:thumbsup:

[PaulR]

Looks very nice! If you haven't changed the rear setup, how about measuring the wheelbase. Comparing that to the original will give you an idea of what's changing at the front.

[Dukedesmo]

Looks very nice! If you haven't changed the rear setup, how about measuring the wheelbase. Comparing that to the original will give you an idea of what's changing at the front.

Wel the swingarm's from an 851/888 but should be the same as a Monster so other than the ride height bolts it should measure like a Monster.

But what do I measure and what do I compare against?

http://www.ducati.ms/gallery/files/9/3/7/0/p1010878a.jpg

BTW engine has a bag over it's head because it hasn't got any fitted (heads that is).

[jerry]

Great work there

[PaulR]

Measure the distance between centres of the front and rear spindles - M900 is 1430mm stock, so if dropping the forks through the yokes so that the bars clear the fork tops gives you greater than 1430mm, your steering will be a little slower and weight distribution will be shifted back slightly. If this is the case, you still have the option of raising the rear hoop, which will shorten the wheelbase, quicken the steering and shift weight forwards slightly (while also increasing ground clearance)
If you need more adjustment at the rear you can add something like this:
http://i994.photobucket.com/albums/af65/funkuncut/hoop2.jpg

[Dukedesmo]

I've just measured it and coincidentally as the bike stands in the above pic (forks down to the yoke) it measures 1430mm (give or take a mm) as you can see, the rear wheel is about 2/3rds back in the chain adjustment slot.

[PaulR]

If your preferred bars fit like that, you're laughing! You can always quicken the steering/raise ride height with the rear adjusters too - the best test is always what it feels like anyway, but at least you know you're starting with a pretty standard setup (and even if someone starts going on about rake/trail and any other more scientific stuff, the way it feels is still what counts...):thumbsup:

[gary tompkins]

Sorry for delay - ended up at the pictures late watching Transformers 3

Will get out and measure for you tomorrow night