M750 Scrambler Project

[Speeddog]

Ohlins spring info here:
http://ducati-upnorth.com/tech/suspensionspring.php

That spring is way too soft, you need something like a 36/105 or 39/110

[koko64]

Thanks heaps.

Those charts are precious data. Ohlins have a strange code a bit like Dynojet jet numbers.

My local suspension shop is still open! They are finishing custom and "special" jobs while trade is quiet. They will have a shock spring for me and are putting my spare forks together which have finally been been rechromed and will be re-sprung, valved and modified for more travel (about 20mm if possible). The 20mm goal is based on the 20mm the forks can be dropped thru the clamps.

I finish one outstanding job today and my business is pretty much closed bar selling stuff thru the post. I'll need this project for my head since my other govt job taxes one's mental health and we all have to mitigate cabin fever.

The project is in full swing!

[koko64]

 Fitted some CCW Exactfit coils, some FCR 39 dirt bike carbs (finishing the details) and another crankcase breather.
Will be in touch with the suspension shop Monday.
I've got to decide where to locate the Ohlins DU440 cannister.

[Kopfjager]

 

[koko64]

Update again on mods list.

Custom seat mods x2. 1 x modified Sargent seat with Airhawk Adventure cushion(solo and adventure riding),
1 x modified oem seat (pillion).
Vacuum tap delete and manual fuel tap (Briggs & Stratton )
Reroute fuel line with Visu filter
Fit fuel hose heat shield tubing

Air box delete, K&N 2780 pod filters with K&N outers
Cut up air box/battery box to support ignition and electricals
Keihin FCR 39 off road carbs
Light Alloy Kaemna Flywheel
CCW Exactfit coils and leads
NGK Racing plug caps
Staintune exhaust

Ducati Scrambler bars
Fat bar risers (Rizoma)
Gel grips
Single throttle cable mod
Ride height and geometry changes
Dual sport Tyres (Pirelli MT60RS).
Bark buster guards modified to suit
Enduro style headlight fairing
Exhaust pipe guard
Fork guards
Single front disc and new M/C with braided line, sintered pads
1100 Evo rear 34mm brake caliper with braided line
Adjustable Brembo front brake lever
Napoleon mirrors
MX type indicators with LED globes and LED flasher relay
Trimmed front guard
Shorai battery
Modified DB killers
Lowered passenger pegs
Inlet manifold wrap, oil cooler cover for mid winter
Trimmed handlebar to suit
Extended side stand
Bar mounted clock and temp gauges

Ohlins DU440 shock
Forks modified and extended to give 25 mm more travel. Fork length increased 50mm, 25 longer via modification and pushed through the clamps another 25mm to obtain geometry and weight bias adjustment.

[koko64]

Bar mounted clock and temp gauge. Analogue clock and large digit gauge as I'm long sighted. This is also the winter/wet bike so the gauge is a good alert for 3°C and black ice. I'll ride down to 0°C/30°F.

That's also why I wanted FCRs with chokes. The performance improvement is substantial.

20200417_202530 by Tony Kokonis, on Flickr

[Pinion]

Nice

[koko64]

20200417_202655 by Tony Kokonis, on Flickr

The LED globes work a treat in the small rubbery MX indicators.

[koko64]

Finally.
Forks rebuilt and extended with 25 mm more travel and a cheap Ohlins spring out of the shop's used spring box for the shock. Forks were rechromed and modified for the purpose. Is there nothing Dave and his crew at Krooztune can't do?

Will fit them in the next day or two.

20200421_143623 by Tony Kokonis, on Flickr

[koko64]

Despite the time and money, I feel vindicated with my choice and methodology. Dave at the suspension shop said people were buying $15,000 Scramblers and spending $2500 on suspension. The M750 was cheap due to its unloved model status and although not having an ideal geometry, has made a great little all rounder. I will have to muck around with ride height, etc, but it's good to keep the mind occupied on technical stuff when business is very slow.

[ducpainter]

How will you address the rear height...extended heim joints?

[koko64]

Possibly. They do have a good 10mm adjustment at least. I'm going to test a few settings and run with whatever feels comfortable. A compromise setting for tarmac and dirt roads is the goal. I have that now but the "new" forks will throw things out being an inch longer. The current forks are pushed down so their caps are nearly flush to the triples while the rear wishbone is in the lowest position. I gave away some front end feel on tarmac to unweight the forks some on dirt roads. II'll have to try the new forks and see.

[ducpainter]

A full diameter in the threads of the wishbone has proven completely adequate on my M900. I believe that gives you more than 10 mm of adjustment, particularly if you have them buried now.

[koko64]

Yeah they're flat at present. I had 10mm at one stage which felt great on the street, but terrible on dirt roads, so I dropped em to shift some weight back. The fork caps are flush, iirc raising the front 20 mm from stock, shifting even more weight back. I have to think about how much fork to show above the clamps.

The 750 certainly requires a different riding style to the  forward biased Evo. It'll be fun testing settings front and rear playing with weight bias and aspect.

[Speeddog]

That Ohlins shock with a 'new' seal head and 10mm of shaft spacer washers will get you 342mm overall C-C
Basically it's an extra half inch of shock travel and the rocker will nearly touch the bracket for the tank

79mm shaft travel, minus ~19mm for the snubber

You'll have to massage the rocker a bit to clear the spring and upper shock body.

That'll raise the rear a lot, and you can run a good bit more sag too.

Ran like that on my M750 for a year.