M750 Scrambler Project

[Howie]

Was hoping for Michelin's, but that's an option if the 185 doesn't foul the chain.

I didn't look at other brands nor am I recommending these tires.  Just that the size does exist.  And, yep, Dunlops are sometimes a little chubby.  Maybe these would work?  https://www.pirelli.com/tires/en-us/motorcycle/all-tires/sheet/diablo-rain    Or  https://www.bridgestone.com/products/motorcycle_tires/products/detail/pr151  I have no idea but a call to them might help.

[koko64]

Only in Oz.

The MT60RS Corsa in 180/55/17 is $322 AUS plus shipping to New Hampshire  .

[koko64]

I didn't look at other brands nor am I recommending these tires.  Just that the size does exist.  And, yep, Dunlops are sometimes a little chubby.  Maybe these would work?  https://www.pirelli.com/tires/en-us/motorcycle/all-tires/sheet/diablo-rain    Or  https://www.bridgestone.com/products/motorcycle_tires/products/detail/pr151  I have no idea but a call to them might help.

The Diablo Rain come in 190/60, but not 180. They'd be tall on a 5.5 rim, but there's every chance they're as plump as a 180 Dunlop. Feeling lucky?

[ducpainter]

The Diablo Rain come in 190/60, but not 180. They'd be tall on a 5.5 rim, but there's every chance they're as plump as a 180 Dunlop. Feeling lucky?

Not lately.

[koko64]

175/55 RX 17 KR404 Rear Dunlop Rain Tire
Intended use for:

    600cc motorcycle rear tire
    Recommended Rim 5.5″ – 6″
    Overall Diameter: 600mm
    Overall Width: 116mm
    45024484

185/55 RX 17 KR404 Rear Dunlop Rain Tire
Intended use for:

    600cc motorcycle rear tire
    1000cc motorcycle rear tire
    Recommended Rim 5.5″ – 6″
    Overall Diameter: 25.43
    Overall Width: 7.36
    45024890

Twist the Throttle With Us!

That 175 would be good. Would be as fat as a 180 Michy if its true to form.

[koko64]

IMG_2515 by Tony Kokonis, on Flickr


Next step is to get a spring for this Ohlins DU440. I'm 200 in shorts, so what do you recommend for my old 750 for scrambler duties? The numbers are no longer visible on the spring but its too soft. What about the oem Sachs progressive spring?

The forks are still not ready, so I hope the chromer hasn't lost them. Since I raised the front and lowered the back, the front feels better in the rough stuff and dirt roads. Went down a steep gravel road today and felt quite ok.

[ducpainter]

I have a 10.5 on my Monster with the Ohlins, and I'm under 200 fully geared. I'd think an 11.5, or 12. You might try emailing Eric, or Nick might have notes on a 200 pounder.

The stock spring will be too soft.

[koko64]

I knew the spring was too soft as it fell through the stroke too quickly and I was using too much compression damping to compensate.
Bugger, the more correct weight springs in my "spring bank" are all the wrong dimensions. I'll visit my suspension guy and try to scab a used spring.

Edit: I think the oem Sachs spring is too long anyway.

[ducpainter]

Before you spend money on a spring, check with someone. I'm going by memory, but I'm pretty sure I'm recalling correctly.

[koko64]

Cheers

[koko64]

I recently had a solid day riding a borrowed Scrambler Icon 800. The bike was an 18-19 model and the suspension, handling, ease of use and smooth engine were a treat. The suspension was very good over rough roads, really soaking up broken tarmac and staying composed. I had read negative reports about the suspension, but maybe this has been resolved on later models. Edit: A recent ride report indeed confirmed changed spring and damping rates for model 2019 giving more compliance and ride quality.

The bike was dead stock and to my surprise it felt very restricted and slow compared to my M750. My M750 has K&N pod filters, jet kit, light flywheel and Staintune slip on pipes. I thought that even a stock Icon 800 should smash my mildly tuned M750. If the Icon was running ok, and it seemed fine and very smooth), then maybe the single throttle body, Y inlet manifold, Euro 4 tune and exhaust Cat have really taken a toll on the 800 motor. The motor was so smooth and easy to use I suspected a heavy flywheel and significant rotating mass of other engine internals.

Overall, despite the surprisingly soft power the bike felt very good on rough back roads and I bet the Icon's motor works great on dirt roads. I was very impressed with the way the suspension used it's 150mm of travel with well controlled damping.

Anyway, just a point of comparison to inform the direction of the M750 project.

[koko64]

Who says Scramblers are just for young hipsters?

[koko64]

In a few weeks I will take my Evo 1100 to the dyno and the suspension shop is literally next door (very handy). I will have info on the progress and viability of the 750 fork rebuild and an appropriate spring for the DU440. The spare 750 forks were sent to the chroming shop but are not ready. I will have to enquire in person to see if not ready means they are too far gone to rechrome, lost, etc.
Dropping the rear ride height to its lowest position and raising the front to the max on the 750 has made the front feel much better on dirt roads and reduced the fork sag through altered weight distribution. This has increased the available fork travel by unloading them more like a dirt bike, letting them ride higher in the stroke, but it has highlighted the limitations of the Sachs shock. The adjustability of the Ohlins DU440 should give me more options to dial them in to handle the rearward weight distribution. I note that I ride the 750 differently around this altered weight distribution, more in the style of riding my mates DR650 or Tiger 800. If the spare forks cant be fixed then oil weight and levels could be adjusted on the current forks as they feel reasonable being unloaded. The unloaded forks would feel like crap trying to ride sportsbike style by weighting the bars and front tyre and hanging off like on my Evo or Gixxer, instead the pegs and rear tyre are weighted and the bike pushed under the upright rider with the wide, high bars. This is second nature to you dirt guys, but a new skillset for me which is great fun.

[Howie]

This may help  https://www.racetech.com/page/title/FTNK%20Fork%20Tubes

Thanks for the Scrambler video

[koko64]

Ive saved that Howie, thanks mate.

Gotta like the pipe..