Stark MX Supermoto & Warp9

[Jasperfield]

I built this up in August '24 and it's the most fun bike ever.

 

[FYR]

I ordered an SM wheelset last week. Pretty excited to get them! Are you running a 5" rear? Looks like you've got the GPR300's, what sprockets are you running?

 

[Jasperfield]

Rear wheels are 4.25", there's no reason for larger, it would only be heavier and a tight fit between the swing arms. Tires are Dunlop GPR 300s. Both sprockets are stock Stark with the rear being 47T. Plenty of torque and speed. The stock chain is used without modification.

 

[Jasperfield]

In about a week I plan to order a Varg EX. This one (shown above) will be for sale with its brand new, unused 18" MX tires & wheels. This one is only lightly used and has very low mileage / hours. I bought it new at end of August.

 

[Jocke_D]

Rear wheels are 4.25", there's no reason for larger, it would only be heavier and a tight fit between the swing arms. Tires are Dunlop GPR 300s. Both sprockets are stock Stark with the rear being 47T. Plenty of torque and speed. The stock chain is used without modification.

I find it the other way
Most tires that fit the 4.25 will get to wide even though the rim is narrower. A proper 160 on a 5" will have a better fit.

 

[Jasperfield]

Not likely. The Dunlop 300s fit very well with arguably more clearance and significantly less weight. But, you can use whatever you wish. The Stark has plenty of power for both.

 

[Jocke_D]

Not likely. The Dunlop 300s fit very well with arguably more clearance and significantly less weight. But, you can use whatever you wish. The Stark has plenty of power for both.

If you have found a tire that works that great. Just saying it's not as easy to just get a narrower rim and expecting a narrower end result, so to say.

For my latest build on a CR500 I did that exact mistake and went with a 4.25 but it ended up being wider when the tire went on.

 

[doates625]

I built this up in August '24 and it's the most fun bike ever.
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Did you do any suspension modifications? What spring and damper settings? I found a Stark Varg supermoto build here where they did a bunch of fine suspension and geometry tuning but wondered to what degree those mods would even be noticeable for a layman.

 

[Jasperfield]

Rear: Stock spring, re-valved for my weight and used low friction piston band, KYB K2C fluid and 150 psi Nitrogen. set-up for a bit softer than stock for SM on street.
Front: Stock spring, re-valved for my weight and used KYB 01M 5wt fork oil at 350cc, set-up a bit softer than stock for SM on street.
I have all the stock parts organized, labeled & stored. I don't race this at all, it's purely for relatively slow playing and short distances.