1988 400WR?

go up one on the front sprocket, that will tame it a bit and you should be able to do a genuine 100 miles an hour in top gear!

Look what was posted on Fakebook tonight!

I like your logic John!

whats your gearing currently? the pipe is likely producing some of the effect, as the uptite is supposed to increase power.
are you still running the mini 6 motoplat? i would imagine too much response from using the aftermarket internal rotors ive seen used

Original Pipe could smooth things out also could try going 2.0 BTDC on timing to see if that helps?

more advance will give better throttle response, so that would be wrong direction for him.

Just from a quick look, it appears to be 13/52, what is the max size front sprocket that can be fitted? Tonight I will have a proper look with the sprocket cover off.

I'll try it once I get the pipe back, it's being repaired at the moment.
Tony.

if so, then yes that would be a bit responsive. nothing insane, tho. i run 14/52 for mostly woods and medium speed stuff on my 430. a 14 will last longer and probably make your chain last longer as well..for the 430 i dislike going taller than 14/52 as its geared too tall in 1st and 2nd for woods work imo...i dislike a ton of clutching...

Oops thought it would calm it down my bad

This is quite brutal in its initial snap, then seems to sign off a bit. After the initial hit, it feels like my previous 400WR, smooth and linear.
Just as a bit of background, I have owned many big bore two strokes and four strokes over the years, but none that had a delivery like this.

I probably sound like I think it's unmanageable, it's not. It just isn't the enduro motor that I remember. I have not had the barrel off, so there could be some "mods" to the porting that are not ideal, I'll have a better idea once the OEM exhaust goes on. If what I'm experiencing is the effect of the Uptite pipe, then maybe I need to adapt to it, or just use the OEM pipe.
Maybe I'm just getting old?
Tony.

Mine still has the external rotor SEM ignition, so plenty of flywheel weight there.

Could be the pipe or Surprize's mate could have tidy'd up the ports a little.

My 400 has a linear power delivery with no Surprizes.

likely a combination of the 13 gear and the pipe, making it a bit abrupt. at least the swede has the super slow gunnar gasser throttle.

I run a 14/52 or 15/52 depending on the ride obviously 15/52 in more open areas
with all the torque you should be up a gear anyway
to answer the question a 17 tooth will fit

Thank you 2premo! 17t would be Baja gearing!

13 is too low, and will be jumpy. min 14 tooth front will tame it down a tad, and 15 if you barely use first. its a well spread gearbox and you can mix those front sprockets for a wide range of riding. that mid range hit will be a blessing with a 14 / 15 combo

I just saw that picky of "Le Camel" at the Echuca dustbowl Vinduro last year.

The highlight being when my esky fell out the back of the ute on the way home and ol mate picked it up. he was seriously annoyed that he didn't find the 3 stubbies that were inside it. he only saw the margarine and the cheese and snags so he left them on the side of the road...

I had a proper look and it is 13/52 gearing, may have to get a 14 and 15 just to cover most conditions.
I think a 15 would be great as you say, and it has the grunt to pull higher gearing.

For the spline on your bike I have from 10 to 16 tooth and there may be a 17 in the book. Not sure what one could actually get at this point. This is one thing these bikes have over the modern ones though it must come at the price of having the output shaft farther from the swingarm pivot.