Two things I don't understand

[norwegian]

Hi
There is a thing that has bugged me quite some time. How do you go down HALF a jet size? Cannot find such a thing, there is nothing between say #151,3 and #150? What is meant by this?

My 97 sx 600 seems to require a reverse angled helix. It has a hauck headgasket, hauck x weights that have all of the weight in the outermost holes, like 13 grams or so alltogether. Still, the sled will overrev at top end. It has a 21/39 gearing and a 39 deg helix, any more helix and it becomes real sluggish down low. I see everywhere that the need should be opposite, more helix at the start, which would make the sled quicker, it makes mine just slower. I guess it's the low gearing, low helix angle and the green spring @70 deg that makes the sled both quick at low end but also overrev like crazy in the mid and high range right?
What's up with this?

 

[MURDER YAMAHA]

150 and 152.5 are full jet steps, 151.3 is a half step

You should not be running a 39 helix, if you have to, its because either your primary spring is too weak, or you have too much weight in the arms. Your over rev up top can be from that gearing as well, as stock is 23/39.

Personally, I would go back to stock weights, then adjust from there.
I used to run 8CR weights(stock for my XTC) and a 51/43 helix, geared down 2 teeth on top.
But, looking back on it, I used to run out of gear all the time with that setup.
I think stock gearing would have been better for what I was doing.

Just my opinion.

 

[norwegian]

Thanks for the jetting info. Seems like I partially solved the other problem with a Hauck roller, I will have to test more tomorrow, can't wait.

 

[pete_man26]

Thanks for the jetting info. Seems like I partially solved the other problem with a Hauck roller, I will have to test more tomorrow, can't wait.

Profile of the weight will adjust your shift curve.
The straighter the profile the more weight you will need to compensate, the more angled profile will require less weight.
The stiffer the primary spring the more RPM you will pull, the softer primary spring will reduce RPM.
Only use as much secondary spring needed to clamp the belt, too much will create heat and slower speeds.
Helix more angle will be like starting in 1st gear in a car compared to 2nd (less load on the motor). Less angle will be the opposite. (more load)

 

[norwegian]

Thanks, this all seem to be solved now. Now I only need to tune for the spesific conditions if needed. Now the issue is traction, it can't hook up at all with the stock track. Probably going with maxx perf transfer rods and a hacksaw 1 inch track when the Covid-19 issue calms down.