The first DS to enter and win the Baja 1000 ran 17 / 37 gearing. It was set up by Ron Woods Racing.
I have run that same gearing on my 2000 DS and when topped out on a smooth fire road, it is scary fast. [img]i/expressions/face-icon-small-shocked.gif[/img]
I ran this set-up for over a year in both sand, on trails and fire roads with no problem however, I run a Big Gun Pipe and Ron Woods CDI w/o rev limit. I'm not sure a bone stock DS would pull this gearing in the sand very well.

 

I have HMF/K&N/Mr.HP ported intake and I always run one toother lower on the front. if I run 20 inch rear tires I run a 15, if I run 22's I run a 14. I have had good luck with this setup.

 

I keep seeing that the majority of you drop a tooth on the front to a 14 or 15. I already feel like first gear is really short with a 16 and 20" rear tires. Do you even use first gear with a 14 or 15 sprocket?

 

AZDUNER,

With 17/37 gearing, do you actually exceed the stock rev limit in 5th gear? Is the rev limiter really holding back that much power? I have thought of going to an increased rev limit, but I am worried about blowing up the motor because it wasn't built for that kind of revs.

 

I wouldnt worry about blowing the motor too much, just dont hammer it till the valves float. I would suggest a rev-limited box if you are worried at all (I wasnt worried that I would personally over-rev, but that I would crash and it would somehow rev up and blow it).

 

I agree w/ Roost.
Also, Bombardier has gradually increased the Rev. Limit since the DS's introduction. It's the same motor internally so they were pretty conservative when they first released it. I think it's really hard to hurt a stock bore motor / stock carb on pump gas.
The only time I have floated the valves is when missing a shift on a hill race and I haven't done that too many times. As a result, I have never thought I needed a rev limiter for the motor's safety.
I'm running 15/40 right now and that seems to be a good all around setup.

 

AZDUNNER,

I have an 02 DS650 Baja, and from the material I have read, the stock rev limit is 7900 rpm. I have read different threads in here about the power difference of increasing the rev limit, both positive and negative. Did you notice that big of a difference, or is the motor past it's power curve anyhow.

Also, don't you lose first gear with 15/40 gearing? I already don't use it with 16/40 and 20" tires.

 

Here is a thought. The DS motor makes most its power below 7K RPM, and the torque curve is even lower. So why would you want to rev it past the stock CDI? On a stock motor after about 7200 the power REALLY starts falling off. If you have some mods, I can see truning it tighter. Stock? I see no need. [img]i/expressions/face-icon-small-confused.gif[/img]

 

The biggest difference I noticed was when running up sand hills.
I don't remember what the stock limiter on a 2000 DS was but I was bouncing off it alot of the time in third gear when running hills like China Wall @ Glamis. I knew there was another 500-1000 unable RPMs there so I went with the Ron Woods CDI and it made a big difference in racing up that same hill.

 

[img]i/expressions/face-icon-small-smile.gif[/img] Well said!

Regear to pull the hill at the proper rpm instead of re-cdi' ing (is that a word?) to pull the wrong gear.

just thoughts dribbling out

222