Hi OMR
The carb had a stock needle and 165 main jet. I purchased a DJ kit and changed to a DJ needle on second groove, and main jet to a 175.
Pilot two full turns.
I also drilled out the two existing holes on the slider thing and didn't dare the other two yet.
I did all the airbox mods with lid on, I ran the tubes into the box.
As far as the spring I will just order a 2005.

I have a K&N air filter and an end cap with repacked baffle.
I haven't fired it up yet since I am in the middle of a major overhaul.
Does the jetting sound about right to you? I am at around 1000-1100ft

Thanks.

 

You must drill the extra 2 vacuum ports to really note a major change.
You just have to be careful and take your time. After you pilot a 1/16 drill, look from the back side for alignment. If not centered, just reinstall the 1/16 drill and side drill to the best location. Now with best location, drill with a 1/8.

If you totally goofed up, buy some JB Weld and plug hole. Let dry 1 day and then start again.

Jetting, for winter, 180-185 DJ main, summer a 175. This with stock CDI and endcap.
Pilot screw out 3 turns winter and 2 1/2 summer. This with 40-45 jet and stock cdi.

OMR

 

Thanks for the info. OMR.

I will try the other two hole this weekend, Change my jetting, and check what size the pilot jet is.
If I got a high performance CDI such as a Big gun, or Ron Woods, How would that affect the jetting?

Thanks again.

 

The RW cdi has no rev limiter and is a race only application. Very aggressive timing. 32 degrees.

I like the new Big Gun. Timing is 28 degrees with a rev limiter around 8500 to 8700 rpm.
This is 2 degrees over stock and good for 2hp.

Jetting with Big Gun is up one in main and raise the needle from 2nd to 3rd groove.

OMR

 

Hey Omr

I have a buddy that has a Predator, would his bike also benfit from the carb mods as well. I still have my stock carb so I can practice on it first.

 

MRDS650,

I would do all the mods for the Predator. They usually run an open airbox or bolt on filter. Thus you have to change the air jet to have the best curve. I do not know what the difference is in the taper of the dj needle, for predator, to stock is. I will send an email to DJ and see if they will share that information.

I posted my summary on the Predator Owners forum and after 2 weeks got not one person asked for help. Thus I killed the posting. I guess Doug Nickolas has that forum believing that he is the only person that knows anything about carbs. I tried to get Doug to share data between eachother and he blew me off. A few years ago he raced a couple of times in wisconsin and when we talked, he would not talk much to me because I was not a polaris owner and like most times, young people do not like to talk to older people. He has been successfull and you would of thought he would want some DS business, but I guess he is so busy and now under contract to polaris.

The atv group in general is a some number and it is ashame we do not try to help each other to enhance our hobby.

OMR

 

OMR,

Do you think the Nicholas Cycle carb mods are similar to your mods?? I have a buddy with a Preddy that sent Doug his carb for this service, but he really doesn't know what was actually done!

Thanks

 

OMR

I ordered my buddy the K&N pro intake kit just the other day because the predy has that stupid air filter design from the factory. I will be installing it in a month or so for him. I am going to make a point to do all your mods to the carb and I will let you know how it turns out. Might even be able to share some dytno results later this summer.

Thanks for your help

 

Dingo2,

Other than he taper ports the inlet side of the carb, I do not know what he does internally. He gets $200 for reworking the carb and I do not know of anyone who actually knows what he changes.

 

The Predator and the DS650 use the same needle from DJ. The assortment of main jets is all that is different.

OMR