Dave's Mods...jetting question?

93' xr650l, supertrapp, clarke 4.7, big bore kit, larger exhaust manifold, excel rims, de-smogged, k&n filter, 18,000miles.

Hi all,

I am planning on doing Dave's mods this weekend, and have read all the material and watched the video. The write-up says to replace the "main jet" and "slow jet", but it does not specify whith what. At the bottom of the page, it say's the jetting should be 55/158 at sea level, are these the new sized jets that I replace the old one's with?

Also, will my local Honda shop sell these new jets, or will I need to get them elsewhere? Price?


Those would be where most people start 55/158 for pilot and main jet size. If you were to change to an aftermarket exaust you would move up a size,this is adjusted to sea level. You should be able to get your jets at your local honda shop,but sometimes not. My dealer ordered them for me,@ about 4 bucks or so each. Hope this helps.

I am at 2,860 ft. above sea level, and I do have an after market pipe. Any recommendations? I really am a noob when it comes to this carb mod stuff.

Thats where I would start then.55/158. What are you running for a pipe? Full system or muffler only?

I am running an older supertrapp pipe with 9 discs in...

I'm about the same elevation with almost the same set up as you, I run 55/165, with 2 3/4 turns out, works great for me.

Ok, I bought the bike used. The guy I bought it from had the carb re-jetted (according to him, for higher altitude) but did not do Dave's mods. He doesn't remember what the new jetting is. Is there a way to find out what jets I currently have in?

Thanks again.

Have to take the bowl off to find out. They usually have there size stamped on them.

Remove the carb,it's easy;then remove the bowl and the jets are right there. aalet us know what you got in there you may be right on.

Thanks for all the help, I did dave's mods over the weekend and found out I am running 52/158 on my jetting currently. I did the rest of the mods and put the bike together. The bike started and ran like it never has before:worthy: ...I am really impressed with the power in 2nd and 3rd gear. I still can't figure out why the first owner did re-jetting, big bore kit, and a pipe, but didn't do the other mods to the carb?

Anyway...thanks again!:lol:

Hey guys what is Daves Mods?

I am sure someone may explain it better and in much more detail than I could, try doing a forum search, I myself am looking it up too, I am thinking of doing the carb mod this summer.

:thumbsup: an inexpensive way of rejetting your stock cv carb. the search engine will come up with the plan to get it done.

did you change the jets? and if so to what? After you get this done you should get some plugs and do some pulls and read the plugs to see how well it really is jetted.

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