I have an RT3 and was looking for a recommended starting point for the jetting for 10,000 ft altitude. Jets r us has an altitude chart for the main jet up to 8000 ft. A 170-180 is the recommended starting point from the stock 230 main but no pilot jet chart. Hoping that somebody in this group has some advice before I spend a ton of $ on jets. The stock 45 pilot and a 200 main is what is in it when I bought it.
Thx in advance.

I'm probably not going to help you much.  Because the right answer is you give the bike what it needs.  You can't jet by a book.  A handful of Jets is CHEAP compared to a new piston and bore. 

Major danger with what you're asking is not sure what your circumstances are but not common to stay at 10,000 feet all the time.  So when you go to a lower altitude, now you're too lean.

Also, you can't ignore other conditions.  Temperature, Humidity, and Barometric Pressure.  **

Carburetors...  especially Mikuni...  compensate pretty well for changes. I've been on rides to high altitude and going down one on the pilot, maybe one clip on the needle, and a couple main sizes usually is fine if you always stay over 5,000 feet or so.  Some don't change anything. 

** Here's a website for racing that shows the "density altitude"...  El Mirage is at about 2,800 feet but due to temp, humidity, and pressure is currently at an equivalent of 6,300 feet.  Later today when the temp comes up the equivalent altitude will be almost 7,000 feet! Point is that you can't jet for altitude alone and I can tell you from experience that stock jetting will run fine even at a density altitude of 7,000 + feet.

 


airdensityonline.com/track-results/El_Mirage_Dry_Lake/


.

 

The jetting I recommend for 10,000 feet is a Gulfstream G650.

I should have been more clear about the bikes intended use. My summer residence is at 10,000 ft. and it will be my around town bike so it will always be above 9000 ft.. The Jets R Us chart seems way too lean so that's why I posted. I understand how to jet and agree with 1 maybe 2 smaller on the pilot and 2 maybe 3 smaller on the main and adjust needle (whatever it calls for). I was just being lazy and cheap!  Thx for reply.

LOL!

It might be fine as is too.  As long as it runs fairly clean I'd just ride it.  Or lean it slightly until it does run clean. Most power on these bikes is achieved when jetting is just shy of too rich.

I am in the midst of the opposite tuning exercise.  RT1 running a 34 Mikuni with a MX jug tuned for 6 to 7k altitude and now at 500 to 1500 feet. The high altitude tune was from years ago was with quality leaded fuel.  And to add to the equation I ran mix then, Blezall geen.  Now I have the oil tank back on and the Autolube.  So to get to the point, I have found that my main jet of 260 at high altitude is not working here at low altitude.  I am going LOWER to a 250 or a 240, the jets have not arrived in the mail yet.  The engine is not happy with the big mains.  Read your plug.  It will tell you what it wants. 

This is a very low buck drill, jets are $4.50 each plus a stamp.  I will say that I am running 93 octane clear no lead whatever the hell that is.  The V8 car engines I am tuning here at low altitude HATE  this fuel, black sooty exhaust, black combustion chambers and black intake runners.  My machinists say get used to it, that is what we have to deal with.  The RT1 is 51 years old, the V8's are 58 years old.  The best advise I have been given is 'What makes your engine happy?".  

Good luck at 10k, don't burn it down, I have done that with a lot of snowmobiles above tree line.

 

All,

"The jetting I recommend for 10,000 feet is a Gulfstream G650."

Geez, the fuel burn for the G-650 would really suck down that low!  Our old, clapped-out U-21's and RC-12's really would like a higher altitude as well, and they're running PT-6A's of one version or another.  Of course, they were as much fun as can be had in something like that down at 300' AGL...

Hammer