Hi all,

I had my Tornado 250 XR rejetted in La Paz and can happily cruise around at 100k even at 4000m - absolutely great! However I'm just concerned about drops in altitude - eg I'm going from 4k to near sea level and then back up to 4k again (from altiplano to Chilr coast and back) - maybe this will take a day or so - should I rejet to avoid engine damage? Someone told me that fuel acts as a coolant so less of it going in the engine is bad news. As a sidenote I dropped to 2300m today and noticed a smell of gasoline and idle speed shot through the roof (corrected this with idle speed screw). Could this be that not enough gasoline is getting through and is coming out the carb overflow?


Many thanks!
RTW

Well . . . if your bike is running a little too rich you lose a little power and some fuel economy. If it is running too lean it will burn a hole in the piston. I would put it back to stock jetting before I went to sea level.

The fuel overflow is a symptom a clogged float needle. Do you have a fuel filter on the bike?

Thanks Juan,

Anyone any ideas what size I could rejet for 0-2000m? It's written 132S on the factory jet - would you say that's lean enough and it wouldn't be advisable r go any lower?

Cheers!

Hi all - so the jet was 125 and this always ran fine in the mountains - can anyone tell me if this would be too lean at sea level? Cheers!

As mentioned, better to sacrifice a bit of high altitude performance for a safe range in the 2000M to sea level area. If the stock Main Jet is a 132, you know that jet is perfect for Sea Level up to about 3 to 4K meters. Above that you would benefit from the 125, as you found out.

But once down below 2000 meters, I would go BACK TO STOCK main jet.

If going UP and Down constantly, try a compromise. I would try a 128 if available. Won't be as good as the 125 up high, but most likely OK at sea level.

But to be SURE ... once down below 2000 meters, pull the plug and have a good look. If it's white or has NO deposits, you may be running too lean. So go up one Jet size. If the plug is a very light Tan (or light Gray) ... then you are PERFECT.

It will be sort of normal for your plug to get more deposits and darker color up high. That's OK as long as it's not JET black and covered in soot.

The other thing you can vary is the air flow. When UP very high, if jetting is a bit Rich, try to OPEN up the air box, remove any restrictors or take side cover off. Run better? It should! Now when you go back down, put restrictors and side cover (if you have one) back in.

Reading plugs is a bit old fashioned these days but it's how I learned and what I know. But with modern fuels it's much more difficult. They burn so clean, hard to tell what is going on. USE CAUTION.

I doubt the fuels in S. America are as clean as US or EU fuels however, so reading your plug should still be a viable option there.

Good luck!

Thanks again mollydog, I learnt to do it myself but recent attempt was ruined by Honda Peru dipshit mechanic destroying screw heads on float bowl causing me all sorts of problems up in the altiplano.