affecting jetting.

[89blaster89]

say i do a plug chop and its perfect right on ready to go plug. and i ride at 250 feet asl, would i be ok to run it at sea level? or would it run to lean and i would have to rejet? what im asking i guess is how much tolerance is there before its running lean and will need rejetted?

 

[Blaaster]

If you jet slightly on the rich side to start with, you should be fine all the way.

I always jet one size bigger for peace of mind, and the power loss is not noticable.

 

[phragle]

If you jet slightly on the rich side to start with, you should be fine all the way.

I always jet one size bigger for peace of mind, and the power loss is not noticable.

You wouldnt be saying that if you had ever riden a perfectly jetted bike....

 

[Blaaster]

You wouldnt be saying that if you had ever riden a perfectly jetted bike....

Well that is fighting talk if I ever heard it.

You can go plait your poop.

 

[gb blaster]

Lmao I don't know about the power difference but I do know that a plug cost 2 bucks and some change and a top end rebuild is a few hundred bucks.

 

[DUALSTROKE]

Well that is fighting talk if I ever heard it.
You can go plait your poop.

Plate not plait

I wouldn't call it fighting talk I would call it real world truth.Theres those who know how and can jet a bike and then theres ones who try and think they know how.But what do I know the power loss is supposedly not noticeable8-|

 

[jus_me]

Lol.. I have yet to get perfect jetting on the blaster "i think" I'm just changing things to much on it lately so I'm playing on the safe side for now.. yet to foul a plug, but I'm pleased with the power. I know i could probably get a little more out of her but its fine right now. If i foul a plug i got a few in the"trunk" just incase..now on the vintage bike.. i believe I'm spot on.. and i can say i do feel the difference than playing the" safe mode" but any little thing on that bike i feel.. more as far as the blaster i don't have as much time on.. so what I'm saying is imo play the safe mode and if you ride your quad allot you will might know the difference , just bring a plug or two with ya.. better changing them on the ride than a piston.. although i have done that on the trail many miles from home.. its not fun, nor really what you want to do.. bring some xtra jets with ya too, its not like it takes forever to change them.. just make sure your float and all is correct before you go.. get back to us and let know how it goes I'm interested in the little if any difference it makes on the blaster.. on my bike i go all over up n down mtns but i feel I'm good.. best luck man..

 

[Blaaster]

Plate not plait

Nope I meant plait, like getting your hands dirty.I:I

I have been tuning 2 strokes for over 50 years, using an oil rich ratio and not yet fouled a plug.

On the good side, jetting on the richer side, I have never fried a piston.

Back to the original question, if you jet one size bigger at 250 feet then at sea level it will be fine.

One can alter the AFR and fine tune the jetting by increasing/decreasing the amount of oil in the premix, for example changing from 32:1 to 25:1 leans out the AFR by approximatly one jet size.

 

[Larry's Shee]

So many variables ​

How close to the razors edge are you?
Temperature
Humidity
Air pressure
Is the motor mild or wild
Can you afford to be wrong
Are you racing or playing

With lots of experience or an EGT gage you can avoid a meltdown.

Don't recall where I saw it, but it called for one size for every 1000'
So you would need 1/4 size bigger
Mikuni pocket jet calculator calls for one size for every 20* If it's 10* cooler from your "perfect" jetting
Add another 1/2 size


Phragle is right as to most power @ PERFECT jetting. You will feel the difference as you go from rich to perfect. Unfortunately as you go over the hump, two things happen. First, the power loss is barely noticeable even on a dyno. However the combustion temp rapidly increases. Do believe Phragle mentioned EGT of 1100* @ "perfect", Aluminum melts @ 1220*F. Do the math, not much room for error