2004 200txt pro jetting at high altitude

[Paclow]

I recently purchased a 2004 200txt pro and am in the process of restoring it.

i purchased the bike from a gentleman at sea level but I live in Denver Colorado and ride at 6000-8000 ft. 

Any suggestions for proper jetting. Pilot jet, main jet, needle and clip position

 

thanks!

Edited December 3, 2018 by Paclow

[oni nou]

2 hours ago, Paclow said:

I recently purchased a 2004 200txt pro and am in the process of restoring it.

i purchased the bike from a gentleman at sea level but I live in Denver Colorado and ride at 6000-8000 ft. 

Any suggestions for proper jetting. Pilot jet, main jet, needle and clip position

 

thanks!

Cannot help with exact jetting but if you want to gain a bit more power then  sealing the gaps around the internal plastic filler piece at the cylinder base [only visible if you remove the jugg] will help up the power as will fitting a 280cc pro reed block [to free up flow]  that has been fitted with boyesen carbon reed petals ALONG WITH a lower compression cylinder head to compliment the 280 reed block[contrary to the usual fitting of a higher compression head at altitude] will also help to gain power when you dial in the jetting to suit ...........S3 in Spain used to sell a Head kit with three different combustion chamber inserts HI STD and LOW.for the 125 cc that should fit your jugg[you would need to verify this] with a small amount of machining to widen the squish area to suit the larger diameter 200 model  bore. I cannot give you exact details of the modification you would have to do some testing and make adjustments to suit as you went along to fine tune the set up for where you ride.

Edited December 3, 2018 by oni nou

[nigel dabster]

FFS he wanted jetting advice not " how best to spend $300".

 

[nigel dabster]

3 hours ago, Paclow said:

I recently purchased a 2004 200txt pro and am in the process of restoring it.

i purchased the bike from a gentleman at sea level but I live in Denver Colorado and ride at 6000-8000 ft. 

Any suggestions for proper jetting. Pilot jet, main jet, needle and clip position

 

thanks!

Is it dellorto?

 

[section swept]

5 hours ago, Paclow said:

I recently purchased a 2004 200txt pro and am in the process of restoring it.

i purchased the bike from a gentleman at sea level but I live in Denver Colorado and ride at 6000-8000 ft. 

Any suggestions for proper jetting. Pilot jet, main jet, needle and clip position

 

thanks!

Proper jetting is a debatable subject when you are well above sea level. At sea level atmospheric pressure is 14.7psi so you need to be able to adequately adjust for the reducing pressure at your current height. Even two identical bikes at sea level might need (by an experts opinion) slightly different jetting in both pilot, main and needle position. You have to compensate for less oxygen in the thinning air, to best achieve the right transitioning from pilot to main and needle a number of running tests need to be done. Spark plug colour at the centre electrode and surrounding nose need to studied to ascertain each jet change etc. But first the engine needs to be in good order with air filtration and as oni nou quite rightly suggests the airbox needs to be properly sealed otherwise your adjustments will be too random for reliability. Whatever anyone says to use will be immediately out the door when you decide to ride at a lower level in height terms. So you will need a number of alternative jets so that you get the best from your engine, it’s no wonder that many a two stroke rider struggles with an engine that is also struggling to breathe with overrich or weak settings. 

Establish a base setting this will be the standard carb set up according to your manufacturers specs. That’s jet sizes, needle position and very importantly fuel/oil mix ratio, that in itself can mess with your settings. I will assume you run 70:1(crystal ball gazing)!

Idle jet, go up in whatever incremental jet stages are available eg 25, 30 etc these will not cost much. If your current idle jet is a 35 then you might try a 45. Again as oni nou rightly points out experimentation will be needed .....at this someone else who runs a bike at high level will say to use this that or the other jet but it won’t be your bikes set up if you see what I mean....?

Main jet, with the needle clip in the manufacturers specified position go up at least 15% in jet size as a starting point. Now run the engine and with out putting loads of revs on see how the engine reacts, crisp clean blips. If the engine boggs down its probably too rich on the idle jet....this is why you are going to need more than one of each jet. 

You can work it out mathmatically by using the percentage difference between sea level pressure and your positions atmospheric pressure. Once you have this you can increase the idle, main jets by that proportion. I don’t know your atm pressure but if it were 15% different then that’s the figure to increase jets by. Needle positions a plug chop test. As oni nou points out the squish band may not have the desired effect at your atm pressure. Whatever you do, my suggestions are purely that so I accept no responsibility for any damage or accidents. I know that some one will pick holes in my post but it’s there in the spirit of helping you to increase your knowledge and gain a good result with your bike. 

KMT should be able to supply jets.......www.kmtproducts.co.uk

?

 

[nigel dabster]

Hes in colorado, wouldve thought a us supplier might be better bet?

Dellorto in uk? Eurocarb are best.

[oni nou]

7 hours ago, nigel dabster said:

FFS he wanted jetting advice not " how best to spend $300".

 

Am I getting up your nose again nigel   he is at altitude with a tiny motor and may want to extract abit more power in the near future.[you know what that is I explained it to you] if he does not use my information; so what...he can choose to ignore it 

[oni nou]

1 hour ago, nigel dabster said:

Hes in colorado, wouldve thought a us supplier might be better bet?

Dellorto in uk? Eurocarb are best.

 

5 hours ago, section swept said:

Proper jetting is a debatable subject when you are well above sea level. At sea level atmospheric pressure is 14.7psi so you need to be able to adequately adjust for the reducing pressure at your current height. Even two identical bikes at sea level might need (by an experts opinion) slightly different jetting in both pilot, main and needle position. You have to compensate for less oxygen in the thinning air, to best achieve the right transitioning from pilot to main and needle a number of running tests need to be done. Spark plug colour at the centre electrode and surrounding nose need to studied to ascertain each jet change etc. But first the engine needs to be in good order with air filtration and as oni nou quite rightly suggests the airbox needs to be properly sealed otherwise your adjustments will be too random for reliability. Whatever anyone says to use will be immediately out the door when you decide to ride at a lower level in height terms. So you will need a number of alternative jets so that you get the best from your engine, it’s no wonder that many a two stroke rider struggles with an engine that is also struggling to breathe with overrich or weak settings. 

Establish a base setting this will be the standard carb set up according to your manufacturers specs. That’s jet sizes, needle position and very importantly fuel/oil mix ratio, that in itself can mess with your settings. I will assume you run 70:1(crystal ball gazing)!

Idle jet, go up in whatever incremental jet stages are available eg 25, 30 etc these will not cost much. If your current idle jet is a 35 then you might try a 45. Again as oni nou rightly points out experimentation will be needed .....at this someone else who runs a bike at high level will say to use this that or the other jet but it won’t be your bikes set up if you see what I mean....?

Main jet, with the needle clip in the manufacturers specified position go up at least 15% in jet size as a starting point. Now run the engine and with out putting loads of revs on see how the engine reacts, crisp clean blips. If the engine boggs down its probably too rich on the idle jet....this is why you are going to need more than one of each jet. 

You can work it out mathmatically by using the percentage difference between sea level pressure and your positions atmospheric pressure. Once you have this you can increase the idle, main jets by that proportion. I don’t know your atm pressure but if it were 15% different then that’s the figure to increase jets by. Needle positions a plug chop test. As oni nou points out the squish band may not have the desired effect at your atm pressure. Whatever you do, my suggestions are purely that so I accept no responsibility for any damage or accidents. I know that some one will pick holes in my post but it’s there in the spirit of helping you to increase your knowledge and gain a good result with your bike. 

KMT should be able to supply jets.......www.kmtproducts.co.uk

?

 

And that is how you answer someone ..........Section swept is a person who can be bothered ......take note nd.

[section swept]

9 hours ago, nigel dabster said:

Hes in colorado, wouldve thought a us supplier might be better bet?

Dellorto in uk? Eurocarb are best.

Quite right? but I thought I would give some information in case our man is new to buying parts. 

[section swept]

8 hours ago, oni nou said:

 

And that is how you answer someone ..........Section swept is a person who can be bothered ......take note nd.

??

[lineaway]

 Try a 38 or 40 pilot and start with a 100 main jet. That should get you going in the right direction. Call your Gas Gas dealer in Pueblo.

[nigel dabster]

On 12/5/2018 at 3:00 AM, lineaway said:

 Try a 38 or 40 pilot and start with a 100 main jet. That should get you going in the right direction. Call your Gas Gas dealer in Pueblo.

Thats how you answer someone in colorado thanks Copey, take note @oni nou

[nigel dabster]

On 12/3/2018 at 2:39 PM, oni nou said:

Am I getting up your nose again nigel   he is at altitude with a tiny motor and may want to extract abit more power in the near future.[you know what that is I explained it to you] if he does not use my information; so what...he can choose to ignore it 

You dont get up my nose i just think you are a pointscoring pathetic being and completely miss time and time again giving simple concise and helpful info to the op.

He "may well" want to extract a bit more power but he not and that wasnt his request.

Youve never explained anything to me ever that i needed to know.

[oni nou]

3 hours ago, nigel dabster said:

 

He "may well" want to extract a bit more power but he not and that wasnt his request.

 

It is supposed to be me that is not English;...............You once PM'd me and said that I wasn't really interested in trials and now I put it to you that you are the one that is not really interested in trials but are more interested in making others on this forum see me as a fraud and know it all who doesn't know as much as you, after all you have been on the forum longer than myself which is of course the well known gauge of how much knowledge a person has.[Well it is in your world anyway]  I put it to you that what really irks you is that you cannot be bothered to correct my many errors and show me up to be the fraud that you know I am ......that would mean you would have to do some work and type up more than one sentence; then put some thought into constructing a coherent argument and finish off by proofreading it to make sure it all made sense.Unfortunately for you and your cause you cannot be bothered to do that and prove to your public that I am just a pretender to your 'Alpha' status.....and so you are destined to be like a foot stamping child that exclaims "Oooooooohhhhh Ooooooohhh Ooooohhhhhh!!!!!!"

Edited December 8, 2018 by oni nou

[oni nou]

2 hours ago, nigel dabster said:

Thats how you answer someone in colorado thanks Copey, take note @oni nou

That's lineaway

2 hours ago, nigel dabster said:

Thats how you answer someone in colorado thanks Copey, take note @oni nou

That's lineaway

 

Edited December 8, 2018 by oni nou