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125 To 200 Conversion


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#1 JanDyb

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Posted 06 July 2009 - 09:56 PM

Hi GasGAs community.

I have heard only difference between 125 and 200 is cylinder and piston. Can anyone confirm that?

I`ve got a 2002 TXT Pro 200 engine with a crack in the casing lying around. Thought I should use the 200 cylinder and piston on my sons 2006 125 and use it for myself. The cylinder is not mint condition, but doesnt look too bad.

What about jets? Should I use a bigger main jet?

Thanks

-Jan

Edited by JanDyb, 06 July 2009 - 09:58 PM.


#2 crasher

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Posted 07 July 2009 - 08:41 AM

hi Jan, jetting remains the same supposedly, although i put a bigger main jet in my daughters bike i think (40 pilot 115 main, 04 pro) using the standard phbl26 carb, weld on flywheel weight is also advisable as they are a bit fierce otherwise, was talking to a guy the other week who had one done at gas gas uk and he had 2 flywheel weights with a spacer for the plastic cover, as well as calming the engine down the weights also stop the bike stalling so easily, i put a slow action throttle on as well, hope this helps steve. (oh almost forgot, you also need to leave the plastic inserts out of the crankcasing, you can if you want it to be really soft put a head spacer in, i have one but didn't use it)

#3 MIKEE

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Posted 08 July 2009 - 09:54 PM

Hi Jan, I've done this with my 07 125 pro and it the way forward...

You get a very nice weight to power and a easy handleing bike.

Jetting wise i left mine with the 125 jets and it ran ok with the delorto carb.

you need to fit a lot of fly-wheel weight to get the bottom end power. (mines 850 grams)

I have now fitted a keilen carb to mine to up the power some more and make it a lot more useable in the bigger trials i do.

Hers a photo of my 200... Posted Image

#4 JanDyb

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Posted 09 July 2009 - 09:33 AM

Thanks Crasher and Mikee

No one of You mentions anything about if my 2002 cylinder/piston is a direct fit on the 2006 engine, so I assume this is OK then?

I have not decidet what I do yet. The 06 125 (becoming 200?) is incredible light and easy to ride, but my 04 300 has an awesome power... :wacko:

I think I have do the 125 to 200 conversion and have a direct comparing session this weekend.

-Jan

#5 benz19

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Posted 09 July 2009 - 08:44 PM

Hi,as long as it is a pro engine then the cylinders are interchangeable right up to current model!

Benz

#6 JanDyb

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Posted 09 July 2009 - 09:15 PM

View Postbenz19, on Jul 9 2009, 10:44 PM, said:

Hi,as long as it is a pro engine then the cylinders are interchangeable right up to current model!

Benz

Thanks

That was what I thought. Nice to have it confirmed.. :wacko:

-Jan

#7 PeterB

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Posted 11 July 2009 - 10:15 PM

Hi Jan,
I used to ride a 2004 200 in the Nationals here, all standard except I fitted the plastic crank case padding from the 125 motor - your bike already has this fitted, leave it in as it makes the motor more punchy, doesn't grip so well but stacks more fun to ride. (the standard 200 motor does not have the padding fitted) I experimented with a small flywheel weight but thought the bike was fine without. The 125 and 200 cylinders are interchangeable. The DellOrto jetting on the 200/125 is ok standard, the motor is very sensetive to any jetting changes, leave the D36 needle in. Move the pick up sensor clockwise (slot the sensor holes) slightly to achieve a slight static ign advance.
Bye, PeterB.

#8 MIKEE

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Posted 14 July 2009 - 09:00 PM

View PostPeterB, on Jul 11 2009, 11:15 PM, said:

Move the pick up sensor clockwise (slot the sensor holes) slightly to achieve a slight static ign advance.
Bye, PeterB.

Hi peter, how far did you move the forward did you you move the pickup sensor and for what gain????

cheers mike

#9 PeterB

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Posted 18 July 2009 - 12:38 AM

Hi Mike,
There is not much room to slot the holes in the pick up sensor, but enough to give a range of 1 to 3mm or adjustment, I set mine up between 1-2mm static advance to give a little more go through the rev range - biggest increase in power was fitting the crankcase padding, lose a bit of smoothness is power delivery though.
Bye, PeterB.





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