Little Honda MTX 125 not running good

[ilver]

I had the chance to buy a very good condition 93 Honda MTX 125 with 5500 original miles. I decided to derestrict it because it was a bit gutless and I have passed my test so no laws are broken.

The trouble is its running a little bad when on a, it sort of kangeroos while going at a steady constant speed. Aceleration is fine and much better with the washer gone from the exhaust.

I have checked for air getting in after the air filter and re sealed where needed. Spark plug is new and it appears the the mixtire is right because the plug is the colour its supposed to be (light brown colour) according to the haynes manual.

Would the bike need rejetting after derestriction? Or would the mixture need altering? Im not very good at fault diagnosis and am stuck for ideas.

Thanks for any help

[Kickstart]

Hi

Almost certainly it would need the jetting playing with. As the primary issue you have is when cruising I suspect it is on part throttle. Try adjusting the position of the needle. Move its locating clip down towards the point to richen the mid throttle mixture, and in the opposite direction to lean it off.

Main jet might also need changing. But that mainly affects full throttle mixture (which is probably the most likely to result in engine damage if wrong).

All the best

Keith
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[ilver]

[ilver]

Now I have taken the carb to pieces I see what you mean Keith.

I have tried all the notches on the needle and the 3rd one down is best (was previously on the second).

Its now runs nearly perfect, I think someone has messed with all the settings before because the oil pump was set way to high.

Is there any more tweaking that can be done to get it absolutley perfect?

$ilver

[Kickstart]

Hi

Might be worth getting a couple of main jets and having a play.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing