Jetting

[Tripleking]

I installed Mikuni VM26-8074 carbs on my rebuilt 71 T250 with a 73 GT250 engine. I am using a 35 primary and I am down to a 125 main jet. Up to about half throttle, it accelerates well. After that it bogs down. I figure I have to drop they main jet size some more, but I am trying to cut down on the trial and error. The engine is mostly stock. It has been bored out 1.0mm. I have pod filters and stock exhaust. Any jet guidance would be appreciated.

[markush]

Moin!

factory setting of the genuine GT250 Mikuni VM26 carbs was:
Main jet: 112,5
Idle jet: 25

I compiled some more data here:
http://suzuki-gt250.de/motornavi/motor.php?b=4

http://translate.google.de/translate?sl ... D4&act=url

bye
Markus

[Suzukidave]

Moin!


http://translate.google.de/translate?sl ... D4&act=url

bye
Markus

Wow !! what a great 250 site .. this really needs to become a sticky in the repair section

[Tripleking]

I still want to be bigger than stock because the engine displacement is a bit bigger, the carbs are bigger and I am going to better flowing (than my pods) Uni filters.

Edit: I see what you are saying. The later 250s got VM26s so I should jet similarly. My bike had the older T250 VM24s

Moin!

factory setting of the genuine GT250 Mikuni VM26 carbs was:
Main jet: 112,5
Idle jet: 25

I compiled some more data here:
http://suzuki-gt250.de/motornavi/motor.php?b=4

http://translate.google.de/translate?sl ... D4&act=url

bye
Markus

[Tripleking]

I am considering using a Unifilter sock filter. However, I do not know which side to use. The 4 inch model is a get length, but the inside diameter is where I have questions. I am thinking the 1.5 inch should work. The next smallest size is 3/4". Any feedback would be appreciated.

[Tripleking]

I measured. 1.5 should work fine.

[Tripleking]

I am now running a 110 main jet and a 25 pilot jet. The bike runs smooth and will rev, but I have to slip the clutch to almost 3,000 before I get enough power to move the bike. Is a needle adjustment in order?

[Tripleking]

Any thoughts as to why the bike has now power (and I mean it will barely move) below 3,000 RPM, but runs great from there on up with my latest jetting package of a 25 primary, 110 main jest and the needle clip in its highest position (lowest needle setting)?

[Suzukidave]

Are you describing it bogging below 3000 ?

[yeadon_m]

I would think it might be too lean off-idle without the stock filter and might be helped by closing the pilot air screw or by increasing size of pilot jets. A guess though!
Mike

[Tripleking]

I just went down from 35 to 25 because the 35 Pilots jets seemed way rich. I guess I should have gone with a 30 I will try adjusting the pilot air screw.

[Tripleking]

Are you describing it bogging below 3000 ?

I guess it is a bog, but it feels more like a dead spot. A bog too me is a rich condition which clears out when the revs come up. This is usually followed by a cloud of smoke. This feels like the bike just isn't getting fuel or fuel/air. It is difficult to get the bike to move, even while slipping the clutch, until the revs come up to 3,000. It runs fine after that. I did not have this problem before moving down from a 35 to 25 pilot jet. It was running rich at part throttle with the 35 jet.

[jabcb]

+1 on Wow!

Would be good to add website under "Link To Cool Sites".

Also noticed an interesting page with an electronic ignition:
http://translate.google.de/translate?hl ... &sandbox=1