Raising needles- possible with carbs in situ?

[chrishiggs]

Hi Folks

Sorry if this is posted elsewhere but can't find any posts...

Just wondering if there's a how-to or similar on raising the jet needles without removing carbs or whether the carbs need to come out first? Got a '99 UK spec GS with a free-flowing pipe from a CRF Honda, standard air filter and still have the horrible flatspot around 5-6k. Upjetted to 125 mains and the plugs look good and healthy when I do plug chop. It seems the next thing to do is raise the needles. As standard they are set at the third groove from the top. Anyone got any suggestions where to go from here and how best to do it with minimal hassle? Thanks in advance!

Chris

[cboling]

I believe you can simply remove the gas tank, pull the diaphragm up (with the needle) adjust it then replace the slide and diaphragm and slide. Replace the cap.

[The Buddha]

Yea needles come out the top, remove top and pull the diaphragms and slides and needles.
Cool.
Buddha.

[BeerGarage]

You don't even need to remove the tank.

centerstand
unbolt
scoot back
prop up


And if you tie a string to the stick and hide and wait patiently, you can use it to catch gearheads.

[ohgood]

You don't even need to remove the tank.

centerstand
unbolt
scoot back
prop up


And if you tie a string to the stick and hide and wait patiently, you can use it to catch gearheads.

LOL !


i was thinkin about how i'm clumsy and gas tank + battery = boom !

[PachmanP]

And if you tie a string to the stick and hide and wait patiently, you can use it to catch gearheads.

Yeah I only fell for that one once...or twice...ok every darn time...

[chrishiggs]

Thanks folks...now anyone got a suggestion on which notch to try? I guess I probably want to move the needle up one notch at a time? (Presumably this means that I actually move the circlip down the needle?) Thanks again

Chris

[the mole]

Yes, if you want the mid-range mixture richer you want to raise the needle, which means placing the clip lower on the needle.

[chrishiggs]

Wow, what a difference!
Raised them by one notch and the flat spots gone- fantastic.
Now that it runs and revs smoothly I'll be looking at the front brake. Waiting for a PFM iron rotor to arrive courtesy of ebay so I'll hopefully be able to stop too! Thanks for the help guys.

[gregvhen]

hey, since the stock carbs are so lean, can I raise the needle one notch even though ive never done a rejet, or will that have a bad effect?  I have stock air and stock pipe, and heard about raising the needle.

[chrishiggs]

If you have a flat spot in the midrange (5-6k revs) it is worth raising the needles. I upjetted for a non standard pipe and still had the flatspot. After moving the needles up a notch it was gone and the motor now revs freely to the redline. If you don't have a flat spot you probably don't need too. If you live in a very hot climate it might be worth doing to make the motor run slightly cooler. Bear in mind if you upjet your fuel consumption goes up!

[Birdmove]

    Do the newer GS500s have grooves and clips? My 1980 GS425ST didn't. I had to remove the carb slides and shim the needles.But it ran great afterwards.

  Jon in Puyallup

[The Buddha]

Euro bikes do, US dont. None of them do, unless you get a DJ type crap.
Cool.
Buddha.