raising the needles....

[Anonymous]

Anyone have step by step instructions for raising the needles in a set of carbs (bs32's) for a 1980 GS750E? The low end is ok, and the high end is ok, but he mid range is stumbling and from what little I know about carbs, the needles are what controll the midrange. I appreciate any help anyone could offer. thanks, Dominick....

[Anonymous]

stumbling

Dom
When you say stumbling is it all the time or when you accelerate or just when you are cruising asong with little load-if the last item is the case, does it stop stumbling when you apply throttle and most ((important )) of all what color are your spark plugs????

[SqDancerLynn1]

mikuni tuning

I have never used one, but I have seen ref to Mikuni Tuning Manual offered by www.Sudco.com happy tuning Lynn

[Anonymous]

Scotty, The bike takes off fine. when you ride soft and slow, it goes ok, but when you get on it a little more, the engine seems to die down for a few seconds before it gets up and goes. When it does go, it goes like hell, and if I keep the rpm's up, I can rip through all the gears no problem. When cruising at a steady speed, I can feal a slight hesitation. The plugs are looking ok to me, according to the guide in my manual, a slight grey tint to them, but not really white or black, and not wet. Everyone tells me I need to rejet, with larger mains and raise the needles, but from what little I do understand about carbs, the main jets controll the high end, and my high end is good, it's just the middle when you first crack on the throttle. Sounds like it's eithor flooding and can't process the ammount of fuel being sent, or starving and cant get up and go untill the extra fuel get's there. the hesitation dissipates when i pull up the choke, so I would guess I need more fuel, but I'm not a mechanic, just a guy that doesn't want to pay $65.00 an hour for one unless I have to. thanks, Dominick.....

[Anonymous]

NEEDLES

If your plug color is good i doudbt that the needles are in need of tuning--others will have to suggest something and i am assuming that you checked ALL of your plugs simply try running gas treatment tnrough a couple of tanks of fuel

[Anonymous]

yes, I checked all the plugs, all seem well to me. I have run through about 4 or 5 tanks of fuel, and tried two or three different fuel system cleaners.( chevron w/ techron, gumout, etc...) they don't seem to be working. Any suggestions on a better fuel additive if the needles don't need adjustment? could the carbs simply need synchronization? I am stumped and the mechanic isn't taking any more work for the summer.. Thanks, Dominick.......

[Don Lobacz]

Yes, you need to raise the needles to richen your midrange. If you feel that it is pulling hard to redline, then your mains are good. The precision washers you need may be available at your local bike shop: there are some that are left over from jet kits, but you also can use the OEM washer that goes between the spring and o-ring in the fuel screw assembly. One washer for each needle (below the clip to raise it) should be enough to produce noticeable results.

[Jay B]

Fuel Starved

You know that sounds a little like you may be starving for fuel when you try to get in it a little. Not that anything needs adjusting but that the petcock or fuel lines cant get enough fuel in there fast enough. You could do one of two things. Get an aftermarket petcock or add bigger fuel lines (Thats what I did). Most folks will tell you to get the aftermarket petcock. BEFORE you do that however I would re-sync the carbs and check the float level. If the floats are too high the bowls might not be filling up and then when you get on it there isnt that much fuel in there to keep up with the demand.

[Anonymous]

thanks for the suggestions guys, I think the needles need to come up. I know that I do need a new petcock, but the fuel lines are all new, I just did that about two weeks ago, along with a new in line filter. I thought the filter may be clogged, and that might be the issue, but even after the new lines were on, it's still sluggish in the middle. I am changing the petcock this weekend, and I'll see if that makes a difference, but if not I plan on raising the needles. I just need some instruction on how to do it, My manual doesn't tell me how, and though I am pretty handy with the tools, I still need the step by step to get me thru it. Thanks for all the help, Dominick.....

[Anonymous]

remove diaphragm cover(watch out for spring)
remove springs
gently pull diaphragm out(check for any damage)
remove circlip (use proper tool)
you should then have washer,small spring jet needle
b4 you go and do this you should ride at about 6000rpm for a little while
pull in the clutch and hit the kill switch
then check your plugs if colour is good then the needle is
probably not the problem.
the petcock(fuel lever)could be part of the problem
also the direction of the in line filter
or if an air lock is in the filter
unsynchronised carbs can also do this,if they're way out.
air filters can also cause problems
go one step at a time the simplest and least costly first
then workyour way in.
good luck
tk

[Dink]

What about?

I had a similar problem with my 1150 it turned out to be the emulsion tubes under the main jets,they were clogged and clearing them fixed it.
Dink