More Carb stuff.... GS1000G 1980

[salty_monk]

Well I took the plunge today & pulled the carbs off. New O - rings (there was a load of sealer on there so I doubt they were leaking), new airbox boots & a general clean up.

Good news is the carbs were spotless, no problems at all from that end.

Carb 2 I can't move the mixture screw stuck fast & the head is butchered.

Anyway, I went through it all, lifted the float bowl heights a little(they were 21.4, I lifted them to around 22.4) & changed the main jets back to stock (115).

I didn't take the needles out as I didn't have any circlip pliers that would get that clip & I wanted it back together.

This bike has an inbox K&N & GS1000E stock Pipes (very similar to the G pipes).

Previously the main jets were 122.5 with the needles made a bit richer (done by TPO's mechanic, it says on the receipt that they are "2 steps" higher).

Anyway, all back together, took a bit to get it started but settled down to a nice idle, better than before, slightly less vibration etc. Mixture screws are 3 turns out still.

Previously the bike would bog down on anything over half throttle, it would then surge as you came back off throttle.

The 115's have not made much difference at all.

I still have issues at around the same points although it does seem to run slightly better higher up the throttle range although it has a funny surge at higher rpm on lower throttle now as well.

If you go WOT (or give it a bit of juice) & then back off I now gets some popping & banging in the exhausts that wasn't there before.

I guess I need to do some throttle chop tests!

Does anyone have any mixture screws (I could do with 2 of them complete with spring etc.)

Does anyone have a carb body for #2 on the rack that I can relieve them of?

I didn't bother changing the Fuel line & Vent O rings as they seem ok & I didn't want to split the rack until I have another carb to go in there.

Any advice welcomed!

Thanks,

Dan

[chef1366]

I bought carbs off Ebay for backups. Any BS34SS will work.
You should split those carbs and dip them. Take the #2 to a machine shop before you bugger the carb body. Know any machinests?

Did you get all the boots (airbox and intake) sealed? You sound lean but the only way to know is plug chops. Just don't do a WOT on PCH through Malibu ;-)

Did you measure the floats at the stepdown from the hinge?

I would of tried stepping down a step at a time from those 122.5s instead of the plunge to 115s.

How far are you from Disney Land? Rapidray is near there and he would be able to help you. Do a search and he posts his phone # on alot of his posts.

[salty_monk]

Hey Bill, I'm keeping my eye on Ebay for another carb rack. I keep missing them & there aren't many around right now.

The carbs are spotless, I don't think they need dipping, unless I'm missing something, they look brand new!

I went straight to the 115's as there's no good reason why it should need anything bigger & thanks to Kent I had a set here. Everything is stock, but stock jets aren't right. Weird huh!

Airbox boots are new & new O rings on the intakes, the clamps are nice and tight, it should all be sealed fine.
Because it runs so well on low throttle & idles well etc I don't think that's the problem, It has to be a fuel thing....

I'm not that far from Disney, around 40mins or so I guess.

Hope you had a good Thanksgiving!

Dan

[hampshirehog]

It's worth having a go at getting the mixture screw out yourself. This is what works for me:

Drill straight down the middle of the screw with a fine bit, say 0.5mm, do a depth of about 7mm. Next drill down the middle with a wider bit - the width of the screw minus a 'sliver' each side to a depth of about 3mm. Then gently tap in a flat head screwdriver that is a tight fit, creating a deep slot in this sliver. Once it feels tight have go at unscrewing.

If you get the screw out you need to check the airway meticulously as the chances are you'll have got some brass swarf in there

Wally

[salty_monk]

That seems like a good way of approaching it. It's funny that side of things is ok when really it shouldn't be & the problems are all at the other end of the spectrum

[salty_monk]

Well thought I'd report back.... I took the bike out for a proper 30 mile shakedown run today with some basic tools in my pocket.

The bike is running much better on the 115's. It seems to be much better today than last night, I suspect that is because it's warmer & also the carbs have been well flushed of remnants of carb spray etc.

I managed to turn the pilot screws in a bit for best idle too (obviously not the stuck one )

It's still a bit surgy on higher throttle positions but nowhere near as bad as it was & I'm still getting a bit more popping & backfiring than I'm used to.
It mainly seems to happen immediately after I grab a big handful of throttle (I get one bang) & the same thing with the reverse (when I let go of a handful of throttle).

I think possibly the drilled slides could be throwing it a bit out of whack? although the idle is solid.

I'm going to try to track down another set of carbs to play with but in the meantime I may pick up a set of 117.5 jets & put them in to see what happens & also get hold of a set of long nose circlip pliers so I can pull the needles & see what's going on in there.

All in all not a complete waste of time.

By the way - one last thought, as I didn't split the rack in the end is it possible for the vent T,s or the fuel line connections to be blocked & would that cause any of these effects? (I don't see how but thought I'd mention it).

More history on the carbs here... http://www.thegsresources.com/_forum...d.php?t=111898 found my old post

[TheCafeKid]

you may try futzzing with the float level again too now that you've switched the jets over. Might make for a difference. The popping coming off decel? And after a handfull of throttle...dunno, just a thought.

[salty_monk]

I raised them approx 0.8-1.0mm so they are now around 22.2 - 22.4 measured from gasket face to the metal plate just below the hinge.

I measured it with the floats compressed, i.e. the inlet valve shut to where the floats stop moving (there's a little click & then they don't go down, or actually up as they're upside down at this stage.., any more).

I guess I could try to raise them a little more, wouldn't that richen the low speed circuit?

Opening up the pilot screws does nothing for the popping.

Dan

[TheCafeKid]

im no carb guru but it was my understanding that you wanted to measure them free, not compressed. Am i wrong here? If im not, that may indeed be part of your problem...adjustment should be done on the tang that sits on the float needle, not bending the floats themselves, at least that is how it has been explained to me, and how ive done it on my carbs.

[salty_monk]

Hmm, I bent the tang not the float but measured them compressed as described. They will probably still be in spec now if that's the case (22.4 +/- 1mm). They all measured approx 21.2 - 21.4 originally the way I did them which would bring them close to 22.4 at a guess..

Maybe I should have left them alone

[Matchless]

Salty,
Maybe I misread, but the height should be measured to the highest part of the rounded part, that means the lower part of the step and not to the metal part where the hinge is!
The measurement should also be done while the float just touches the little spring loaded pin in the back of the needle, without compressing it at all. On some carbs you have to lift the float a bit as its weight pushes the pin in.

Also have a look at the little tang on the side of the main jet column. It is the top of the metal bracket that holds the needle seat in. That is the backstop for the float when the bowl is empty. Mine had two pushed right back against the column and the float got slightly stuck there when at its lowest. Just bend these to run parallel with the column and engage the float squarely. I do not think they do much else.

[salty_monk]

Hmm, they are probably high (or low) then depending on how you look at it but I have still only changed the 0.8 - 1mm from what they were. I guess they were probably set wrong to start with too..... My Clymer manual wasn't too specific on how to do this hence the cock up...

Thanks for the tip, I will have to pull them out again. What affect would it have? Would this cause the banging I'm getting?

The article on this site seems to suggest that it will act to richen the whole range so maybe I don't need those bigger jets...

http://www.factorypro.com/

Dan

[TheCafeKid]

when upside down..if im understanding this correctly..raising the hight of the floats changes the amount of fuel allowed into the bowl before the float valve shuts off..for instance..mine are supposed to be set at 26mm..two of mine were set much lower, thereby allowing more fuel into the bowl before shut off, causing my two cylinders to be rich. RAISING your floats will lean out your overall mixture. The popping you hear may actually be due to build up of fuel causing backfire. Im sure you will probably need the stock jets. Keep em in there and raise your float hight to the directed hight in your manual, and dont measure from the gasket surface, you need to measure without the gasket, from the mating surface to the top of the floats themselves, without pushing the float in. Best method ive found is using the depth finder on the vernier calipers, set them to the desired hight and go from there. Just a suggestion, others may have a better way, but this i have found to be most accurate. Be precise, because they are soo damn touchy. On CVs i notice there is a range rather than a set hight...you may have to experiment within that range to find the best setting for your application. Hope this helps.

TCK

[chef1366]

Turn the carbs upside down and let gravity push down the float. Then measure at the step down from the hinge or the highest part before the float curvature.

[salty_monk]

That seems like two conflicting pieces of advice.... I measured at the step down from the hinge at the gasket face (not with the gasket, off the metal, that bit Clymers did tell me!)

Do I measure off the highest part of the float (grey) or off the shiny metal, sorry - I have my slow hat on today