New Owner + Lunchbox/Pipe/Rejet Info

[Jon.]

Hi all,

I'm a new owner of a 1992 GS500E and so far really enjoying the bike (minus the paint scheme which I'm not mega keen on, Purple with Pink decals). It's only got 12k miles and it a relatively unabused example owned from new by a family friend and barely used at all in the last 2 years. (Pics to come sometime soon)

So far I've done all the general maintainance I'm confident doing i.e oil and filter change, clean and oil chain, new iridium spark plugs and a good clean!

I'd been lurking on the site for a while before trying to get as much info as I could from posts and the Wiki and already had a new exhaust (a UK performance full exhaust from a company called Viper), K&N lunchbox air filter and new jets for rejetting ready to go before I'd even collected the bike.

All the mods went on in one go, full exhaust, lunchbox and I rejetted to 40/150/1Washer/3Turns whilst also giving the carb a good clean.

BUT

The bike now runs like absolute pap. When its still cold and warming up and I come to a stop the bike will nearly or completely stall out so I have to hold the revs open slightly at a stop to stop it dying. Its also plagued with rough spots through the range, sometimes bucking, struggling or overcoming a flatspot, and power seems to be topping out at about 9k revs. Once the bike is warmed up it will sometimes have an even stranger problem of when I come to a stop (or start the bike up again if its been off but still warm) the revs will shoot up on their own to about 4k and then over 6-7 secs slowly return back to the 1.2k idle. I also changed the spark plugs after the new setup and the old plugs were black with soot so I'm guessing its running rich, though to be fair I dont know how they looked before I installed the new setup (though I was under the impressions the run lean from stock?) I will check how the new plugs are looking and update this tonight.

I'm loathed to put it back to stock but if I cant sort out the problems then I'm going to bite the bullet and just put it back to normal to save the headache with stock filter and stock exhaust with a slightly more ideal jet setup (40/125/1Washer/3Turns). I do have a 145 and 140 mains I could try instead of the 150 and I can try to have a fiddle with the air mixture screws though I'm not sure how to really diagnose optimal settings for the screw. Am I right in thinking that with the air mixture screw all the way closed before your about to turn it out however many turns it is at its leanest and as you turn the screw to your desired setting 1-2-2.5-3 turns that your making the mixture richer as you go? Or have I got it the wrong way round?

Any advice on the problems I've got with the current setup would be greatly appreciated

Hi again and thanks in advance
Jon.

[Chanse]

20, washers and 147.5 is what buddha sent me out for the same set up. Get in touch with him for more in depth review. But should be the same. your pilots might be too big. and I think I ran 2 washers. Its been a while.

[The Buddha]

Chanse: Dude slow down ... he has a 92, you have a 04+ - very different carbs ... you can swap in the whole carb, just not the jets from one to other.
Cool.
Buddha.

[007brendan]

Sounds like you might have an air leak, dirty carbs (though, if you just changed the jets, I imagined you cleaned them), or old gas, possibly with a little bit of water in it.  Check around the intake boots for leaks.  40/150/1 washer/3 turns is what I use.  I do notice a rough spot in the mid range, around 5.5K, but it pulls strong above and below that, up past 10K, and idles much better with the 40 pilots.  

[s10nova]

jon, everything you've described is pretty much exactly what my bike does/has been doing except for when it runs...my bike runs great when it's running, cold start ups/start up's require long choking etc...when i start it though like you described, good luck with your bike, also same mods on my bike except the "gasP" dynojet jet kit, but lunchbox and jardine exhaust, also revs shoot up when i come to stops etc..

[Jon.]

Sounds like you might have an air leak, dirty carbs (though, if you just changed the jets, I imagined you cleaned them), or old gas, possibly with a little bit of water in it.  Check around the intake boots for leaks.  40/150/1 washer/3 turns is what I use.  I do notice a rough spot in the mid range, around 5.5K, but it pulls strong above and below that, up past 10K, and idles much better with the 40 pilots.  

Thanks Brendan, going to take the carbs off again tonight and reclean it as best I can. Whats the best way to check for leaks? Spray some WD40 around the boots/exhaust ports and see what blows/sucks from the bubbles?

[Jon.]

jon, everything you've described is pretty much exactly what my bike does/has been doing except for when it runs...my bike runs great when it's running, cold start ups/start up's require long choking etc...when i start it though like you described, good luck with your bike, also same mods on my bike except the "gasP" dynojet jet kit, but lunchbox and jardine exhaust, also revs shoot up when i come to stops etc..

Well at least I'm not the only one then to be fair I'm probably being a bit harsh about it when its running, its actually not too bad, I'm probably just more pissed off about the idling/revs shooting up to enjoy the normal running at the time. Have you managed to figure out what was causing your problems? The revs shooting up and slowly coming down at a stop worries me the most :S

[s10nova]

nope havent figured it out, as the bike warms up it get's ...."better" or more consisisten to the point of when i get to a stop and the revs shoot up i'll just adjust the idle screw

[Jon.]

Hi all, thanks for all the tips so far, sorry its been a while since my last post but I know have an update.

So I checked for any air leaks and found none. The exhaust still leaked from the manifold from time to time so I put that back to standard and figured I might as well put the stock airbox back on as well. Because of this I rejetted the carbs back to stock (or the ideal stock setting as given in the wiki) to 40/125/1Needle/3Turns. BUT the thing is still running like crap and really rich. I put brand new plugs in again and they fouled almost straight away with a black sooty deposit which was sometimes wet with petrol/gas. The exhaust was coughing and spluttering even at a decent idle (around 1200) and the revs would come down quite slowly if you rev it.

So I'm at a loss again. The bike is basically all back to stock, still running like crap and now I've no idea where to start. Two questions though:

When I rejetted for the second time I tried to check the float settings but found this quite a difficult task to get exact. I tried the usual method of carb upside down, lean it over until the metal clip of the float needle started to touch the metal tab of the floats. Then I tried checking the height using adjustable calipers measuring from the rim of the carb at gasket level to the top of the float plastic. They seemed to be only 1-2mm out but when i tried to adjust them by bending the metal tab it seemed to make hardly any different to the height even with the tab bent harshly up or down. Is there something I'm doing wrong?

Second question is only the same one again about the idle air mixture screw. If its screwed all the way in to then make adjustments out to 3 turns am I making it 3 turns richer or 3 turns leaner? As in could i just screw it to say 4 turns and this would be leaning the mixture to compensate for the richness or would I just be making it richer??

As always any help/advice appreciated

[skirecs]

I got pods and a slipon, wiki says 40,150,2 and i found that was unbelievable rich
lots of smoke, bogging until 5k, if i went to full throttle output would decrease

so i took my old stock 122.5's put them on the lathe and drilled with with a #54, about a 138-139 i think and it runs great now, such a level power from 5-11k and the 40 makes idle really nice too

i think im 2 turns out, might go a little more in next warm day

so try some smaller jets and check your plugs