What else can I do?

[Escobarclan]

1982 GS1000s Katana, MTC open header exhaust, pods.

Guys, I've gone through every part of this bike. With alot of help from ya'll I've eliminated several possible problems, I hope you can point out what I'm missing.

My bike has a hunting idle, and pops (exhaust) every now and then. Also, she hesitates badly at low end in gear, gains speed and then she leaves everything behind.

Valves adjusted, carbs sync'ed, air screws set using 'highest idle' method, petcock, plugs, wires, compression, fuel, boots (new), are all checked and good.

Main jets aren't marked at all, so It might not have the stage 3's it requires, and I'll get the kit, but that wouldn't affect the idle hunting anyway.

She is SO CLOSE to being done. The CMA rally is coming up soon, and I need to be out there showing some real muscle to those harley dudes.

Can anyone throw me a bone?

 

[Nessism]

Unfortunatly, you have an unknown jetting configuration so it's hard to know for sure but it sounds like the pilot circuit is overly lean for a start based on the hunting idle. The main jets are sure to lean as well unless they were changed; the fact that the bike runs well at high rpm seems to indicate that they may be okay though.

 

[Escobarclan]

Thanks Ness, based on what you told me, what would you do?

 

[Nessism]

If you don't mind spending the money, get the jet kit and slam it in. It should get you close jetting wise but if you are running an open header (shame on you) you are going to have to fuss around even more with the jetting. If you don't want to order the jet kit, order one step up in your pilot jets (look in the manual to learn the base configuration), and then do some plug chops to judge high rpm mixture - hopefully you live in the outback or your neighbors are not going to be happy.:shock:

 

[Dave8338]

Follow this...

Follow this...

Just a site I stumbled on while working on another bike. It applies to exactly what Nessism wrote, suggested, and will work every time.

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

 

[Escobarclan]

Thanks for the link Dave, been there but I can't use it until I get the right gear(i.e. jets, pilot jet).

Ness, I'm still pretty new to the bike aren, but I learn fast. What do you mean when you're talking about plugs and chops?

Does the kit come with a new needle?

By the way, my neighbors each have Harleys (no kidding), they tinker with them all the stinkin' time, with their little glasspacks and 'hog idling'.

So now I have a true monster Suzy Kat. I've opened her up a little on the main road real close to their houses. They can't complain, they've woken my kids many times with their "american made muscle"

So, and I'm not a snide or rude person.... screw em'. I've got the big dog now. We still get along, but they don't goose their bikes when they drive by anymore. Peace!

 

[Guest]

The CMA rally is coming up soon, and I need to be out there showing some real muscle to those harley dudes.

she's real mean! even just having her PARKED should do the trick :-D

 

[tkent02]

1982 GS1000s Katana, MTC open header exhaust, pods.

Guys, I've gone through every part of this bike. With alot of help from ya'll I've eliminated several possible problems, I hope you can point out what I'm missing.

My bike has a hunting idle, and pops (exhaust) every now and then. Also, she hesitates badly at low end in gear, gains speed and then she leaves everything behind.

Valves adjusted, carbs sync'ed, air screws set using 'highest idle' method, petcock, plugs, wires, compression, fuel, boots (new), are all checked and good.

Main jets aren't marked at all, so It might not have the stage 3's it requires, and I'll get the kit, but that wouldn't affect the idle hunting anyway.

She is SO CLOSE to being done. The CMA rally is coming up soon, and I need to be out there showing some real muscle to those harley dudes.

Can anyone throw me a bone?

Start with a series of plug chops to find out what is going on inside the engine. Learn how, it's worth it.
Sounds like the needle is a bit low and the pilot is a bit lean, but check the top end too... Don't want to burn anything up.
Too lean on the main jet hauls ass, until the engine fries. Won't be long.
If the jets aren't marked it is some type of jet kit, Mikuni marks theirs.
Why are you showing real muscle to the slowest bikes on the planet?

 

[TheCafeKid]

Yes, plug chops, while they can be a bit tedious and frustrating, are essential if you want to get a non stock bike running well. Basicly its a process of running the bike at a certain throttle position for a given amount of time, and then, at the same time, cutting the throttle and shutting the bike off, as you coast into your driveway. When the bike cools, you can pull the plug, and the colour of the plug can help tell you alot about what is going on in the cumbustion chambers. A nice tan colour is what you're shooting for, but other colours can tell alot. For instance, a white chalky colour indicates a severe lean issue, or a black sooty colour can indicate a over-rich problem.

Think of your throttle as divided into three or four sections. Each can tell its own story in the different stages of running using plug chops. There are those who can explain this a bit better than I, but give it a shot. Go out and buy a couple extra sets of new plugs, as they will give you a clean base to work from, put a set in, hit your neighbourhood street in third gear and 3/4 throttle for a few miles (uphill i hear works even better) and then as you get back to your place, just before you hit the drive, cut throttle, and shut the motor off at the same time. Then give the plugs a look when they cool enough to pull. What colour are they? Lean-ness is bad news, as you can cook valves, rings etc. It may feel like its running great, but be lean enough to do damage.

SO...do a search on plug chops, and ask around. Without special equipment, this is one of the only ways you are going to be able to tell where you sit with your jetting set up and your pods and pipe.

 

[Guest]

hit your neighbourhood street in third gear and 3/4 throttle for a few miles

WAAAAAY over the speed limit :shock:

 

[TheCafeKid]

Too true. Im guessing here, as unfortunately ive never had a speedo on my GS while it was running. (has since been taken care of tho) What would you recommend? 3/4 in 2nd?

 

[Escobarclan]

lol, psy. Ok, I ultra cleaned my plugs, re-gapped and ran her in 3/4 throttle, 3rd gear up a long hill.

Don't ever do this on a Kat. Holy s&*t.

The lengths I'll go through to get her running right.

Anyway, I stopped and pulled the plugs. I could not believe she was running rich.

Should I lower the floats? Turn in the air screws? I don't think the jet
needles are adjustable.

Can the plug test work in just idle? It's too late now to run her around, but I'll do it first thing in the morning.

 

[tkent02]

lol, psy. Ok, I ultra cleaned my plugs, re-gapped and ran her in 3/4 throttle, 3rd gear up a long hill.

Don't ever do this on a Kat. Holy s&*t.


Can the plug test work in just idle? It's too late now to run her around, but I'll do it first thing in the morning.

Learn how to do this, it's nothing dangerous. Three separate tests for three separate carburetor circuits. Before you start, put a little anti-seize on each plug, don't install the plugs very tight. No need to wear out the plug threads in the head, you will be pulling them out hot. Bring a pencil and paper, keep track of each plug at each test. The low throttle chop, just putt around a few minutes at about 20 0r 30mph or so, keeping the throttle open but just barely, in the correct gear for this speed. It takes a while to color the plug because there's not much going on inside the combustion chamber. This tells you about the mixture from the pilot circuit, the low power stuff. Pay attention to how it runs and feels, you can tell rich from lean. If it runs well and the plug isn't black it's probably doing OK. This one is probably the most important to get right, it sucks at have your engine screw up momentarily at the apex of a slippery corner.

Mid range, go out on a highway and run it at about 1/4 to 1/3 throttle for a while, up a long grade is wonderful but not required as it doesn't take that long to get a good plug read, it happens faster. This tells you about your mixture from the position of the needle. If it spits and pops that would be rich, if it surges, wanders or loses power for a while and comes back on that would indicate lean. If it runs smooth and nice it is close, looking at the plugs will tell you exactly. You need to see a little color here, a mixture resulting in lean white insulators will run fine but eventually burn things up.

Full power is done in one hard blast, full throttle through the gears like a drag race. Does not take very long at all to get the plugs colored, you don't need to do insane speeds. You do need to find a place safe to go faster, where you can see any cops, and yet still be able to safely pull over to remove the plugs. The mixture from full throttle is controlled by the size of the main jet. Definitely need to see a color other than white, too lean here will burn things up in a hurry.

For each of these reads, you need to actually chop the engine. A few seconds under closed throttle as you slow down will taint your readings. Simultaneously hit the kill switch, pull in the clutch and close the throttle. This leaves the plug looking exactly as it was during the run at the power setting you are testing.

To get the mixture right at idle, you adjust for highest rpm, not sure on your carbs but you are looking for the peak combustion temperature here, it won't hurt anything to be lean at idle because there's not enough heat in the combustion to damage anything.

If the main circuit or even the needle circuit is too lean you can burn the valves and even pistons up from the excess heat.

You are having problems with your low power running, I would start there. But still check the full power read, a mixture a little too lean is very powerful indeed until something expensive burns up.

 

[Escobarclan]

thanks tkent, I'm going to go through the whole range when it stops raining and the road dries up.

I took my carbs off and reset the floats at .88, which is half the tolerance for my kat. I just noticed her leaking gas out of one of the pods, took the bowl off and found that the needle wasn't sealing up very well.

Also, I just realized that the #2 and #3 exhaust pipes werent getting very hot, whereas #1 and 4# were. All of this at idle.

Any input?

I guess I'm going to get a carb rebuild kit, as well as a dynojet stage three kit to eliminate any of those possibilities.

 

[tkent02]

thanks tkent, I'm going to go through the whole range when it stops raining and the road dries up.

I took my carbs off and reset the floats at .88, which is half the tolerance for my kat. I just noticed her leaking gas out of one of the pods, took the bowl off and found that the needle wasn't sealing up very well.

Set them all to the spec in the manual, if something leaks replace it.

Also, I just realized that the #2 and #3 exhaust pipes werent getting very hot, whereas #1 and 4# were. All of this at idle.

Could be related to valves not being adjusted correctly, possibly ignition, most likely an idle mixture issue.

I guess I'm going to get a carb rebuild kit, as well as a dynojet stage three kit to eliminate any of those possibilities.

Start at the beginning, you have adjusted the valves, have you checked the compression? Clean the carbs, replace the orings, synch them up again - take your time and do all of it.