Plugs look Good, but bike acts like it's loading up

[jake42]

I posted this on my other topic, Low RPM stumble, but this is different enough that I made a new topic.

About a month after rejetting with a V&H exhaust and K&N pod filter I noticed  some weird hesitation down low.  I took the plugs out on saturday thinking maybe I was too rich and they were loading up.  The plugs were nice and tan, but I cleaned the contacts anyway and the weird low rpm hesitation disappeared.  My carb settings are currently 150/40/2#4's and 3 turns out.  I'm thinking I may be too rich, but the plugs aren't saying it.

Jake

[The Buddha]

So is it still stumbling or not... If still stumbling... You might want the advancer modded by Bob.B. Or some else may be wrong... maybe the spark is getting doused out by the in comming charge... This friend of mine used to loacte the sparking point into the chamber instead of the valves... like mark the outside if the plug where the electrode is and poistion it such that the spark will go where you want it. Or use platinum plugs.. or something that doesn't have the spark killed so easy... or run a hotter plug... cos liquid gas will vaporise better and the plug stays clean.
Cool.
Srinath.

[jake42]

no it quit the stumbling after i cleaned the contacts. So what I guess what I'm asking is, am I too rich. Should I try to lean it up a little or maybe just try the hotter plug?

jake

[Ed_in_Az]

 

[The Buddha]

Platinum plugs are great... a hotter plug actually is for situations where you have the mix turned up so rich... the stock heat range is running so cold it doesn't clean... in reality as cold as you can get is best for the engine's longevity, its bad for sparkies... they carbon up and dont clean off... and carbon has to be burnt off... so the hotter plugs while they make the same spark as the stock heat plug... they get rid of carbon better. I'd say run the standard plus you are currently using... If you foul it more than 1 a month... then hotter and at that time get platinum in the hotter plug. If the standard is ok... leave it alone... and when you ahve to change it.. platinum. Bosch platinum's cost $1.99... about the same as a copper NGK.
Cool.
Srinath.

[adevries18]

Along similar lines (I think) I just took my first spring ride on my '95 GS. I stopped and started several times and not all, but some of the times, the bike would lose power mid-ride (at speeds as high as 65mph) -- "coughing" and sometimes backfire continuously. I checked my plugs before I winterized it and they were fine, and the carbs were cleaned a year ago when I bought it. What's up? Should I re-check the carbs?
I'm not even close to re-jetting - this is all stock stuff.

Thanks!

Anna

[jake42]

Platinum plugs are great... a hotter plug actually is for situations where you have the mix turned up so rich... the stock heat range is running so cold it doesn't clean... in reality as cold as you can get is best for the engine's longevity, its bad for sparkies... they carbon up and dont clean off... and carbon has to be burnt off... so the hotter plugs while they make the same spark as the stock heat plug... they get rid of carbon better. I'd say run the standard plus you are currently using... If you foul it more than 1 a month... then hotter and at that time get platinum in the hotter plug. If the standard is ok... leave it alone... and when you ahve to change it.. platinum. Bosch platinum's cost $1.99... about the same as a copper NGK.
Cool.
Srinath.

YOu wouldn't happen to know the number on the bosch platinum plugs by chance would you?

jake

[KevinC]

I hesitation down low is probably the idle mixture. The plug colour won't tell you anything really, unless you do specific plug reading runs at a fixed throttle opening, with clean plugs. You could well have a rich idle circuit and main jet, but a reasonable needle setting, and the plugs will likely look nice and tan if you spend most of the time at mid-throttle openings.

Rather than arbitrarily setting the idle mixture at 3 turns out, you should slowly turn one of the screws in from maybe 3 1/2 turns out, with the bike idling and warmed up after a ride, until you reach a peak in the idle speed. You may have to take a few runs at it to get the right point. Turn it out (richer) 1/4 turn from there. Re-set the idle speed, and then do the other side.

[The Buddha]

Yes KevinC is right... mix screw at 3 is a start... I have said that many times myself... somehow when you mentioned the issue I didn't say it... anyway... if the bogging is gone... dont worry about it unless you are gas fouling plugs or more bogging often. The platinums are in my virago... never had anything but stock on the GS... In fact dont know anyone who has tried platinums in the GS.
Cool.
Srinath.

[Kerry]

...some of the times, the bike would lose power mid-ride (at speeds as high as 65mph) -- "coughing" and sometimes backfire continuously. I checked my plugs before I winterized it and they were fine, and the carbs were cleaned a year ago when I bought it. What's up? Should I re-check the carbs?

It wouldn't hurt to check the carbs again, but I have some "pre-check" questions:

1) Your bike is 9 years old.  How many miles does it have on it?  I'm wondering if the air filter may be dirty, causing a too-rich condition and possibly un-ignited fuel.

2) What do your plugs look like NOW?  The timing isn't adjustable on these bikes (except for the use of an ignition advancer), so the spark shouldn't be happening too late or anything.  Since the timing of the spark should be OK, I'm wondering what the quality of the spark is like.  (Not quite sure how you would check that, except to look for obvious coloration problems on the plugs.)

[adevries18]

Thanks for the advice. I'll check up on that and get back to you. Nothing to do with the petcock, huh?

[Kerry]

Nothing to do with the petcock, huh?

Losing power, sure.
"Coughing", maybe.
Backfiring?  I don't see how...

Wish I could be of more definite help.

[jake42]

in reference to the Bosch platinum's.

Doyou think if i took my NGK number to someplace like advance auto that they would carry them.  I checked at my local salvage guy, but all he had were stock NGK's.

Jake

[The Buddha]

That's how I got platinums for the virago. Just dont ask the clueless dolts any difficult questions. You'd be allright.
Cool.
Srinath.

[Shadowhawk]

I had the same prob. with my Gs450.  Once, it finally pissed me off, and I ran the piss out of it.  It started running great.  After some trial and error, I found that I have to run the bike firmly(not hardcore, but I have to wind it out some) to keep the plugs working properly.  Granted I run one step colder on my plugs(a lesson learned from how I drive my cars), so this may not work perfectly for you, but it is a cheap fix, so it may be worth a try.

Good Luck
Don
'83Gs450Ld

[Lars]

I had the same prob. with my Gs450.  Once, it finally pissed me off, and I ran the piss out of it.  It started running great.  After some trial and error, I found that I have to run the bike firmly(not hardcore, but I have to wind it out some) to keep the plugs working properly. Granted I run one step colder on my plugs(a lesson learned from how I drive my cars), so this may not work perfectly for you, but it is a cheap fix, so it may be worth a try.

Good Luck
Don
'83Gs450Ld

LOL