GS1000 plug-reading help

[bikeboy]

Hi guys. Could someone interpret these plugs for me please?



This is after a short 5km ride. Plugs were cleaned before ride. Bike is a 1000 with a 1100 wiseco kit fitted less that 1000km ago, so only just run in really. has a no-name 4-1, but not sure if jets have been changed? They are DENSO W22ESR-U, as recommended by the guy that did the motor work.

#1 looks OK, #2 is starting to richen up, and #3 & 4 are black as. What actions should I take based on these readings?

thanks for any advice, and let me know if there's more info required.

cheers
ian

[dr_fosg8]

I would start by verifying the jets in the carbureters are the same in 2,3, and 4 as in number one.

[Testarossa]

If the jets are the same in all four carbs, then the next step would be to look for air leaks in #1. Maybe a cracked boot, here? Also verify correct float levels in all carbs.

[cowboyup3371]

Why would you check for an air leak in #1 if it looks good but the others are too rich? Wouldn't that point more to some carb adjustment on those three?

Have you cleaned and synced the carbs recently? Do you have the stock air box or are you using pods? Have you messed with the intake air settings at all?

[BassCliff]

Hi,

Unless you are doing "plug chops", the plugs will only give you a reading of the last throttle opening at which the bike was running. But three of those do look pretty rich.

Are they gapped properly (.031" or so)? Are the carbs clean? Is the air intake system in good repair? Are you getting full voltage to the coils?

Here's some plug info for you:

How To Read Your Spark Plugs
(Everything you ever wanted to know about reading your spark plugs, but were afraid to ask.)

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp
http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

More technical/racing articles about plugs:
http://www.4strokes.com/tech/sparkplg.asp
http://www.4secondsflat.com/Spark_plug_reading.html
http://www.dragstuff.com/techarticles/how-to-read-plugs.html


Thank you for your indulgence,

BassCliff

[SqDancerLynn1]

I would start with NGK B8es plugs and check the coil voltage. Then start checking the carbs

I would also check the petcock, valve adj and maybe a compression test

[Testarossa]

Why would you check for an air leak in #1 if it looks good but the others are too rich? Wouldn't that point more to some carb adjustment on those three?

Have you cleaned and synced the carbs recently? Do you have the stock air box or are you using pods? Have you messed with the intake air settings at all?

Sorry for my potential ignorance, but with a 4 cylinder 4 carburetor arrangement, I will look for the difference in the one cylinder. As I said, I'm going to assume that the jets are all the same. Could three be different? I suppose, but not likely in my eyes. If it were ignition related, it would show up on two cylinders at minimum, no? The only way I could see that if it were jetted correctly, and three of four plugs were fouled would be if the bike were flooding on three cylinders due to improper float adjustment or needle and seat not sealing. Thus my recomendation to check float heights. My theory is that an airleak on #1 is masking an overly rich condition that exists on all four cylinders.

[BassCliff]

My theory is that an airleak on #1 is masking an overly rich condition that exists on all four cylinders.

Hi,

This is a valid theory too. I think what everyone is recommending is to go through the entire system and check everything to be sure. Get the right plugs (NGK B8ES), clean the carbs and install new O-rings, check the float height, replace the air intake boots and the intake boot O-rings, seal the airbox, maybe replace the "airbox to carb" boots, check the voltage at the coils, install new plug caps (they're cheap), etc. To make it reliable, it might as well be done right.

To the OP, have you disassembled the carbs to clean them and verify proper jetting?


Thank you for your indulgence,

BassCliff