Quick Spark plug question

[stuart9726]

HI all,
I havent posted a question here for a long time as a search normally pulls up the results I need. Im hoping you guys will be able to answer this one for me.
I have a 1992 GSX750F
I pulled the spark plugs out today and found that cylinders 1 & 3 were kind of whitish and 2 and 4 are black, what could be causing this?
Any help would be greatly appreciated, sorry if this has already been asked and answered in a previous thread.

I do have a photo of the plugs but cant seem to upload it. The black plugs are dry, not wet and oily btw.

[maniac1886]

I would say one of 3 things.

A. the easy one. Your carbs are out of sync. I would adjust all 4 of your fuel air mixture screws to 2.5 turns out from the bottom. Then put a manometer on them to put them in sync.

B. A little more difficult. One coil send spark to 1 and 3 and the other sends spark to 2 and 4 so the coil powering plugs 2 and 4 could be failing or not getting enough voltage for a strong spark

C. The most time consuming, your carbs could be dirty and therefore are not sending the same amount of fuel to the plugs causing them to be uneven.

White/Ash color = Lean or too much air, not enough gas
Black = Rich, too much fuel and not enough air.

[stuart9726]

Thanks for the quick reply Maniac. I will start with A then work my way through.

thanks again.

[stuart9726]

Can someone please explain the correct technique for testing resistance in the coils

[shpielers]

Resistance in them, or voltage at them?

[GSXFJim]

I would say one of 3 things.



B. A little more difficult. One coil sends spark to 1 and 4 (left coil) and the other sends spark to 2 and 3 (right coil)....


White/Ash color = Lean or too much air, not enough gas
Black = Rich, too much fuel and not enough air.

Fixed.....

[92xjunker]

Voltage needs to be 11v minimum to have a strong spark.

[stuart9726]

Thanks guys, will let you know how it goes.
Checked the resistance plug to plug and got aboit 35 in both, so good there, I believe.
Took the rocker cover off to check the valve clearances, noticed that timing was out, so took all the cam holders off and reset the timing. Putting the cam holders back on and 3 of the bolts just snapped, not even close to torque, like hardly even tightening it.
Helicoiled 2 no probs, but the 3rd wouldnt take a coil, accidentally used a drill bit that was .5 too big.
so now im having a sulk whilst I contemplate what to do next

[shpielers]

Timing was out?? How'd that happen?

Might want to check your cam chain tensioner - spring might be shot on it.
Also check the stretch on the cam chain. The manual has the service limit, but I think you just measure between 21 pins same as the chain to the rear wheel.
Your timing got off somehow, best to poke around and figure out how/why before it goes again and you bend a valve etc

Good luck with the helicoils. Heard good things about timeserts too (spelling??)

[stuart9726]

Honestly, dont know spielers. The cam chain tensior bolt wouldnt seat right, think its been threaded so just keptbspinning and wouldnt actually tighten. So I have ordered a new whixh is on its way.

It gets worse though. Was putting the rocker cover back on and when I got down to the last bolt, the whole bloody cam holder snapped, wtf....... has this happened to anybody else before. Found up suzuki and they have told me that they are only available when you purchasr themwhole cyclinder head.

time to scrap it I think.

[cool4kats]

Were you using the right torque specs. Manual in NM. If you were using a ft lb setting, SNAP! You can guess how I know. I know this does not help now. You could try sourcing parts from a salvage yard.

[shpielers]

Or ebay

Salvage yard preferable cube cause you can physically look at something and kit rely on pics that aren't great and "forget" to show important details

[stuart9726]

Hi Kat, didn't get a chance to use the torque wrench. Was just snuggling them all on, lightly before I went over them all with the torque.
Taking it to an aluminium welder this morning, he thinks he maybe able to sort it.

Fingers crossed.