Cold #2 Pipe

Hey guys,

I'm stumped, sorta. On idle my #2 cylinder is not firing. I have >140 lbs compression so the cylinder shouldn't be the issue... At idle 3/4 pipes are hot to touch, while #2 is pretty warm but not great.

I had my colortune plug in the hole, but get this... I broke it off at the base while trying to loosen it. Before breaking it I noticed that the spark seemed weak at that hole, I mean barely noticeable, but when i gave it a little throttle it seemed to get lots of spark.

I swapped 2 & 3 and the problem stayed with the hole and never followed the plug, so i'm guessing it must be idle circuit related...

Am I ok to check spark on the hole by using a plug in the cap and holding the strap against a metal part of the engine? i'm trying to exhaust all options before removing the carbs again... Thanks!

Marcel

 

Given the large number of COIL Issues that are becoming common, especially in the past 18 Months; I think you should consider replacing your Coils as a Preventative Maintenance project / Performance Mod.

Consider it a Performance Mod, really!

DYNA and ACCEL make Coils that are an upgrade to stock.
I think the Plug Wires come in various colors.

There are Mounting Kits for DYNA's; that make their installation straight-forward.

 

Did you swap the plug wires only while keeping the spark plugs in the same hole, or did you swap wires AND plugs?

 

Hey,

I swapped just the wires between 2 & 3... Rick, thanks for the suggestion; it's something i should likely do at some point. What i'll probably try first is swap out a set from my 650 wreck... If that's the issue it'll have saved me mucho dinero so far.

Very odd issue though guys, and while yes it points to idle fuel supply the small spark seems to point to the coils perhaps.

Marcel

 

Couldn't it be just a bad spark plug in #2 hole?

 

Clean all the connections first then bring your coil or to be safe both coils and have them tested at your local shop. Personally I had a pair of accells only last 2 years. Junk. Went with dynas. It was on a KZ900 though. Make sure you get the right omhz ratings

And the color of your wire is the least important thing to judge when buying coils....like getting a new fridge, or car, or motorcycle!

Edit - and I just ordered a set of dynas with wires for a customer of mine. about $180. Although he has an electronic ignition. (He got tired of having me check points, he rides about 700-1,000 in a week)

 

If the Left Coil serves #1 & #4
The Right Coil serves # 2 & #3

The #2 Pipe is Cold, ... and you swap Coil Plug-in's to the Harness ... and then have the 2-Hole come-alive and the miss is now elsewhere.

It points to the Coil.

Both of my 900's Coils are bad.
I have already replaced one on my 750.
The 900's getting DYNA's.
The 750's chugging-along on a used one.

 

If plugs 2 & 3 are fed by the same coil and leads are swapped. And the problem remains at the same hole. The coil is not the issue.

Try a plug swap. see if the problem follows the plug.

 

The TEST is to swap the COIL Plug-in's to the Harness.
NOT the wires.

If the results are the same, ...

Take a SPARE Plug.
Plug it into the #2 Plug Cap.
Using insulated pliers, ... Ground the Spare Plug to the Block.
See if the Plug sparks when you run the Plant.

 

Marcel[/quote]

If plugs 2 & 3 are fed by the same coil and leads are swapped. And the problem remains at the same hole. The coil is not the issue.

[/quote]

is the cylender flooding?

 

At the end of the day ... if only ONE cylinder is cold ... it can't be a coil.

A dud lead (either shorting out or not connected to the coil) or dud plug. A plug swap with any other plug would tell if it's the plug. If the problem moves with the plug. that is the problem. If the problem stays , the lead is the issue.

A short is easy to see when the motor is running (especially if parked in a dark area)

 

It could be indeed. Even NEW plugs are duds ... such is life. Too many times have I heard ... But the plug looks ok.

Easy simple checks FIRST are always best.

 

I've tried a few but no, no new ones...

Had the wire off and i seem to be getting spark, compared to another plug as well they're similar. There must be something up with my pilot circuit on that carb (still). looks like i'm pulling the rack yet again, with choke it runs fine on all 4, the pipe is nice and hot but when the choke is off there's no fuel getting in...

My god, if my father in law shows up on his Spyder and has no riding buddy i'll lose some son in law credits for sure

I do have a spare rack of carbs as well luckily... perhaps if worse comes to worse i could swap jets, etc... Thanks for all the input, i love this forum and all my online brothers and sisters

PS: my valve clearances were checked last fall before storage...

 

Those pesky pilot passages/jets are SO easy to clog. When the 550 went down two pipes I thought spark first also, but turned out to be some black debris packed into the pilots. The K&N filter that was on there didn't seal up real well to the box, and that was right after I bought the bike and there was no in-line filter for the gas.

So get it clean & keep it clean..problem solved.

 

The problem didn't follow the wire..... the problem stayed at the same hole. HOWEVER, the leads that you swapped still came from the SAME coil, which would point to the coil. BUT, the difficulty HERE, is that the coil should be firing both wires as the same time. In THAT event, BOTH the 2 and the 3 pipes should be cold. But, at worst, the cold pipe should switch to 3 if it were a dead lead.

What I'm thinking is that it is indeed a coil that is failing......there is enough charge retained to fire one lead but not good enough to fire both. For whatever reason, cyl 3 fires a little more easily which allows the spark to be strongest ther, regardless of which lead you had put on it.

All of that to say, yeah.....sounds like a bad coil..

Dave F

 

Dave you swayed me...

i'll swap out with another coil first. The PO said it took a while to warm up and I guess it would if it only ran on 3 holes at idle... As bad as it sounds i'm glad i had my poor old maxim to compare behavoiurs with, live and learn fellas. Stay tuned.

Marcel

 

I would strongly recommend the Dyna's....

 

Damn,

swapped out the coils and the problem persisted (figured it was worth a shot and is painless compared to a carb pull).... Carbs are off again and everything looks good so far. I did remove those Air jet covers on all carbs, and shined up teh emulsion tubes with wd-40 and fine fine sandpaper; hopefully they'll go back on tonight and i can resume pissing off my neighbours.

I'm thinking the battery might be suspect as well, but i hate taking my battery to places and get a wishy-washy answer... would a low batter impact just one cylinder like that? I know until you get above 2kRPMs it's all battery and it's from the PO... That being said once above 2k i'm into the main jets, blah blah blah.

Marcel

 

Get it running, then open the 'choke' some, keeping a hand on your cold exhaust. If it heats up, it's starving for gas. Or try spraying some unlit propane around the carbs and see I'd you can find an air leak around the inlets around #2

 

Hey Rick,

Pipe gets hot on choke, that's for sure so it must be idle related and starving for fuel on idle

The question is if it's related to the spark (battery) or fuel (carbs). I'm cautiously optimistic that removing those air plates might help some, that and removing the air jet cover plates and extra attention to the emulsion tubes. Jets all looked to be in the correct position...

Anyone ever have a case of the choke plunger things letting air in that way? i was thinking of changing that one out from my old rack, but i don't want to chagne too much at once.

m