Real Trouble this time...

[legaleli]

Maybe. I was out for a 150K run yesterday. Awesome time but on the last 40 or so I ran into firing issues. I might have just been running the carbs too rich and I'm fouling plugs.

That said, one of the guys I was riding with asked me to run the bike hard in 3rd gear - up to the red line, and then back off completely and let the bike run down with no throttle. He would ride behind and tell me what he saw and smelled.

Keep in mind that my left exhaust pipes are 1 and 2 ONLY. My right exhausts are 3 and 4 ONLY (no H - pipe).

On full throttle my RIGHT exhaust blows some smoke all the way from 3K up to 10K. My LEFT exhaust starts to blow smoke somewhere around 6K up to 10K.

When I throttle off from 10K down to "normal revs" my left pipe blows "whitish" smoke, and my right pipe is clear.

Any thoughts as to what is going on here? Carbs have been pulled and cleaned less than 1000K ago. All seals are good including intake and air box.

 

[ChicagoBob]

Ring blowby?

Ring blowby?

Usually, smoke on trailing throttle indicates blowby from worn piston rings. Maybe a compression and leakdown check is in order.

 

[legaleli]

OK... so assuming I need rings and pistons... what are my options?

 

[rustybronco]

OK... so assuming I need rings and pistons... what are my options?

Don't assume. lets see those compression readings and some detailed pictures of the spark plugs.

 

[legaleli]

Don't assume. lets see those compression readings and some detailed pictures of the spark plugs.

You got it...

JHILLIER449!!!!! I need you!!!!!!

 

[bobthebiker88]

definitely sounds like more info is needed. do you have a fuel filter on your carbs? like a paper media filter, not those little pancake mesh pieces(same basic stuff as petcock screen I think)

I've seen carbs get gunked up with stuff making them run like crap in as little as 20 miles if there is something in your tank you didnt know of, especially something like rust, or sediment.

 

[trippivot]

how long since the oil and filter change?

Do you a consistent amount oil coming out at oil change time, or do you have to add oil to keep the level in the window between oil changes?
those are the oil sealing questions.

how is the ignition system on your bike?
Are the plugs snapping bright blue with them hooked up to the wires and sitting on the engine? if the spark aint snappy blue and on time "F mark" you need to work on that detail being perfect on that before carburetion.
I like to do this check at night, you can see the contrast between orange and blue in the dark easier.

is the upper engine case vent dry and free ventinng, or is it a oily dripper that pushes fluid out the top?

assuming they are fouled with fuel and gas,,,
get some new plugs, sometimes cleaning a badly fouled one is a waste of time,

Ride it and tell us more

 

[legaleli]

how long since the oil and filter change?

Do you a consistent amount oil coming out at oil change time, or do you have to add oil to keep the level in the window between oil changes?
those are the oil sealing questions.

how is the ignition system on your bike?
Are the plugs snapping bright blue with them hooked up to the wires and sitting on the engine? if the spark aint snappy blue and on time "F mark" you need to work on that detail being perfect on that before carburetion.
I like to do this check at night, you can see the contrast between orange and blue in the dark easier.

is the upper engine case vent dry and free ventinng, or is it a oily dripper that pushes fluid out the top?

assuming they are fouled with fuel and gas,,,
get some new plugs, sometimes cleaning a badly fouled one is a waste of time,

Ride it and tell us more

I'm going to take a look at the plugs today. This happened just (a couple of hours) after I washed the bike... maybe something got wet that should be dry...

 

[legaleli]

OK... I checked the air box for leaks, replaced the plugs with four new ones, and even backed off the air mixture to "two turns" from all the way in (lean). I am still getting intermittent firing and backfiring. It feels like an electrical issue or something to that effect.

I'm going to look at my coils (I replaced them) to see if something is amiss.

 

[tom203]

OK... I checked the air box for leaks, replaced the plugs with four new ones, and even backed off the air mixture to "two turns" from all the way in (lean). I am still getting intermittent firing and backfiring. It feels like an electrical issue or something to that effect.

I'm going to look at my coils (I replaced them) to see if something is amiss.

Did this problem develop with replaced coils or did you replace coils because of this intermittent firing problems? Check connections from signal generator to ignitor box and at coils. This sounds electrical- worn rings won't cause this. If you weren't sparking consistently, you'd get smoke.But I don't see how you're pushing 10k revs in this situation.

 

[legaleli]

Did this problem develop with replaced coils or did you replace coils because of this intermittent firing problems? Check connections from signal generator to ignitor box and at coils. This sounds electrical- worn rings won't cause this. If you weren't sparking consistently, you'd get smoke.But I don't see how you're pushing 10k revs in this situation.

Oh for the days of contact breaker points and coil ignition...

 

[tom203]

Oh for the days of contact breaker points and coil ignition...

Not me, I don't want to go back there! I fiddled with too many points and crazy aftermarket ignition systems.

 

[legaleli]

Not me, I don't want to go back there! I fiddled with too many points and crazy aftermarket ignition systems.

I think my issue is electrical now... so I'm going to make a post there... the issue is 1 and 4