Fire in my exhaust (2001 m600)

[Radracer6]

Hi

I just replaced all my fuel hoses with new ones. I used 5/16 on the lines all the way fom the tank to the carbs. I also just installed a danmoto slip on. When i rev the bike up above 3 k i see flames inside the exhaust. Looks awesome but i assume something is wrong? Too much fuel? Or is it the exhaust?

Bike is a 21k mile 2001 m600 with a jetkit from ca cycle works. Removed snorkels and k and n filter. I didnt notice flames when i had the stock cans on and prior to changin the fuel hoses and removing snorkels.

[Dellikose]

Sure sounds like you are running way too rich...unburned fuel being ignited in the muffler. Have you set the air fuel screw to the recommended position (3 turns out from seated I believe)?

Check your spark plugs...black and sooty is indicative of running rich, along with a strong gasoline exhaust smell.

I have seen bikes on hard accel, and a sudden closing of the throttle backfire with flames.

I wouldn't think it is the air box, since opening it up would allow more airflow, and actually lean it out a bit.

[Radracer6]

I have the screws out 3.5 turns per the factory pro jetkit instructions. Should i go 4 or 4.5?

I feel like i may be running lean. I had exhaust popping on my sc1000 and it turned out it was running lean. Would make sense with the open exhaust i just put on? Maybe screw in the idle screws?

Also when i had the stock cans on i didn't hear any popping in the exhaust (maybe because it they are way quieter). But since the only thing i changed recently were the fuel hoses and the new slip on, could maybe a small kink somewhere in the hoses cause a delay in fuel delivery and then the sudden pop/ignition in the exhaust?

[Dellikose]

You are right about the lean condition causing a pop/crackle. I've found a pretty good write up here:

http://www.mikuni.com/tg_backfires_in_exhaust.html

Let me know what you think after taking a look at that. Also, I still think taking a look at your plugs will tell you a lot about how it is running. Check this site out on how to "read" them:

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp?mode=nml

A pinched line could also be the culprit, is this issue intermittent or does it happen all of the time? Only with a sudden throttle closure?

[Howie]

You are likely lean.    Have you taken the bike on the road?   Esay shade tree test.  Put the snorkels back on.  Better?  You are lean.  Worse?  You are rich.  No difference?  Try a little choke.  Also, look at the spark plugs for color.  If you are running slip-ons, not full exhaust back pressure was not changed much.  Kinked fuel lines is a good place to start.  I would check that before anything else.

[Radracer6]

Ok will try that. It happens when i close the throttle.

One question on test.
If I put the snorkels back on, it leads to allowing less air in the box, and hence bike was running lean before (too much air) ?

If no kink and no change with snorkels should i try to run in the screws from 3.5 to 3 or 2.5?

Also reading the links provided above. The stock cans didn't have any clamps between the exhaust headers and mufflers, and the new pipes just slightly slide in and are fairly lose, could this be causing a leak or is this too far down the exhaust?

[Howie]

Ok will try that. It happens when i close the throttle.

One question on test.
If I put the snorkels back on, it leads to allowing less air in the box, and hence bike was running lean before (too much air) ?

Yes.

If no kink and no change with snorkels should i try to run in the screws from 3.5 to 3 or 2.5?

Too many unknowns to answer that one.  You could try 1/2 turn in either direction and see what happens since you can return to the origional setting.

Also reading the links provided above. The stock cans didn't have any clamps between the exhaust headers and mufflers, and the new pipes just slightly slide in and are fairly lose, could this be causing a leak or is this too far down the exhaust?

Your '01 does not use clamps, the muffler inlet simply slips into the double wall female.  Yes. if air is drawn in there you will get flames.  If there is a leak there exhaust paste might help

Flame on decel is a sign of rich, but could still be either.  Rich means unburned fuel that can ignite when mixed with fresh air at high temperature.  If lean enough to cause misfire you will also have unburned fuel plus more heat.It might have existed before.  You would most likely not see flame on the OEM muffler.  Any backfire or popping from the air box? 

[Radracer6]

After I initially installed the jetkit last summer i left the snorkels in and with the stock exhaust on a cold morning start and initial warmup if i revved it a little i would hear a popping from the airbox, yes.

I removed the snorkels recently and didn't hear airbox popping on the startup this time.

[Dellikose]

Did you pull those plugs yet?

[Howie]

After I initially installed the jetkit last summer i left the snorkels in and with the stock exhaust on a cold morning start and initial warmup if i revved it a little i would hear a popping from the airbox, yes.

I removed the snorkels recently and didn't hear airbox popping on the startup this time.

Cold morning start doesn't count since cold engines need a richer mixture, the reason you have a choke lever.

[Radracer6]

I'm gonna run a bunch of these tests tomorrow and pull the plugs. The air filter in there has been there since i bought the bike used last year and not sure how long before that, i want to change that and see if that makes a difference. If i don't get the filter tomorrow would removing the airbox cover give me a good idea if airflow is the issue?

[Radracer6]

Update

So I pulled the plugs today and they were black at the ends. Pics below



So it looks like it is running a bit rich. Please note these plugs were in since summer. After the factory pro jet kit but before the new exhaust and brand new filter.

I have the following setting per factory pro instructions
New emulsion tubes
Main jet #140 (132.5 stock)
Pilot jet #40 ( I believe stock is also 40)
Needles at position #4
Mixture screws at 3.5 turns out
Floats adjusted to 14mm height
Snorkels removed

So I replaced the old kn filter with a new k&n today and fired it up, I wanted to get the exhaust popping and flaming on video however it didn't flame and pop as it did before. Only thing I noticed is it seemed delayed/boggy revving 1/4 throttle to about 2500 rpm and felt strong past that 3k rpms and up. I've uploaded the video below

[Dellikose]

Did you replace or clean those plugs before you put them back in and shot your video?

After 1/4 throttle, the needle jets take over from the pilot jets. You could move the needle position down (away from the tapered needle end) to lean it out.

You could also ask Factory Pro directly since they know more that I ever will.

[Radracer6]

Yes cleaned em. Got the kit from ca cycle works. Shot them a mail.  It seemed to be running good after 1/4 but boggy before. Maybe mixture screws too far out too? Will see what they say

[Howie]

Start with new plugs, cleaning plugs often is not enough particularly when they are glazed like one seems to be in the photo.  Then , while warm and running, equally turn the idle screws in 1/4 turn at a time.  If the bike is still running when the screws are lightly seated the bike is getting fuel from somewhere, most likely, either your float setting is too high, the float needle and seet are snot fully closing or fuel is entering through the cold start enrichment circuit.  If the bike stalls before the screws seat the idle air jets are likely clogged.