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Old 04-18-2011, 10:23 PM   #61
Turbocloud3
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Default Re: Is your KLR Backfiring...???

Well, being a new member to this site and all, I started looking through the threads for good advice concerning the backfiring issue. I found just the right answer in this thread! I am not sure who this Wyman fellow is but he hit the nail on the head. Loose header nuts... Who would have thought. I believed I was chasing carb issues this whole time.
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Old 04-30-2011, 07:34 PM   #62
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Default Re: Is your KLR Backfiring...???

My '09 backfires both on accel and decel and seems to be getting worse.Plug is a little white and exhaust pipe has some black carbon build-up, but not too bad.Bike has a FMF exhaust and dyno jet kit with a K&N filter.Any ideas as to what is causing this? It runs fine but the backfire has to go!would love some feedback as to how to go about solving the problem,Thanks,Tom
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Old 05-13-2011, 11:45 PM   #63
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Default Re: Is your KLR Backfiring...???

my 08 has been poping on decel , nuts are tight so I got a new gasket for good measure, is it suppose to be an oval metal crush type like I picked up or did I get the wrong part?
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Old 05-14-2011, 02:42 AM   #64
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Default Re: Is your KLR Backfiring...???

Just some information from the wise older friends/mentors from over the years, whom I'm blessed to have:

Backfiring during deceleration is 'usually' (we are talking in terms of Vegas odds here) caused by unburned fuel and air in the exhaust system, and components of the exhaust system being hot enough to ignite that. Hence, the audible popping, and blue or orange flames popping out of the exhaust pipe if you see this in the dark. Hot rod cars, and dragsters are common places to see this, but I've seen it on old 2-cycle motorcycles.

1.) Your jetting is too rich.
2.) An exhaust seal is not sealing, hence air is entering the exhaust system giving the unburned fuel something to ignite with. Oxygen is required for burning.
3.) The engine is running too 'hot'. This can be caused by many things. (A.) Too lean of a fuel/air mixture, (B.) too hot of a spark plug causing parts in the combustion chamber to be too hot, (C.) an air leak in the intake tract, or (D.) too close of an intake or exhaust valve may cause external oxygen to enter the cylinder making it run too lean (i.e., hot).
4.) Ignition timing. Our KLR bikes are stone-cold reliable in this aspect, but if the ignition timing is too far advanced it may be giving the excessively-high heat causing combusion in the exhaust system.

My $0.02.
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Old 05-14-2011, 09:53 AM   #65
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by timeklr View Post
my 08 has been poping on decel , nuts are tight so I got a new gasket for good measure, is it suppose to be an oval metal crush type like I picked up or did I get the wrong part?
yes, copper oval crush gasket...you are golden...
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Old 05-14-2011, 11:38 AM   #66
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by wymanwinn View Post
yes, copper oval crush gasket...you are golden...
Thank you
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Old 06-01-2011, 07:49 PM   #67
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Default Re: Is your KLR Backfiring...???

my nuts were loose and I tightened them no torque wrench so I'll have to get a 3/8's torque wrench but they are tight now (will have wife verify later)
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Old 06-01-2011, 10:49 PM   #68
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Default Re: Is your KLR Backfiring...???

Mine has an issue with popping that is very specific and repetitive.

Let me explain.....
When I am running at a slightly higher RPM 4-5,000 and running in say
1st, 2nd, or 3rd on the twisty forest service roads in N.C. and I
back off the throttle and allow the bike gearing to control my speed
downhill, the "pop", which is usually a single pop, occurs at the very
moment that I touch the throttle to accelerate. It happens only at
that point and only a single "Pop". Weird huh? I do NOT get popping
on decel. Just the lone "POP".

I have tightened the nuts. I have done the 22 cent mod, 2 washers,
and drilled the slide. I have installed a thumb screw enricher and
have it about 2-2.25 turns out. I have a DG "O" with a silence insert
and no spark arrestor. All leaks on the pipe have been eliminated.
I have ordered a new copper seal for the header but it hasn't arrived.
I also have a UNI filter with no airbox mods.

I was "told" that there is some kind of "smog" equipment behind the
right front side panel that injects air into the backside of the
combustion that is to aid in burning off unspent gases to reduce
emissions. This is not to be confused with the Ca models smog pump
on the left mid/rear side. I was "told" that this could be disconnected??????

HELP!
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Old 06-05-2011, 03:56 PM   #69
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Default Re: Is your KLR Backfiring...???

sho nuff - popping on decel - found the outboard nut loose. Thanks wyman!

Since I had her skirt off, I decided to clean the carb, install a "T" handle extended fuel screw, and desnorkel as well. Seemed like a good idea at the time.
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Old 06-11-2011, 12:01 PM   #70
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Default Re: Is your KLR Backfiring...???

Noob question...

Could someone post a link to a description of how to tighten my header bolts and adjust my pilot mixture screw?

Also, what size of copper cush gasket should I get?
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Old 06-11-2011, 06:21 PM   #71
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by Garrat9 View Post
Noob question...

Could someone post a link to a description of how to tighten my header bolts and adjust my pilot mixture screw?

Also, what size of copper cush gasket should I get?
The header bolts are where the exhaust header attaches to the front
of the cylinder. Tighten to 15 ft lbs or 180 inch lbs with a torque wrench.

Copper gasket order from here: https://www.cheapcycleparts.com/

To adjust your pilot screw: https://www.klr650.net/forums/showthr...highlight=cent

I replaced my copper gasket. When I removed the old one there was nothing wrong with it. I replaced it anyway and torqued to spec.
Still have the lone pop. Gonna plug the hoses to the smog pump this week. Prolly Monday. I will take pics and post here.
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Old 06-13-2011, 04:39 PM   #72
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Default Re: Is your KLR Backfiring...???

New crush gasket, $10 and new acorn nuts $1.10 a piece at my local shop. No leaks and torqued to 15 ft lbs
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Old 06-13-2011, 04:52 PM   #73
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by tmills View Post
New crush gasket, $10 and new acorn nuts $1.10 a piece at my local shop. No leaks and torqued to 15 ft lbs
get it hot...let it cool down and re-torque...
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2006 KLR685...Critter
1998 Honda VFR800+...Kitty

CHECK YOUR OIL AT EVERY FUEL STOP!!!
OR IT COULD COST $1000 or MORE!!! think about it
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Old 06-14-2011, 12:56 PM   #74
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Default Re: Is your KLR Backfiring...???

Can't thank you enough! I had checked most of the bolts about week ago and I guess I just didn't think about those, and they were about to fall off! Now my two bros exhaust sounds awesome again!
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Old 06-15-2011, 08:38 AM   #75
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by wymanwinn View Post
get it hot...let it cool down and re-torque...
on the agenda for today thanks Wyman
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Old 06-15-2011, 06:35 PM   #76
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by toms89cherokee View Post
My '09 backfires both on accel and decel and seems to be getting worse.Plug is a little white and exhaust pipe has some black carbon build-up, but not too bad.Bike has a FMF exhaust and dyno jet kit with a K&N filter.Any ideas as to what is causing this? It runs fine but the backfire has to go!would love some feedback as to how to go about solving the problem,Thanks,Tom
Well TOMS,
I had DJ stage II w/ 150 jet, Airbox mods, (snorkel gone and L-mod, Leo Vince X3 with the open silencer and factory air filter. It ran great. It kind of got too loud for me so I put in the quiet tube. New i was going to have to change jets, so I changed DJ jet from 150 to 146, then 142. Still backfiring. Well, I ended up with .020 shim, factory needle and 145 keihin factory jet that was on the bike new. 2 turns on air screw and no backfiring and minimal decel pop. Live and learn but I know now if I want to scream and run to the max I already had it figured out for my altitude. Also listen to wymans advice. Check your header bolts and exhaust for leaks.
Please let me know if this helps.
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Old 06-15-2011, 08:02 PM   #77
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by wymanwinn View Post
get it hot...let it cool down and re-torque...

Or if you grew up around Nortons, retorque every time you ride.
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Old 06-15-2011, 09:05 PM   #78
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by Pigasus View Post
Or if you grew up around Nortons, retorque every time you ride.
isn't that the truth....

and Nortons were the reason Hylomar was developed....the ONLY case sealant to keep oil in them for at least one race weekend....
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2015 BMW S1000R...Duke
2006 KLR685...Critter
1998 Honda VFR800+...Kitty

CHECK YOUR OIL AT EVERY FUEL STOP!!!
OR IT COULD COST $1000 or MORE!!! think about it
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Old 06-16-2011, 02:59 PM   #79
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Default Re: Is your KLR Backfiring...???

"get it hot...let it cool down and re-torque..."


Going to do that to my wife this weekend!

Couldn't help it.
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Old 06-18-2011, 02:04 PM   #80
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Default Re: Is your KLR Backfiring...???

Quote:
Originally Posted by Frogrider View Post
Mine has an issue with popping that is very specific and repetitive.

Let me explain.....
When I am running at a slightly higher RPM 4-5,000 and running in say
1st, 2nd, or 3rd on the twisty forest service roads in N.C. and I
back off the throttle and allow the bike gearing to control my speed
downhill, the "pop", which is usually a single pop, occurs at the very
moment that I touch the throttle to accelerate. It happens only at
that point and only a single "Pop". Weird huh? I do NOT get popping
on decel. Just the lone "POP".

I have tightened the nuts. I have done the 22 cent mod, 2 washers,
and drilled the slide. I have installed a thumb screw enricher and
have it about 2-2.25 turns out. I have a DG "O" with a silence insert
and no spark arrestor. All leaks on the pipe have been eliminated.
I have ordered a new copper seal for the header but it hasn't arrived.
I also have a UNI filter with no airbox mods.

I was "told" that there is some kind of "smog" equipment behind the
right front side panel that injects air into the backside of the
combustion that is to aid in burning off unspent gases to reduce
emissions. This is not to be confused with the Ca models smog pump
on the left mid/rear side. I was "told" that this could be disconnected??????

HELP!

Allright here's the deal.....I tried it all, torqued,
new crush gasket, torqued and re-torqued.

Still had the POP!!!

TODAY I fixed the POP! Here's what I did........

https://www.klr650.net/forums/showpos...postcount=4946
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1999 KLR 250 - Teal?
2008 KLR 650 - Green
2001 Kawasaki ZG 1000 Concours - Black
"Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure, or nothing." Helen Keller
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