popping on deceleration

Message

ofblong · #11 Unread post by **ofblong** » Tue Mar 31, 2009 8:30 am

jonnythan wrote:
debtman7 wrote: I'm guessing that going down a steep hill (we're talking like 40 degrees here)
People always greatly, greatly, greatly overestimate how steep slopes are!

40 degrees? I don't think so

I know of quite a few that are that steep in the UP of michigan. Trust me they are the type of streets people take the LONG way around during the winter.

jonnythan · Tue Mar 31, 2009 8:58 am

ofblong wrote:I know of quite a few that are that steep in the UP of michigan. Trust me they are the type of streets people take the LONG way around during the winter.

Really? 40 degrees?

Are you sure?

HYPERR · #13 Unread post by **HYPERR** » Tue Mar 31, 2009 9:36 am

jonnythan wrote:
debtman7 wrote: I'm guessing that going down a steep hill (we're talking like 40 degrees here)
People always greatly, greatly, greatly overestimate how steep slopes are!

40 degrees? I don't think so

Haha you're right Jonnythan. I'm an avid skier and skiers do the same thing. A 40 degree slope would literally look like a vertical drop.

The steepest street in the world is the one in New Zealand(I forgot the name) but it is 19 degrees according to the Guinness Book of World Records. An 19 degree slope on a street is totally insane.

jonnythan · Tue Mar 31, 2009 9:43 am

HYPERR wrote:
jonnythan wrote:
debtman7 wrote: I'm guessing that going down a steep hill (we're talking like 40 degrees here)
People always greatly, greatly, greatly overestimate how steep slopes are!

40 degrees? I don't think so
Haha you're right Jonnythan. I'm an avid skier and skiers do the same thing. A 40 degree slope would literally look like a vertical drop.

The steepest street in the world is the one in New Zealand(I forgot the name) but it is 19 degrees according to the Guinness Book of World Records. An 19 degree slope on a street is totally insane.

I believe the steepest double blacks out here in the east generally max out at 30-35 degrees... and that includes some damn steep trails.

But yes, the steepest roads don't get anywhere near 40. That would be insane. The steepest ones on the entire planet don't even get to a 40% grade.

debtman7 · #15 Unread post by **debtman7** » Tue Mar 31, 2009 1:05 pm

Well ok, hard to eyeball, but pretty darn steep, little hilly area behind me if you coast down you'll easily double your speed at the bottom

So I clamped down those pipes and it's much improved, but I still get a bit of burble from time to time. Since clamping that down, it seems like I'm getting a bit more puffing where the cans meet the pipes. Right there it's just a slip on, with two springs keeping it tight and the cans clamped onto the frame. There's really nothing to tighten there, and I get some puffs of exhaust coming out. How do I seal that up?

debtman7 · #16 Unread post by **debtman7** » Tue Mar 31, 2009 1:48 pm

Oh also, I pulled my plugs and they're very white.

Could that be from running it before cleaning out the carbs, when it was gummed up? Or from the exhaust leak? Or do I have more detective work to do?

I'm going to replace them and take it for a decent ride and see how it looks, hoping it was from prior problems though...

HYPERR · #17 Unread post by **HYPERR** » Tue Mar 31, 2009 2:59 pm

debtman7 wrote:Well ok, hard to eyeball, but pretty darn steep, little hilly area behind me if you coast down you'll easily double your speed at the bottom

So I clamped down those pipes and it's much improved, but I still get a bit of burble from time to time. Since clamping that down, it seems like I'm getting a bit more puffing where the cans meet the pipes. Right there it's just a slip on, with two springs keeping it tight and the cans clamped onto the frame. There's really nothing to tighten there, and I get some puffs of exhaust coming out. How do I seal that up?

Most decent auto parts stores sell a tube of exhaust leak sealant like this.

debtman7 · Tue Apr 07, 2009 11:01 am

Allright this is making me crazy...

I tigthened things down, used some high temp copper sealant in the slip on joints, went for a ride and thought it was better. But I may have been wrong, it seems to be doing it as bad as ever now.

I can find no more exhaust leaks. I've covered the pips with my hands after spraying soap water everywhere and see no leaks. Feel no leaks, engine back to the cans. I've sprayed carb cleaner all over the intake connections, airbox, carbs, etc and detect no intake leak.

But I'm still popping on deceleration, and low RPM cruising. I've tried adjusting the mix screws from 2.5 out to 4 and all I can really say is that it seems worse the more in they are, but I'm not sure. Even at 4 turns out it still pops.

What's next? I mean, I hear people say this is 'normal' with an aftermarket exhaust but I don't recall it ever being this bad... Is it possible the pilot circuit is still a little clogged? I thought I cleaned it out pretty well. Bike idles and runs strong, I notice no performance loss, stumbling, surging, idles perfectly.

HYPERR · #19 Unread post by **HYPERR** » Tue Apr 07, 2009 11:39 am

debtman7 wrote:Allright this is making me crazy...

I tigthened things down, used some high temp copper sealant in the slip on joints, went for a ride and thought it was better. But I may have been wrong, it seems to be doing it as bad as ever now.

I can find no more exhaust leaks. I've covered the pips with my hands after spraying soap water everywhere and see no leaks. Feel no leaks, engine back to the cans. I've sprayed carb cleaner all over the intake connections, airbox, carbs, etc and detect no intake leak.

But I'm still popping on deceleration, and low RPM cruising. I've tried adjusting the mix screws from 2.5 out to 4 and all I can really say is that it seems worse the more in they are, but I'm not sure. Even at 4 turns out it still pops.

What's next? I mean, I hear people say this is 'normal' with an aftermarket exhaust but I don't recall it ever being this bad... Is it possible the pilot circuit is still a little clogged? I thought I cleaned it out pretty well. Bike idles and runs strong, I notice no performance loss, stumbling, surging, idles perfectly.

How does it run?

On my KLX, I changed the pilot, main, needle, fuel screw, airbox snorkel, added a FMF powerbomb header, & a HMF muffler. I sealed the leak at the connection of the muffler to the best of my ability but the bike still pops at decel when the throttle is completely closed. However the bike starts instantaneously hot or cold, needs no warm up, and runs like a raped ape, all while returning 55 mpg. I really cannot imagine getting the carburation any more spot on that I have achieved. So I'm not really going to worry about it.....and I've actually come to love that pop pop pop sound.

debtman7 · Tue Apr 07, 2009 11:44 am

Well, it runs great... Plugs look good, maybe slightly on the whitish side but not bad. On a 60 degree day like today it requires maybe 30 seconds of half choke, idles well, runs strong. Just popping way more than I remember if ever doing. Part of it might be that I'm in a hilly area. Previously I never had hills to contend with so I never got much popping. Around here I've noticed the popping is most pronounced going downhill, either coasting or light throttle down hill. On a flat spot coasting, not a whole lot of popping. So maybe I'm just noticing it more because of the hills...

I guess what I'm trying to figure out is if there is anything else I could/should check out. I mean, could this be caused by a little bit of gum still in the pilot circuit? Or some electrical issue? Before I accept it as fact of life I'm trying to rule out all the other possibilities