KTM 640 SM Exhaust modification - Page 4

meat popsicle · 04-23-2006, 11:44 AM

Quote:

Originally Posted by Sycamore

Yeah I know, I'm busy tracking down all the BST threads looking for advice on mixture setting and my head is spinning. I've only had the bike a few days so I haven't even figured where the mixture screw is.
And it seems the owner manual doesn't want people touching the carb.

You SM has a BST? OK, creeper has his guide HERE. It is indexed under "LC4 Setup Threads".

Flanny's PDF of his guide is available in my Yahoo briefcase, also indexed under "Other External Links to Downloads". Lots of stuff in there that you might want to 'borrow'.

Plenty of other useful stuff and fluff in the index. Hopefully I will get the edits done soon and have some cleaning and new additions soon.

Sycamore · 04-23-2006, 12:38 PM

Meat, thanks for the links, seems like that's what I need.

IMO the index is fine as it stands, it's damn useful. That index is quite an incrdible & addictive thing actually.

The bike's already popping a bit & idling not so good just from removing that first muffler plate so I guess it needs to be a bit richer.

Problem with the 640 SM is that it has no rev counter, so it's hard to adjust idle mixture screw based on that method of setting a higher idle speed and then adjusting. After listening to a few minutes of idling you kind of forget what the previous idle sounded like...

How much would you turn your idle mixture to counteract just a bit of leanness from opening the pipes slightly?
Don't need to answer that if it's going to open a can of worms...

Thanks anyway for the suggestions so far

meat popsicle · 04-23-2006, 12:48 PM

No tach? Dang...

The best person to answer your question is more than likely creeper. I have never tried to tune a bike w/out a tach; perhaps there are some others who have that know other diagnostics besides RPMs.

Read over creeper and Flanny's guides; they might have some info for ya.

Perhaps you could turn it a hair and then go for a ride and see how that influences the popping? "idling not so good" means what? Idle hunting? The idle dropped lower after the change?

PS - thanks for the compliment on the index, however I say you're full of dirhams...

Sycamore · 04-23-2006, 02:43 PM

I suspect the idle always was a bit slow, now it seems to have dropped slightly, stalled twice. Nothing major though, I'll try a light touch on that mixture screw..

I just came back from a ride (1.30 am, hot as hell outside) and I also noticed that the mid-throttle acceleration now seems a bit dull or flat - that would correspond to something I saw on Flanny's site about running lean on the main jet.
I tried a bit of choke for a hundred yards or so and the throttle seemed to get more of a kick - does that make sense? Making the mix a bit richer? Or maybe that's oversimplifying it.

And all of this would (I think) correspond to my heavy-handed opening up of the muffler.

Which is fine - as long as there's consistency with symptoms. Unpredictability is what I don't like.

Quote:

Originally Posted by meat popsicle

PS - thanks for the compliment on the index, however I say you're full of dirhams...

i wish i was.

lost1 · 04-26-2006, 07:38 PM

I bought my Adventure in AUstralia and it had the exact same exhaust as yours. I tried to modify it. Nothing worked other than cutting it open, removing the offending pieces and rewelding it. Basically its not really worth the effort as the thing weighs as much as if it were made out of brick. Order a good aftermarket and wait for it to arrive in the emirates, inshaallah.

Sycamore · 04-27-2006, 02:45 AM

Quote:

Originally Posted by lost1

I bought my Adventure in AUstralia and it had the exact same exhaust as yours. I tried to modify it. Nothing worked other than cutting it open, removing the offending pieces and rewelding it. Basically its not really worth the effort as the thing weighs as much as if it were made out of brick. Order a good aftermarket and wait for it to arrive in the emirates, inshaallah.

I hate waiting! I will order one when I get enough money, inshallah. I priced Staintune from Oz, I like it but it aint cheap. Maybe in a few months.
As a temporary fix I cut out the first plate, and then drilled 6 x 10mm holes thru the second back plate, so my brick exhaust sounds much better now, not too loud but good, and much more airflow out the back. The carb was suddenly a lot more lean, so now I'm doing the carb jetting and at the same time putting on a smaller back sprocket.
I'll see how it goes latter today if the damn wind stops, we've had sandstorm for the past 2 days...

overlandr · 04-27-2006, 03:21 AM

Quote:

Originally Posted by Sycamore

I hate waiting! I will order one when I get enough money, inshallah. I priced Staintune from Oz, I like it but it aint cheap. Maybe in a few months.
As a temporary fix I cut out the first plate, and then drilled 6 x 10mm holes thru the second back plate, so my brick exhaust sounds much better now, not too loud but good, and much more airflow out the back. The carb was suddenly a lot more lean, so now I'm doing the carb jetting and at the same time putting on a smaller back sprocket.
I'll see how it goes latter today if the damn wind stops, we've had sandstorm for the past 2 days...

Heard good reports of the DAM from Germany via Sommer

meat popsicle · 04-27-2006, 07:30 AM

Quote:

Originally Posted by overlandr

Heard good reports of the DAM from Germany via Sommer

good tip overlandr! go griz got one and he dug it. very quiet, but flowed well. Your orders from Germany might be better than Oz, shipping-wise. And the dam is a slip on; not sure if the Staintune slips on the stock midpipe.

overlandr · 04-27-2006, 07:43 AM

Quote:

Originally Posted by meat popsicle

good tip overlandr! go griz got one and he dug it. very quiet, but flowed well. Your orders from Germany might be better than Oz, shipping-wise. And the dam is a slip on; not sure if the Staintune slips on the stock midpipe.

They both look similiar stainless steel type oval or round - Jerome the RTW guy said the Dam was the best sound he'd heard ('cept Akra!). I picked up a used Dam in the UK but won't get it for another 6 months or so!!

lost1 · 04-27-2006, 10:09 PM

oh I know sandstorms alright. I rode by myself from Sanaa to Musqat through the desert almost 10 years ago on a Suzuki DR 600. That was one tough ride, following wadis and goat tracks for weeks...

I was in Dubai last year for a short visit. It was too hot for riding. Imagine. I live in Canada where its too cold, too much snow etc. Trust me I would rather be too hot.

I hope you have this exhaust thing all fixed up. I drilled mine out too before finally giving up on it.

lost1

meat popsicle · 04-27-2006, 10:20 PM

Quote:

Originally Posted by overlandr

... I picked up a used Dam in the UK but won't get it for another 6 months or so!!

What courier service is that?!?

lost1 · 04-27-2006, 10:29 PM

Meat, you got the angle all wrong, How in the hell are we supposed to see the DAM exhaust pipe.

meat popsicle · 04-27-2006, 10:54 PM

Quote:

Originally Posted by lost1

Meat, you got the angle all wrong, How in the hell are we supposed to see the DAM exhaust pipe.

You are one sick puppy lost1! You're gonna fit right in here...

Sycamore · 04-28-2006, 05:42 AM

I recognize that baby, if the shot was a better angle you'd see that it's got Acrapovic pipe, not DAM.
BTW notice the aftermarket Corbin seat, there's a bit of wear but it's still good for a few thousand miles.

Sycamore · 04-28-2006, 05:48 AM

Quote:

Originally Posted by lost1

oh I know sandstorms alright. I rode by myself from Sanaa to Musqat through the desert almost 10 years ago on a Suzuki DR 600. That was one tough ride, following wadis and goat tracks for weeks...

I was in Dubai last year for a short visit. It was too hot for riding. Imagine. I live in Canada where its too cold, too much snow etc. Trust me I would rather be too hot.

I hope you have this exhaust thing all fixed up. I drilled mine out too before finally giving up on it.

lost1

How many air filters did u go through?
If you were here in summer, you'd remember that it gets up to 50 degrees C (120 F). I'd raher be too cold thanks. The killer in Dubai is that heat combined with massive humidity. 10 minutes on the bike & you are soaked.

04-23-2006, 12:48 PM	#48
meat popsicle Ignostic Joined: Feb 2004 Location: Circumlocution Office of Little Dorrit Oddometer: 13,844	No tach? Dang... The best person to answer your question is more than likely creeper. I have never tried to tune a bike w/out a tach; perhaps there are some others who have that know other diagnostics besides RPMs. Read over creeper and Flanny's guides; they might have some info for ya. Perhaps you could turn it a hair and then go for a ride and see how that influences the popping? "idling not so good" means what? Idle hunting? The idle dropped lower after the change? PS - thanks for the compliment on the index, however I say you're full of dirhams... __________________ Kronreif Trunkenpolz Mattighofen LC4 640 Its not so much staying alive; its staying human that counts.

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04-23-2006, 12:38 PM	#47
Sycamore ^OP d00b Joined: Mar 2006 Location: Dubai, United Arab Emirates Oddometer: 1,692	Meat, thanks for the links, seems like that's what I need. IMO the index is fine as it stands, it's damn useful. That index is quite an incrdible & addictive thing actually. The bike's already popping a bit & idling not so good just from removing that first muffler plate so I guess it needs to be a bit richer. Problem with the 640 SM is that it has no rev counter, so it's hard to adjust idle mixture screw based on that method of setting a higher idle speed and then adjusting. After listening to a few minutes of idling you kind of forget what the previous idle sounded like... How much would you turn your idle mixture to counteract just a bit of leanness from opening the pipes slightly? Don't need to answer that if it's going to open a can of worms... Thanks anyway for the suggestions so far

04-26-2006, 07:38 PM	#50
lost1 Adventurer Joined: Dec 2003 Oddometer: 53	I bought my Adventure in AUstralia and it had the exact same exhaust as yours. I tried to modify it. Nothing worked other than cutting it open, removing the offending pieces and rewelding it. Basically its not really worth the effort as the thing weighs as much as if it were made out of brick. Order a good aftermarket and wait for it to arrive in the emirates, inshaallah.

04-27-2006, 10:09 PM	#55
lost1 Adventurer Joined: Dec 2003 Oddometer: 53	oh I know sandstorms alright. I rode by myself from Sanaa to Musqat through the desert almost 10 years ago on a Suzuki DR 600. That was one tough ride, following wadis and goat tracks for weeks... I was in Dubai last year for a short visit. It was too hot for riding. Imagine. I live in Canada where its too cold, too much snow etc. Trust me I would rather be too hot. I hope you have this exhaust thing all fixed up. I drilled mine out too before finally giving up on it. lost1

04-27-2006, 10:29 PM	#57
lost1 Adventurer Joined: Dec 2003 Oddometer: 53	Meat, you got the angle all wrong, How in the hell are we supposed to see the DAM exhaust pipe.

04-28-2006, 05:42 AM	#59
Sycamore ^OP d00b Joined: Mar 2006 Location: Dubai, United Arab Emirates Oddometer: 1,692	I recognize that baby, if the shot was a better angle you'd see that it's got Acrapovic pipe, not DAM. BTW notice the aftermarket Corbin seat, there's a bit of wear but it's still good for a few thousand miles.