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Old 03-10-2013, 09:46 PM   #74566
Rumlover
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Quote:
Originally Posted by motolab View Post
I don't remember arguing that the weight of the shim could have an effect on slide height, although it is a valid point.I agree when it comes to the weight of the shim, but disagree when it comes to preload on the spring. I have done dyno testing that demonstrates that clipping two coils off a BST40 slide spring on an LC4 richens the mixture in the bottom half of the rpm range by an amount I would call significant. Adding preload should have the opposite effect. In fact, some FP jet kits come with heavier slide springs for that very reason, that is to help overcome inordinately rich mixtures that were caused by opening up airboxes and installing the appropriate main jet (that is one that that provides the correct mixture at high rpm). Dyno testing I have performed demonstrates that it works. On the other hand, others here claim that shimming the needle cured a stumble. Make no mistake, if the stumble was cured by shimming the needle, then it was cured by lowering the slide instead of by raising the needle, unless the issue was at a point where the slide is against the stop. If the issue was at a point where the slide is against the stop, then that means the throttle is most of the way closed (i.e. 1/8 opening or under), which then in turn means that in reality the wrong circuit was used to fix the problem (it should have been fixed with pilot jet size instead).Well .002" to .004" is awfully small, to a point of not really producing a discernible result. However, regardless of what thickness of shim is chosen, you are correct that a shim will move the needle higher in the emulsion tube for a given slide height, except you are neglecting that, for a given intersection of throttle position and rpm, the slide height will at the same time be lower than it was.You have to define "corrects". If by that you mean that the symptom is gone, then perhaps. To me, just because the symptom is gone does not mean the problem has been corrected. To me corrected means that the mixture has been brought to where the CO is between 3 and 5 percent, or to where best power is being achieved for a given intersection of throttle position and rpm, and doing so was not to the detriment of some other intersection of throttle position and rpm (or at least the best compromise). Remember that the symptoms can be gone, but that the mixture can still be poor enough to cause hot running, detonation & poor mileage on the lean side, and carbon deposits, oil being washed off the cylinder wall & poor mileage on the rich side.My suggestion always includes the admonishment, "Don't have an accident trying to look at the marks while riding. If you do, I'm not responsible!" In other words, if you feel you can't do this safely, don't do it. Clearly, it's up to the individual to decide.

I'd like to ask you, what is your opinion of people who make a habit of attempting to hold others responsible for the choices they make?

Regards,

Derek

Yes .002 is awfully small. it was an error and I corrected it to .02 a few minutes after I wrote it. Sorry for the confusion.

I still am not convinced on that small bit of preload accounting for the entire difference. Maybe I miss read but your conclusion was based upon cutting springs, not actually preloading it. But regardless why do you discount the needle being higher in the needle jet for any given slide height. Surely that accounts for some of the increase in richness even if the slide is slightly lower.

To your question:
I believe people are responsible for their own actions, and have a responsibility to exercise a little common sense and judgement when taking the advice of others. That is why I would never go riding down the street and trying to read 1/16 incremental marks on my throttle while trying various throttle positions. Maybe I am not as sharp as others, but sooner or later my eyes are going to be in the wrong place and I might miss that truck pulling in front of me.
So yea you are off the hook and not responsible for others, but it still sounds a little ridiculous to me.
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Old 03-10-2013, 09:50 PM   #74567
eakins
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Derek,
You post alot of variables that people should check when having problems (thank you!), but often there are not answers/solutions to what people should do to fix the issues. Granted people are not responding so well with throttle position feedback for solutions and that's not your fault.

When know the DR, in stock form, is lean. Some surge.
When modified some stumble off idle as a result. (still dealing with my issue with that.)

You say you've done alot of dyno testing with different carb settings.
How about a to do list (a baseline of mods to do) for those with stock carbs who want better performance.
Let's assume a stock muffler and everything else. Where to start and see how the bike works?

-adjust pilot jet to where?
-what jet sizes?
-what if anything to do to the carb?
-where to set the needle?
-check and set the float to what height?
-drill another hole in the slide or not?
-mods to the airbox?

get my idea?

Then maybe a aftermarket pipe list and a list to check when you have off idle stumble.
You seem to have the same conversation over and over with people checking in, but it does not seem they've responded that it's been resolved.

Question? I'm confused.
You recommend the non-US adjustable needle to tune and richen the bike. It's the same shape as the US needle. Yes? So then you can raise it to richen (or lower it to lean) the bike.

If it's the same shape then why would adding a washer shim under the US needle not have the same effect as lower the clip on a non-US needle. Both methods raise the needle up higher and thus come out of the emulsion tube faster thus releasing more gas. The position of the slide is the same either method. Am I missing something here???

Thanks, Bill


Quote:
Originally Posted by motolab View Post
I don't remember arguing that the weight of the shim could have an effect on slide height, although it is a valid point.I agree when it comes to the weight of the shim, but disagree when it comes to preload on the spring. I have done dyno testing that demonstrates that clipping two coils off a BST40 slide spring on an LC4 richens the mixture in the bottom half of the rpm range by an amount I would call significant. Adding preload should have the opposite effect. In fact, some FP jet kits come with heavier slide springs for that very reason, that is to help overcome inordinately rich mixtures that were caused by opening up airboxes and installing the appropriate main jet (that is one that that provides the correct mixture at high rpm). Dyno testing I have performed demonstrates that it works. On the other hand, others here claim that shimming the needle cured a stumble. Make no mistake, if the stumble was cured by shimming the needle, then it was cured by lowering the slide instead of by raising the needle, unless the issue was at a point where the slide is against the stop. If the issue was at a point where the slide is against the stop, then that means the throttle is most of the way closed (i.e. 1/8 opening or under), which then in turn means that in reality the wrong circuit was used to fix the problem (it should have been fixed with pilot jet size instead).Well .002" to .004" is awfully small, to a point of not really producing a discernible result. However, regardless of what thickness of shim is chosen, you are correct that a shim will move the needle higher in the emulsion tube for a given slide height, except you are neglecting that, for a given intersection of throttle position and rpm, the slide height will at the same time be lower than it was.You have to define "corrects". If by that you mean that the symptom is gone, then perhaps. To me, just because the symptom is gone does not mean the problem has been corrected. To me corrected means that the mixture has been brought to where the CO is between 3 and 5 percent, or to where best power is being achieved for a given intersection of throttle position and rpm, and doing so was not to the detriment of some other intersection of throttle position and rpm (or at least the best compromise). Remember that the symptoms can be gone, but that the mixture can still be poor enough to cause hot running, detonation & poor mileage on the lean side, and carbon deposits, oil being washed off the cylinder wall & poor mileage on the rich side.My suggestion always includes the admonishment, "Don't have an accident trying to look at the marks while riding. If you do, I'm not responsible!" In other words, if you feel you can't do this safely, don't do it. Clearly, it's up to the individual to decide.

I'd like to ask you, what is your opinion of people who make a habit of attempting to hold others responsible for the choices they make?

Regards,

Derek
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eakins screwed with this post 03-10-2013 at 09:55 PM
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Old 03-10-2013, 10:03 PM   #74568
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Quote:
Originally Posted by greener556 View Post
Bike surges at lower RPM's is the main issue. Bike is really cold blooded, not sure if that can be fixed. Snorkel has been removed, GSXR muffler mod in the works.

Leaning towards this guys solution: http://www.advrider.com/forums/showp...5&postcount=71
Had the same symptoms as you and the suggestions in that link worked for me.
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Old 03-10-2013, 10:07 PM   #74569
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Quote:
Originally Posted by Rumlover View Post
But regardless why do you discount the needle being higher in the needle jet for any given slide height. Surely that accounts for some of the increase in richness even if the slide is slightly lower.
Once again, you are neglecting that when the spring has more preload in it, the slide height will be lower than it was before for a given intersection of throttle position and rpm, while the needle will be in an unchanged position (unless the slide is against either stop).
Quote:
So yea you are off the hook and not responsible for others, but it still sounds a little ridiculous to me.
Why does it still sound ridiculous? Does everything you wouldn't do sound ridiculous? Some people won't ride motorcycles at all. What would your response be if they told you your being a proponent of motorcycle riding "sounds a little ridiculous" to them?

Regards,

Derek
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Old 03-10-2013, 10:22 PM   #74570
Rumlover
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Quote:
Originally Posted by motolab View Post
Once again, you are neglecting that when the spring has more preload in it, the slide height will be lower than it was before for a given intersection of throttle position and rpm, while the needle will be in an unchanged position (unless the slide is against either stop).Why does it still sound ridiculous? Does everything you wouldn't do sound ridiculous? Some people won't ride motorcycles at all. What would your response be if they told you your being a proponent of motorcycle riding "sounds a little ridiculous" to them?

Regards,

Derek
I am not neglecting that the slide is lower with more spring preload. I pretty much conceded that in both posts. Why do you fail to see that at its now "lower" position the needle is higher in the needle jet (with a shim) for that position, and that also has an impact.

It still sounds ridiculous to me because I think it is bad advice. It's my opinion, get over it.
And no that doesn't apply to everything I wouldn't do, just the stuff "I think" is ridiculous.
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Old 03-10-2013, 11:02 PM   #74571
gofast1320
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40F0 muffler

Got my two brothers mid-pipe back from Jesse to mount my 40F0 muffler on my bike. Got it on and really like the change in sound. Seems to fire up easier and the low end off idle pull is better.
Previously I'd noticed a little stumble and got to thinking about all the different comments I've seen on here regarding removing the snorkel, adjusting clips, bigger jets etc. and the jist of it seems to be that introducing more air intentionally or a leak has more affect on stock DRs because of a chronic lean from the factory condition.
I'd had a jacked up, gummed or clogged needle seat that let fuel overflow into the airbox. Just running a couple of tanks of fuel with Stabil in it cleared up the leaking seat problem. I'd forgotten about removing that little nipple thing over the 1/2" outlet on the front at the bottom of the airbox to let all the gas run out. . I sealed that and the popping on deceleration has stopped.
Back to the mid-pipe business- I'd sent mine to Jesse to get the right flange welded on along with his bracket and other small parts to mount my muffler. They've got their act together. I got all of that with 2 photos showing what goes where and the install was a breeze. His stuff fits perfectly.

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Old 03-10-2013, 11:25 PM   #74572
motolab
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Quote:
Originally Posted by eakins View Post
You post alot of variables that people should check when having problems (thank you!), but often there are not answers/solutions to what people should do to fix the issues. Granted people are not responding so well with throttle position feedback for solutions and that's not your fault.
I've posted how to tell at which throttle position the problem is occurring at. I've posted which circuits are responsible for what throttle positions. I and others have also posted various methods to determine whether the problem is rich or lean. I have explained that it's fairly easy to "tell where you are" once you bump up against the most minor of lean misbehavior (with the caveat that doing so can be dangerous depending on compression, exhaust flow, timing and quality of fuel). People have been given all of the information to tune themselves within the confines of what is possible without a dyno. If they can't figure it out, they are not following the instructions for whatever reason (fear of damaging the engine is a good reason), or they are up against the limitations of what can be done without gas analysis or HP readings.
Quote:
How about a to do list (a baseline of mods to do) for those with stock carbs who want better performance.
It sounds to me like you want the answer without doing the work. That's unfortunately not how it works.
Quote:
Where to start and see how the bike works?
You can start where you are (perhaps temporarily using better fuel to prevent damage). The engine will tell you what it wants, but not without your listening to what it is trying to tell you.
Quote:

-adjust pilot jet to where?
-what jet sizes?
-what if anything to do to the carb?
-where to set the needle?
-check and set the float to what height?
-drill another hole in the slide or not?
-mods to the airbox?

get my idea?
Yes. I get the idea that, once again, you want the answer without doing the work. I have made one specific recommendation, where the trend is strong enough to in my mind guarantee the validity, and that is to stay away from the DJ needle. There is no instance I can think of where such a shape will be useful for a DR, and especially not with airbox mods, where the change in shape from stock is in a direction exactly opposite of what would be beneficial.
Quote:
Then maybe a aftermarket pipe list and a list to check when you have off idle stumble.
Perhaps you would like to provide me with a bike, a selection of pipes, and perhaps pay my bills while I tune all of the combinations of parts we can conceive of, realizing of course that all we would end up with are trends, as bikes with the same combinations of parts may still run differently and want different jetting. I have given a list of things to check when there is an off idle stumble several times. I've also requested that people clearly define what they mean by "off idle". In most cases, no clarification was given. I can give no further advice without knowing precisely what throttle position is being referred to, as I can't determine what circuit is responsible without having that information.
Quote:
You seem to have the same conversation over and over with people checking in, but it does not seem they've responded that it's been resolved.
I'm pretty sure they have, but if they hadn't what would that prove? Are you implying that the information I have given is incorrect?
Quote:
You recommend the non-US adjustable needle to tune and richen the bike. It's the same shape as the US needle. Yes?
Correct.
Quote:
So then you can raise it to richen (or lower it to lean) the bike.
Yes, raising the needle richens the mixture, and lowering it leans the mixture.
Quote:
If it's the same shape then why would adding a washer shim under the US needle not have the same effect as lower the clip on a non-US needle. Both methods raise the needle up higher and thus come out of the emulsion tube faster thus releasing more gas. The position of the slide is the same either method. Am I missing something here???
Yes, you are missing that for a given intersection of throttle position and rpm, shimming the needle clip lowers the slide rather than raising the needle (unless the slide is against either stop).

Regards,

Derek
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Old 03-10-2013, 11:49 PM   #74573
motolab
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Quote:
Originally Posted by Rumlover View Post
Why do you fail to see that at its now "lower" position the needle is higher in the needle jet (with a shim) for that position, and that also has an impact.
There is only one condition under which what you are saying could be true, and that's if, for a given intersection of throttle position and rpm, it's the slide rather than the butterfly that's causing the most restriction.
Quote:
It still sounds ridiculous to me because I think it is bad advice.
That it's ridiculous because it's bad is not really an argument. That said, it is possible that there may be some misunderstanding about how this can be done in a relatively safe manner. I do not advocate riding around and looking at the marks at whatever random time a symptom crops up. Rather, I suggest opening the throttle to each of the marks in a premeditated manner and letting the engine accelerate through the range to whatever rpm it will (based on how well/poorly it is tuned - top gear usually gives the best data and acceleration won't be as brisk). It should certainly possible to find a stretch of road with little traffic and no driveways/side streets to do this on, especially since the largest opening that requires the use of a mark is 1/4. 1/16 and 1/8 openings are so small that they can be tested in a medium sized empty parking lot.
Quote:
And no that doesn't apply to everything I wouldn't do, just the stuff "I think" is ridiculous.
How do you respond to people who think that things you like to do/advocate are ridiculous?

Regards,

Derek
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Old 03-11-2013, 12:08 AM   #74574
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Quote:
Originally Posted by motolab View Post
There is only one condition under which what you are saying could be true, and that's if, for a given intersection of throttle position and rpm, it's the slide rather than the butterfly that's causing the most restriction.That it's ridiculous because it's bad is not really an argument. That said, it is possible that there may be some misunderstanding about how this can be done in a relatively safe manner. I do not advocate riding around and looking at the marks at whatever random time a symptom crops up. Rather, I suggest opening the throttle to each of the marks in a premeditated manner and letting the engine accelerate through the range to whatever rpm it will (based on how well/poorly it is tuned - top gear usually gives the best data and acceleration won't be as brisk). It should certainly possible to find a stretch of road with little traffic and no driveways/side streets to do this on, especially since the largest opening that requires the use of a mark is 1/4. 1/16 and 1/8 openings are so small that they can be tested in a medium sized empty parking lot.
How do you respond to people who think that things you like to do/advocate are ridiculous?

Regards,

Derek

You either totally miss my point about needle position , find it irrelevant, or just enjoy confusing the issue. I really don't care anymore!

I see no need to continue to justify my opinions to you about what I think is ridiculous or why. I have already commented more then enough.

Good Night
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Old 03-11-2013, 12:45 AM   #74575
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Quote:
Originally Posted by Rumlover View Post
You either totally miss my point about needle position , find it irrelevant, or just enjoy confusing the issue.
None of the above.
Quote:
I really don't care anymore!
Well, that's unfortunate. I much prefer it when people reach an understanding together.
Quote:
I see no need to continue to justify my opinions to you about what I think is ridiculous or why. I have already commented more then enough.
As you wish...

Regards,

Derek
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Old 03-11-2013, 06:10 AM   #74576
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Quote:
Originally Posted by Rumlover View Post
You either totally miss my point about needle position , find it irrelevant, or just enjoy confusing the issue.
if i correctly understand what derek is saying, it's that, if you shim a stock needle, you change the spring tension, which lowers the slide. if you get an adjustable needle and raise it w/o shimming, the needle is raised, but the spring tension remains the same; therefore you have no lowering of the slide.

of course, i could also be completely off the mark here!

doug s.
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Old 03-11-2013, 06:30 AM   #74577
Mambo Dave
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Quote:
Originally Posted by doug s. View Post
if i correctly understand what derek is saying, it's that, if you shim a stock needle, you change the spring tension, which lowers the slide. if you get an adjustable needle and raise it w/o shimming, the needle is raised, but the spring tension remains the same; therefore you have no lowering of the slide.

of course, i could also be completely off the mark here!

doug s.
You may be on to what he's saying.

But then it would hit the wall of what the suspension guys say about springs - that their rate and tension don't change by pre-load, which is what a shim would do, unless they were a progressive-rate spring and it took up some lower-rate squish of the spring.

Not that I care that much one way or the other - my DR650 with ProCycle's needle and kit seems to run just fine. When push comes to shove, and when the needle wears the slide, I'll buy one of the better carb options out there.
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Old 03-11-2013, 07:34 AM   #74578
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Any of you people have a Wee Strom along with the DR650 willing to send me a PM about your observations as to the dirt ability of the Wee and the road abilty of the DR and how much of an overlap there is. I have some friends with WeeStroms at are tyring to talk me into adding one. I'd love to have more bikes, but is there enough difference to be worth it.

I thank you in advance for you thoughts. No need to clog up this thread with this talk, unless you feel it adds to the value of this thread.
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Old 03-11-2013, 07:45 AM   #74579
Rumlover
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Quote:
Originally Posted by doug s. View Post
if i correctly understand what derek is saying, it's that, if you shim a stock needle, you change the spring tension, which lowers the slide. if you get an adjustable needle and raise it w/o shimming, the needle is raised, but the spring tension remains the same; therefore you have no lowering of the slide.

of course, i could also be completely off the mark here!

doug s.

I will try to explain my position one last time (I really regret bringing it up at this point)

Assuming the carb is running on the needle circuit:
I understand that preloading the spring will cause the slide to be slightly lower then previous.
However the shimmed needle will still be raised in the slide. So unles the loss of slide height is greater then the amount the needle is raised by the shim, the needle will still be higher in the needle jet and flow more fuel.

Also the shimmed needle will always be higher in the needle jet for any given slide height. Motolabs explanation doesn't seem to think that is significant and makes it sound (to me) like the needle and slide are working independently. I know that wasn't his intent, but that's how it came across.

Anyway I was simply trying to point out that I don't think the loss of slide height is greater then the gain at the shimmed needle. And even if it is the flow through the needle jet will still be higher for the new slide height when compared to the same slide height for an unshimmed needle.

Hope that is clear as mud
Just one mans opinion

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Old 03-11-2013, 07:46 AM   #74580
ShadyRascal
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I have both and love the smoothness of the Wee on the road. The Wee is fine on gravel roads but any kind of mountain fire road with tighter corners the Wee gets to be a pig real quick.

Overall I'd say the DR is a better street bike than the Wee is a dirt bike. It's just more of a comfort thing for me with the Wee, I travel longer distances pretty regularly. But whenever it gets dirty, I want to be on the DR, and some roads or trails I'll just avoid with the Wee. All depends on your terrain and length of trip I guess.
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