DR750 & DR800 owners thread - Page 603

Ladder106 · 01-13-2011, 09:00 AM

HellicksHelmet,

I'm enjoying watching your innovations but feel I should point out a few things that I'd consider doing differently.

First, reading the older posts of this thread you'll notice that other riders have had difficulty getting the DR to run and fuel well after making air box modifications. It seems that single cylinder engines are the most difficult engines to work with in the intake tract/airbox system due to power pulses and air box resonance.

The "pod" type filter you're designing may run really well but may also run up against some resonance and flow problems.

Second, the depth of the filter medium you're using is at least half of the thickness that I'm used to seeing with filter foam. The K&N is the only one that may be thinner.

Using WD40 as filter oil is something I strongly question. You stated you have had good results with this and I'm certainly a very long way from seeing the conditions in which you ride....but....I've always considered WD40 as more of a "solvent" than a lubricant. It was really never designed as a lubricant but as a product to displace water (WD = water displacement) from electrical parts. We use it at the firehouse (as a solvent) with great success to clean roof tar off our axes and power saws.

Any filter oil I've ever used has a sticky - tacky feel to it to trap and hold onto any dirt trying to pass through the foam.

Yes, I've seen many many bikes back in the Cafe-racer days with open velocity stack who's owners swear that there is no problem running engines like this on the street. I find that wisdom questionable.

So, once again, I'm not trying to sound like an "expert" or trying to "piss in your messkit". But there are some sound reasons for rethinking or modifying your project.

Apologies for throwing tact out the window but I felt this should be said.

hellicks hellmet · 01-13-2011, 09:26 AM

Quote:

Originally Posted by Ladder106

Apologies for throwing tact out the window but I felt this should be said.

No harm done, in fact I appreciate other opinions, especially when they're supported by facts!

Firstly, you're being kind when you're talking about my "innovations"... they're hardly more than a cheap way of fixing my issues.

Secondly, you're not the first one I've heard talking about WD40 as a solvent. As much as I believe your experiences with it as a tar cleaning agent, this one (which I bought from a respectable shop in Germany) doesn't seem to do that trick. I've tried cleaning a range of stuff with it and it just covers everything in a thin film of oil. On the other hand, I agree that airfilter oils (like the one K&N provides with their filters is much stickyer). It's just my (cheap) solution to repelling damp from the foam.

Now, I'm not going that far tuning my bike so as to talk about resonance in the airbox & stuff. IMO, in this improvised airbox there will be none. I've tried a similar trick on my KLR (single cylinder, single carb) and it works fine (it's my second year with this contraption on it). That being said, it's true that I generally ride in "clean" and dry conditions. I'm an occasional rider, and I only ride in the rain if it happens to catch me on the road and in a hurry.

I've bought the Big mainly to have a bike that copes with the poor quality of the most of the roads we have here, but still manages to pull a decent 130 km/h occasionally on the highway (btw, the rear transplanted sprocket has 42 teeth, instead of the 47 I took off

. that should make a bit of difference). So the bike won't be seeing much offroading (sorry to disappoint some of ya).

Anyway, I guess I'll try and see. There's nothing wrong with Ebay customers.

hellicks hellmet · 01-13-2011, 09:31 AM

Quote:

Originally Posted by nejauks

Danger of becoming ebay client!

Don't discriminate! Ebay clients are very nice people, I even know know one that lent me his bike!

nejauks · 01-13-2011, 10:06 AM

More foam, more foam! This is SOS signal.

hellicks hellmet · 01-13-2011, 10:08 AM

Quote:

Originally Posted by nejauks

More foam, more foam! This is SOS signal.

It's gonna stay with us for a while...

ztaj · 01-13-2011, 08:34 PM

Quote:

Originally Posted by nejauks;14932069/

Now that is a cool smiley/emoticon thingy /\ /\

Aaaand while I'm here....
I had 1 muffler from a ducati 1198 fitted to the big the other day

what a racket, it's as loud as it was before but a nicer, deeper tone anyway, the bike will idle but stalls when I try to take off, it goes o.k above 4500 rpm but below that is rubbish

. Pulls like a schoolboy above that though
Does anybody have any clues as to what I could try. Main jet is 122.5 pilot jet is standard (and can't be changed) clip is middle pos. on the needle. Or am I looking at the wrong things ?

Ladder106 · 01-13-2011, 09:34 PM

Not being able to make the pilot larger is going to be a problem.

I'd say you need a larger pilot and raise the needle (lower the clip) a notch or two. Try two first to try to compensate for the small pilot.

Have you tried holding the "choke" open when you try to accelerate. Obviously you can't hold the choke and operate the clutch at the same time but if you can at least get the bike moving you might see of opening the chock will make things better. This should tell you you need a larger pilot....like you didn't know that already.

bluesman · 01-13-2011, 11:52 PM

hellicks hellmet,

My two cents...
I believe you right, WD40 over here is not much of solvent (thou still is to some level) but problem with WD40 lays somewhere else.

WD40 is hygroscopic. It's function means that your filter will absorb moisture from air much better with WD40, e.g. it will "wet itself".
Bad or good - no idea, can't tell, specially since some water in mix is good - but it will alter way engine run.

So, as long as you will keep airbox "box" in place and filter inside it will be OK. But if this filter replacing airbox - second problem comes to play.
DR is very sensitive to air stream instability. Which is inevitable problem with any filter without airbox.
Then there is "back draft wave" problem of course - but that one is very difficult to predict.
Air stream aberrations when bike moving let say at 60+ kmph is different matter. This just always bad.

Filtering quality - it's a proven problem unfortunately. IF you run DR on dusty roads or offroad you will end up with scuffs on cylinder wall. If you run DR only on usual mostly dust-free roads you will not see effects of it for a while. But why limit yourself to particular conditions? Wrap one more coarse foam layer and then again usual foam layer and you OK.

Also - just suggestion...DR have impressive intake pulses. E.g. on openings that are large in that tin can foam will be pulled in every intake pulse. This is why all aftermarket filters use some form of "base". You can easily take care of it by wrapping layer of metal net around tin can first . I believe that material available in DYI shops and on the DYI market. I know you have plenty of them where you live.

bluesman · 01-13-2011, 11:58 PM

Quote:

Originally Posted by ztaj

Now that is a cool smiley/emoticon thingy /\ /\

Aaaand while I'm here....
I had 1 muffler from a ducati 1198 fitted to the big the other day

what a racket, it's as loud as it was before but a nicer, deeper tone anyway, the bike will idle but stalls when I try to take off, it goes o.k above 4500 rpm but below that is rubbish

. Pulls like a schoolboy above that though
Does anybody have any clues as to what I could try. Main jet is 122.5 pilot jet is standard (and can't be changed) clip is middle pos. on the needle. Or am I looking at the wrong things ?

Use old method of analysis - pilot and air controls up to 1/4 of throttle, slide between 1/8 and 1/2, jet needle 1/4 to 3/4 etc.

But Ladder is right - being unable to touch pilot you need to compensate with all other stuff. For example needle jet/needle do contribute to mix as of 1/8, not just from 1/4. Just less profound effect.

ztaj · 01-13-2011, 11:59 PM

Thanks Ladder... I'll raise the needles

I pulled the carbs out (in about 15 mins, getting good at that) and found one of the clips had come off

so that may have been the cause. I'll take the carbs to the shop tomorrow and get them to check float levels too, as it's something I struggle with.

Ooops.. just saw your post B/man, mixture screw is set at factory setting, now would the bike be running richer or leaner ?

bluesman · 01-14-2011, 12:30 AM

basically fully open exhaust means leaner mix...I cannot tell without seeing what part of 1098 can you using. If just "end " of it - it is practically empty box, most of stuff is in first stage of exhaust system.

You say it runs very good above 4500 - that means main jet is spot on. If it does not react properly on throttle in low rpms but moves - I guess mix is too rich on that part of throttle opening. If it just weak in low rpms but reacts to throttle mix would be leaner. BTW - easiest way to tell: put your hand against exhaust gases exit in idle, if it feels really hot - mix is too lean. If it feels so that you can keep you hand there for a while - then it's OK. Of course it'll be just idle, but anyway...

hellicks hellmet · 01-14-2011, 02:58 AM

Quote:

Originally Posted by bluesman

hellicks hellmet,

My two cents...
I believe you right, WD40 over here is not much of solvent (thou still is to some level) but problem with WD40 lays somewhere else.

WD40 is hygroscopic. It's function means that your filter will absorb moisture from air much better with WD40, e.g. it will "wet itself".
Bad or good - no idea, can't tell, specially since some water in mix is good - but it will alter way engine run.

So, as long as you will keep airbox "box" in place and filter inside it will be OK. But if this filter replacing airbox - second problem comes to play.
DR is very sensitive to air stream instability. Which is inevitable problem with any filter without airbox.
Then there is "back draft wave" problem of course - but that one is very difficult to predict.
Air stream aberrations when bike moving let say at 60+ kmph is different matter. This just always bad.

Filtering quality - it's a proven problem unfortunately. IF you run DR on dusty roads or offroad you will end up with scuffs on cylinder wall. If you run DR only on usual mostly dust-free roads you will not see effects of it for a while. But why limit yourself to particular conditions? Wrap one more coarse foam layer and then again usual foam layer and you OK.

Also - just suggestion...DR have impressive intake pulses. E.g. on openings that are large in that tin can foam will be pulled in every intake pulse. This is why all aftermarket filters use some form of "base". You can easily take care of it by wrapping layer of metal net around tin can first . I believe that material available in DYI shops and on the DYI market. I know you have plenty of them where you live.

You deffinitely have a point. I will rethink my design. Thanks 4 the input!

yuvalbo1 · 01-14-2011, 11:12 AM

Greetings friends.
from Africa Angola.
This is their way on two wheels

Uploaded with ImageShack.us

HLK · 01-14-2011, 12:24 PM

Quote:

Originally Posted by bluesman

So, as long as you will keep airbox "box" in place and filter inside it will be OK. But if this filter replacing airbox - second problem comes to play.
DR is very sensitive to air stream instability. Which is inevitable problem with any filter without airbox.
Then there is "back draft wave" problem of course - but that one is very difficult to predict.
Air stream aberrations when bike moving let say at 60+ kmph is different matter. This just always bad.

Put more simple: I am convinced that CV-carbs need a source of "clean", non-turbulent air, which the airbox provides. I think of the airbox as a damper. Any external change in air pressure will have its effect on the slide and thus mixture at roughly 1/4--1/2 throttle. I guess a flat slide pumper carb or (Alpha-N based) fuel injection is less affected by this....but overall I'm very skeptical about modifying the stock airbox, let alone removing it completely.

If you modify the intake on a stock bike, you're also altering the mixture (due to the nature of CV carbs). I believe this is why my GPZ500s ran better with a 1" hole strategically drilled in the airbox. It was not an extra volume of air that could now reach the cylinder, it just simply leaned out the fat mixture at high rpm / large throttle openings. To compensate, I had to turn out the pilot screw. Et voila, 1000rpm extra powerband...which is pure gold when you're on a small twin chasing the big bikes in Germany's Black Forest. I didn't develop this mod myself....but it worked.

Most of the DIY tuning focusses on improving "flow", removing restrictions in the intake (cutting holes in airboxes, K&N filter) and outtake (bigger diameter exhaust) and adding fuel (bigger jets etc) to match the supposed larger volume of air that passes the engine.

But does it really work like that? This article makes a pretty good point of why air velocity is equally or even more important than flow: http://www.mototuneusa.com/think_fast.htm

What if Suzuki put in the "snorkles" to maintain velocity of the intake air?

I'm not trying to criticize anyone's particular approach to tuning here...I just think it's a really interesting subject, worth a healthy discussion.....especially if it leads to our DR's making even moooorrrrrree powerrrrr.

Power is nice. I like power

POWAAAH.

BTW I infected a friend with the DR BIG virus. He had a GSX-750F something (the ugly one)...and now rides a black DR800 SR43, just like mine.

bluesman · 01-14-2011, 01:15 PM

well, about snorkels - when they out and exhaust is stock it ran worse. At least my SR43 when I cut out filter ran worse. But that was pure experiment - since new exhaust have larger diameter and less restriction for flow to maintain "back pressure" I had to give it more air. And larger mains.

It is really tricky area...my other bike - Firestorm...owners of that model spent years trying to play with airbox. EVERYTHING made it only worse.
The only working recipe developed by GURU who created BSB Moriwaki Firestorms included much more than just specific measurements of airbox cut....

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01-13-2011, 09:00 AM	#9031
Ladder106 It's a short cut, really Joined: Jan 2005 Location: Davis, CA Oddometer: 4,268	HellicksHelmet, I'm enjoying watching your innovations but feel I should point out a few things that I'd consider doing differently. First, reading the older posts of this thread you'll notice that other riders have had difficulty getting the DR to run and fuel well after making air box modifications. It seems that single cylinder engines are the most difficult engines to work with in the intake tract/airbox system due to power pulses and air box resonance. The "pod" type filter you're designing may run really well but may also run up against some resonance and flow problems. Second, the depth of the filter medium you're using is at least half of the thickness that I'm used to seeing with filter foam. The K&N is the only one that may be thinner. Using WD40 as filter oil is something I strongly question. You stated you have had good results with this and I'm certainly a very long way from seeing the conditions in which you ride....but....I've always considered WD40 as more of a "solvent" than a lubricant. It was really never designed as a lubricant but as a product to displace water (WD = water displacement) from electrical parts. We use it at the firehouse (as a solvent) with great success to clean roof tar off our axes and power saws. Any filter oil I've ever used has a sticky - tacky feel to it to trap and hold onto any dirt trying to pass through the foam. Yes, I've seen many many bikes back in the Cafe-racer days with open velocity stack who's owners swear that there is no problem running engines like this on the street. I find that wisdom questionable. So, once again, I'm not trying to sound like an "expert" or trying to "piss in your messkit". But there are some sound reasons for rethinking or modifying your project. Apologies for throwing tact out the window but I felt this should be said.

01-13-2011, 10:06 AM	#9034
nejauks Gnarly Adventurer Joined: Dec 2010 Location: Latvia Oddometer: 142	More foam, more foam! This is SOS signal.

01-13-2011, 09:34 PM	#9037
Ladder106 It's a short cut, really Joined: Jan 2005 Location: Davis, CA Oddometer: 4,268	Not being able to make the pilot larger is going to be a problem. I'd say you need a larger pilot and raise the needle (lower the clip) a notch or two. Try two first to try to compensate for the small pilot. Have you tried holding the "choke" open when you try to accelerate. Obviously you can't hold the choke and operate the clutch at the same time but if you can at least get the bike moving you might see of opening the chock will make things better. This should tell you you need a larger pilot....like you didn't know that already.

01-13-2011, 11:52 PM	#9038
bluesman Beastly Adventurer Joined: Feb 2007 Location: Hoegaarden, Belgium Oddometer: 2,993	hellicks hellmet, My two cents... I believe you right, WD40 over here is not much of solvent (thou still is to some level) but problem with WD40 lays somewhere else. WD40 is hygroscopic. It's function means that your filter will absorb moisture from air much better with WD40, e.g. it will "wet itself". Bad or good - no idea, can't tell, specially since some water in mix is good - but it will alter way engine run. So, as long as you will keep airbox "box" in place and filter inside it will be OK. But if this filter replacing airbox - second problem comes to play. DR is very sensitive to air stream instability. Which is inevitable problem with any filter without airbox. Then there is "back draft wave" problem of course - but that one is very difficult to predict. Air stream aberrations when bike moving let say at 60+ kmph is different matter. This just always bad. Filtering quality - it's a proven problem unfortunately. IF you run DR on dusty roads or offroad you will end up with scuffs on cylinder wall. If you run DR only on usual mostly dust-free roads you will not see effects of it for a while. But why limit yourself to particular conditions? Wrap one more coarse foam layer and then again usual foam layer and you OK. Also - just suggestion...DR have impressive intake pulses. E.g. on openings that are large in that tin can foam will be pulled in every intake pulse. This is why all aftermarket filters use some form of "base". You can easily take care of it by wrapping layer of metal net around tin can first . I believe that material available in DYI shops and on the DYI market. I know you have plenty of them where you live.

01-13-2011, 11:59 PM	#9040
ztaj not quite so broken Joined: Jul 2008 Location: Nelson-ish New Zealand Oddometer: 686	Thanks Ladder... I'll raise the needles I pulled the carbs out (in about 15 mins, getting good at that) and found one of the clips had come off so that may have been the cause. I'll take the carbs to the shop tomorrow and get them to check float levels too, as it's something I struggle with. Ooops.. just saw your post B/man, mixture screw is set at factory setting, now would the bike be running richer or leaner ?

01-14-2011, 12:30 AM	#9041
bluesman Beastly Adventurer Joined: Feb 2007 Location: Hoegaarden, Belgium Oddometer: 2,993	basically fully open exhaust means leaner mix...I cannot tell without seeing what part of 1098 can you using. If just "end " of it - it is practically empty box, most of stuff is in first stage of exhaust system. You say it runs very good above 4500 - that means main jet is spot on. If it does not react properly on throttle in low rpms but moves - I guess mix is too rich on that part of throttle opening. If it just weak in low rpms but reacts to throttle mix would be leaner. BTW - easiest way to tell: put your hand against exhaust gases exit in idle, if it feels really hot - mix is too lean. If it feels so that you can keep you hand there for a while - then it's OK. Of course it'll be just idle, but anyway...

01-14-2011, 11:12 AM	#9043
yuvalbo1 Adventurer Joined: Sep 2010 Location: israel Oddometer: 53	Greetings friends. from Africa Angola. This is their way on two wheels Uploaded with ImageShack.us

01-14-2011, 01:15 PM	#9045
bluesman Beastly Adventurer Joined: Feb 2007 Location: Hoegaarden, Belgium Oddometer: 2,993	well, about snorkels - when they out and exhaust is stock it ran worse. At least my SR43 when I cut out filter ran worse. But that was pure experiment - since new exhaust have larger diameter and less restriction for flow to maintain "back pressure" I had to give it more air. And larger mains. It is really tricky area...my other bike - Firestorm...owners of that model spent years trying to play with airbox. EVERYTHING made it only worse. The only working recipe developed by GURU who created BSB Moriwaki Firestorms included much more than just specific measurements of airbox cut....