ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-16-2012, 07:31 PM   #71896
fullmonte
Reformed Kneedragger
 
fullmonte's Avatar
 
Joined: Nov 2005
Location: Chattanooga, Tennessee
Oddometer: 5,068
Quote:
Originally Posted by Mambo Dave View Post
I've seen examples of different internals in fork legs in mountain bike forks, but they have a fork brace.
Yep, but the forks on my mountain bike would cost more a grand to replace.
__________________
"If you are looking for the typical ride to a restaurant, eat tacos, hold the middle finger over the food, stop and take a picture of a gravel road type ride, you probably won't be interested." - dlrides

"A guy I know was the lead researcher for the University of Utah federally funded study of cellphone and texting use while driving. He found that your twice as dangerous as a drunk while using your cell phone and I think it was up to six times worse if the driver was texting."-dakardad
fullmonte is offline   Reply With Quote
Old 12-16-2012, 08:20 PM   #71897
motolab
Beastly Adventurer
 
motolab's Avatar
 
Joined: Feb 2006
Oddometer: 2,400
Quote:
Originally Posted by BergDonk View Post
So you're not a fan of the latest SFF (Single Function Forks) MX forks as fitted to the latest KXs and RMZs?



Admittedly these have bigger (stiffer and stronger) axles than a DR, but small differences in oil levels and spring rates in a DR fork will not make a difference to the perceived or actual performance. Theoretically yes, in practice, no. In fact I doubt any pair of springs would measure the EXACT same rate due to manufacturing tolerances.
No, I'm not a fan, however see http://www.advrider.com/forums/showp...ostcount=72041.

Regards,

Derek
motolab is offline   Reply With Quote
Old 12-16-2012, 09:05 PM   #71898
Kommando
Grumpy Young Man
 
Kommando's Avatar
 
Joined: Nov 2006
Location: Spacecoaster FL
Oddometer: 7,079
Quote:
Originally Posted by Mambo Dave View Post
If that were the case, Fork Braces would never had been invented.

I think he has a good point there when he suggested making sure they're close to even in an attempt to do whatever we can to make a better-handling bike. Redneck riders won't agree to it, but then they tend to be the ones adjusting the preload to get a change out of rate.
Redneck?





As opposed to just buying stiffer springs that come with some kind of warranty and a spec'd rate, instead of permanently cutting/sanding the stockers and hoping for the best?



'Too funny.
Kommando is offline   Reply With Quote
Old 12-16-2012, 09:29 PM   #71899
Mambo Dave
Backyard Adventurer
 
Mambo Dave's Avatar
 
Joined: Oct 2011
Location: 11 ft. AMSL
Oddometer: 5,181
Quote:
Originally Posted by Kommando View Post
Redneck?





As opposed to just buying stiffer springs that come with some kind of warranty and a spec'd rate, instead of permanently cutting/sanding the stockers and hoping for the best?



'Too funny.
Well, it wasn't meant as an insult.

I've bought aftermarket springs before, and I saw exactly what I was getting - they, too, were pretty much the same wire diameter, but substantially shorter. I felt like an idiot for not chopping the original springs after that considering that bike cost me less then $1000.

If was building up a track bike or something then, sure, I'd go for aftermarket springs again. For the DR650 I'm going to go with cutting them (at least once) equally, and adjusting pre-load to where it should be. With me skipping the part of doing an actual calculation of weights this bike will see, plus my weight, the guesstimation of cut springs will bring me just about the same chance of getting it 'right' as if I were to buy a known spring rate for a bike I really haven't ever fully loaded yet, and don't know the weight for anyhow.

I'm still holding that preload adjusts preload, and that's best reserved as a setting unto itself.
Mambo Dave is online now   Reply With Quote
Old 12-16-2012, 09:37 PM   #71900
TrophyHunter
Beastly Adventurer
 
Joined: Aug 2009
Location: San Diego
Oddometer: 2,130
I was under the impression (possibly mistakenly) that fork braces cut out some of the side to side flex when cornering, too. I don't have them on the DR, but sure seemed different when cornering on the Strom. I could be a victim of my own imagination and marketing.
__________________
www.dualsportmoto.com
2005 DR650 2003 DRZ-250
2013 HD Road King '73 Hodaka Wombat

"It's a small amount of gas, but it represents a long walk" My Dad...
TrophyHunter is offline   Reply With Quote
Old 12-16-2012, 09:55 PM   #71901
motolab
Beastly Adventurer
 
motolab's Avatar
 
Joined: Feb 2006
Oddometer: 2,400
Quote:
Originally Posted by Kommando View Post
Redneck?





As opposed to just buying stiffer springs that come with some kind of warranty and a spec'd rate, instead of permanently cutting/sanding the stockers and hoping for the best?



'Too funny.
Springs can be cut and rate targets hit quite precisely. It's not hard to figure out how much of an increase in rate each coil (or fraction thereof) will be worth. As mentioned before, you can also measure the rate as you go. On bikes with little or no aftermarket support, or if you just need a rate that isn't being manufactured, it's the only choice you have available.

Regards,

Derek
motolab is offline   Reply With Quote
Old 12-16-2012, 10:18 PM   #71902
procycle
Beastly Adventurer
 
procycle's Avatar
 
Joined: Jun 2007
Location: Center of the DR650 universe
Oddometer: 2,215
Quote:
Originally Posted by Mambo Dave View Post
Wow! what a great idea! Not sure where I'd get the measuring apparatuses, but a damned fine idea!
Measuring apparatus.
See post #106
http://tw200forum.com/index.php?/top.../page__st__90?
__________________
Clarke's second law of Egodynamics: "For every expert, there is an equal and opposite expert." - Jasper Fforde
www.procycle.us - Everything for your DR650 and lots of other great stuff!
DR900 Big Bore Stroker buildup
TurboDiesel Corvette - go to the end to start at the beginning
procycle is offline   Reply With Quote
Old 12-16-2012, 10:21 PM   #71903
procycle
Beastly Adventurer
 
procycle's Avatar
 
Joined: Jun 2007
Location: Center of the DR650 universe
Oddometer: 2,215
Quote:
Originally Posted by TrophyHunter View Post
I was under the impression (possibly mistakenly) that fork braces cut out some of the side to side flex when cornering, too.
Controlling flex during cornering is probably the main purpose of a fork brace. The other benefits are secondary.
__________________
Clarke's second law of Egodynamics: "For every expert, there is an equal and opposite expert." - Jasper Fforde
www.procycle.us - Everything for your DR650 and lots of other great stuff!
DR900 Big Bore Stroker buildup
TurboDiesel Corvette - go to the end to start at the beginning
procycle is offline   Reply With Quote
Old 12-16-2012, 10:21 PM   #71904
blackcap
Studly Adventurer
 
blackcap's Avatar
 
Joined: Jul 2008
Location: Wollongong aka stink-town, Australia
Oddometer: 538
Quote:
Originally Posted by motolab View Post
Slide carbs will always have a loss in bottom end to lower midrange of the rpm range at the larger throttle openings because the air velocity (and therefore the quality of the metering) is proportional to the engine rpm and inversely proportional to the throttle opening. Slide carbs require you to learn throttle control. When tuned properly (I say "tuned properly" because it is possible to mask many problems with an overly rich mixture), you cannot open the throttle to WOT or near WOT suddenly from low rpm without significant hesitation (its even possible to stall the engine if you dont back off). A properly tuned accelerator pump will help this, but is not likely to completely mitigate the problem. On the other hand, CV carbs allow you to open the throttle all the way from low rpm and will pull smoothly when tuned correctly, because the height of the slide automatically attempts to maintain a consistent velocity.

The ability to open the throttle to WOT from low rpm without hesitation with a CV carb does come with a price, and that is in a comparative lack of responsiveness in those areas where the combination of throttle position and rpm does not cause too much of a loss in in intake velocity with the slide carb.

Another area where the CV carb has an advantage is in the ability to change the fuel delivery curve based on rpm via the needle shape. On a slide carb, you can add or subtract fuel via tuning a circuit responsible for a given throttle position, but you cannot change the shape of the delivery curve in terms of rpm. For instance, if you had a lean and a rich spot at different rpm at a certain throttle position, you could fix the lean spot while making the rich spot even richer, or you could fix the rich spot while making the lean spot even leaner. You could not fix both. Unfortunately, these types of scenarios happen quite frequently.

The throttle pull on the TM40 is also quite a bit heavier than on the BST40.


Regards,


Derek
i knew i could count on you for more information than i could imagine i needed. its good to have people out there that understand this stuff and can give good reliable advice. the slide has the single stock hole, im after reliability, not performance here. the elbow has a unifilter attached to it but ill check the hose and connections, may even need a new filter. so is there any advantage in terms of the reliability of the slide and guide in going for the TM40 or am i better to persist with the stock carb?
__________________
"One must die sometime and to die with ones boots on is very noble" - Carl Stearns Clancy, first RTW motorcycle, 1912-13

Australia to Iceland on a DR650 http://oztoice.wordpress.com
and facebook https://www.facebook.com/oztoice
blackcap is offline   Reply With Quote
Old 12-16-2012, 10:26 PM   #71905
JagLite
Beastly Adventurer
 
JagLite's Avatar
 
Joined: Jun 2010
Location: Anchorage Alaska
Oddometer: 1,101
Thumb cutting fork springs

Here is a good tool to help figure spring rates when cutting springs:
http://motorcycleinfo.calsci.com/Sus...aseForkSprings

I cut 4" off of the close coil end of my springs but I also lowered the front end 4" for my street tracker.
Coil bind is a concern when cutting a large percentage of the length so figure carefully.
__________________
Attitude ~
The difference between
Ordeal and Adventure
James
JagLite is online now   Reply With Quote
Old 12-16-2012, 11:38 PM   #71906
Adv Grifter
on the road o'dreams
 
Adv Grifter's Avatar
 
Joined: Jan 2010
Location: Passing ADV Stalkers in California
Oddometer: 6,128
Quote:
Originally Posted by BergDonk View Post
Fork braces don't just assist the axle to keep the sliders working up and down together, they also reduce fork twist generated under brakes that you get with a single disc. The DR forks are faily flexxy and this is a particularly noticable improvement that you get with stiffer USDs. When thay flex, they also bind a bit, so their bump absorption is not as good when loaded as a stronger fork is.
Good points!
A fork brace can reduce "stiction" and bike can feel more planted mid corner over bumps, rider feedback is better. Less stiction means better overall feel, better control, more confidence.
Adv Grifter is offline   Reply With Quote
Old 12-17-2012, 12:00 AM   #71907
Adv Grifter
on the road o'dreams
 
Adv Grifter's Avatar
 
Joined: Jan 2010
Location: Passing ADV Stalkers in California
Oddometer: 6,128
Quote:
Originally Posted by SprintST View Post
Hi guys,
Quick question. I'm on the road in southern Argentina and can't replace my chain for a few days. I adjust at the tightest spot, of which there shouldn't be one after only about 10k kms. When I'm on the loaded bike the chain is quite loose. Better loose than tight, I know, but does anyone have any suggestions on other courses of adjustment? When should the damn thing be adjusted? Loaded? Loaded, with my fat ass on it as well? Unloaded? On side stand? Upright under its own weight? Rear wheel off the ground?

Will a sticky point chain ever "unstuck"? It's at 4+2 on the adjuster cam now.

It's all cleaned up, lubed and awaiting your collective wisdom.

Cheers!
A nice place to be!
You're doing the right thing keeping your chain adjusted on the loose side.
Follow advice given on adjustment. Keep cam adjusters the same.
QUESTION:
Are you having to adjust chain frequently? Is it getting loose every day or three? If YES to either question ... then you probably need a NEW chain ASAP. How many kms. on current chain? Brand? O ring? X ring? No ring?

Have you taken a look at your sprockets? If not ... do so now! Are you carrying any spare sprockets?
Worn sprockets eat chains quickly. You need to buy spare front sprockets and change them about every 10K to 12K kms. Really adds LIFE to you chain.

Rear sprockets wear more slowly, last longer but just as important and will fuck you if you ignore it. Cheap chains will probably only last 15K kms or so. A high quality X ring chain can go 40K kms. Same goes with good sprockets. Worth the money.

I have no idea what sort of quality you can get in Argentina ... but I would recommend stock Suzuki sprockets and a DID VX2 (VM-2) X ring chain ... if you can afford one. If Suzuki too expensive there ... try for JT, Sunstar or Renthal sprockets ... or AFAM if available. All decent but NONE as good as OEM Suzuki ones.

Kinks in your chain:
Just another indicator your chain may be on the way out. Use WD40 (or Kerosene or Gas oil) to try to free up the kink. It may or may not free up.
No big deal ... just another indicator chain is most likely nearing its end ... impossible to say how long without seeing and feeling it. Can you pull the chain off the rear sprocket more than a 1/4 inch at the 3 'oclock position? If so ... Could be worn out.

!Suerte y que le via bien!
Adv Grifter is offline   Reply With Quote
Old 12-17-2012, 12:31 AM   #71908
motolab
Beastly Adventurer
 
motolab's Avatar
 
Joined: Feb 2006
Oddometer: 2,400
Quote:
Originally Posted by blackcap View Post
i knew i could count on you for more information than i could imagine i needed. its good to have people out there that understand this stuff and can give good reliable advice. the slide has the single stock hole, im after reliability, not performance here. the elbow has a unifilter attached to it but ill check the hose and connections, may even need a new filter. so is there any advantage in terms of the reliability of the slide and guide in going for the TM40 or am i better to persist with the stock carb?
The TM will definitely wear less than a BST as the slide does not rise and fall with every intake event, but when the body finally does wear, it's shot, as there is no replaceable guide.

The FCR is better in this regard, as it has a roller slide and therefore very little wear, and the parts that do wear are replaceable. The roller slide also allows the throttle pull to be a lot lighter. The FCR is therefore definitely a better carb than the TM, but the FCR is harder to tune, the reason being that all openings besides idle and WOT are controlled by needle shape and clip position. This may sound like an advantage, until you realize that for all intents an purposes, the needle must simultaneously have the correct diameters at heights that control 1/16, 1/8, 1/4, 1/2, and 3/4 openings (if the "dots are connected" then the areas between these openings should be acceptably close). On the other hand, the TM needle only has to have the correct diameters at heights that control 1/2 and 3/4 openings, as 1/16 and 1/8 openings can be controlled by the pilot jet size and 1/4 opening can be controlled by the needle jet size.

Regards,

Derek
motolab is offline   Reply With Quote
Old 12-17-2012, 12:41 AM   #71909
LexTalionis
Inciteful
 
LexTalionis's Avatar
 
Joined: Nov 2008
Location: San Jose, CA
Oddometer: 441
Derek!

Quote:
Originally Posted by motolab View Post
As shimming the needle clip preloads the slide spring beyond standard, it results in lowering the slide rather than raising the needle (except when the slide is against the stops). I would not shim the needle clip unless the goal is actually to lower the slide for a given intersection of throttle angle and rpm. Note that the additional preload from shimming the needle will also make the slide come off the stop at a later point in terms of rpm and throttle position (i.e. more velocity will be required to get it to come up off of the stop).

The most proper way to refer to the idle mixture screw (aka pilot screw) on a BST carb is as a fuel screw, as it does not adjust air and fuel simultaneously. There are things called air screws on carbs where you adjust the idle mixture by changing the quantity of air being bled into the pilot circuit. The reason this is important is that a fuel screw makes the idle mixture richer by screwing out and leaner by screwing in, whereas an air screw makes the idle mixture richer by screwing in, and leaner by screwing out. Fuel screws are usually on the downstream side of the slide, and air screws are usually on the upstream side (although I have seen occasional exceptions).

Regards,

Derek
Ahhh... Derek! I love you, man, even though we've never met. You may recall I sent you an email months ago congratulating you on your work for your buddy restoring that odd Ruskie (if I recall the origin of the machine) motorcycle - making one running bike out of three shipped back from overseas in boxes. And indeed, as I typed out "A/F" I did hesitate, trying to recall your admonition of over a year ago to me on this very usage. But I couldn't dredge up the memory, so you had to correct me once again!

I've read every one of your posts, trying to retain some glimmer of the vast knowledge you have regarding fueling, and I've archived your posts about what to look for regarding the wearing of internal carb parts; and, you're in my Rolodex, especially since you're located so close to me. Alas, a lot of your wisdom goes over my head. As do your most recent comments addressing my alterations to my DR - though, some of my thick-headedness may be the result of too much after-game celebration: the Niners kicked butt on the Patriots earlier today.

Regarding me and my DR, I'm an old dog and content if my fueling is 85+% correct; interestingly, that's the same figure I use for personal satisfaction when balancing my wheel/tire assemble using the axle supported by the backs of two kitchen chairs. Compared to the miserably lean condition of the carburation and the subsequent miserable low-speed riding experience when I took possession of the bike new, the current condition is vastly improved and did not cost me a cent as I already had a suitable washer left over from installing a DJ kit in my ZX-10. And I get ~50mpg.

I'm wondering: a month or more ago you and ProCycle got into a discussion about the benefits of your expertise regarding carb adjustments. Proposals were made, ProCycle offered to pay the cost of your service in return for the before/after results, and a poster offered his bike as the test mule. Did anything ever come of that? If you and ProCycle are interested, I'll donate my bike for a week, you're about 20 miles up the peninsula from me. My bike is totally stock except for the adjustments noted and removal of the snorkel.

Lex
__________________
The older I get, the better I was.

LexTalionis screwed with this post 12-17-2012 at 01:02 AM
LexTalionis is offline   Reply With Quote
Old 12-17-2012, 12:59 AM   #71910
LexTalionis
Inciteful
 
LexTalionis's Avatar
 
Joined: Nov 2008
Location: San Jose, CA
Oddometer: 441
Quote:
Originally Posted by motolab View Post
Slide carbs will always have a loss in bottom end to lower midrange of the rpm range at the larger throttle openings because the air velocity (and therefore the quality of the metering) is proportional to the engine rpm and inversely proportional to the throttle opening.

Regards,

Derek
I was just jolted back four decades to a men's room in an engineering building on the University of Minnesota campus.

As I was holding my own, I gaze at the wall, and thereupon some wag had scrawled in permanent marker:
"The angle of the dangle is proportional to the heat in the meat, and inversely proportional to the mass of the ass."

Engineers!

Lex
__________________
The older I get, the better I was.
LexTalionis is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 05:59 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014