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 06-22-2012, 10:09 PM   #66271
Feelers
Gnarly Adventurer
 
Joined: Aug 2010
Location: Northeast Ohio
Oddometer: 181
Does this make sense to everyone?

Does this look reasonable?

My DR has a stock motor, stock airbox, and stock carb. It has a GSX-R exhaust and probably a jet kit (at least a different jet.) Supposedly, the stock DR puts out 36 - 40 HP depending on the dyno and basic mods. My DR is just barely capable of hitting 100 mph according to a vapor which should be fairly close.

So, I looked at this: http://www.4strokes.com/forums/topic.asp?TOPIC_ID=12968
(The chart a little above midpage.) 36 Hp and 100mph gives a Cd-A of 0.5m^2... which is the purple line. Seems accurate.

Then, I looked at this familiar site: http://www.procycle.us/bikepages/dr650.html
Namely, notice that the 780cc big bore kit puts out 54Hp. I'll assume the 790cc kit can put out 55Hp. I am pretty sure this is without the big valve kit as the 725cc with a big valve kit puts out 53Hp.

Also, notice the Uncorked DR Hp at 5500 RPM. 35Hp.
Now check out the rpm where the DR780 produces 35Hp. Approximately 3800 rpm! This bike loves the mid 3000rpm range! 5500rpm feels kind of busy...

Then, I looked at this site: http://www.gearingcommander.com
I put in the DR650. In top gear, the DR650 travels 85mph at 5500 rpm.
Imagine cruising 85mph at only 3800rpm! That's the fastest I'd want to cruise as that's the fastest speed limit in the US I think. I am not saying that 85mph would be enjoyable, but the bike could do it easily with the 790cc kit.

Finally, check out the Hp vs. Top Speed Chart. Sticking with the purple line, but going to 55Hp gives the DR650 a top speed of about 115mph!

Anyway, I was pretty excited about this. I keep fantasizing about a twin-engined enduro that fits the same bill as the old DR, but I'm always turned off by the complexity, extra 100 pounds, prices, etc. I think with the extra cc's, the DR would be the best 50/50 adventure - exploring - continent crossing bike hands down for a solo rider.
And yes, I'd add $1,000 to that bike rather than buy a KTM or Husky.
Feelers is offline   Reply With Quote
Old 06-22-2012, 10:49 PM   #66272
johnkol
Gnarly Adventurer
 
Joined: Aug 2011
Location: SF Bay Area
Oddometer: 134
Quote:
Originally Posted by Snowy View Post
So if a well set up XR is a bench mark you can relate to, then that's it in a nutshell.
I had an XR350R back in the late '80s; I enjoyed it while I had it, but that was because I didn't know better. The IT200 that I got immediately afterwards was a better fit, and a Husky 250 was a revelation. I couldn't go back to riding the XR or IT anymore.

I know that the XR350R does not resemble the XR650R; the former had the famous rubbery but judiciously underdamped frame, whereas the latter has a rigid frame in line with modern standards.

If I allow myself some latitude in extrapolating from the XR350R to the XR650R, I can see what you are saying about the relative capabilities of the latter and a DR -- and I'm afraid what I take from this comparison is that I might not like the DR no matter how many mods I perform on it.

BTW, I actually did try an XR650R before getting the DR, but I did not like its riding position at all: it placed you inside the bike, an old-school concept that I thought had died in the '90s. One of the main reasons I got the DR was because it has a modern riding position, one that places the rider on top of the bike.

So right now, with the Shinko 705s on my DR, I cannot possibly determine how much of its behaviour on dirt roads is due to the tyres or to something else. Mind you, I had never ventured onto dirt roads before without knobbies (and most of the times, those knobbies were not even DOT-approved), so my current experience with the DR is a first for me. Hence, until I put some decent tyres on the DR, I will keep an open mind and take it one step at a time.

Thanks for the feedback!
johnkol is offline   Reply With Quote
Old 06-22-2012, 10:49 PM   #66273
doug s.
Beastly Adventurer
 
Joined: May 2011
Location: md
Oddometer: 1,268
feelers, yust fyi, according to jeff at procycle, the 725 and the 780 dyno charts both include upgraded cams and big walve heads. it seems the torque, not the hp is where the 790 really excels over the 725.

in any ewent, my bike, w/stock motor, fcr39 carb, k&n cone filter, hi flow midpipe w/fmf powerbomb header and tsukigi gsxr1000 can and stock gearing, will run all day at 80-85, and pull strongly to at least 100. (according to the vapor trailtech, not the stock speedo). as i don't run dirt w/my bike, i am considering dropping a tooth in the rear sprocket (or changing rear tire to 150/70/17 from 150/60/17) yust to lower the rpms; i am sure the bike will still run 80-85 yust fine...

doug s.
doug s. is offline   Reply With Quote
Old 06-22-2012, 11:42 PM   #66274
Snowy
Beastly Adventurer
 
Joined: Dec 2008
Oddometer: 1,616
Quote:
Originally Posted by doug s. View Post
most folks who go to pumper carbs report fuel mileage changes from a couple mpg worse to a couple mpg better. and snowy, you are the first i have heard who would rather not do it even if it were not an extra cost; especially for the dirt, due to better response and better smoothness...

re: pros-n-cons - not a lot of money for a pumper, if you shop used. (i have ~$175 into mine, and i haven't sold my upgraded stock carb yet.) and similar fuel mileage if properly set up. and all around better performance in any condition. i see zero cons going to a pumper.

doug s.
For the steeper shale and rocky trails the modified carb is fine. Any more go and it just wheelspins.

The XR650R went heaps quicker on climbs and such, but it was on proper enduro tyres.

Different geometry. I put exactly the same tyres on the DR and it tends to spin more. It's to do with swingarm pivot point and the RMZ suspension I have. Although better than the stock DR suspension, it has obviously the same tendency to squat in the rear under throttle as the RMZ does.

Great if you know how to use it for small tight super cross tracks to get the bike to squat for a big jump from a short take off...not so great for getting on the gas on a long climb.

The XR will tend to bite harder when you get on the throttle hard. You can feel the rear rise slightly when you get right up it. The higher the swingarm pivot in relation to the centre line between the rear axle and the counter shaft sprocket when at full rider sag, the more the rear wheel will bite under throttle. The linkage ratios and shock valving play a part.

You need the torque of the engine, and not the power down low with a trail bike. Tractability in the lower rev range, and just off idle. In the videos I shoot where I'm climbing I'm really being careful with throttle control most of the the time to control wheelspin. If it spins on these climbs you lose momentum so fast that literally the rear end will step out, you have to get off the throttle, and forward progress stops and the inevitable crash starts. It may take a few metres and 20 secs to play out, but it marks the begining of the end on a steep shale climb.

I have the standard carb working so close to a pumper and working so well at low revs and right off idle for the setup on this particular DR that there would simply be no significant gain. I have never had it at wide open throttle on a climb any where ever. I have never needed more acceleration than the standard carb would deliver. I'm riding at the limit of my suspension, my tyres and most importantly my ability when I'm in more technical terrain. The engine doesn't come into it really.

For my other DR that has a DR rear end and Racetech shock internals etc, yes, I would bother. Different geometry, different use, different set up, different result in the dirt and on tar.

My set up on my trail DR is for trail riding. It works best at low throttle, short shifting, using the engines torque. I did a lot of reading and measuring and comparisons between different set ups and their design characteristics before choosing it. All around for what I do I think it's the best set up. Like all things, there's a level of compromise.

It depends on exactly what sort of riding you do, what the setup is on your bike, and where you ride as to the perceived benefits of a pumper carb.

As for fuel consumption gains, I have never in all the years I've modified cars and bikes, had a performance gain and a fuel consumption gain at the same time. When I modified Chev engines, if I got the advertised fuel consumption benefits from these "performance" parts I fitted, I calculated that I'd have the only 80mpg 327 Chev in history.

I think guys that fit pumpers and are really excited about it spend more time on tar than I do, and there they have a tangible result.
Snowy is offline   Reply With Quote
Old 06-23-2012, 01:10 AM   #66275
BergDonk
Beastly Adventurer
 
BergDonk's Avatar
 
Joined: Nov 2010
Location: Snowy Mountains Oz
Oddometer: 3,038
Quote:
Originally Posted by Snowy View Post
.........I've chased Bergdonk through the trees and he does it, I think, without knowing he's doing it.............
My technique, when I'm on it, which isn't so often these days being an old fart, FWIW, is to run into a corner under brakes, because I'm on it, and need to slow for the turn, and not just by rolling off the throttle. As I start to turn with the front loaded, ease the front brake, and turn some more. Loading the front, apart from forcing the tyre to grip somewhat like Snowy says, steepens the steering head when compressing the forks, and makes turning quicker. Keep the rear brake on, and maybe pull the clutch if its tight slow going, this'll facilitate some rear end steering and get it to pivot around the steering head a bit/lot. Once you are at or just past the mid point of the turn, throttle on against clutch, and control drive with the rear brake, and may or may not still be just feathering the front brake. At 2/3 to 3/4 turn, front brake is off and throttle is on. Control exit drive with the rear brake. Its all subtle, and smooooooth.

Off to Canberra tomorrow, leaving here at 06:00, and will be delivering some training and encouragement to some noobs for the day to boost my pension a bit.

And any berm, rut, gutter you can take advantage off is good.

And Snowy, must catch up for a ride again sometime?

Steve
__________________
shed time IS quality time
BergDonk's DR650 BergDonk's XT1200Z
BergDonk is offline   Reply With Quote
Old 06-23-2012, 03:24 AM   #66276
Snowy
Beastly Adventurer
 
Joined: Dec 2008
Oddometer: 1,616
What sort of training?

I'm still waiting to do an instructors course. Rang around and got info ages ago, work got in the way, then surgery, then kids and their lives going off track, then moving their kids in with me....

The usual stuff that steps in and destroys your will to live...

Someone told me there's light at the end of the tunnel...with my luck it'll be attached to a train.


But I have bikes. So it's bearable.
Snowy is offline   Reply With Quote
Old 06-23-2012, 04:27 AM   #66277
ralfmuller
Adventurer
 
Joined: Jul 2006
Location: Brisvagas, Australia
Oddometer: 13
Update - finally sorted!

Well... this one was a doozie!

Some info/update for anyone out there who has/may come across any similar issues in future.

I had a chat to Carl at Procycle (had some other order stuff happening) and he seemed to think that it definitely sounded like a ground issue. (Thanks Carl for all of your logic input and knowledge - and for taking the time to be helpful - appreciate it!).

So, long story short - I went through my entire Vapor and dash install - and could just not make sense of it. Unplugged the vapor etc. and still had the issue - so obviously unrelated.

I then went through all of the indicator connectors again - just to make sure they were seated correctly (even though I had done this a few days ago already).

Turns out that the rear right indicator connector into the harness (2-pin) must not have been seated correctly and most probably was not getting a good earth connection through the pin! Unplugged the connector, plugged it in again and voila - all of a sudden everything worked again as it should!

Plugged the vapor and dash back in - all ok.

Thanks for all the input and help, if nothing else I hope this helps someone else out there. There is a lesson here - earthing issues can be really painful!

Out.


Quote:
Originally Posted by ralfmuller View Post
Ladies and Gents, this one has me stumped.

The history:
  • Did the trail tech vapor and indicator dash upgrade
  • Split the harness on the indicators to allow left/right indicators on indicator bar
  • Installed LED's for indicator bar (came with vapor)
The result:


Everything works beautifully - speedo, power to it, tacho, indicator bar, high beam, low beam, neutral etc... BUT


My indicators have issues:
  • Left indicators (front and back) work normally - normal flash rate and all ok
  • Right indicators - front works BUT flashes at double speed, rear DOES NOT work at all!
  • Indicator bar for Right indicators flashes at double speed also


What I have tried to resolve this issue:


1. Checked indicator bulbs - bulb is fine (changed left to right and back etc. right side does not work, left does)


2. Checked voltage on right indicator seat/connector - is pulsing voltage (I think? as it should) at the double rate - hard to tell with Digital multimeter and slow screen response)


3. Swapped the vapor dash indicator bulbs FROM LED back to incandescent bulbs


4. Purchased a new flasher unit ELFR-1 (http://www.customled.com/products/fl...sher_relay.htm)


5. With new solid state flasher unit, the right rear indicator still doesn't work, however the front does and it now flashes at normal speed.




I am literally at a loss at this point - not sure what else to do here... has anyone else come across this before?



Any tips/hints/tricks?


Thanks
ralfmuller is offline   Reply With Quote
Old 06-23-2012, 06:37 AM   #66278
procycle
Beastly Adventurer
 
procycle's Avatar
 
Joined: Jun 2007
Location: Center of the DR650 universe
Oddometer: 2,154
Quote:
Originally Posted by Snowy View Post
I have ridden TM40 equipped DRs and been unimpressed. Yes they went a little harder, not much, but by God they drank a lot more fuel.
If that's the case then the TM40 was definitely not set up correctly.
__________________
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 06-23-2012, 06:44 AM   #66279
sandwash
Beastly Adventurer
 
sandwash's Avatar
 
Joined: Oct 2007
Location: Flagstaff Az
Oddometer: 1,234
Stock vs Pumper carb= apples and oranges
__________________
97dr650
sandwash is offline   Reply With Quote
Old 06-23-2012, 06:46 AM   #66280
Albie
Kool Aid poisoner
 
Albie's Avatar
 
Joined: Mar 2004
Location: NWA
Oddometer: 8,773
Quote:
Originally Posted by Snowy View Post
After my "highly controversial" carb mods to the standard carb, I have ridden TM40 equipped DRs and been unimpressed. Yes they went a little harder, not much, but by God they drank a lot more fuel.
I've found it depends on how you ride the bike. My buddy has a stock carbed bike with stock exhaust and only the snorkel pulled. He gets 46 MPG when we ride real easy. I get 40 with my TM 40. When we ride hard, his mileage drops down to 38, mine stays at 40.
Albie is offline   Reply With Quote
Old 06-23-2012, 07:49 AM   #66281
maynard911
Gnarly Adventurer
 
Joined: Sep 2009
Location: Bisbee AZ
Oddometer: 142
Quote:
Originally Posted by eakins View Post
been REAL happy with NGK iridium plugs over the copper version.
bike runs better & starts easier.
http://www.procycle.us/bikepages/dr650.html#engine
Could someone explain to me the 'why' of this. It's not that I disbelieve the statement, I just don't understand why it is true.
It seems to me that the purpose of a spark plug is to provide an air gap for the spark to jump across. I can see where making the electrodes out of unobtanium type metals would make them more durable but why would the engine run better than with a standard plug in good condition?
__________________
Maynard " Youth is fleeting, immaturity is forever"
maynard911 is offline   Reply With Quote
Old 06-23-2012, 07:53 AM   #66282
Olas
the darkness
 
Olas's Avatar
 
Joined: Aug 2007
Location: Englewood, CO
Oddometer: 3,927
Quote:
Originally Posted by sandwash View Post
Stock vs Pumper carb= apples and oranges
+1

You can try and make the CV carb work like a pumper, but it will never be a pumper. Im glad I ditched mine before I dumped too much time into trying to make it something that it is not.

Sent from my DROIDX using Tapatalk
__________________
Rebuild threads:
'92 XT600, '87 XR250R
Lighten up, Francis.
Olas is offline   Reply With Quote
Old 06-23-2012, 08:38 AM   #66283
doug s.
Beastly Adventurer
 
Joined: May 2011
Location: md
Oddometer: 1,268
Quote:
Originally Posted by Snowy View Post
For the steeper shale and rocky trails the modified carb is fine. Any more go and it just wheelspins....

...You need the torque of the engine, and not the power down low with a trail bike. Tractability in the lower rev range, and just off idle. In the videos I shoot where I'm climbing I'm really being careful with throttle control most of the the time to control wheelspin. If it spins on these climbs you lose momentum so fast that literally the rear end will step out, you have to get off the throttle, and forward progress stops and the inevitable crash starts. It may take a few metres and 20 secs to play out, but it marks the beginning of the end on a steep shale climb.

I have the standard carb working so close to a pumper and working so well at low revs and right off idle for the setup on this particular DR that there would simply be no significant gain. I have never had it at wide open throttle on a climb any where ever. I have never needed more acceleration than the standard carb would deliver. I'm riding at the limit of my suspension, my tyres and most importantly my ability when I'm in more technical terrain. The engine doesn't come into it really.

For my other DR that has a DR rear end and Racetech shock internals etc, yes, I would bother. Different geometry, different use, different set up, different result in the dirt and on tar.

My set up on my trail DR is for trail riding. It works best at low throttle, short shifting, using the engines torque. I did a lot of reading and measuring and comparisons between different set ups and their design characteristics before choosing it. All around for what I do I think it's the best set up. Like all things, there's a level of compromise.

It depends on exactly what sort of riding you do, what the setup is on your bike, and where you ride as to the perceived benefits of a pumper carb.

I think guys that fit pumpers and are really excited about it spend more time on tar than I do, and there they have a tangible result.
while i am a tar rider, not a dirt rider, i find your comments interesting, because most of the comments i read from other riders indicate that the pumper offers far better dirt performance, because of everything you mention that is important to you: working best at low throttle, low revs and right off idle; short shifting, using engine torque, etc... i'm happy for you that you have your stock carb dialed in w/your magic touch that makes it so good that, in your words, it's almost as good as a pumper.

most folks don't get their stock carbs almost as good as a pumper, and for those who do, well, as you say, it still isn't quite as good as a pumper. considering that shopping used and re-selling your stock carb will result in a net cost not much more than fiddling w/the stock carb, i still think ditching the stock carb is the best action for most folks. and, for those less inclined to futz, yust buy a new carb already set-up, and plug-n-play. if you can't futz, you will likely also be frustrated trying to properly set up your stock carb. and, based on the overwhelming reaction of those who have gone to pumper carb set-ups, they also think ditching the stock carb was the best solution.

snowy, i can't help but conclude you simply have some emotional attachment to your stock carb; perhaps cuz you are happy you were able to get its performance so close to a pumper. i can understand this. audio is also one of my passions (fortunately my hearing is still in good shape); i have a +10 year old $150 dac that i have tweaked and it acquits itself well when compared to modern dacs in the $8k range... i am not sure it's worth spending that much more to get negligible (if any) improvements...

doug s.
doug s. is offline   Reply With Quote
Old 06-23-2012, 10:10 AM   #66284
Mongle
Knuckle dragger
 
Mongle's Avatar
 
Joined: Dec 2009
Location: North Carolina Y'all
Oddometer: 2,331
Quote:
Originally Posted by maynard911 View Post
Could someone explain to me the 'why' of this. It's not that I disbelieve the statement, I just don't understand why it is true.
It seems to me that the purpose of a spark plug is to provide an air gap for the spark to jump across. I can see where making the electrodes out of unobtanium type metals would make them more durable but why would the engine run better than with a standard plug in good condition?

Going out on a limb here-

Theory #1:The only thing I could think of is the unobtanium plugs produce a Hotter spark (not to be confused with heat range- see below) or a larger spark. It is all about getting a complete fuel burn by the time the piston reaches TDC. Lets call these plugs more efficient at making a charge of fuel burn which would make the engine more efficient.

Theory #2: a lean fuel mixture is harder to ignite then a rich mixture. Maybe the people that feel the diffrence in the plugs have a leaner mixture then those who don't feel the diffrence. The plug is better able to ignite the leaner mixture makeing the bike "feel better". This is why you see cars with individual coil packs now. They need the extra energy because they are trying to get more performance (HP) out of less fuel (milage).


Little info: people have talked a little about heat range but I'm not sure they understand it's intended function. I will try to explain it best I can: The heat range of a plug is how much heat the plug can dissapate before burning up the electrode. The idea behind the heat ranges is to keep the plug clean and from burning up. If you look down in a plug with a light you will see that a "hotter" plug has more porcelain protuding then a "colder" plug. This is to keep the porcelain hot to burn contaminants off of it. The shorter porcelain of the colder plug allows heat to be transfered quicker to the metal body. The trick is to find the proper plug. The most basic way to check you heat range is to look at the threads. You are usually looking for 3-4 threads that show signs of heat. The porcelain should not have any buildup on it either. If you see that there are 7-8 threads showing heat and the porcelain is white from heat (or the electrode is torched off ) you need to go with a colder plug. If you only have 1-2 threads showing heat and the porcelain has contaminants/black you need to go hotter. DO NOT confuse a dark plug with needing a hotter plug. Too many people see a black plug and immediately put a hotter one it. If you have any type of oil burning issue or a rich fuel mixture these things need to be fixed BEFORE determining heat range. Going hotter on a plug does not fix a rich mixture or oil burn issue.

On my DR I saw that the plugs showed 4-5 threads of heat on the stock plugs. I didn't go colder because the electrode looked good and the plug was clean. For my normal riding I felt the standard plug was fine. I also would expect to see more heat on an air cooled engine. If I was going to do track days, lots of sand riding, or anything where the engine would be working hard for long periods I would probably go to the next colder plug.

Hope this helps someone.
Mongle is offline   Reply With Quote
Old 06-23-2012, 10:38 AM   #66285
Feelers
Gnarly Adventurer
 
Joined: Aug 2010
Location: Northeast Ohio
Oddometer: 181
Quote:
Originally Posted by doug s. View Post
feelers, yust fyi, according to jeff at procycle, the 725 and the 780 dyno charts both include upgraded cams and big walve heads. it seems the torque, not the hp is where the 790 really excels over the 725.

in any ewent, my bike, w/stock motor, fcr39 carb, k&n cone filter, hi flow midpipe w/fmf powerbomb header and tsukigi gsxr1000 can and stock gearing, will run all day at 80-85, and pull strongly to at least 100. (according to the vapor trailtech, not the stock speedo). as i don't run dirt w/my bike, i am considering dropping a tooth in the rear sprocket (or changing rear tire to 150/70/17 from 150/60/17) yust to lower the rpms; i am sure the bike will still run 80-85 yust fine...

doug s.

The charts for the Big Bore Kit do include the upgraded cams and says so in the Q&A. The Big Bore Kit charts do not include the Big Valve Head.
In the Big Valve Head Charts, the base 725cc line matches the Big Bore 725cc line in the Big Bore chart. The 725cc w/Big Valve Head output is higher. This supports my assertion that the big valve head is not included in the Big Bore charts.

Also, Hp = (Tq x RPM) / 5252. The horsepower increase is exactly proportional to the Horsepower increase.
Yes, the torque is the DR's strong suit since it can't run high rpms due to heat, but Torque isn't used in those theoretical calculations for top speed - Horsepower is. And, 54 Hp plus another 10% for a big valve head would let the DR beat a 690 - in a drag race....

Yes, my bike will run 80 - 85mph just fine also, but I wouldn't be too keen running it at those speeds for too long. Above 75, and my temperature starts increasing quickly. And boosting the front sprocket to a 16 tooth only drops 85mph rpms by 300 rpm to 5200 rpm.
Feelers 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 08:12 PM.


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