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Old 07-14-2012, 10:16 PM   #67201
Thumper Dan
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Quote:
Originally Posted by NordieBoy View Post
There are no additional horses to be gained.
The shape of the torque curve and the smoothness of the bottom end are where the difference lies.

PS. It's worth it
Yes, exactly! And to make it clear, I'm not after horsepower but just that low down torque that one expects from a 650. I had an XR350 many years ago and it would easily want to pop up on the back wheel in first and second gears. The DR well, it just wants to accelerate and I do notice these gains with the TM40...... BUT, I thought there would have been noticeable torque gains. But alas!
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Old 07-14-2012, 10:45 PM   #67202
Feelers
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Quote:
Originally Posted by Mr DR650 (2011) View Post
Yes, exactly! And to make it clear, I'm not after horsepower but just that low down torque that one expects from a 650. I had an XR350 many years ago and it would easily want to pop up on the back wheel in first and second gears. The DR well, it just wants to accelerate and I do notice these gains with the TM40...... BUT, I thought there would have been noticeable torque gains. But alas!
I hate to point this stuff out now, because I just get bullied for questioning the masses...But, here are my thoughts - not having actually experienced a pumper myself...

Torque is Force x Distance. The distance is the distance from the center of the crank to where the rods connect. The force is the force of the explosion pushing the piston which is PSI created by the explosion times the piston surface area. The only possible thing you are changing by swapping carbs is the PSI due to a slightly different air/fuel ratio (which could also be adjusted to be the same by the stock carb.

The only difference you will possibly notice is when the AP sprays - during a quick turn of the throttle. Supposedly, the pumper reacts faster than the BST carb because the BST carb relies on a pressure differential to build to lift the slide and needle whereas the slide and needle are lifted directly with the throttle in the pumper. (It would be interesting to see how fast the slide lifts in the BST...). So theoretically, you should get a little harder pull exactly during the throttle twist (aka: throttle response) due to the accelerator pump, but once the throttle is stationary at whatever opening you want, acceleration will be the same with both carbs.
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Old 07-14-2012, 11:49 PM   #67203
NordieBoy
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Quote:
Originally Posted by Mr DR650 (2011) View Post
Yes, exactly! And to make it clear, I'm not after horsepower but just that low down torque that one expects from a 650. I had an XR350 many years ago and it would easily want to pop up on the back wheel in first and second gears. The DR well, it just wants to accelerate and I do notice these gains with the TM40...... BUT, I thought there would have been noticeable torque gains. But alas!
Also the XR had a shorter swingarm, so was more prone to wheelies anyway.

The DR ends up with as much torque at 3,000rpm as a stocker at peak...
Only about 10% increase overall but much more area under the curve.
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Old 07-14-2012, 11:58 PM   #67204
NordieBoy
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Quote:
Originally Posted by Feelers View Post
So theoretically, you should get a little harder pull exactly during the throttle twist (aka: throttle response) due to the accelerator pump, but once the throttle is stationary at whatever opening you want, acceleration will be the same with both carbs.
Close.

In the CV, the slide is not connected to the throttle cable.
The slide will continue to rise until the diaphragm vacuum is equalised against the diaphragm spring.
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Old 07-15-2012, 01:29 AM   #67205
BergDonk
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Carbs

In theory, flat slide carb can flow more air because once the slide has lifted clear of the bore, there is no flow obstruction like the throttle butterfly left in the BST creates. The preferred FCR, a 39 mm and smaller, may only flow the same, dunno. The big difference is throttle response, but this is dependant on getting the pump squirt right, else you can have a lean or rich bog. The improved smoothness at low revs I don't understand, but with my FCR its real, and was a big surprise to me. I can only assume that the CV slide does some fluttering at low revs that the flat slides don't suffer from.

And here in Oz we seem to have more energy dense petrol than in the 'gas' in NA, so leaning everything off a size or so from NA specs is usually needed to get it working right over here.

Steve
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Old 07-15-2012, 04:23 AM   #67206
barko1
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Quote:
Originally Posted by BergDonk View Post
And here in Oz we seem to have more energy dense petrol than in the 'gas' in NA, so leaning everything off a size or so from NA specs is usually needed to get it working right over here.

Steve
You guys, or Sheila's, don't have cornstalks in your gas tanks do ya
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Old 07-15-2012, 09:13 AM   #67207
Paddle007
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My two cents worth. And FWIW I am really happy my FCR

Another thought about the BST is it richens the mixture as the needle is raised by the diaphragm. The diaphragm is responding to pressure differentials of atmospheric pressure and engine vacuum. Alot of talk to say it raises relatively slowly. It does a good job of metering the fuel for what the engine can handle at varying loads. If you twist the throttle wide open at lower rpms the BST if tuned properly, only delivers the fuel the engine can handle.

Now the FCR. No diaphragm but the slide and needle move in perfect conjunction with your wrist. What this means is you need to be in tune with your engine at lower rpms as it does not need the slide and main jet wide open. Sometimes a gradual increase in the wrist/fun factor is more beneficial than wide open. If the back tire can spin crack it hard. If you have good traction modulate the throttle and you DR will be happier.
Quote:
Originally Posted by Feelers View Post
I hate to point this stuff out now, because I just get bullied for questioning the masses...But, here are my thoughts - not having actually experienced a pumper myself...

Torque is Force x Distance. The distance is the distance from the center of the crank to where the rods connect. The force is the force of the explosion pushing the piston which is PSI created by the explosion times the piston surface area. The only possible thing you are changing by swapping carbs is the PSI due to a slightly different air/fuel ratio (which could also be adjusted to be the same by the stock carb.

The only difference you will possibly notice is when the AP sprays - during a quick turn of the throttle. Supposedly, the pumper reacts faster than the BST carb because the BST carb relies on a pressure differential to build to lift the slide and needle whereas the slide and needle are lifted directly with the throttle in the pumper. (It would be interesting to see how fast the slide lifts in the BST...). So theoretically, you should get a little harder pull exactly during the throttle twist (aka: throttle response) due to the accelerator pump, but once the throttle is stationary at whatever opening you want, acceleration will be the same with both carbs.
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Old 07-15-2012, 09:29 AM   #67208
skysailor
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Dumb question number 506!
I do week long flights. Have a new battery in my '02. If I haven't used it for 10 days or so, I have to boost/charge the beast. Is this normal?
Lyle
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Old 07-15-2012, 09:36 AM   #67209
poppawheelie
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Quote:
Originally Posted by skysailor View Post
Dumb question number 506!
I do week long flights. Have a new battery in my '02. If I haven't used it for 10 days or so, I have to boost/charge the beast. Is this normal?
Lyle
No. Battery charge should be good for at least 30 days. Simplest test of alternator is to put voltmeter across battery at cold start up. Alternator should charge at least 14 volts. If it's a wet cell, are you sure the battery is full of fluid?
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Old 07-15-2012, 10:15 AM   #67210
Rumlover
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Battery

The battery on this bike has always seemed marginal to me. Even when new they don't crank very well. If mine sits for a week or more off the battery tender I am concerned. I have just resigned myself to always leaving it on a tender, even during the riding season. I have owned the bike since new, and had good quality batteries -- always been the same.

I will probably fork over the money for one of those pricey ones that procycle offers next time, or look at modifying the battery box (if even possible) to accept a bigger battery.
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Old 07-15-2012, 10:46 AM   #67211
barko1
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Quote:
Originally Posted by skysailor View Post
Dumb question number 506!
I do week long flights. Have a new battery in my '02. If I haven't used it for 10 days or so, I have to boost/charge the beast. Is this normal?
Lyle
Again,no. I bought a DR that had sat for nearly 4 years, with a charge that battery lasted a few weeks, of course it needed a new one. Mine will fire up after weeks of sitting. If the jetting is spot on it really doesn't crank at all, immediate firing. I usually buy the cheapest (Walmart) batteries.
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Old 07-15-2012, 11:27 AM   #67212
Rumlover
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Quote:
Originally Posted by barko1 View Post
Again,no. I bought a DR that had sat for nearly 4 years, with a charge that battery lasted a few weeks, of course it needed a new one. Mine will fire up after weeks of sitting. If the jetting is spot on it really doesn't crank at all, immediate firing. I usually buy the cheapest (Walmart) batteries.
I hope your good luck continues. If you ever have a need to "crank it" for very long (or more than a couple of times) it won't last very long. It will always charge back up (if it is a good battery), but it just doesn't have much cranking power or reserve to begin with (I am referring to oem equivilant types).

It is simply too small for the application. Suzuki would have put a bigger one in if there was room. Heck my old 250 timberwolf has a bigger battery, as do most ATVs --- why? because they have the room.

Rumlover screwed with this post 07-15-2012 at 12:20 PM
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Old 07-15-2012, 11:28 AM   #67213
BlueRidgeKat
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Has anyone here put the Givi E21 hardbags on their DR like these ??

http://www.happy-trail.com/Suzuki-DR...cks-DR650.aspx

If so I'd like to see a side view picture of it if you have one. I had the E21's on a V-Strom 650 I sold and they are not much on capacity but are quite handy and "cheap".
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Old 07-15-2012, 11:34 AM   #67214
eakins
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Quote:
Originally Posted by Rumlover View Post
The battery on this bike has always seemed marginal to me. Even when new they don't crank very well. If mine sits for a week or more off the battery tender I am concerned. I have just resigned myself to always leaving it on a tender, even during the riding season. I have owned the bike since new, and had good quality batteries -- always been the same.

I will probably fork over the money for one of those pricey ones that procycle offers next time, or look at modifying the battery box (if even possible) to accept a bigger battery.
part of the issue is an undersized battery cable.
tpi has a cable upgrade kit.
http://www.tpimotorcycleparts.com/in...category_id=69
i switched over to a ETX9 DEKA AGM battery and this battery has plenty of additional crank power on my DR. AGMs can sit for a very long time with no issues. mine sat all winter and then cranked up just fine in the spring w/o being on a battery tender.
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Old 07-15-2012, 11:44 AM   #67215
Rumlover
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Quote:
Originally Posted by eakins View Post
part of the issue is an undersized battery cable.
tpi has a cable upgrade kit.
http://www.tpimotorcycleparts.com/in...category_id=69
i switched over to a ETX9 DEKA AGM battery and this battery has plenty of additional crank power on my DR. AGMs can sit for a very long time with no issues. mine sat all winter and then cranked up just fine in the spring w/o being on a battery tender.
Good tip on the cable! Thanks

I currently have the big crank agm (I think it is a rebranded DEKA). Still seems to crank the same to me, as did the OEM and walmart ones. Maybe I am just picky, but I am use to batteries spinning the motor briskly on my other toys -- this one just seems to be a little lazy about it. I will try the bigger cable next time.
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