Eddieb's DR build thread.

**GSers** · 15th March 2011, 11:21

Originally Posted by NordieBoy

All the FCR's have the throttle position sensor.
In a race situation, no one cares if it backfires on the overrun. Trail riding they do.
YZ's are race bikes after all.

Similar with the missing leak jet. Race bikes are not usually ridden off idle with slow throttle openings.

With the carb size, the 725 and 780 may benefit from a 40 or 41mm pumper but mxrob has tried them on the 644 with high comp piston and 223 webcam, with performance drops.

The 650 port sizes and combustion chamber are very old tech.
Even a mid-80's Yammy 600 had bigger valves.

A few anomalies going on here Nordie throtle position sensor is an option as for the air cut valve Im picking its been added to overcome a lean out area in the idle / compensating jetting. Why would you want to through fuel down the combustion chamber on overrun all your doing is washing the lubrication from around the piston rings increasing wear all modern egines cut fuel on overrun these days for the sake of fuel economy.
http://www.motorcyclecarbs.com/About...etor_C1745.cfm
These guys say that the Air Cut-off Valve (Std with Hot Start & TPS)
we now know that this is not true.
But very interesting topic

Another interesting resource
http://www.keihin-us.com/am/tuning/
GSers

**NordieBoy** · 15th March 2011, 15:43

Originally Posted by GSers

A few anomalies going on here Nordie throtle position sensor is an option as for the air cut valve Im picking its been added to overcome a lean out area in the idle / compensating jetting. Why would you want to through fuel down the combustion chamber on overrun all your doing is washing the lubrication from around the piston rings increasing wear all modern egines cut fuel on overrun these days for the sake of fuel economy.

The air cut valve only works on shut slide, high vacuum conditions.
The spring behind it is a strong little bugger that makes it difficult to put it back in after you've checked the diaphragm and jets to see if they're OK 'cause your bike is still backfiring.

A bit of fuel wash or being kicked off the track for being too loud...

Modern engines cut fuel on overrun 'cause they're fuel injected, sensor'd up and can.

mxrob set his DR up that way - closed throttle, manifold pressure high = no fuel = No popping.

On my old SR185 it was called a "coasting enrichener".

Note: This may all be made up, but it sounds good to me.

**GSers** · 15th March 2011, 18:27

Looks like anyone loking for the ultimate carb for this conversion should be looking for the WR450 Carb as it looks like it has all the bits on that Nordies looking for.
GSers:

**Phreaky Phil** · 15th March 2011, 18:42

Originally Posted by gav24

Yeah that whole fording depth thing is a bit of a myth I reckon, Cut the whole top off the airbox and get even more flow going on. If you are riding through water that is the height of the base of the seat then well done! The bow wave created by riding pushes water away anyway.
If your pushing through then the water will be as high as the muffler opening so you probably wouldnt do it anyway without taking some steps to block off a few other oriffaces. Ooo errr!
My aftermarket foam air filter just about refuses to get dirty anyway - even pretty dust proof! Good design suzuki (yes it is oiled! I double checked that one when it stayed so clean!)

I'll have to disagree with you on this one, even though I will probably be removing my snorkel. Recently we found a bit of flooding that got a bit deeper than i thought, and even with the snorkel in i had water in the airbox. Without it I think we would have been in trouble

**NordieBoy** · 15th March 2011, 19:18

Originally Posted by Phreaky Phil

I'll have to disagree with you on this one, even though I will probably be removing my snorkel. Recently we found a bit of flooding that got a bit deeper than i thought, and even with the snorkel in i had water in the airbox. Without it I think we would have been in trouble

But the bottom of the snorkel is only about 5mm higher than the top of the airbox?

Almost touching the seat.
Had to think light smooth thoughts...

**gav24** · 15th March 2011, 19:54

Originally Posted by Phreaky Phil

I'll have to disagree with you on this one, even though I will probably be removing my snorkel. Recently we found a bit of flooding that got a bit deeper than i thought, and even with the snorkel in i had water in the airbox. Without it I think we would have been in trouble

Yeah - true, but hey 5mm difference!
I think you would have had a bit of water anyway

Maybe it seeped in the side as the seal isnt exactly the greatest, or the bottom as I dont really trust the rubber one way valve on the drain vent...

Solution - Bigger bow wave - ride faster

Either gonna end up bone dry or wet like you would have done anyway!

**Dawn Patrol** · 15th March 2011, 20:07

Originally Posted by NordieBoy

But the bottom of the snorkel is only about 5mm higher than the top of the airbox?

Almost touching the seat.
Had to think light smooth thoughts...

I was thinking

thoughts. The snorkel is pointing sideways so that has to help a bit and the piece inside the airbox directs water away from the filter.
PS; This is Phil, Im on Dawns laptop

**gpcustom** · 16th March 2011, 16:41

just letting you guys know i might be doing a few dr650 bash plates at a very cheap price probly $125 each. Only doing this as im hoping to buy a new bike tonite and i may blow (as in trademe and i may get caught in the moment)the budget so wont have the funds to have it shiped down as well as buying the bike

Im buying a adventure bike HOPFULLY. have done the road thing for a bit now i want to get back to off road

**NordieBoy** · 16th March 2011, 17:06

Originally Posted by gpcustom

just letting you guys know i might be doing a few dr650 bash plates at a very cheap price probly $125 each. Only doing this as im hoping to buy a new bike tonite and i may blow (as in trademe and i may get caught in the moment)the budget so wont have the funds to have it shiped down as well as buying the bike

Im buying a adventure bike HOPFULLY. have done the road thing for a bit now i want to get back to off road

Padmei's after a green DRZ400 one as well...