BSR36 question

[Barry Ries]

    I'm thinking i would like my DRZ to be more responsive when I give her the gas,  I'm happy with the power just want more pop when I first twist the throttle.   I know that the people with CVK 40's enlarge a hole to let the vacuum pull up the piston faster, is there a similar modification i could do to the BSR 36 to speed things up a bit?  Maybe improve the ability to lift the front wheel?

[roleyrev]

Mmm maybe an FCR carb (FCR39 - from thumpertalk?) - you have just described the reason most people change.

[GuyGraham]

Have you got the lighter spring from a dj jet kit

This allows the slide to lift faster

With this fitted I understand it is on the limit as any faster lift rate would result in bogging issues due to lack of an AP squit like the FCR

 

Get the FCR if you want to make real difference

[Barry Ries]

21 minutes ago, GuyGraham said:

Have you got the lighter spring from a dj jet kit

This allows the slide to lift faster

With this fitted I understand it is on the limit as any faster lift rate would result in bogging issues due to lack of an AP squit like the FCR

 

Get the FCR if you want to make real difference

No lighter spring I got the JD kit.

[Boshwa]

Enlarging the vacuum hole in the slide will make the slide react to pressure changes fast, making it feel more connected to your throttle. It won't feel as smooth, but will feel more responsive.

Edited October 12, 2018 by Boshwa

[Barry Ries]

23 minutes ago, Boshwa said:

Enlarging the vacuum hole in the slide will make the slide react to pressure changes fast, making it feel more connected to your throttle. It won't feel as smooth, but will feel more responsive.

  That's what I figure, just wondering if anybody has tried it and has recommendations regarding optimal sizing of the holes,    And I'm not feeling like buying an $800.00 carb right now.

[ohiodrz400sm]

  That's what I figure, just wondering if anybody has tried it and has recommendations regarding optimal sizing of the holes,    And I'm not feeling like buying an $800.00 carb right now.

I had to he DynoJet way back when and while it did improve response somewhat, it didn't hold a candle to the Edelbrock Quick Silver carburetor that replaced it

[Bm1997]

14 minutes ago, Barry Ries said:

  That's what I figure, just wondering if anybody has tried it and has recommendations regarding optimal sizing of the holes,    And I'm not feeling like buying an $800.00 carb right now.

Picked up my CVK40 for $100 plus the Schnitz needle and a new main jet for slightly more than $30. Can probably sell the stock carb on eBay and get some of that money back. Very cost effective way to get the responsiveness you're talking about.

[Barry Ries]

2 hours ago, Bm1997 said:

Picked up my CVK40 for $100 plus the Schnitz needle and a new main jet for slightly more than $30. Can probably sell the stock carb on eBay and get some of that money back. Very cost effective way to get the responsiveness you're talking about.

  I am considering that option.  But just drilling a hole seems easier

[Noble]

I'd go easy on enlarging the slide holes.  That works in some applications but is not a tried and true popular mod for the DRZ400. For the motor to accelerate it has to drag the flywheel and the rest of the motorcycle with it.  If the motor can't do that, you get a bog.  The BSR36 is limited by the lack of an accelerator pump.  The whole purpose of the vacuum controlled slide is to only open the carb s fast as the motor can respond. Just snapping the throttle open faster may not be the answer. 

[Barry Ries]

1 hour ago, Noble said:

I'd go easy on enlarging the slide holes.  That works in some applications but is not a tried and true popular mod for the DRZ400. For the motor to accelerate it has to drag the flywheel and the rest of the motorcycle with it.  If the motor can't do that, you get a bog.  The BSR36 is limited by the lack of an accelerator pump.  The whole purpose of the vacuum controlled slide is to only open the carb s fast as the motor can respond. Just snapping the throttle open faster may not be the answer. 

  I'm sure you can go big and foul everything up,  but i'm thinking a small enlargement might be a good thing.