Drz400 434 kit e cams and single layer base gasket Jetting for bsr36

Hi looking for some jetting help with my 04 drz400s i just installed a cylinder works 434 kit with single layer base gasket and e cams, also have a full big gun exhaust and the 3x3 air box mod. I have a james dean jet kit running the red needle (as I'm in florida heat) on the 3rd clip with a 25 pilot and 155 main jet. It seems great on the bottom end much more torque than I'm used to with the stock 400 but runs out of power just over halfway to redline, it may be just the smaller stock carb is not handling the extra hp but racing a stock 400s its only faster if i keep rpm low shifting really quick. if we do roll ons at higher rpm in 5th i don't pull away much if any. Anyone who has done the 434 and kept the stock carb please advise if u found a jetting combo that worked all over the rpm or do i have to have the fcr39 to get more power thru-out the rev range. I just can't afford one for another month or two so hoping i can get my stock one close enough. I have a CA drz400 with the emission hose capped on carb, not sure if these carbs are any different for jetting specs. i was running a 160 mj with the 400 and was told i only have to lower my mj for the 434 due to it sucking more fuel now. Any help greatly appreciated! I have tried changing the needle up and down 1 clip from the middle, only change i saw was it not starting as easy with the needle dropped (clip raised) 

Try running it with the airbox door off. If it gets better then you need to lean out the main jet a little more. Big bores tend to be better at low to mid power but they don't like to rev like a 400.

Hi looking for some jetting help with my 04 drz400s i just installed a cylinder works 434 kit with single layer base gasket and e cams, also have a full big gun exhaust and the 3x3 air box mod. I have a james dean jet kit running the red needle (as I'm in florida heat) on the 3rd clip with a 25 pilot and 155 main jet. It seems great on the bottom end much more torque than I'm used to with the stock 400 but runs out of power just over halfway to redline, it may be just the smaller stock carb is not handling the extra hp but racing a stock 400s its only faster if i keep rpm low shifting really quick. if we do roll ons at higher rpm in 5th i don't pull away much if any. Anyone who has done the 434 and kept the stock carb please advise if u found a jetting combo that worked all over the rpm or do i have to have the fcr39 to get more power thru-out the rev range. I just can't afford one for another month or two so hoping i can get my stock one close enough. I have a CA drz400 with the emission hose capped on carb, not sure if these carbs are any different for jetting specs. i was running a 160 mj with the 400 and was told i only have to lower my mj for the 434 due to it sucking more fuel now. Any help greatly appreciated! I have tried changing the needle up and down 1 clip from the middle, only change i saw was it not starting as easy with the needle dropped (clip raised)

Why not throw a CVK40 on it instead of messing with the stocker! With a BB, exhuast, cams, Higher compression the stocker carb isn't gonna cut it. I'm not sure but I don't think it would hurt your MPG much over stock and it would pull alot better and be a he'll of alot cheaper then an FCR

I know the stocker is less than adequate but don't want to do a half measure and know the fcr39 is the way to go, so for now just want to get what I can from the stock carb.

Use Blue needle clip 3...Red , clip 3 is way too lean ,even for big bore......You really need a better carb to get that thing to rip in the top end

Hi looking for some jetting help with my 04 drz400s i just installed a cylinder works 434 kit with single layer base gasket and e cams, also have a full big gun exhaust and the 3x3 air box mod. I have a james dean jet kit running the red needle (as I'm in florida heat) on the 3rd clip with a 25 pilot and 155 main jet. It seems great on the bottom end much more torque than I'm used to with the stock 400 but runs out of power just over halfway to redline, it may be just the smaller stock carb is not handling the extra hp but racing a stock 400s its only faster if i keep rpm low shifting really quick. if we do roll ons at higher rpm in 5th i don't pull away much if any. Anyone who has done the 434 and kept the stock carb please advise if u found a jetting combo that worked all over the rpm or do i have to have the fcr39 to get more power thru-out the rev range. I just can't afford one for another month or two so hoping i can get my stock one close enough. I have a CA drz400 with the emission hose capped on carb, not sure if these carbs are any different for jetting specs. i was running a 160 mj with the 400 and was told i only have to lower my mj for the 434 due to it sucking more fuel now. Any help greatly appreciated! I have tried changing the needle up and down 1 clip from the middle, only change i saw was it not starting as easy with the needle dropped (clip raised)

Try blue needle clip # 5 and 175 mj.

Try blue needle clip # 5 and 175 mj.

 

That's going to be too rich M8.... :huh:

Edited by Craig-o

Yeah 175 sounds too rich especially for a 434. I have a ca bike with the emissions removed and carb line capped, is there any difference in the ca carb vs all the rest? Today I swapped the carb from my friends bike non ca and it fired up easy, did not need any throttle which is usually what stops the starter. It fired up 5 times in a row no problems so I went for a ride. His carb has red needle 3rd clip, 155mj and 22.5 pilot with extended fuel screw. It ran good but lacked the low end torque of previous ride but was better higher up in the revs. After 10-15 mins I stopped for gas and it would not restart, motor turned over quick, same as the 5 times before but no signs of it firing to life. It did restart but only from a high speed bump start with a little throttle.

It's weird because he has same settings as me on his carb and it felt a lot different where the power was. Also tried my ca carb on his bike and it runs great, starts great actually runs better but I think that's just because he was running his fuel screw setting a little lean

Nobody else out there with a 434 kit and stock carb? I'm sure someone has gone thru this already. I guess I'll keep tuning until I get it running better. It's lost a lot of power just by changing the fuel screw to extended. Turning it all way in or out doesn't seem to do much. Not as much torque down low. And my friends stock drz400 is beating me on 4th and 5th gear roll ons no problem. Taking the air box cover off does not seem to help it any should I try a 150mj in there? And I notice a really flat power band. Plug was black with the 160, 155 in there now. Also will the whole rev range be affected by a fuel screw not set right? Or just the off idle snap.

I really want third to come up with no clutch and just walk past a stock Drz with ease. Surely that's possible with 434 kit, single layer base gasket, e cams, and a full big gun exhaust? Also running k&n filter. My friends stock Drz has a James dean jet kit and yoshi slip on that's it he's getting past me every race. Was hoping for 45hp so far feels more like 35

I think there arent many people that would do a big bore kit while still using the stock bsr36 carb. Seems like a waste of a big bore kit.

I think there arent many people that would do a big bore kit while still using the stock bsr36 carb. Seems like a waste of a big bore kit.

 

With whatever carb is used , increasing displacement is always going to be a positive move ....of course an Fcr is going to be better, but some guys are on a budget.

 

There are some threads about using a cheaper CVK40 carb around on the forum, a nice cost effective performance increase to be had via this option...

Edited by Craig-o

Haha yes I know the stock bsr is holding me back, so new development is a friend let me borrow his spare fcr39mm! I'm not sure what bike it came from as it has a tps with wires cut, a hot start lever but looks like the newer version not the older slant. It was on my friends Drz briefly but he said it never ran perfect. I installed it earlier tonight and it's better but not perfect, I did get 3rd up with no clutch but think my main jet is off as the stock Drz still keeps up almost neck and neck from a roll on in 5th from 40-90. Now I have this magical carb does anyone have a baseline jetting for the 434 cams and single layer base gasket? I'm in fl so sea level and temps 75-95 is it worth buying the James dean jet kit for the fcr or is the stock needle good enough and just by jets individual? Thanks everyone I'm getting close to riding bliss I can feel it, ImageUploadedByThumper Talk1406275174.658898.jpg

ImageUploadedByThumper Talk1406275218.378599.jpg

Ok so it is the Fcrmx model...Does your bud know it's origin.?

 

generally in a warm climate with big bore, open pipe,  3x3 mod I would run with :

OCEMP needle, clip 3 

155 main jet

45 pilot jet

2 turns fuel screw

Do the O ring mod

200 main air jet

100 pilot air jet

 

As a side note I would never just throw in a carb without inspecting/ rejetting it correctly for the application .... :)

Edited by Craig-o

Thanks I know it would be a good ife to check but carb was from a friends 440, he bought the bike with it. Did a 200 mile run on her Sunday and all is good apart from full throttle bogs? It was running faster at 3/4 throttle, finally took it off to find the main jet lying in the bowl! I knew it was going thru too much gas haha. The main jet had some kind of adapter to fit a smaller in length jet like the stock carb. I have a 45 pilot with silver needle with no markings on it. I replaced it with emp needle as a friend had one. I have no air jet on the left side if boot and a 100 air in the right. With a 67.5 jet beside my main. Upon measuring the intake side with caliper it's saying 39.9mm does that mean I have a fcr40mx? And would the jetting be different for a 40 vs 39? I'm about to see how she runs with a main jet in there... Will get back to you soon, thanks for the help guys

ImageUploadedByThumper Talk1406700781.610269.jpg

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