Jump to content

to swap back to duel carbs or not


Recommended Posts

hey fellows just looking for some opinions. I just got my motor back together and broke in. Im debating putting a set of keiln 34s on herwith the boost bottle ive got it sitting in a box out in the garage planed on doing it to start with but liked the single set up alot on my stocker. so i put it on the stroker. Heres what im running.Long rod 4mm crank super stock pistons with cool head 21 cc domes. and vito big bore jugs. Im using trinity 2 into 1 carb setup with fmf fatties.

whats the real benefit of the boost bottle. coupled with a set of 34's over the 35 im currently running.

Link to comment
Share on other sites

well, making the switch strait to the 34's will probably be a trade-off from bottom end to top end.........i would not go any bigger, and a little smaller if you want to keep a bit of bottom end.......that being said, the duals should flow better at any size....do you already have intakes for the 34's?

Link to comment
Share on other sites

I like my single carb setup. It has tons of bottom end. Im going too put a 4mill crank and go too 66mm bore and i may stay with the single for the torque and bottom end. The builder of this motor has done several like this and claims they work great. Then again I like too play in the tree shots, hills and soft sand. So im not in 5th or 6th much. It falls on its face in the high gears. Im considering going back too 2 carbs also. If i do im going too use 30mm oko most likely. I have some 35s but i think they may be too big.

Link to comment
Share on other sites

thanks for all your input. really like the bottom end on this thing it dose feel like its missing top end. must be the wierd issue i thought i was having. seems like it just wont push like it feels like it wants to. It pulls like crazy then just like wtf i guess its just ive got room to give it all it wants most the time but for trails its awesome ah the choices. i just dont know ive got the set up for the 34's including boots. just not sure i hated waiting for the power to come on. must be my shifting. the single seems to allow a little quicker shift. dose any one else on here that runs a single carb. is that the consensuses of the group.

Link to comment
Share on other sites

thanks for all your input. really like the bottom end on this thing it dose feel like its missing top end. must be the wierd issue i thought i was having. seems like it just wont push like it feels like it wants to. It pulls like crazy then just like wtf i guess its just ive got room to give it all it wants most the time but for trails its awesome ah the choices. i just dont know ive got the set up for the 34's including boots. just not sure i hated waiting for the power to come on. must be my shifting. the single seems to allow a little quicker shift. dose any one else on here that runs a single carb. is that the consensuses of the group.

 

 

YES! I'm a BIG fan of the 2into1 carb setup. I'm not a fan of the trinity unit though. It gives up some on the top end because the air has to make such a drastic turn to go from one side to the other. I've seen GREAT things from the GRAYDON 2 into 1 unit. I honestly feel that it MAKES power over the 2 carb setup. Most guys will say that 2 carbs will give you more flow....But remember with 2 carbs, each carb only pulls 1/2 the time. As the motor pulses, so does the flow thru the carbs. With a Graydon 2 into 1 the carb is set back farther and the runners leading to the motor are about 4" long. This makes your motor get a tunnel ram effect. Also the single carb flows non-stop. Just like a motor on a super speedway...Wide open. A 35PWK with a 50 pilot and a 178 main was a rocket on a 350 with a milled head and a backyard porters stage 2 port job. That bike out ran the 4-strokes in the woods. Even with a +6 arm. On the sand with the +6 and a set of 21X12X8- 12 paddle extremes, (set up for Michigan sand riding) it was putting beatdowns on Trinity 4 mill stock cylider bikes with stage 4 port work. And it was a RAT BANSHEE, which really pissed of the guys with the polished Trinity bikes when this old faded hunk of banshee with zip-ties holding cracked plastic together, that was stored outside under a tarp showed up and out runs them.

If you like the single carb, stick with it. Spend some money on a timing plate and set it at +4 to +6, then spend $150 and get some good custom cut domes from a site sponser. You'll really be happy with the performace boost. I'm looking for a Graydon set-up right now for the wife's new bike. It's my woods bike/her dune ride.(should have kept my mouth shut.) LOL. My 2 cents...Good Luck.

Link to comment
Share on other sites

thanks for your input i do have the adjustable stator its only set at 2 and a half. I have tryed degreeing it in a bit more just a little worried of detonation. I only run high test fuel. Occasionally ill add a little ass-atone to the mix that dont add but a couple a points to the octain rating though. too exspencive to run race fuel. And im running 21 cc domes. do you all think four degrees is too much.

Link to comment
Share on other sites

With +4 timing you will be just fine. I run the single carb setup with +4 and 20cc domes. I mix my gas half super and half1 110. I've never had any detonition problems.

Check out my mods in my sig. I've ran this setup for a season and a half and really liked it. Hit me up if you need any parts polishing or accessories.

Link to comment
Share on other sites

Most guys will say that 2 carbs will give you more flow....But remember with 2 carbs, each carb only pulls 1/2 the time. As the motor pulses, so does the flow thru the carbs

That is true, but as rpms increase so does the speeds of the pulses. At some point they have gotten to a point where it is like a constant flow. Now you have 2 cylinders breathing through 1 carb. That is the point where the 2:1 carb costs you horse power.

 

2 smaller carbs will give you just as good bottom end, and you will have a better top end over the 2:1.

Link to comment
Share on other sites

That is true, but as rpms increase so does the speeds of the pulses. At some point they have gotten to a point where it is like a constant flow. Now you have 2 cylinders breathing through 1 carb. That is the point where the 2:1 carb costs you horse power.

 

2 smaller carbs will give you just as good bottom end, and you will have a better top end over the 2:1.

 

When your left cylinder reed is closed...the left carb doesn't pull. That's always 1/2 the time. No matter what the speed. So are you saying that a simple 350cc motor will be faster breathing 1/2 the time through a 28 bore carb vs. 1/2 the time through a 35pwk?

Link to comment
Share on other sites

I like my single carb setup. It has tons of bottom end. Im going too put a 4mill crank and go too 66mm bore and i may stay with the single for the torque and bottom end. The builder of this motor has done several like this and claims they work great. Then again I like too play in the tree shots, hills and soft sand. So im not in 5th or 6th much. It falls on its face in the high gears. Im considering going back too 2 carbs also. If i do im going too use 30mm oko most likely. I have some 35s but i think they may be too big.

 

Yull be fine bud, I run 2 35mm PWK's on my dune ported 350 with CPIs and it has awesome power all over the place. Bottom to top, I love it.

Link to comment
Share on other sites

A lot of people on here that have the singles are under the mis-conception that it has more power on the bottom end. It doesn't really have much more than a set of duals at all. It is actually faster acceleration they are feeling because of the carb velocity the kit creates. You can properly setup a set of duals to feel almost identical if you use the right parts. The duals will also make more mid-top power than the single setup as well.

Edited by Snopczynski
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...