33 or 35mm for single carb?

[Wallynut]

I ordered a 35mm trinity 2 into 1 set up, finally got here, and it's a 33pwk. Part of me says send it back, the other part of me wants to get this put on and see how it runs with it, but once I open the packaging I'm stuck with it. Anyone out there know what, if any difference there is between them. Right now all I have pipes, K&N air cleaner. Plan on timing, fly wheel and somewhere down the road I might port for trail/mx, but not right away. I know some have said that 35 is the way to go.

[PUSH THE THROTTLE]

I'd send it back. For what you have you'll be fine with a 33 but since you plan on porting you better have the 35. I'm guessing you paid for the 35 so you should get the 35. I'd call Trinity and see what they'll do for you, when I ordered mine they overnighted it for free after an ordering mishap.

[sredish]

I'd send it back. For what you have you'll be fine with a 33 but since you plan on porting you better have the 35. I'm guessing you paid for the 35 so you should get the 35. I'd call Trinity and see what they'll do for you, when I ordered mine they overnighted it for free after an ordering mishap.

If your planning on porting I'd say send it back for the 35mm. However, I know Banshee76179 runs a 33mm with porting and likes it a lot. I, personally would make the effort for the 35mm while you can, you open it up and a few months or so down the road wanna port it and want more flow, you're screwed.

[Wallynut]

Thanks for the replies guys. I've got today to think it over, not gonna get an answer till tomorrow anyway. Will say one thing, I really like how the Keihin's are designed compared to the stock. I've looked this carb over and all the info on the net that I could find at Carbparts and Sudco, puts the stock carbs to shame in all respects.

 

There has to be something about why Trinity went to these sizes (33 and 35) for the single carb setup and not something larger like the 4 strokes use. I read one of the threads(while doing a search on 2 into 1) that sredish mentioned velocity thru the carb might be one of the reasons. Sure wish I could afford to experiment with that idea.

 

Got another question-for those that switch to dual carbs of this type, how do they synch them? IS there a need for a cross-over tube like on the stock?

Edited October 31, 2004 by Wallynut

[sredish]

There has to be something about why Trinity went to these sizes (33 and 35) for the single carb setup and not something larger like the 4 strokes use. I read one of the threads(while doing a search on 2 into 1) that sredish mentioned velocity thru the carb might be one of the reasons. Sure wish I could afford to experiment with that idea.

Yes, there is a need for the crossover tube. I'm not much for explaining the whole deal behind it, but without a doubt, if I ever go back to dual carbs, I'll be using the Pro Design Intake and it has the spots for a crossover tube. I've seen dynos with just a change from stock to PD Intake and there's a nice increase in performance. I've heard the Boss intakes are good as well, tho I've never seen dynos showing the added power.

 

I wish I had the money to experiment with carb sizes also. I'm sure Trinity did some testing before they offered the kit to the public. If I hadn't sent my cylinders off for porting, I'd consider trying a 33mm. I think with the stock setup, the 33mm will work better. More velocity would mean more vacuum for the fuel and I think it would give better response, and make it easier to jet. I don't necessarily think the power will be a whole lot different with the 33, I just think the air velocity has a lot to do with how a carb performs and a 35mm carb is a big carb. With porting, it'll be flowing more air so there's the increase in velocity.

 

Some people say why not just use a 38mm or something for a stroker, but at mid throttle or low rpms, there's less need for airflow and with a 38mm or bigger, there won't be much velocity at all and I think the power will suffer. I might try it one day. I'd still like to experiment with a 33 as well, and I just might!!

 

Good luck on your carb decision.

[grounded]

I have a 33 on mine , my engine is not ported but has the head shaved , timing , flywheel and so on, and by the recomendation of the engine builder its fine but full porting would need a 35.

[banshee76179]

I run the 33mm and love it, tried the 35mm 2 many problems"jetting". I run a small woods port /stageII. Any bigger port job, I would recommend a bigger carb like a 35 or 38.. Maybe, this winter I gonna try a differ. port job "other than trinity" and go bigger carb. But, I love my 2-n-1 carb setup over a stock set-up..

[FIRST BANSHEE]

There has to be something about why Trinity went to these sizes (33 and 35) for the single carb setup and not something larger like the 4 strokes use.  I read one of the threads(while doing a search on 2 into 1) that sredish mentioned velocity thru the carb might be one of the reasons.  Sure wish I could afford to experiment with that idea.

Yes, there is a need for the crossover tube. I'm not much for explaining the whole deal behind it, but without a doubt, if I ever go back to dual carbs, I'll be using the Pro Design Intake and it has the spots for a crossover tube. I've seen dynos with just a change from stock to PD Intake and there's a nice increase in performance. I've heard the Boss intakes are good as well, tho I've never seen dynos showing the added power.

 

I wish I had the money to experiment with carb sizes also. I'm sure Trinity did some testing before they offered the kit to the public. If I hadn't sent my cylinders off for porting, I'd consider trying a 33mm. I think with the stock setup, the 33mm will work better. More velocity would mean more vacuum for the fuel and I think it would give better response, and make it easier to jet. I don't necessarily think the power will be a whole lot different with the 33, I just think the air velocity has a lot to do with how a carb performs and a 35mm carb is a big carb. With porting, it'll be flowing more air so there's the increase in velocity.

 

Some people say why not just use a 38mm or something for a stroker, but at mid throttle or low rpms, there's less need for airflow and with a 38mm or bigger, there won't be much velocity at all and I think the power will suffer. I might try it one day. I'd still like to experiment with a 33 as well, and I just might!!

 

Good luck on your carb decision.

I had the 35 on and switched to the 38 off my 250r, it has a little less on the bottom, but I gained 5 mph on top. It definitly pulls harder. I have only bolt on parts no porting.

[sredish]

 

 

Some people say why not just use a 38mm or something for a stroker, but at mid throttle or low rpms, there's less need for airflow and with a 38mm or bigger, there won't be much velocity at all and I think the power will suffer.  I might try it one day.  I'd still like to experiment with a 33 as well, and I just might!!

I had the 35 on and switched to the 38 off my 250r, it has a little less on the bottom, but I gained 5 mph on top. It definitly pulls harder. I have only bolt on parts no porting.

[Wallynut]

Well, I've decided to keep the 33mm pwk. They were willing to switch and pay for all shipping, but figured I would see how it works out. Porting is way down the road, and with some of the suspension items I want to also change, it may be just fine. Suppose I better go shop for jets tomorrow on my to the voting booth.