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The Big Question is answered.


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Well we ran my motor today with a single 35mm pwk, and with a set of dual mikuni tm 28mm's bored to 30mm. Motor was ran on a land and sea crank dyno.

 

Motor is a dynoport ported 350 (186 degree exhaust duration), pro circuit pipes, v-force reeds, wiseco pistons, 175 psi compression.

 

Single carb shined at under 6800 rpm. At 6500 rpm, it was making 2 more hp than the dual carbs. Soon after 7k rpm, the dual carbs came on hard. Ultimately at peak rpm of 8250, it made 62.71hp with the single. Roughly it held torque at 41 ft lbs-42.5 ft lbs from 6900 rpm to 8000 rpm.

 

The duals as said started pushing hard after 6900 rpm. Peak was 66.78 hp at 8650 rpm. The torque curve or torque backup maintained 42 ft lbs-42.5 ft lbs from about 7250 rpm- 8150 rpm.

 

V-force reeds on a 9k rpm motor are a joke. Stock cages, boots, with stock boost bottle, and carbon tech mid reeds made 2 more peak hp than the v-force reeds did.

 

Best timing ended up at +5.

 

And for the guys who are putting humongous singles on, the 35mm pwk on my bike made .3 hp less at 7/8 throttle than at wide open. This indicates that the 35mm carb is borderline too big for a 350 that revs to 9k rpm.

 

So, 2 into 1 makes better lowend power and has better throttle response. Dual carbs pull more rpm and make more peak hp. So obviously trail, play, and mx guys could benefit from a 2 into 1 setup. Drag racers, hill shooters, and high speed riders can benefit from dual carbs and the extra rpm/hp they pull from the motor.

 

Single pwk 35mm guys, Perfect jetting on my bike with max power was 195 main, eej needle, 2nd clip positon from the top.

 

Quicktime video link.

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very nice that answers alot of questions

thats amazing but almost not surprising that the VF3 made less power i dont know why it dont surprise me

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vf3 reeds dont seem to be worth it. My motor guy who was for the most part right about all the predictions said the vf3's provide very low opening tension like they are supposed too. However, they just dont seem to work as well as stock cages with carbon tech reeds, or even fmf, and boyesen setups. He had a hunch they were a bit of a hoax, so he threw them on the dyno and proved it.

 

I may post the charts, I haven't had enough time to scan them yet.

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vf3 reeds dont seem to be worth it. My motor guy who was for the most part right about all the predictions said the vf3's provide very low opening tension like they are supposed too. However, they just dont seem to work as well as stock cages with carbon tech reeds, or even fmf, and boyesen setups. He had a hunch they were a bit of a hoax, so he threw them on the dyno and proved it.

 

I may post the charts, I haven't had enough time to scan them yet.

 

thanks for posting this info! was always interested in how much of a difference there was between 1 into 2 and a dual carb set up. like the test showed,the reeds don't really make much of a difference on an engine with this small of a displacement. they only are claiming 3-5 hp on an 800cc tripple cyl, prostock snowmobile engine. we need more posts like this on the HQ. props to you snopczynski ! :beer:

Edited by the grinch
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Thanks a lot, Snop...you saved me 400 beers on reeds I was skeptical about in the first place!! I'm running the Boyesen 2-stage "Power Reeds" and was thinking of switching to the VF3s.

 

I looked on the http://www.dynoport.com/index.html site and couldn't find anything on their porting. I wanted to check out the intended performance mod. Is this where yours was done?

 

:thanks: for the next beer binge!!

Jay From San Diego.

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