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need more bottom end


bigdaddy69

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I have an agressive dune/play ported motor from Jeff at FAST. The motor has alot of mid to top end but almost dead on bottom. Here lately Ive been getting beat alot because I dont get out of the hole very quick. Should I go with a 2 into 1 carb setup? or what other options do I have? I just would rather get out in front rigth off the start and stay that way, as oposed to being behind at the start and pulling them on the top.

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I have an agressive dune/play ported motor from Jeff at FAST. The motor has alot of mid to top end but almost dead on bottom. Here lately Ive been getting beat alot because I dont get out of the hole very quick. Should I go with a 2 into 1 carb setup? or what other options do I have? I just would rather get out in front rigth off the start and stay that way, as oposed to being behind at the start and pulling them on the top.

Seems like i have read in a ton of places that the 2 into 1 is the way to go for low to mid.

Also the Shearers may be top end also.

Edited by shee4speed
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I HAVE A 97 BANSHEE THAT ROSSIER ENGINEERING BUILT "THERE KNOWN FOR BUILDING RACEBOATS" THEY HAD DUNCAN RACING DOING THE PORTING AND SOME OTHER STUFF AND IN THE ATV SPORT MAGAZINE THAT MY QUAD WAS FEATERED IN THIS ARTICLE WAS IN THERE.

 

 

Duncan recommended Paul Turner midrange pipes with Duncan Fat Boy silencers. On the intake side, he said we could use the stock airbox, but would need a new K&N filter, and a Pro Design intake flange. From there, the air would mix with the fuel in Keihin PJ34mm carburetors. It would enter the cylinders through the unique Pyramid reed valves and reeds, with the added benefit of a Master Flow intake manifold system.

 

We also added a Motion Pro twist throttle (easily the most controversial product installed on this machine among our test riders), and new Tag Metal handlebars

 

 

 

I DONT KNOW IF YOU HAVE THE BOOSTE BOTTLE OR THE PYRIMID REED VALVES BUT THEY DO ALOT.

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yea my buddies bike has the trinity 2 into 1 setup and that thing smokes off the start. I'm just curious what I would lose on top if I went to the 2 into 1 setup myself? I'm also concerned about needing an oversized/billet bowl if I go to a 2 into 1 setup, becuause I was at Little Sahara last weekend and from saturday morning until about 2 o'clock sunday I burnt over 15 gallons of premix.

 

I filled the tank COMPLETLY full and couldnt make it from south camp to north camp. about 3/4 of the way there I would have to turn around and come back.

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I have an agressive dune/play ported motor from Jeff at FAST. The motor has alot of mid to top end but almost dead on bottom. Here lately Ive been getting beat alot because I dont get out of the hole very quick. Should I go with a 2 into 1 carb setup? or what other options do I have? I just would rather get out in front rigth off the start and stay that way, as oposed to being behind at the start and pulling them on the top.

 

i have an aggresive dune port from jeff. the trick with it is to start in second and you have to slip the clutch, otherwise it'll spin the rears for like ten feet and then fall off the pipe...that is of course on sand with 8 paddle haulers and 14/41 gearing...

 

 

DON"T get the 2 into 1 carb for that motor, i've had bad luck with mine in the dunes. and it makes the the left side run a lil leaner then the right.

 

you need to adjst your riding style to the motor, trust me on this one. it took me awhile to get used to it..

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I have an agressive dune/play ported motor from Jeff at FAST. The motor has alot of mid to top end but almost dead on bottom. Here lately Ive been getting beat alot because I dont get out of the hole very quick. Should I go with a 2 into 1 carb setup? or what other options do I have? I just would rather get out in front rigth off the start and stay that way, as oposed to being behind at the start and pulling them on the top.

You have top end pipes on it for one , but i thought you were having traction issues...? Please give me a call if you need something different. Maybe gear it down a bit...

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Jeff, I was having traction issues. I got that all worked out between gearing and lowering the front. Now I just get left outta the hole. Right now I have a 14 tooth front and stock rear. About the pipes, I love the shearers (sp) they pull hard on top it just takes awhile to get on the pipe. Should I go back to a midrange pipe? Or will cpi's come on quicker?

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Put in all that info I asked ya. For one, it sounds like your gearing may be too tall (unless you run a 18"-20" paddle). Those pipes are definitely only top end also. What is the majority of the riding you like to do? I am a big advocate of the 2 into 1, but to presribe you one, I need to know the facts.

Edited by Snopczynski
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I dont think it has much to do with your engine setup, you should be alright with all that you have from what I've seen.

 

You need to learn to slip the clutch and keep it in the pipe until you can get it going. Can you rev it and drop the clutch and just spin the tires? If you can just practice launches for a couple hours until you can slip that clutch and get your bike off the line. You could always add a paddle as well and just keep dropping the clutch until you find the right combination

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A pipe swap is the quickest way. First off, the 2-1 carb is not going to work well with those pipes. I'd consider a set of FMF Fatties (not Gnarlies) or maybe even T5s. I'm personally not a Toomey fan but they'll have a smoother power delivery than the Shearers, just a tad less topend. Your 33mm carbs are holding you back on the lowend. If I were you, I'd go to a pair of 28s or 30s and that'll help to. Again, changing the pipes will cost you a little top end but you'll more than make up for it in the bottom and mid and you'll have a quad that hookups better, comes out of the hole better and is easier to ride.

 

I'm a huge fan of the 2-1 carb but it does have it's application and from what I can tell, you'd probably be better suited with a smaller pair of duals. Also, Fatties are generally underrated. They're great pipes to have on a stockbore ported motor. They respond very well to porting and produce a nice overall powerband.

 

14t up front is fine, I would not go any smaller with your mods. I actually prefer a 15t front sprocket on a stockbore ported motor and I'd suggest you try a 15t with 2nd gear starts. It should let you come out of the hole quicker with more traction and make up ground faster.

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A pipe swap is the quickest way. First off, the 2-1 carb is not going to work well with those pipes. I'd consider a set of FMF Fatties (not Gnarlies) or maybe even T5s. I'm personally not a Toomey fan but they'll have a smoother power delivery than the Shearers, just a tad less topend. Your 33mm carbs are holding you back on the lowend. If I were you, I'd go to a pair of 28s or 30s and that'll help to. Again, changing the pipes will cost you a little top end but you'll more than make up for it in the bottom and mid and you'll have a quad that hookups better, comes out of the hole better and is easier to ride.

 

I'm a huge fan of the 2-1 carb but it does have it's application and from what I can tell, you'd probably be better suited with a smaller pair of duals. Also, Fatties are generally underrated. They're great pipes to have on a stockbore ported motor. They respond very well to porting and produce a nice overall powerband.

 

14t up front is fine, I would not go any smaller with your mods. I actually prefer a 15t front sprocket on a stockbore ported motor and I'd suggest you try a 15t with 2nd gear starts. It should let you come out of the hole quicker with more traction and make up ground faster.

 

 

I think we need to know his tire size before recommending gearing.

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