Taper-boring a carb???

[Narly R]

Well I FINALLY got my 350, and I need a bigger carb, but I was wonderin if this would work? They guy at our local bike shop said that it would work?! Im shure it would work, but does the carb hold up good still? Thanks!

[seven]

I had this done to my banshee carbs and it worked well but not as good as getting the right carb.

[Narly R]

well the guy at the bike shop said that this would work even better than getting a new carb cause of a lot of thing! He said that a aftermarket will acually take power away on the bottom and mid-range. But Tapering tha carb will give you power in all these ranges! But I dont think he was right!:confused:

[seven]

You do lose a little bottom end with a bigger carb. But you dont gain as much either. You can only bore the carb bigger to the slide becouse if you go past the slide. So you are still restricting how much air/fuel the carb can deliver. If you have the money i would getthe bigger carb, if not i would taper bore.

[seven]

Also just look at any pro quad specs and almost all use a 38 carb.

[AndrewRRR]

Are you considering boring the stock carb? If you are I would say don't do it. When I got my 350 motor done, I had a stock carb (34mm PJ) that was taper bored to 39mm (by previous owner, not me). It worked fine when the motor was a 250 but it gave me nothing but trouble with the 350. I called LRD and they said they have no idea what the pilot/needle/main specs should be because you aren't supposed to bore a 34mm that far, lol.
So I did it right and got a 38mm air stryker from them. It worked well for that motor. Then I got it really ported and got a 40.5mm taper bored ESR gas carb. If you are building it for MX I'd get a 38mm A/S, if you are building it for a dune screamer or drag racer, get 39 or bigger.
ESR carb:

[Narly R]

um, it will be from 36 to 38 so it shouldnt hurt it? It will be a niks 350 engine!????

[Glamis400ex]

sounds like you've already made your mind up, just looking for the ok....just do it, see what happens.

Glamis

[Narly R]

yea, i acually think Ill go with a 39 mm! Need as much power as I can get!!!:D

[AndrewRRR]

Yeah i'd just buy a 39, otherwise you'll pay to taper bore your carb, pay for a ton of jets and needles to get it running right, then pay for a 39mm carb after you give up and throw it away. lol
I got my 38mm A/S from LRD (they have 39's too). They throw in the pilot, needle, and main jet for a 350 when you buy from them. It was $220.

[Narly R]

Sounds like a good deal! Well i decided not to bore it! :ermm: But do you guys know what setting I should have my needles for the 350? AndrewRRR, what do you have your needle set at, well never mind you have a 39 mm carb and I have a 36! Well theres only one needle right? What should I have it at? And will I only have to change the main get?:confused:

[AndrewRRR]

Actually there are many needles. To start out i'd run a 50 main (may be a tad fat but better safe than sorry), and the needle that came with the carb will probably work (I ran a DEJ in the 38, I'm trying a DEG now). I usually start on the 4th notch down. A 180 main should be ok. Do a plug check to see what it looks like. I ran a 180 in my 350 with the 38mm, so on a 36mm it should be plenty.
You'll probably end up wanting to get a bigger carb eventually but for now that jetting should be alright.

[Narly R]

Weel thge main jets Im going to get will be a 165 160 everything between a 150 and 160! I think ill prolly end up with a 152-154??? But well see! Im not shure what the needle should be on? Ill try the 4th notch, and go from there!??

Andrew, would you want to go to Spinreel the middle of next month?

[AndrewRRR]

Isn't stock jetting like 155? I'm gonna throw a 185-190 in mine today to start jetting. lol. I'd rather foul plugs than burn up a new engine to start out.
I'd be down with going riding next month if the weather is decent. I'm not totally sure where we are gonna go for Memorial Day weekend yet, but I'll definately be riding then.

[Jekyl_22]

Does that mean your four wheeler is working now or what? I am still waiting on my case, still........

[Narly R]

Um yea she rips and tears!:huh no its still setting!
Im going to hopefully get it started tomarrow. Im waiting on a lonestar axel:D I tried staring it yesterday and it wont fire!!!! I have to talke it back up to the guy mon. This is getting annoying!!!

But Andrew, its 140-142, thats what Iv been told I ran a 140, So I have a 160 in it right now, so I think Ill end up with a 152-154? Well see once it starts! But IM DEFENTLY GOING TO START BIG AND GO SMALL!!! (darn caps):grr