reed spacers for a single carb ?

[extreem9]

I have a couple of questions for you guys about my carbs.

1.So will I see any benifit to installing reed spacers to my single carb setup?

2. What do you guys think about single carbs are they better than a dual setup? I had some guy tell me that dauls are better because you can get more air into the motor. That doesnt make any sense to me because the single carb is bigger and the cylinders are sucking the air/fuel mixture at different times.

Edited June 26, 2007 by extreem9

[swrbansheeboy]

i have read that depending on what side of your reed cage you install the spacers you can get more top end or more low end. i guess more pre reed fuel mixture would be considered more top end or more crank case volume that would be considered more bottom end in my way of thinking but i never noticed any difference when i put them on my twin carb bike. in theory a single larger carb would be better cause like you said, only one piston pulls at a time but in practice for some reason the dual carb bikes seem to have more top end than the singles. i know the single set up seems to have way better low end but why i have know idea. maybe it has to do with the extra capacity between the carb and reed cages since the dual setup has basicly half the volume of the single carb. maybe turbulance has something to do with it since the fuel mixture has so much area to flow into v.s. a dual where it's a straight shot into the reed cage. i'm sure someone smarter than me on here can give you a good explanation...

[dajogejr]

It will make absolutely no difference at all...leave the spacer off. I had spacers for my cub, tried them before and after the reeds...made 0% difference....

 

Twin carbs are the choice for drag racing, etc... A single carb setup is good for a casual duner, trail bike...but you'll never find a true drag bike running a single carb. Even a large 39 to 41mm carb won't flow what is needed to feed alky to an engine ....which is the way most drag racers go...

 

One carb to tune and one throttle return spring to pull sure does sound nice on a play bike...though...LOL.

 

There are quite a few items out there that in theory do this, or are supposed to do that...and add performance gains.

 

Boost Bottles, reed spacers, Roost Boost, etc... In theory they should perform, in reality they don't.

Reed spacers are good for stock cylinders if you're going to larger aftermarket carbs to clear the clutch arm...otherwise....they're just eye candy and one more place a leak could occur...

[Wallrat]

Most of the guys that run reed spacers are only doing it because often times the clutch lever hits the bottom of the carb. There are some people out there that will say that single carb intakes that are short (like Trinity) can also benefit from the added distance/volume between the carb and the reeds. I think its supposed to help the top end. I never really bought into it. I've made two single carb intakes. On the first one I was catching the clutch arm on the carb so I ran spacers. Then I made a new intake that angled up a hair more so that the carb would clear the clutch arm. I never noticed any difference between the two setups.

 

As far as question #2 goes... It's really a matter of preference. Duals are the only way to go if you're trying to maximize your top end. There's no doubt that you lose a little bit off the top when you go with a single carb. However I personally feel that for every other shee out there that isn't used 75%+ for drag only then a single is a better choice. Sure you lose maybe 5% AT MOST off the top end, but you gain some bottom end (which the banshee seriously lacks) and a whole heap of throttle response. Plus your throttle pull is seriously reduced.

 

Besides that, jetting changes are stupid easy and quick, so your more likely to change your jetting for the different temps in the morning, afternoon, and evening. Most dualers don't change their jets 2x/day because its a pain in the ass. So really, you probably gain back that 5% top end just by having perfect jetting on every ride instead of just living with a slightly rich condition during the warmer part of the day.

 

If that's not enough, engine problems are also much easier to diagnose and fix with a single carb. Except for having a hole in the metal intake (unlikely), single cylinder running can only be spark, reeds, cylinder, or pipe. Spark is easy to check by swapping plug caps, and really the reeds are the only other part that's likely to fail. A plugged jet results in the engine dying, not running like crap while one piston melts a hole through itself. There's more space around the engine, so almost every job is 10x easier to work on. You'll never melt an outerwear and you can keep your dual clamp on's and swap to the other clean one halfway through the weekend.

 

But other than all that, single carbs suck.

Edited June 26, 2007 by Wallrat

[dajogejr]

Most dualers don't change their jets 2x/day because its a pain in the ass. So really, you probably gain back that 5% top end just by having perfect jetting on every ride instead of just living with a slightly rich condition during the warmer part of the day.

 

I'd agree with everything said except for these two points. I can promise you on a drag bike it's more than 5% of a top end loss in power.

Also...anyone that is into drag racing, 95% of them run alcohol....and use a power jet to tune fuel needs....on the fly, as the day goes on.

 

Just my experience....

 

However, I'd agree...not many tune the bike as the day goes on, but if the temps don't change drastically...say, 15 to 25 degrees....the performance degradation is minor if at all...

[Wallrat]

Ah I should have made it clearer...

 

Draggers are a breed apart and will do just about anything to get an edge, so of course they'll change their jetting. And yeah, if somebody actually tried to rig a single carb to a top end drag bike, especially on alky, that would not only be ridiculous but an amazing waste of power.

 

My post was directed more towards the 95% of the population that uses their bikes for duning, trail riding, cruising, and maybe the occasional race against a couple buddies.

 

Out in Glamis where I ride, temp swings of 30+ degrees are pretty normal.

[dajogejr]

Ah I should have made it clearer...

 

Draggers are a breed apart and will do just about anything to get an edge, so of course they'll change their jetting. And yeah, if somebody actually tried to rig a single carb to a top end drag bike, especially on alky, that would not only be ridiculous but an amazing waste of power.

 

My post was directed more towards the 95% of the population that uses their bikes for duning, trail riding, cruising, and maybe the occasional race against a couple buddies.

 

Out in Glamis where I ride, temp swings of 30+ degrees are pretty normal.

 

Yep...I agree...and I knew what you meant. Just more of an info post for the others...

Yes...we are most definitely a breed of our own...

lol

 

I know I'm getting off topic a bit, but...I wouldn't mind building a duner banshee...light port job, and a single carb just to kick it over and ride it. No maintenance every other run...just ride it. I suppose that's why I got my 400EX....but, I want to go a little faster...

 

:biggrin:

[Snopczynski]

I have had dual 28's, stock carbs and now my 2into 1 with the pwk 35mm carb. Honestly in all my play riding and the occasional drag racing runs at Sandfest and up the drag hill I noticed no difference between having 28mm carbs and the single carb. Obviously both setups were better than stock though. We have a few guys in the group that run single 35mm pwk on a 4mill, 36mm lectron on 4 mill, and a 38mm lectron on a 6 mill. They all like the setup alot.

 

As for my reed spacers I did it to clear my clutch arm a little more so I could tilt the carb sideways in the bike and change the main jet out in the pwk. Technically that trinity intake is very short and could possibly benefit from being spaced out a little. I have no clue if there was a gain cause I put the spacers on at the same time that I put in my carbon tech reed petals on, and I know I got a gain, but dont know which made more of a difference.

[extreem9]

Thanks for all your info guys, I think I am just going to stick with my single setup on my bansh bein that I am only a recreational duner. An d scratch the carb spacers since there really is no difference, I just pawn them off to some unsuspecting non BansheeHQ owner! Here is a pic of my baby, loaded up and ready for the dunes.