Opening a Carby can of worms!

[AussieHard]

Please keep your answers simple so I can follow

I will be working on a 74, 78, & 80's XS with some mild mods but till 650 and no repashe or anything fancy.

I am I best sticking with stock carbies?

What is the benefit of a 2 into 1 set up?

Other carbies to swap and adding on diff filters or velocity stacks?


Does any of it really make a BIGperformance or power difference?

 

[retiredgentleman]

upper right corner of page..............."Search" box...............type in Carbs.............you'll get lots to read. Just be aware that its similar to asking what oil brand to use...............you'll get dozens and dozens of opinions.

click on "Tech" top of page................scan down..........tons of info on your questions.

 

[AussieHard]

upper right corner of page..............."Search" box...............type in Carbs.............you'll get lots to read. Just be aware that its similar to asking what oil brand to use...............you'll get dozens and dozens of opinions.

click on "Tech" top of page................scan down..........tons of info on your questions.

Yeah I know but most of those threads are a bit too detailed and subjective.

Hence I opened with:
Please keep your answers simple so I can follow!

Just looking for an overview that is simple.

 

[pa23driver]

no real advantage to the single carb except it's easier to tune - seems like a bitch to get running though

if i were you i'd stick with stock carbs mainly due to the fact that there is plenty of help and guides available for the stock carbs

if you add free-er flowing air filters you could increase your main jet size and get more power out of the bike. if you use different filters you might have to rejet the 1980 650 as i understand they're pretty lean to begin with.

i'm running pod filters and a free flowing muffler on stock head pipes (commandos from Mike's) i bumped my main up 2 sizes, dropped the needle and increased my pilot by a size and i've gotten a very noticeable performance improvement.

 

[gggGary]

There are some sharp guys on here that do carb work. No one can tune to your bike unless they have your bike but.... I would see if you could get 5twins to do a set of BS34s for you. That would be my suggestion as to the best set for you. IMHO the foam float 81+ BS34s are your best bet. But carbs are like "which oil is best?" We all have opinions.

 

[grizld1]

You want the bottom line, clear and simple, so here it is. Get the machines running well with stock carbs and air boxes and think about performance carbs and/or intake mods later. The fewer modifications you have to deal with at one time, the simpler your trouble shooting becomes.

 

[pregrid]

He said "carbies"

 

[BigJimmyW13]

You want the bottom line, clear and simple, so here it is. Get the machines running well with stock carbs and air boxes and think about performance carbs and/or intake mods later. The fewer modifications you have to deal with at one time, the simpler your trouble shooting becomes.

^^^^^ This guy and 5twins are the guys that are writing the carb guides so trust what he says. Otherwise, start here. Learn as much as you can to start with.

http://www.xs650.com/forum/showthread.php?t=43

 

[AussieHard]

Thanks guys, not in a rush to change them if they have no issues. But everyone always seems to be messing with them or swapping them. Was starting to think there might be a significant reason for it. Also good to know what to keep an eye out for if it comes up at a bargain price.

 

[littlebill31]

Again, I love my 34's, but I only changed the jets. Pods and cut exhaust with the right jets and my bike freaking rolls. I would like a single carb, but don't want to have to modify stuff. Simpler is better.

 

[5twins]

I'm quite happy with my stock carbs as well. I don't think the $300 to $600 for aftermarket carbs is worth the return you get. I think you'd get more for your money with a big bore kit.

 

[blackbetty]

Personally, I opted to rebuild my 38's and put my money towards a PMA kit....

 

[retiredgentleman]

I have found that my stock BS38's work very well. I get instant starts, brisk acceleration, a top speed well above legal limits, and 56 mpg...................whats not to like?

It depends what you are looking for. If you want quick acceleration around town, just put on a 36 rear sprocket................very simple and low cost.

Because carbs appear to be a mystery to many people, they get blamed for every malfunction that appears on their bike.

The stock Mikuni carbs are well designed, just study how they work and replace any worn out parts.

Be aware of "marketing" where everyone gets caught up in the latest product fad.

 

[bluebikerblan]

Please keep your answers simple so I can follow.
Am I best sticking with stock carbies?

You want the bottom line, clear and simple, so here it is. Get the machines running well with stock carbs and air boxes and think about performance carbs and/or intake mods later. The fewer modifications you have to deal with at one time, the simpler your trouble shooting becomes.

Short and simple.....amen & amen! Blue

 

[Sundie]

the only veering from stock i would ever do is on bs34's, replacing the needle/needle jet with the cdn style. if you open op your carbs and the needle has only one position, that's the US style.

linked 38's are fine stock, no matter what you do to intake/exhaust - *unless* you're spinning 6k plus all day long - ie: track.

 

[SpoogeMCMM]

Did the KZ1000s come with BS34s on them stock? what bikes came with them? cause i have a ton of bikes in the garage and im all for robbing peter to pay paul ya know.

 

[gggGary]

Don't know, but BS34s from a Krotchlicker 1200 aren't BS34s on an XS650. BS34 is a series designation with near endless variations. a few parts might interchange, but a lot of them won't.
A KZ750 twin has BS34s but the Bodys, throttle shafts, fuel paths, brackets jetting are all different than on an XS650. I was going to save a set for parts till I realized it wasn't worth doing.

 

[SpoogeMCMM]

Don't know, but BS34s from a Krotchlicker 1200 aren't BS34s on an XS650. BS34 is a series designation with near endless variations. a few parts might interchange, but a lot of them won't.
A KZ750 twin has BS34s but the Bodys, throttle shafts, fuel paths, brackets jetting are all different than on an XS650. I was going to save a set for parts till I realized it wasn't worth doing.

aaahhhhh, the infamous Krotchlicker 1200 series carbs. lol okay i gotcha, just was wonderin cause i hear so much about those carbs on here

 

[5twins]

Gary, one thing you should have looked at was the butterfly plates and what number they were. These were never sold as a separate part and now about all you can do is scrounge them if you need replacements. I've come across bent ones, filed ones, all sorts of P.O. mayhem reaped upon them. Replacement was the only option. So far I've been able to pull the needed #135s for the BS34s from some Yamaha XS400 carbs and some late '70s Suzuki GS425 carbs.