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View Full Version : SU carb tech and tuning ???



LD83
11-03-2010, 11:09 AM
Hey guys I just picked up a brand new SU carb for my bike. carb came with some paperwork but really didnt help me out to much. Basically I would like to know how this thing works? Best way to get a cold bike started? and how to tune?

I find that this carb works really nice when bike is running but it seems hard to get my bike going. Help me understand...Please.

This is what It says to do :
Turn fuel on and let sit for a few seconds
lift up slide and pump fuel 5 or 6 times
turn on choke
start motor...

Problem is I do this and bike wont start. I dont really understand how this carb could actually work to get a bike started. This is why... There is no acclerator pump so of course your gonna have to pump some fuel with that tickler pump. then gas flows out of the slide or piston whatever we call it. Once again thats a good thing. Problem is that it seems like the gas just sits there between the slide and butterfly. but the butterfly is closed actually it is open just a little bit when you but the choke on. Is that all the choke does on these things? kinda just like bumps up idle speed? So question is. How is this bike gonna fire when the butterfly is barley open then theres a puddle of fuel followed by a closed piston? I understand the CV principles once running first....Please help...

Speedfiend
11-03-2010, 11:32 AM
An SU on a brit? Huh?

LD83
11-03-2010, 11:40 AM
No its on a shovelhead. I just wanted to ask the guys that should know something about these carbs. Drop some knowledge on me.

Speedfiend
11-03-2010, 2:49 PM
Sorry for my snarkyness. Maybe you'd find more help in the American Bikes and Tech section. All we know here is Amals.

cntrhub
11-03-2010, 5:12 PM
Sorry for my snarkyness. Maybe you'd find more help in the American Bikes and Tech section. All we know here is Amals.

I think we agree to disagree. One must enter the pit and commit no matter the race face is face it. Not your carb. If you want to look like jj all over again... I do not... Will not... EVER have hat slime on me.

CC is my pit, your pit, and why deny pit. I pit tea the fool that does not commit to the CHOP. Man wants SU... Another wants wee-teas. CC is sea-sea my dick? See the balls hang heavy? Tell Ha Tell hey day gay fast, I'll pea in your cereal before you take the last swallow and look down.

I am not gay. I just use your dick in a court of loop. At least I hate everything about a man and his carb beer toot tear. I'm just glad I am not in the middle of dishit because your rules did not say what theory matches what brand is same old theory.... Excuse ME! :killerjob:

Dis is day underground and bike runs or run out and play wit yours is just saying. Not day way to act jj like help or bow out. Help me fish for some tech so we do not look like jj jackshot Jerking off the tech.

I am going to set the fish out in the sun now... I will be right back to see if you helped or maybe we can tech the shit out of this place or you will see not one short blip of a few words. I am cut from the same cloth ass it were. I'm the shitty part of town the underground does not want me dare ass it wear; you do not want to see the mare of the shitty once you start INN....

We bring out THE LAP... Joey The Wrench is going to try like hell to pluck your feathers every lap, every lap till the tech flies over your head look out..... Mess wit the LOOP.... You are UP.

cntrhub
11-03-2010, 5:56 PM
http://www.sw-em.com/SU_HS6_explode.gif

Does this look AMAL GP10 to you, Speed?

REmote Float? Yes? Vacuum suck out the hole generic? Float fill the remote fandango?

LD, this here the carb? Probably not... But we have remote float here. Carb works on vacuum pull.

Carb relies on both main and low. Go clog your main... Fire the bike up don't believe me I stopped listening to the pros. That is why I am so gunshit ready shy is get your gun clean and ready you mess with one step look all jj'dickissing and you want me to suck on that tech?

41 ~ Closes off 40.
40 ~ Can cause a ring around the perfect taper and leak.
40-41 ~ Can leave a running gas shadow or etch at the bowl and you can adjust the height that way. Or at least know where it sits when dry.
31 ~ Some bowls; can be tilted, where you can see the float stop at the gas etching, hitting 40 and adjust from there.
11 ~ With 12, will slide up and down and wear. If that air gap is too wide, air will move up that slide on the side, where 13 acts as the stopper pin from spinning.
12 ~ Is banging back and forth in 2. For every action, there is a pulse in and one out. There is your X bang, Y slide up; wear points = Air did not pick up gas and pull fuel out of jet. Rather, it moved to the shortest path like electricity does.

Everything else is mechanical, meaning, yes, you see and have gas. So that means, a workable clean carb. That means float is closing off fuel. You see gas being pulled maybe, but no enough. You do not see gas pouring in with petcock on so no float work needed.

You may have to use a manometer even for single cylinder work. You need to get the jetting to it's highest point. Maybe 5 is the low speed screw. Say for argument sake you turn that till you find the highest idle or the highest merc point at the meter. That should at least get it starting easier. Because you figure; if that what it wants now running smooth? Why not at any time then shit. So in the morning, you'd think it should run the same, nothing has changed.

Make sense?

OldGoldGarageCo
11-03-2010, 6:17 PM
Um, I hope this helps, I like SU carbs, have one on my ironhead, and I run it with a velocity stack and I cover the mouth and kick it over a few times with the ignition off, this forces fuel into the chamber, and then turn the ignition on and start kicking.....also, mine is an old SU from a Rolls Royce, never owned a Rivera version, but here is a good tech article I been saving, I think it should apply to yours...

OldGoldGarageCo
11-03-2010, 6:27 PM
it's a long fucking article....

BTW, great carbs, good gas mileage and not flat spots...and they feel awesome when you crack your shin on them...

LD83
11-04-2010, 12:07 AM
Thanks for the articles. I look forward to reading and hopefully figuring out mine. Any other info would be killer

Speedfiend
11-04-2010, 5:11 AM
I sincerly hope it all works out with the shovel! Cheers.

Loffer
11-16-2010, 11:52 PM
[QUOTE=cntrhub;105650]I think we agree to disagree. One must enter the pit and commit no matter the race face is face it. Not your carb. If you want to look like jj all over again... I do not... Will not... EVER have hat slime on me.

CC is my pit, your pit, and why deny pit. I pit tea the fool that does not commit to the CHOP. Man wants SU... Another wants wee-teas. CC is sea-sea my dick? See the balls hang heavy? Tell Ha Tell hey day gay fast, I'll pea in your cereal before you take the last swallow and look down.

I am not gay. I just use your dick in a court of loop. At least I hate everything about a man and his carb beer toot tear. I'm just glad I am not in the middle of dishit because your rules did not say what theory matches what brand is same old theory.... Excuse ME! :killerjob:

Dis is day underground and bike runs or run out and play wit yours is just saying. Not day way to act jj like help or bow out. Help me fish for some tech so we do not look like jj jackshot Jerking off the tech.

I am going to set the fish out in the sun now... I will be right back to see if you helped or maybe we can tech the shit out of this place or you will see not one short blip of a few words. I am cut from the same cloth ass it were. I'm the shitty part of town the underground does not want me dare ass it wear; you do not want to see the mare of the shitty once you start INN....

We bring out THE LAP... Joey The Wrench is going to try like hell to pluck your feathers every lap, every lap till the tech flies over your head look out..... Mess wit the LOOP.... You are UP.[/QUOTE

WHAAAA? . SU carbs are not used on brit bikes , period. Its nice to help people but theres plenty of places to ask. You make no sense. :asshat:

cntrhub
11-17-2010, 1:14 AM
Sure it does. If that does not make sense, then fuel spark and compression do not make sense, cupcake.

Be very careful how you present the tech. Those 3 variables speak volumes and to struggle through just one variable, it will ring your chime you do not see the absolute one way OTTO operates no matter what you toss in front if it's mouth.

Pressure and Vacuum will too, send you right to the fish market counter, you bring start, fool, and cupcake to run the OTTO. It runs in an absolute venue and if you contribute to that tech, please be as absolute in the specific as you can be. If not... Fish Fries, baby cakes!

I will blow you away in that technical speak we stop messing around and then get down to business. There is no messing around here in my pit. It is hard enough to figure out what is being said on the author's end. That is when I speak the generic and not specific. Everyone wins.

You want to help answer a specific question, be my guest. Is it OK if I answer my way? You don't mind, right? I am not about to hook your bait. I am not about to yes or no you is watch out if I do. Have you notice no one wants to answer that technical q&a of the; did they stick their nose in the subject and now where are they?

You do know who I am talking about and that fuel signal sunk in the bowl. It is sucking on it's own bottle. Someone toe day [sticking their foot in mouf] told me the main has a channel to the low speed? Was not the low speed jet sunk in the bowl, hello?

Did you want to have your theory of vacuum and cupcake now? Or does pressure vacuum seem the more logical how a carb operates in the generic... Via cupcake jetting? Pass the icing I need to recover the topping it was sucked off?

I will run you around when you make no sense tell me I make no sense. YOu beer tear see the absolute and do you see how you see those steps appear? You say nothing because you did see the steps as per book savvy is you? You are going to come tell me I'm an ass because you cannot read the factory shop manual? Where do you think I get my info? Pillsbury doughboy? You are free to answer tech questions and someone more in the savvy dept would like to point out your post. Make me look like jj > Not in your lifetime, cakecup.

If I saw something that do not follow in step and someone adds a cupcake theory to that step and you found that out of the blue? More air is same air. Someone cupcake'd "MORE" and when you get it wrong.... The fish comes out to play like a shark attack on your post is toast it like it was going out of style. :D :rolleyes:

Loffer
11-17-2010, 2:59 AM
Sure it does. If that does not make sense, then fuel spark and compression do not make sense, cupcake.

Be very careful how you present the tech. Those 3 variables speak volumes and to struggle through just one variable, it will ring your chime you do not see the absolute one way OTTO operates no matter what you toss in front if it's mouth.

Pressure and Vacuum will too, send you right to the fish market counter, you bring start, fool, and cupcake to run the OTTO. It runs in an absolute venue and if you contribute to that tech, please be as absolute in the specific as you can be. If not... Fish Fries, baby cakes!

I will blow you away in that technical speak we stop messing around and then get down to business. There is no messing around here in my pit. It is hard enough to figure out what is being said on the author's end. That is when I speak the generic and not specific. Everyone wins.

You want to help answer a specific question, be my guest. Is it OK if I answer my way? You don't mind, right? I am not about to hook your bait. I am not about to yes or no you is watch out if I do. Have you notice no one wants to answer that technical q&a of the; did they stick their nose in the subject and now where are they?

You do know who I am talking about and that fuel signal sunk in the bowl. It is sucking on it's own bottle. Someone toe day [sticking their foot in mouf] told me the main has a channel to the low speed? Was not the low speed jet sunk in the bowl, hello?

Did you want to have your theory of vacuum and cupcake now? Or does pressure vacuum seem the more logical how a carb operates in the generic... Via cupcake jetting? Pass the icing I need to recover the topping it was sucked off?

I will run you around when you make no sense tell me I make no sense. YOu beer tear see the absolute and do you see how you see those steps appear? You say nothing because you did see the steps as per book savvy is you? You are going to come tell me I'm an ass because you cannot read the factory shop manual? Where do you think I get my info? Pillsbury doughboy? You are free to answer tech questions and someone more in the savvy dept would like to point out your post. Make me look like jj > Not in your lifetime, cakecup.

If I saw something that do not follow in step and someone adds a cupcake theory to that step and you found that out of the blue? More air is same air. Someone cupcake'd "MORE" and when you get it wrong.... The fish comes out to play like a shark attack on your post is toast it like it was going out of style. :D :rolleyes:

No theory , just fact . You are just wrong, twinkletoes. Amals . You can use an SU if you want but that would be as irrelevant as your rediculous posts. I think its time to take your medicine, the schitzo is raging in your brain today. ;)

Blackjack
11-17-2010, 3:49 PM
Genius.

650 Thunderbird preunit.

SU carb, from the factory.

http://1.bp.blogspot.com/_5buP6V8GdTM/S6jmUQShXwI/AAAAAAAAAbA/cUIqLcQguDQ/s320/6tj.jpg

http://tonupclassics.blogspot.com/2010/03/1952-triumph-thunderbird.html

cntrhub
11-17-2010, 5:35 PM
http://2.bp.blogspot.com/_5buP6V8GdTM/S2DZ8U5KKZI/AAAAAAAAAAc/bZP4tjWbfS4/S1600-R/bloglogo.jpg

Loffer > :cool: It's not me. I just report the facts ma'ma mirror me gland. :eek: I learn from you more than you all learn from the ton up is he mus have seen her chest adjusters and that lower jet that has the hair in the main jet is she wanted it so bad and you guys wee were walking away from that rolling fish market is she is the, "Counter Lady." Did you count the horse flies drop to the ground once she did that jet drop?

Loffer...... Don't JJ the place UPit TEE or we are going to goHA, Ton'inn!