Jump to content

SU's Setups


Recommended Posts

Check this out. On ebay. Says it is a Datsun L-series Lynx BUT made to run British SUs! Nifty.

 

Though I read somewhere that the japanese SUs are better. Still neat!

 

Posted Image

 

Nice find! The connection between two sides looks a little small to be a balance tube, maybe that's the difference. Looks like a great intake to mod for a Carb'd turbo setup though :cool:

 

I found my stacks on Ebay but the seller has since stopped listing them :( They were $50 shipped from the UK. Haven't found any other like them for sale!

Link to comment
  • Replies 78
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

The Black knobs on top of your SU's is the "dash pot" it has a little brass 'weight' in it that when you stomp on your accelerator the oil in the 'dash pot' slows the piston from rising to quickly and forces your mixture to stay a little richer until you reach speed. I have the 'high performance SU turning guide' and people argue on what is the best oil & dome spring to use. For my crazy SU set-up I decided to go with a stiff dome spring and no oil so when I stomp on it, I get a slightly leaner mixture but bigger airflow. Unless your certified crazy such as myself I recommend keeping a little oil in the domes :) Hope that helps!

 

 

THat makes it quite clear, THANKS! But what's with the 2 little breathers coming off your carbs? (Are they breathers, hose things with the blue things on them?)

Link to comment

Check this out. On ebay. Says it is a Datsun L-series Lynx BUT made to run British SUs! Nifty.

 

Though I read somewhere that the japanese SUs are better. Still neat!

 

Ebay Linky

 

!BYYGyyw!Wk~$(KGrHgoOKigEjlLmbZRpBKhKc1JF9Q~~_12.JPG

 

you can run HS6 hitachi carbs on here (Z SU's) just fine with a little finessing of the flange bolt holes.

 

Oh and vintage Harley guys run the SU dry...The company that makes the monster SU for harley is called rivera.

Link to comment

THat makes it quite clear, THANKS! But what's with the 2 little breathers coming off your carbs? (Are they breathers, hose things with the blue things on them?)

 

Well the float bowls have a atmosphere breather line that normally connects to the air filter, alot of people just leave them open to them air if not connected to the air box. However I had some extra little air filters and from the ammount of dirt/crap/water I get up on my engine in the NW I though: 'why not put a filter on them' Debris in your float bowls can be very annoying! My only advice there is to use very free flowing filters otherwise you can build up a vacuum and starve your carbs for fuel.

Link to comment

Well the float bowls have a atmosphere breather line that normally connects to the air filter, alot of people just leave them open to them air if not connected to the air box. However I had some extra little air filters and from the ammount of dirt/crap/water I get up on my engine in the NW I though: 'why not put a filter on them' Debris in your float bowls can be very annoying! My only advice there is to use very free flowing filters otherwise you can build up a vacuum and starve your carbs for fuel.

 

 

I am getting quite an education in this thread. Thanks so much!

Link to comment

My SU question of the day: How much throttle shaft/body wear can you have, and still be able to run? I have a noticeable amount of play (on a set from P&S I've never used), but how much is too much? On the Other Forums when the subject in mentioned, it always is implied there is Zero Tolerance for wear, but how about by Real World/Ratsun standards? I've read worn shafts causes bad idle, but does this mean 1. Won't idle at all. 2. Idles, but really rich. 3. Will idle if you set the idle speed up to 1200 RPM or something fast. 4. Some horrible scenario I haven't thought of.

I understand sending the bodies to Z Therapy is what should be done, but that costs a lot of money.

 

Cheap Guy Len

Link to comment

Len, I bought my SU's untested off ebay for cheap. They were really dirty and looked to have been used up pretty good. I cleaned them up and bolted them on, and it runs good. I have some shaft wear, confirmed by spraying starter fluid into the shaft area (idle increases). I have my idle set at around 800-900 and it's been fine.

 

It's not the perfect scenario but for my intents and purposes, they work just fine. Rebuilds are expensive, honestly I could probably use one, but I chose not to because of the costs.

 

I say bolt them on and check the performance and function first.

Link to comment

anybody know where to get parts for these carbs. opened my float bowl today to see why it was over flowing and the float was full of gas and sunk. I cant seem to be able to find any new ones on this web. I just drilled a small hole in it to drain the gas then soldered the hole shut and the existing hole filled with jb weld. it got me home from work but dont know how long it will hold

Link to comment

anybody know where to get parts for these carbs. opened my float bowl today to see why it was over flowing and the float was full of gas and sunk. I cant seem to be able to find any new ones on this web. I just drilled a small hole in it to drain the gas then soldered the hole shut and the existing hole filled with jb weld. it got me home from work but dont know how long it will hold

Go to my How To for the Air Cleaners...I have part numbers on the last post...

http://community.ratsun.net/topic/5294-su-air-cleaners-for-a-ratsun-price/page__st__20

Link to comment

Len, I bought my SU's untested off ebay for cheap. They were really dirty and looked to have been used up pretty good. I cleaned them up and bolted them on, and it runs good. I have some shaft wear, confirmed by spraying starter fluid into the shaft area (idle increases). I have my idle set at around 800-900 and it's been fine.

 

It's not the perfect scenario but for my intents and purposes, they work just fine. Rebuilds are expensive, honestly I could probably use one, but I chose not to because of the costs.

 

I say bolt them on and check the performance and function first.

 

jun - Thanks for the info. I know the "right" thing to do is have the bodies re-bushed, but doing it "wrong" first is the story of my life. I'm happy if things just run. Running good is a luxury. I got these carbs off a decent looking 720 L20b truck at P&S. It has occurred to me that bad carbs might be why it ended up junked. I guess the price of gaskets and some time would give me an idea if they are runable.

 

If Z Therapy is still selling the SU DVD, I recommend it. It is pretty long, but you will learn a ton about SUs from it. More than any of the books, I think.

 

Len

Link to comment

jun - Thanks for the info. I know the "right" thing to do is have the bodies re-bushed, but doing it "wrong" first is the story of my life. I'm happy if things just run. Running good is a luxury. I got these carbs off a decent looking 720 L20b truck at P&S. It has occurred to me that bad carbs might be why it ended up junked. I guess the price of gaskets and some time would give me an idea if they are runable.

 

If Z Therapy is still selling the SU DVD, I recommend it. It is pretty long, but you will learn a ton about SUs from it. More than any of the books, I think.

 

Len

there are some good videos on you tube by university motors that explain a bunch also

Link to comment

jun - Thanks for the info. I know the "right" thing to do is have the bodies re-bushed, but doing it "wrong" first is the story of my life. I'm happy if things just run. Running good is a luxury. I got these carbs off a decent looking 720 L20b truck at P&S. It has occurred to me that bad carbs might be why it ended up junked. I guess the price of gaskets and some time would give me an idea if they are runable.

 

If Z Therapy is still selling the SU DVD, I recommend it. It is pretty long, but you will learn a ton about SUs from it. More than any of the books, I think.

 

Len

Temporary "fix" if you don't get your engine compartment too dirty would be to apply Dow Corning DC4 silicone grease around the shaft to carb body junction. The DC4 will at least temporarily seal the leak, if that's what the problem really is. If no improvement, then you have problems beyond shaft to body wear. If it does work you might see if cutting shortening and resealing a silicone spark plug boot at the seal area would keep dirt off and prolong the agony of deciding to rebush. Good Luck!

Link to comment
  • 1 month later...

are you running a balance tube?

 

Yes, yes I am :), if you look at the square piece in between over there, its a hollow square piece of metal, I chose square cause the throttle cable bracket was super easy to make :). As soon as I get the head back from the shop do to a bad HG, Il post some better pics of the finished product :).

Link to comment
  • 3 months later...

Yes, yes I am :), if you look at the square piece in between over there, its a hollow square piece of metal, I chose square cause the throttle cable bracket was super easy to make :). As soon as I get the head back from the shop do to a bad HG, Il post some better pics of the finished product :).

 

So where are those better pictures? Hows the thing run???????

Link to comment
  • 5 months later...
  • 1 month later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.