SK racing carbs

[grannyknot]

Blue, I can't help you on the accelerator pump, mine where working well so I didn't dig in there.

I have found plain old methyl hydrate is the best stuff for dissolving all that gum, works like magic.

Then I pull out these puppies,

Everytime I go to the dentist I ask if he has any dental tools they are throwing away and he always has a few for me. They my not be new enough to use on teeth but they perfect cleaning carbs and they are free.

[Reverend]

I just had flashback when i saw your picture. For some reason my jaw began to hurt...

Good info Blue!

And guess what, i just uploaded the PDF manual.

https://www.dropbox.com/s/96qmbxwgf81ud9p/SK%20Racing%20Carburetors%20Manual.pdf

[73str86]

I read this thread yesterday and was going to post the manual but it looks like it's already been done. Here's a recent photo of mine. I paid $800 for them including the intake. They are 45mm and I have about 8 hours worth of cleaning into them. I noticed that like a photo posted above, mine don't have any model # stamps on the top plates. The 2.9L engine is fairly modified (check my build thread for specs) and they seem to do ok. They are even running admirably on the factory mechanical fuel pump. I plan to go with a Mazda RX7 unit when I find one. I have some vacuum leaks I'm dealing with right now, and timing is still set by ear.

Does anyone know where to find the SK sight tool or another method of setting the floats to factory specs?

[grannyknot]

73str86, I have an SK fuel level sight tube tool in the mail on its way to me right now, I'll post pics when I get it.

I purchased it from, Z Car Customs- JDM - HOME: Brian is a really good guy to work with. It's more than a bit pricey at $75 plus shipping from Japan for an eye dropper with gradations but to get the float level PERFECT you need it. I set my float levels by using a vernier caliper and the tech manual and engine runs well except it doesn't like to start which is indicative of the wrong float level, ...so I bought the tool.

I'm sure once I get my float levels set that I will be mailing this tool around the continent to others if you are interested.

Chris

[240260280z]

Just ordered some parts from Japan:

- 6mm insulating spacers

- 3 rebuild kits

- part #60

Took the carbs apart.... starting to clean. Yeah.

[240260280z]

[240260280z]

Blue, the only thing the factory would have used is a thin rubber O ring, that might be a hard tap to find.

Congrats on your buy, with all your carb knowledge I'll be interested to hear what you have to say about the rebuild and the performance.

Chris

UPDATE:

Thanks Chris! I used a DENTAL TOOL-like instrument to pluck out the rubber ring (as you expertly guessed). Some liquid wrench and a healthy hammer via a punch loosed up the remnants of that progression hole screw-cap. Did it on my lunch break.

I have now completely disassembled the 3 carbs. The only casualty is the loss of one of the secondary small springs in the adjacent arm of the pump rod. I am not sure if it was there in the first place.

I like the 50 DCO style throttle valve return spring.

Getting the aux venturi and venturi out was challenging for 4 of the 6 throats (2 came out with finger pulls, the other 4 needed taps on the aux venturi cross brace to drive out like a wheel bearing race from a hub. Some corrosion seems to be the cause. I'll lube when I rebuild.

I also have a question about the big screw at the bottom of the fuel area (you have to remove the bottom plate to see it)? Is it a stop for the main jets?

The quality and precision of the metal work is much better than the DCOE's I have worked on.

Edited September 20, 2013 by Blue

[grannyknot]

Blue, I didn't open those covers, #78 because I didn't have new paper gaskets but the big screw may be nothing more than a plug covering an access hole used for machining purposes, it is not listed on the exploded diagram and that may be the reason.

"The quality and precision of the metal work is much better than the DCOE's I have worked on."

I agree and without a doubt the founders of SK were racers using Webers on their cars and got tired of tearing them open to change anything.

Finally they said "We can do better than this, we can improve on this design" and they did.

I've heard Weber sued (as they had every right to) and part of the settlement was that SK could openly advertise in Japan but no where else. They could ship anywhere in the world but "dealers" couldn't carry any stock so as to inconvenience the buyer.

I have done some hunting and have found very little info on the company and most of what I know is heresay from old mechanics.

Chris

[Reverend]

By the way, ive ordered the paper gaskets straight from the factory shop, very fast and very cheap. Also they have very polite customer service, i guess its kinda culture related too to be superduper polite.

[240260280z]

I found out what that screw in the bottom does! It holds the central jet holder assembly into the carb body. there are O rings in this unit that would probably dissolve with carb cleaner.

I noticed the part had separated while bathing in methal hydrate as you recommended.

Thanks again Chris!

[grannyknot]

Just a warning to anyone reading this thread! Methal Hydrate although one of the milder cleaners does react with certain material! I'm not a chemist, just a backyard mechanic with some experience and I have found that med-long term contact between MH and rubber, SOME gasoline rated rubber (neoprene) and aluminum is not good. I'm not concerned with legalities,

I just don't want anyone reading this thread to go and soak their carb in MH and think they can pull it out and use it.

Short contact with MH, no more then a minute, (I keep mine in a common utility spray bottle) is fine as it evaporates very quickly. If your carb is old and dirty it needs a rebuild.

Blue, what part seperated?

[240260280z]

The big cluster that holds the jets... it looks like a tower of aluminum.