Yet another carb thread

So, I started on the spare carb rack that I have. I managed to loosen all the screws, but a few of them are buggered up pretty good. I want to replace them, but I'm not sure what style heads I should go with. I don't want Philips, so it's between Allen and standard hex.

Also, when I pulled the pistons out the needles from three of them stayed stuck in the carb body. Is that a problem?

 

Yes, that is a real problem! The needles are supposed to stay with the vac pistons.

 

i replaced all my carb fasteners with allen bolts i ordered from Chacal. they look super sharp.

 

Ok, so once I get them out of the carb, are they just going to go back in? Or do I need to replace something?

 

They should not come out of the pistons. Did they break off, or did the piston body bottom break allowing them to come out the bottom? IIRC, they have to be removed from the top of the piston.

 

Pics might help. I have a feeling when you say needles you mean emulsion tubes (which do stay in the body). Otherwise something is definitely broken, or the PO did something very wrong.

 

Here is a pic of the one bore with the needle and one bore without

 

Here is what the pistons look like

 

Oh my...that's not good. There should be an E-clip that retains the needle in the slide. You can unscrew the plastic screw inside the slide with an allen key and do some 'vestigatin'. Is the hole in the slide bore enlarged?

How gummed up are these carbs? Hopefully the needle is just glued into the emulsion tube. If it's actually jammed, the needle will be damaged.

You can remove the emulsion tube by removing the main jet in the float bowl, then driving it out from the bottom. The emulsion tubes are just press fit in from the venturi side. Consider soaking the emulsion tubes and needles in carb cleaner to free everything up before driving them out.

 

These are extremely gummed up. Like "throttles stick shut" gummed up. I had half a mind to run the whole rack through the dishwasher while the Mrs. wasn't looking...

 

I just noticed that this is a *spare* rack. Whew! I was really getting worried there for you. Take your time and spray any parts you want to disassemble with carb cleaner (I recommend B12 Chemtool) and/or Kroil.

 

Yep. there are relatively functional carbs on the Seca. This was an extra I got with it from the previous owner. I don't think a motor could run with carbs in this condition.

I had to heat some of the screws to get them out, but I got them all except bowl drain screws. I'm keeping bowls on while I unscrew things on the other side so that I don't break anything.

I don't think I can heat anything else. Maybe I will dump the whole thing into some hot water to loosen things up without burning o-rings.

 

why not just go ahead and burn the o-rings? from the sounds of it, it's filthy enough where new rubber would probably be a good idea anyway.

 

Honestly, don't expect to reuse any of the rubber bits in a spare rack of carbs except the diaphragms. The rest is probably dried out and cracking. And if you have the parafin fluid from chacal, treat those diaphragms so they stay well oiled and pliable.

And take your time with the bowls. Kroil helped me with the Turbo Seca drain screws. When I did the seca (first attempt) I certainly wasn't patient enough, broke easy-outs in the bowl, and had to just plug the whole mess up with JB Weld. So keep your patience on those.

Are you rebuilding these as a back up? Or to replace the one's you're using now? Or just inventoring parts? If you are planning a rebuild and swap, I'd suggest rebuilding your BEST set of carbs, and simply switch out the parts from the spare rack that you need. You might have a little more down time, but you want to use the best of the two assemblies on your bike.

 

Take all the rubber you want to keep off the carbs and boil the rack in water, or even better lemon juice. Boiling water will clean and loosen almost anything on the carb and the lemon juice just does a better job of cleaning. 15-20 minutes should do it. then use compressed air.

 

The needles have a pressed-on plastic head cap that retains the needles in place.......your needles got stuck (glued to) the emulsion tubes really badly, and when the vac pistons were removed they snatched the needles right out of their plastic head caps (which are still living inside the vac pistons). Sometimes the needle heads can be pressed back into the head cap successfully......

 

Burnt rubber can stick to the metal and then I'd have to scrape it out.

I don't, really. I just don't like destroying stuff if I don't have to, it's good practice, anyway.

I'm thinking heat might help. I like using a small welding tip to heat bolts and screws, it really concentrates heat without affecting too much area.

I want to rebuild this set and swap it in. Then I can rebuild the other set at leisure and keep it for a spare.

 

Well, I keep plugging at it. I got one of the stuck needles loose and managed to press it back into the cap. So far, so good.

The shaft seals are shot. The O-rings on the fuel lines are shot. The enrichment valve covers seem ok.

I have the carbs separated and I think I am going to pull the butterflies and then dunk them. I have never seen anything this crusty...

 

You might try giving a Ultrasonic Cleaner a call.
Maybe you can arrange to "Piggy-back" on a big job.

Worth a shot.

http://www.brightblinds4u.com/blind_cleaning.html

 

Well, I am still proceeding bit by bit.

I pulled apart the rack - the o-rings on the gas line are definitely gone.

I managed to pull out one of the stuck needles and got it back into the cap that holds it. Then, I took one of the carbs with the stuck one and stuffed it into a can of carb cleaner. After a day or so the emulsion tube came out with the needle still stuck in it.

Then, after some more soaking the needle pulled out and I was able to press it back into the cap as well. Also, the float needle finally fell out.

I can also finally read the numbers on the jets. The two jets under the diaphragm read 225 and 80. What did these carbs come out of?

 

Harborfreight sells one. Like anything they sell it's hit/miss.

I'd be curious to give it a test too, with my pending carb job.

 

I bought the cheap HF ultra sonic cleaner. Didn't really do much for me. Tried different solutions and times.

Now it just takes up space. Buy cans for B12 Chemtool instead.

 

The AIR Jets:: 220 & 80 are the same for 750 Maxim.

 

Thanks. So, it looks like this is a 750 carb set. Are Maxim and Seca jetted the same?

 

I think there are some variations.
Canadian Bikes and UK Versions get Jetted differently.
Emissions requirements not at stringent.

 

Moving right along.

Got all the needles unstuck and back into plastic caps. Got the nozzles out and soaking in a can of Berryman. Popped out idle mixture screw caps. Loosened butterfly screws.

I still need to get the needle valves and enrichment valves unscrewed.

Also, got a screwdriver ground to fit the jets and tried to move a couple of them. Success.

The next big thing would be bowl drain screws. They look like they will need heat.

After the last few things are pulled bowls and bodies are getting boiled.


The jets I have in these look like the standard North American XJ750 jets per what Chacal says. I don't think I need to get new ones, just clean the hell out of the ones I got.

 

Pulled the enrichment valves and the needle valves. Ecch.

Two needle valves has screens that completely disintegrated. One enrichment valve spring is snapped. Looks like the list of parts I will need is getting longer.

Oh, and one of the shaft seals literally had a chunk missing.

This is a seriously abused set of carbs...

 

Disassembly almost complete. The bowl drain screws came right out with a little heat from a #0 welding tip. All that's left is the idle mixture screws. They are loose, nothing stuck there, but I ran out of room in the egg carton and need to find an appropriate container.

Reading through Chacal's catalog I see needle valves, but no screens. Do I have to buy the whole thing to get the screen? Can I get screens separately anywhere?

Also, in it's current state the bike needs the enrichment on to stay running. It's got a 4 into 1 exhaust - would that account for that? You are supposed to put in bigger fuel jets with that kind of exhaust, right?

 

The pilot jet/ circuits are plugged. No low speed or idle fuel getting through. Be real careful probing and cleaning out the ports behind the butterflies. Use nylon bristles from a brush or something similar.

MN

 

The pilot jet/ circuits are plugged. No low speed or idle fuel getting through. Be real careful probing and cleaning out the ports behind the butterflies. Use nylon bristles from a brush or something similar.

MN

 

I'm thinking of checking with Wagamon Bros., they are an engine rebuilding shop near me, to see if they have some sort of cleaning device that will take care of carb bodies and bowls. I bet they have a hot tank of some sort, maybe even an ultrasonic cleaner.

 

Cylinder head service in So Mpls has an ultrasonic cleaner. Give Tom a call and see if he would be willing to give your carbs a shot.

 

I spoke to Wagamon Bros. They said they could run the bodies and bowls through the wash, but they wouldn't be sure of the results. They said I should call Carburetor Shop in St. Paul.

I called Carburetor Shop. He said he would do it, but it would cost $40 or more. That seems kinda pricey for just running some stuff through the wash...

 

There is nothing cheap about The Carb Shop over in Maplewood.
My friend Tom just got his ultrasonic cleaner and he says it's great, it even blasts the carbon off of pistons and heads he puts in there.

MN

 

Spoke to a different guy at Wagamon. They have a carb cleaner tank AND an ultrasonic cleaner. I dropped off the bodies and bowls with them, they said they will try both and see what get them the cleanest.

Ordered rubber bits from Chacal.

All of the brass bits (valve seats, nozzles, jets, screws, plungers) have been sitting in a can of carb cleaner for various lengths of time. Nozzles have been there for about a week. By the time I get the parts and the bodies back, it would be a couple of weeks, so I'm pretty sure they will be clean.