I have a Mikuni round slide on my 69 Servi Car and the manifold is aluminum and unlike any I have seen in kits on the market. It is held in place with metal bands with a rubber gasket between the halves. The inserts in the cylinder appear to have either screwed onto or replaced the cylinder nipples entirely.. I have purchased the correct manifold with nuts and copper bushings to replace this apparently early kit but I need to figure out how the cylinder inserts are secured. (I also have a set of Peek bushings on stand by.) Anybody seen this set up before, worst come to worst I can put it back up with with a ton of grey RTV that the former owner used on the install, not my favorite choice. If need be I will purchase new nipples if I can figure how to remove current ones. I am attaching some shots and any suggestions or input form anybody who is familiar with this set would be greatly appreciated. Thanks all and Happy New Year......

 

One hopes and assumes your current flanges are threaded into the cylinder like the stockers
The holes on the OD could be used to rotate them out with a punch and hammer ?
Spanner wrench?
GOOD LUCK

 

I have never seen that, but it looks like a kit from back in the day and not homemade, maybe that is a good thing.

The nipples spin into the threaded inlet that is part of your cylinder. In a stock application their are rivets to hold them in place. One picture looks like you might have allen head set screws. Take them out and put a small plumbers wrench on that chunk of aluminum, it should just spin out.

Installation of new nipples is another thing, lets see what you have first when you get those aftermarket nipples removed, good luck.

Pick below you can see the rivet holding the nipple to the rear cylinder.

 

Didn`t know about the rivet ^
Learned something today
TNX

 

Thanks one and all. I am going to see if there are set screws in the holes with a lot of light and magnification and go from there. I sent the pictures to Abe at 45 Restoration and he has never seen this kit or set up before, believes it could be a one off from back in the day.....

 

The holes look to be outboard of the original cyl. casting.
If there are set crews , I'm not sure what they would be "biting into"

 

Good point.......

 

Pictures of what you are dealing with, nipple removed in these pics. Factory cylinder is threaded, nipple screws into cylinder. The end of the nipple is flat, that is the mating surface in the cylinder which is also flat. That is the seal to prevent intake leaks, the only seal. Very archaic methodology. Second picture you can see the rivet removed. Allen head set screws were used in lieu of rivets by lots of guys for ease of use. Knuckleheads have the same issues, now you know, you will see them on other bikes.

You spin the new nipple in until it bottoms out in the cylinder. Then using some kind of internal wrench (collet) keeping it tight, you drill a hole into the nipple via the hole in the cylinder. Then install the rivet with an anvil inside the nipple and a big hammer. Threads in cylinder must be completely clean to allow for easy rotation and complete sealing.

I have used JB weld on the threads, rivet and mating surface to assist in sealing, if it leaks you are sunk. If John Z sees this you will tell you what goop he uses, might have been Yamabond.

Nipple replacement is one of the hardest projects on a flathead, exasperated with the motor in the frame. I have done it twice, once solo and once with John Z. Neither event was fun, but both times successful. Tom Cotten is a linkert expert that is in the process of retiring. About 8 years ago when I did it the first time he made me rivets based on the opening size in my cylinder. They made a nice plug fit.

After all of that fun, you must do a bubble test of your manifold to make sure you got it right. Use the PEEK seals, throw the brass ones away, PEEK works and seals better. Good luck.

 

No offense to the OP, but after reading Architects "how to"
You might be opening a big can of worms just to get back to the "correct" carb
You had the Mikuni running well IIRC
Good luck

 

I got to the garage for awhile this afternoon. I used my automotive camera to get an up close view of the holes in the inserts, there are no set screws that these 76 year old eyes can see and there does appear to be a rivet head in both intake barrels. I got out my long pointed cold chisel and hammer and gave it a try, even used some heat, nothing budged a fraction of an inch. I quit before I got to the point of damaging the inserts to a point where they would not be reusable. I have soaked both o rings in silicone, cleaned up all the excess gray RTV on the manifold and inserts, ordered some new stainless steel clamps if using the old system is the only option. I going to think on it a day or two. Days like today make me sorry I quit drinking a while back..........