Solex/Mikuni linkage differences?

[broke]

Hi all,

This is odd I know, but I'm hoping someone here may have hit a similar issue to the one I'm having here.

I have these nice original SK Sanyo (later they became OER) throttle bodies that I would like to set up a centre pull cable for. They appear to use the same "towers" as Mikunis for the throttle stops and return springs. After determining that Weber and Dellorto setups were too different to modify I was lucky enough to find what looks like a NOS Toyota 2TG/18RG style interconnecting linkage



You can see from the pictures that the towers are different heights which is fine, the problem seems to be that the throttle angles are all wrong - you can see when I hold the new linkage over the old that the throttle opening stops would hit long before the throttle is fully opened and the ball stud for the cable would swing from almost horizontal to being quite vertical, instead of hanging down below the carbs and coming up to horizontal like all the pictures I've seen show.


Mikunis aren't big here, so I don't have any others I can look at. I've dug around on the internet and it seems there are several types of Solex/Mikuni PHH. Do I just need a linkage from a different style of Solex/Mikuni, or is it that the throttles I have just aren't that similar? The throttle shaft size and spacing for the mounting screws is a perfect match for the Mikuni linkage, btw.

[510rob]

A few thoughts...

1) you could weld and cobble linkage bits, make new bits, weld and cobble and file, etc, and get there. No problems with that, just time and patience...

2) you could modify your manifold to accept a main linkage shaft and get there with a different sort of welding and cobbling and filing...

http://s293.photobucket.com/user/badkro ... 4.jpg.html
(this pictures is from Randy Wagoneer, a member here)

3) you could bypass most of the cobbles by purchasing a brand new Kameari manifold setup with linkage...

http://www.rhdjapan.com/kameari-intake- ... pe-l4.html

4) I have a set of those throttles too, but I don't have those crazy fuel rail bits for mine. If you could post pictures of the fuel rails, that would be much appreciated.

5)links to the OER complete setup, for ideas...
http://www.rhdjapan.com/oer-racing-spor ... 6-l28.html
http://www.rhdjapan.com/kameari-intake- ... -fj20.html
http://www.rhdjapan.com/oer-manifold-li ... 6-l28.html

[broke]

I actually already have that manifold, it's not a Kameari part as such but a Harada Shokai manifold sold by Kameari and others. It's pretty nice, much better than my crappy Lynx one but I want the Datrally one now.



Still some modification involved though, the original SK Sanyo manifolds used a TPS mounted off the SK manifold linkage shaft. The new OER throttles have the TPS mounted off a special boss on the side that these don't have. I found a Nissan TPS and mount kit on Yahoo Japan that will fit once the flat area is drilled and tapped for it. These throttles also use a threaded pressed-in stud instead of a ball stud, so I'd have to get new drop links to suit.




The fuel rails are a bit weird, they seal using the normal O-ring style at the top, however at the bottom the injector seals using an O-ring on the shoulder of the injector instead of the usual seal around the pintle cap. I've test fitted a Toyota Celica XX/Supra injector and it seems like a good fit other than that the injector isn't pushed onto the lower O-ring enough to seal. A washer up the top would fix that though. The rails also crash into my K&N filters, so some kind of spacer will be needed there. Or open trumpets....





If I did it again I'd just use the old Nissan L20E style mounts at the bottom (they fit perfectly) and some universal fuel rail and clips at the top.

I'm still hoping someone's going to chime in and tell me they have the centre pull linkage I need, because modifying this one to my satisfaction will take more time and patience than I have right now, and I'm quite keen to ditch the entire J-hook, looooong throttle rod (it's RHD) and all that crap and fit the Lokar cable setup.

[510rob]

here are a few pictures of the setup I had played around with a while ago...

IMG_3440_1024x768.jpg (113.55 KiB) Viewed 5889 times

IMG_3441_576x768.jpg (62.06 KiB) Viewed 5889 times

IMG_3442_1024x768.jpg (77.75 KiB) Viewed 5889 times

IMG_3443_1024x768.jpg (149.5 KiB) Viewed 5889 times

IMG_3444_1024x768.jpg (114.54 KiB) Viewed 5889 times

IMG_3445_1024x768.jpg (117.29 KiB) Viewed 5889 times

IMG_3446_1024x768.jpg (83.16 KiB) Viewed 5889 times

IMG_3447_1024x768.jpg (127.37 KiB) Viewed 5889 times

IMG_3448_1024x768.jpg (107.53 KiB) Viewed 5889 times

...now that I think about it, I guess I never did get around to making any kind of cable attachment for it.

[broke]

So yeah, I did some more searching and found ANOTHER set of linkages with the throttle shafts at a different angle. They were cheap, looked very well used indeed and someone had already hacked off the throttle stops, so I won't feel bad about modifying these. They are a bit worn where the flats on the throttle shafts go, so I'll have to sort that somehow too. But the operating angle is perfect for a cable pull.

I was thinking about building up the throttle shaft hole with some kind of bronze nickel/silver type brazing rod then carefully filing it back. Anyone got any better ideas?





For those of you interested, there seem to be 3 different types of Solex/SK/Mikuni type lever and return spring tower out there. From top to bottom: Mikuni type 1, Mikuni type 2 (Toyota style?)



For the throttle cable I bought a scooter cable just to get the 90 degree elbow. I'll use that in conjunction with the Lokar cable kit once that arrives, I'll probably make a bracket that attaches to the manifold where the holes for the linkage bar are.

I also have to drill and tap the bosses on the throttles because although the casting is there, they aren't drilled on both sides. I'll need them all drilled so I can have a mount for the TPS and both central throttle levers. This was pretty scary, lined it up tonight and drilled some pilot holes before realising I don't have a 4.2mm drill bit. Hopefully I drilled them straight enough - I was just holding the throttles with my feet and using a normal electric drill.....

[broke]

Edited so pics are visible!

[Hakosuka510]

I was thinking about building up the throttle shaft hole with some kind of bronze nickel/silver type brazing rod then carefully filing it back. Anyone got any better ideas?

I'd worry about the shaft eventually working free against the brazing. This was always a problem on 2-cycle Yamaha kart racing engine where the Walbro brass carburetor shaft had the steel linkage arm peened onto it, and would eventually work loose after repeated use. I'd say take a second linkage arm where the flat cutout is in good shape, cut that section out and braze or weld it overtop the one you're using.

Also, are you still in need of the miniature heim type linkage struts? I have a bag of various used ones I've brought in from Japan over the years, and I might have what you need. EDIT: Oh wait, you're in New Zealand, sorry. It'd probably cost more for me to send you some used ones than what you can buy them for new.

Did you get your TPS adapter from the seller in Japan who is always doing those beautiful ITB setups and RB cam angle sensor conversions for the L-series engines? I love his work.

[broke]

I was thinking about building up the throttle shaft hole with some kind of bronze nickel/silver type brazing rod then carefully filing it back. Anyone got any better ideas?

I'd worry about the shaft eventually working free against the brazing. This was always a problem on 2-cycle Yamaha kart racing engine where the Walbro brass carburetor shaft had the steel linkage arm peened onto it, and would eventually work loose after repeated use. I'd say take a second linkage arm where the flat cutout is in good shape, cut that section out and braze or weld it overtop the one you're using.

Also, are you still in need of the miniature heim type linkage struts? I have a bag of various used ones I've brought in from Japan over the years, and I might have what you need. EDIT: Oh wait, you're in New Zealand, sorry. It'd probably cost more for me to send you some used ones than what you can buy them for new.

Did you get your TPS adapter from the seller in Japan who is always doing those beautiful ITB setups and RB cam angle sensor conversions for the L-series engines? I love his work.

Yeah I wasn't sure if it would be hard enough either. I didn't want to hack up my original arms but I'm resigned to doing it just to get a proper fit on the shaft and throttle stops that work. I'll just try to do it tidily with the TIG. I don't need the rod ends as going to centre-pull will eliminate the bellcranks totally.

Haven't seen the RB CAS before, but yes that's the guy I bought it off. He does nice work. Maybe I should have just emailed him and asked him to start making billet centre pull linkages instead!

[Hakosuka510]

Another thought: if you don't want to hack up original linkage, then look at cable bell cranks on various Japanese throttle bodies at a junk yard. I know a lot of those are actually interchangeable with SK shaft ends. No one will ever miss them...