Possible Alternate Carb Main Jet Sources? Thread size and pitch info needed (1 Viewer)

[Stumpalama]

I recently acquired a free carb and rebuild kit and decided what better time than now to rebuild it and replace my current set up that is do for a rebuild.

During the disassembly process, I noticed the primary main jet was mangled and had to drill it and use an ez-out to remove it. It is obviously unusable now.

I was looking for replacements and quickly realized new Aisin jets are NLA. I have found Japanese motorcycle jets that match the jet orifice size, but I'm not sure if they are the proper thread diameter and pitch.

Has anyone tried threading these motorcycle jets into their carb? If so, what did you use?

 

[vszUnclear]

Recently did the same research and couldn't find any aftermarket options. Hope you do though.

 

[Spike Strip]

Sorry for the small hijack, but anybody know what size jets come in the Trollhole carbs, for 60s? Since Marshall imports from the manufacturer, he might be able to get quantities of replacement jets ... Also, jets come in some of the Keyster kits, but they're too small IIRC for stock USA spec FJ60 use.

 

[Stumpalama]

Through a bunch of different word combo searches in Google, I came up with this: http://forums.off-road.com/suzuki-geo-all/205617-toy-carb-jets.html; which led me to this: http://www.pjmotorsports.com/mikuni-jets.html#main jets, which gives dimensions of the jets.

I think I'll order 1 or 2 and give them a go.

 

[Spike Strip]

Post up results. Also, both those guys are on MUD, I believe. Weber Sarge and AZtoyguy or AZtoyman ... might try PMing...

 

[doug720]

Those are motorcycle sized jets, I don't recall the 60 series jet size, but they are much larger in OA size.

I bet whatever style jets used in the 60's are used in many other Japanese vehicles of that period, so available somewhere?

 

[Spike Strip]

Stock USA-spec 60 jets are 1.47 and 2.00 I recall Jim C. saying they're purposely rich to work with USA smog crap.

 

[Stumpalama]

Those are motorcycle sized jets, I don't recall the 60 series jet size, but they are much larger in OA size.

I bet whatever style jets used in the 60's are used in many other Japanese vehicles of that period, so available somewhere?

After measuring my existing jets and determining the Mikuni jets are the same diameter and have 147.5, 150 and 200 sized jets, I ordered some jets to try them out. I picked them up from Parts Reloaded for $2.90 each.
I also ordered the Keyster carb kits 398 and 381. They included the 200 sized jets but one kit came with a 129 sized primary jet and another came with a 132 sized primary jet; both are too small since the stock jet for the '81+ is a 147 primary jet. Both kits also came with a new power valve and jet and 2 slow jets, sizes 65 and 90.

The Mikuni jets are scheduled to arrive Tuesday. I'll post up what I find then.

 

[Stumpalama]

The Mikuni jets fit just fine and work flawlessly. The heads of the jets are thicker (stick into the fuel bowl more) but without any adverse impact to performance.

Parts Reloaded is a great source for all sizes of jets for Aisin carbs.

 

[doug720]

An old way of making jets in sizes not available is just to drill them out to the size you want. Obviously, you can only go bigger, so buy small and drill bigger. Easy and it only costs the price of a drill bit and a few minutes!

Good find!

 

[Stumpalama]

Mine was mangled and I had to use a drill to back it out.

 

[Infinity00]

Need to rejet, everything on my rig is new or rebuilt. Just got a A/F on it and its running rich. Which mikuni jets fit?
There's 102.221 series or 100.604 series, which did you buy?

I know this is an old thread but a goodie

 

[Infinity00]

I found the answer on jetsrus. The difference is just the head diameter. The 100.604 has a larger head, 8mm vs 6. I haven't measured the original jet size so I still don't know which to go with.

 

[Spike Strip]

What jets are in there now? I'm guessing from your location you're at a high elevation? You could try a 1.38 primary. Those were available from Toyota not too long ago. Also, leaner jets are what usually come in the Keyster rebuild kits as that's what the ROTW got.

 

[Infinity00]

Didn’t see this until today so I’ll respond now. I thought I needed to rejet but once I really deep dived into my system and read a lot of people saying they never had to rejet at my altitude, I started to wonder if I was barking up the wrong tree. I ended up fixing some other problems, like gaskets on the base of the carb, and on the carb spacer. I also found a slightly clogged primary slow jet and the gasket set I used didn’t have a hole cutout properly for the slow cut channel at the top of the carb. Also, the first AFR meter I had was narrow band and I didn’t know I really needed a wide band. After all that and with the help of a wide band, it ran really well.

 

[swelltimes]

I'm stumbling thru a rebuild on the carb for my 6/77 FJ-40, which came from CA. Looks like a lot of the original jets aren't available, so thanks for the resources in this thread!