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Posted by: Aaron Cox Jan 18 2009, 07:15 PM

Ok, I have tried lots of Carb Linkages over the years, and CB performance tends to be revered near the top end with regards to value and performance. There are a few other linkages out there that I like also...

So fast forward 5yrs, and the CB performance linkage has accrued some sucky slop from years of ball in hole wearing. Slop = bad, causing the carbs to not be synched during mid throttle....

Mind you this is the second or third crossbar replacement... even with grease, the hole gets ovaled and sloppy.

So, how do we fix this? How can we improve upon their design, BUT not go purchase ANOTHER linkage?

Well, simple my friends. A little machining, and parts selection and bobs your uncle!


Step 1, Purchase spare set of CB linkage base plates. Proceed to lop off the uprights near flush with the ridge for the air cleaner.



Step 2: Bring beer to a buddy, and he will let you use his mill. Or will even mill things for you



Step 3: Order a bunch of parts from mcmaster.com, Heim Joints, Shoulder Bolts, and Springs ... Followed by - Find out that mcmaster carr will send you homo pinkish red heim joints and laugh at yourself.

Step 4: Drill and Tap Base plates for heim Joints





Step 4: Measure 3x, and cut your new extra long cross bar to length, drill and tap ends to fit the shoulder bolts.



Step 5: Install stainless springs, Stainless Shoulder bolts, and use blue loctite on all threads.




Step 6: Install onto car, note what a great success it is, and drink copious amounts of beer to give yourself a pat on the back.




The setup works great.
It gets rid of the big extension lever on the offset version of the CB plates.... Gets rid of the worn ball and socket pivot, And self centers like the original linkage did.

Hindsight, I would order bearings instead of heim joints next time, and possibly order slightly stiffer springs, or possibly add tension springs on the other side of the heims to increase centering ability.

Enjoy

Posted by: So.Cal.914 Jan 18 2009, 07:32 PM

Posted by: Aaron Cox Jan 18 2009, 07:33 PM

Additional:

The goal was to mimic the TRIAD design, but improve on it also. Ideally, you use the centering spring technology used on CB's design, but improve upon it with heim joints like Triad uses.

A marriage of 2 good systems = a better system for less money.
245 for a linkage is too much.... The way i did it, can be made for ~ 60 bucks or so.


Triad Linkage

Posted by: r_towle Jan 18 2009, 07:35 PM

Nice job. I had a setup like that on a race car...it was an old school linkage...
The one thing to watch (at least on a hypo motor) was that the motor itself, therefore the position of the carbs, expands up to a half inch.

Rich

Posted by: KaptKaos Jan 18 2009, 07:40 PM

Great thread! Who wrote it? :ducks:

Posted by: Aaron Cox Jan 18 2009, 07:40 PM

Good point-
Thats what the springs are there for. I designed upwards of 3/8" expansion into the bar. As the motor grows, the spring force lessens and the bar still stays centered

Posted by: r_towle Jan 18 2009, 07:56 PM

Welcome back from your self imposed exodus.
Are you finally and Engineer?

Rich

Posted by: scotty b Jan 18 2009, 08:30 PM

HIGH FIVE


Attached image(s)

Posted by: FourBlades Jan 18 2009, 08:56 PM

Classic thread????

John

Posted by: Jake Raby Jan 18 2009, 09:05 PM

Cool! One of the things on my task list has been to make a production unit "update kit" to do this with the CB linkage easily. It does make a world of difference.

Posted by: Aaron Cox Jan 18 2009, 10:25 PM

All you need is a few poor college kids who like beer to machine kits for you the hardest part of mass producing a kit would be the custom bar lengths....

Only took a few hours start to finish

Posted by: So.Cal.914 Jan 18 2009, 10:56 PM

I am going to make one. Very cool idea.

Posted by: craig downs Jan 18 2009, 11:14 PM

Awesome
I miss your project threads, they are always fun to follow along. I hope you have more up your sleeve.

Posted by: '73-914kid Jan 18 2009, 11:31 PM

Hmmm....I just bought a bought a complete CB set.
Brand new, and after daily driving use, how long is the linkage going to last?
This would be any easy thing for me to make, but I would like to find out how long it will be before I get the fitting ovalling out.

But first, I'll need to get my engine so, but everything actually seems pretty strong and tightly clearanced, so I'm not sure what I'll do.....

Posted by: Aaron Cox Jan 19 2009, 01:02 AM

You'll notice some slop after a year or more.....

You could always just replace the bar and balls when it happens....


BTW - why does CB performace REAM you on shipping? 12 bucks to ship a cross bar.... and they dont tell you what it costs up front....

Posted by: Phoenix 914-6GT Jan 19 2009, 01:07 AM

Nice work Aaron It's always fun making things

Posted by: ConeDodger Jan 19 2009, 01:10 AM

Great thread but it looks like SirAndy took that second pic with his old camera!

Posted by: ottox914 Jan 19 2009, 07:19 AM

Dd you read step 2 carefully- bring beer to a buddy. It doesn't mention who was to consume the beer. Shame to waste it on the photographer!

Posted by: biosurfer1 Jan 19 2009, 11:33 AM

No kidding Aaron...I bought my fuel pump for them and they charged $35 shipping for a $50 pump. When I called to ask "WTF" she said they made a mistake and she would credit the difference back to me. My mistake was I didn't ask what the credit would be....it was $17 so shipping was still $18 for an item that would have EASILY fit in a $5 flat rate box from USPS.

I hate when companies do that!

Posted by: rhodyguy Jan 20 2009, 10:11 AM

springs allowing for side loading suck. much like the stock cb. next time drill, tap and the bar ends using bolts with jam nuts to keep the bar where you want it when the engine is heated up. just like a triad. so...orginal linkage cost, make a throttle cable holder(we've been down this path), eventually have to endure a shitty carb snapping and poping engine, $60+ on improvements, beer, for those of us who are unable to impose upon a friend add what ever the market will bear for machining and you'll almost have a triad. mine is powder coated your's isn't. hi aaron.

Posted by: Mark Henry Jan 20 2009, 10:30 AM

I like the triad for one main reason that I can see right off the bat...see how the link arm is almost straight 90 degrees to the carb throttle shaft. That gives you no side loading on the carb throttle shaft.
What I don't like is it looks a bit flimsy.

Yours looks good Aaron, but the 90 degrees to the throttle shaft is very important to making it smooth and to stop premature wear of the shaft bearings.

Posted by: Elliot Cannon Jan 20 2009, 12:59 PM

Nice project Aaron. Looks like something even I could do. Hey! shouldn't you be looking for a job?

Posted by: Phoenix 914-6GT Jan 20 2009, 01:17 PM

flimsy? Didn't apear to be when I had one. Very solid actually.

Aaron's system looks very nice and cost effective

Posted by: Mark Henry Jan 20 2009, 01:35 PM

I said "looks" I can't tell the metal thickness from the pic.
Why I'd be saying that is it does look a lot like the el-cheapo Type 1 linkage at first glance.

Posted by: Aaron Cox Jan 20 2009, 09:36 PM

Mark,

Are you suggesting that the drop links should be vertical or as colinear as possible with the carb shafts? The position can be adjusted very easy. (they have allen set screws to set the distance from the carb)

I might be min-interpreting what you are asking about.

Kevin,
So you deal with play (up to a half inch) when the motor isnt fully warmed up or super warm?
Swapping out springs would be easy.... but I like to account for the play, versus letting it flop around until warm.

Posted by: t collins Jan 21 2009, 05:29 AM

Aaron whats the McMaster part number for the heim joint you used?
Thanks,

Posted by: 9146986 Jan 21 2009, 08:41 AM

Good work Aaron!!

Posted by: Brett W Jan 21 2009, 08:54 AM

The Bugpack bell crank works better than the CB cross bar. You have to modify it to remove the slop, but it is a better choice. I have had both and now I only use the Bugpack bell crank setup.

Looks like you did a good job with your mods. I hope it will work right longer than the original design.

Posted by: Mark Henry Jan 21 2009, 09:16 AM

Yes, the droplinks should not push in/out on the end of the throttle shaft.
Think of setting the endplay on a crank, you don't want it push/pulling it in that way as it causes wear.

This is one of the reasons I also like the bellcrank type, BTW I make my own.

Posted by: Aaron Cox Jan 21 2009, 07:43 PM

Ahh, The arms are too long is what you are saying... so it is putting a load in the direction of the shaft. Got it...

Look at the triad again, As it goes through the travel, it will put a side load on the shaft also.....

Posted by: Eric_Shea Jan 21 2009, 10:49 PM

Is it 2009 and... did Aaron Cox just post a fuching "How-To" article???

Watch for the flaming, flying, flesh eating sculls!!! Armageddon is upon us!!

Way-ta-go smartboy.

Posted by: Aaron Cox Jan 22 2009, 08:00 PM

Ayup... The end is nigh!

See what else i can modify for fun... LOL

Posted by: jcb29 Jan 25 2012, 03:43 PM

Bugpac has several linkage products. Which one are you refering to? I also have a 2.0 with dual Webbers and am looking for a better allignment or linkage system.