Carby pictures

[Whitty]

team,

I want to have a shot at fixing my carby up and doing the spring mod to have the secondary open up at what. Problem is I can't figure how to do it as I am not real smart Does anyone have any good piccies they can post up, and any info about what sort of spring i need to find. I have had a look on the "other" forum but the only photo I can find is really crappy, and I need more info than what it gives.
Also, I changed gearboxes on the weeekend, and the new one is from an F8 - now behind my F5 while the original is getting fixed. The speedo drive gear on the F8 gearbox is a female end - same as my cable. Can I just machine up a flat bit of steel to fit between the two to keep my speedo going?? Or do you have to change the cable??
Thanks for your help..............................

[cuz]

Just a flat bit of steel will be fine

[Brayden]

Whitty, here are a couple of pics from Barry's modified secondary linkage. Some people just use a spring to flick the secondary butterfly open at what, but the problem is that this will leave a nasty flat spot in your rev range.
Barry's method allows a smooth transition and is setup to open gradually with applied throttle.

[Whitty]

Does the piece directly above the nut come around and push on the secondary lever/knob thingy underneath the spring?? And naturally the spring will pull it back when you get off the throttle....very tricky. If that is how it works, that is way better than snapping it hard open with a spring. Looks like it involves a fair bit of tooling around...is the cam on the secondary lever just a bolt/sleeve setup? Looks like I will be hitting the mechanical workshop on night shift....

Thanks for that Brayden, much appreciated. Anyone else have any different setups??

[Brayden]

Whitty, I'll colour code the image tonight and point out what bit does what action.

[barry]

The timing of the second throat is set by the degree of rotation of the first throat.(using an old base as a template)I cut out what looks like a crab claw with a ring at one end that will fit neatly over the shaft.
It wasn't all that hard, just getting the timing right was a bit fiddley( I had to make about 6 before I got it right)
If you look closely at the bottom of the arm in the pic you will see a bit sticking out that when the throtle is turned back it comes in contact with the arm and moves the secondary shaft closed( a must for safety reasons in case the shaft sticks). There really isn't all that must tooling involve.I used a drill for making the holes a round file to make them bigger and a hack saw to cut the hole thing out.

[Brayden]

I've just updated the first pic with some numbers, and I'll try and use them to clarify Barry's information a bit.

1. Throttle cable pulls and turns primary throttle clockwise.
2. This lug catches on point #3 as it turns.
3. This little 'U' bracket turns point #4 (secondary throttle) counter clockwise
4. Secondary throttle is turned progressively to what as accelerator is pressed further.
5. Spring pulls second throttle closed as accelerator is released.

(Point 'X' is where the vacuum pot would normally clip on)

How'd I do Barry? Accurate?

[barry]

Very close I wish I had a picture of it of the carby and a brake down of the way it operated. (tipical mad scientist no notes)

[pullbackandgo]

I wish I had a pic of mine! (maybe tomorrow) On the pic the fork (3 in pic) lookin thing has replaced another part that used to be there that had just one prong.(the bottom one of the fork). All you need to do in order to get the secondary opening is to tie(wire or spring) the shaft(right of the 3 in the pic) to the bottom prong. It will then open only after you've pushed it passed half throttle.(...and no it doesn't just spring open...) it will then move with the throttle. (I think I sent you a vid of it brayden?? post??pls?? ) Works a treat!! but now i'm wondering if this way is better... Cause this way the secondary is opening the whole time isn't it??

[Brayden]

Hmm, don't recal ever seeing a vid mate. Perhaps you could send it again? admin@tamon.org

[barry]

The arm (fork 3)is a floater the spring keeps it in the closed position until the throttle(2) is turned to the degree that it comes in contact with it at that point it moves the second throat(x)open via the link(4) on the shaft.
The throttle(2) has a boss or bent section std that rotates with the shaft that touches tha arm(3) the setting of this is important because if it open to early you just fuel up the motor, if to late it starves the motor when it needs it most, under acceleration (ie to over take another car, something almost unheard of in a std mytboy.) If you use an old base of a 800 or so to get the setting right then you will have success.

[Whitty]

Thanks Barry for your help, I am going to have a look over the next few days and have a go at it next week some time........wife and kids permitting.

[Whitty]

Have done this job - Brayden I have e-mailed a couple of pics of the carby to you if you want to post them up - just in case someone else wants to do it one day. Goes a bit better now!!!!!

[Brayden]

Got the pics mate, I'm going to compile them into an article with the information from this thread so anyone who wants to do the mod can get the know how.

Cheers.

[Josh]

Got the pics mate, I'm going to compile them into an article with the information from this thread so anyone who wants to do the mod can get the know how.

w00p!