Author Topic: Shift fork rod locating screw  (Read 2813 times)

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Offline tony27

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Shift fork rod locating screw
« on: October 20, 2014, 02:11:53 pm »
Can somebody confirm the sizes of the screw that fits into the groove in the shift fork rod, I had a locked up gearbox yesterday at the local eNZed VMX series round as I was about to take the last group out for their look lap. It turned out that the rod had moved out into the sprocket cover
I missed the first pre75ish race due to having no time to find the problem with the evo class being second race of the day & pre75 third. Managed to push the rod back into place & refit the top plate & had no problems for the rest of the day
When I loosened off the sprocket cover it was under pressure from the rod, I lifted the top plate off & there was no damage that I could see to anything in the gearbox, I can't say the same about the special screw which has quite a notch out of it.
I have a new locating screw sitting here but it's quite a bit longer than what is in the bike & need to know if I need to modify it before fitting
I can take a photo of both if needed

Offline VMX60

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Re: Shift fork rod locating screw
« Reply #1 on: October 20, 2014, 05:53:49 pm »
Tony
A common CZ problem 4 speed or 5 speed

The std screw 6mm

Total 6mm x 28mm
thread part is 18 to end of taper
Pin is 5mm dia and 10mm long
As you know fitted to the left side of engine case. some CZ guys grind a 2nd flat to the other side of the shaft and fit two screws.
You must fill the c/shaft sprocket side hole with sealant to stop the shaft also.
On all my Zeds fit a wire tie by drilling the web on the left side crankcase to stop the shaft coming out a hitting the clutch basket.

Cheers
 

Offline tony27

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Re: Shift fork rod locating screw
« Reply #2 on: October 20, 2014, 06:12:29 pm »
Thanks Murray, by eye the turned down part is about 4mm on the 1 fitted so I'll measure up the other & modify it if needed.
The silicon plug must have been pushed out by the rod moving sideways
The bike had been given a serious workout by D Veda last weekend, was the first CZ he'd raced in years & he managed to win a all in race on it, seems if a modern 4T makes it to the second oil change it's now a vmx bike. I don't think that had any bearing on it happening but it was certainly good to see a 41 year old bike smoking the field full of disc braked bikes

Offline VMX60

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Re: Shift fork rod locating screw
« Reply #3 on: October 20, 2014, 06:35:52 pm »
Tony

Yeh your right a A grade rider on a good old ZED is hard to beat . :)

41 years old CZ IRON and will last another life time as well , Best VMX value all round bike by far .

Cheers

Offline VMX60

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Re: Shift fork rod locating screw
« Reply #4 on: October 21, 2014, 02:52:53 pm »
Tony

Rechecked two motors today and you are right the Pin dia is 4mm x 10mm not 5mm

Sorry getting OLD  :o

Cheers

Offline tony27

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Re: Shift fork rod locating screw
« Reply #5 on: October 21, 2014, 03:15:39 pm »
The other 1 here is 32mm overall with 20.5mm of thread & pin diameter of 4.5mm so I'll modify it sometime around midnight tomorrow at work, have the gearbox full of kerosene at the moment to help remove the water that got into the oil while the cover was off on sunday getting the rod back into the correct position

Offline tony27

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Re: Shift fork rod locating screw
« Reply #6 on: October 23, 2014, 07:59:39 pm »
Quickly modified it sometime around midnight last night & tried it before leaving for work this arvo, works perfectly
Thanks Murray