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Cable gear adjustment?
Northpole - 14/8/12 at 07:49 PM

I have some kind of a problem with the gear shift in the transmission. It seems not to go perfectly in gears.

When in 1st I hear some "clunk" sound from the clutch area or maybe from the transmission.

Note: The transmission was just fine when building the car and testing 1st and 2nd gear in the garage but is was not on the floor, the wheels where free.

But after installing gear shifter and cabel gear to the gear lever/axle, it seems the transmission does not go perfectly in gears. It shows 1st 2nd etc on the GiPro (gear Indicator) but this very annoying and not so good sound comes.
- I did remove the clutch cover and all the discs are fine, all seem to be in perfect order inside the clutch.

Is it nesserary to adjust the cable gear exactly?

Or does anyone have a good advice for me?

Thanks

ReMan - 14/8/12 at 09:13 PM

This sound perfectly normal
Most BEC's clunk, particularly into 1st and through 2nd

maccmike - 14/8/12 at 09:46 PM

mine clunks from N to 1st. bikes do it too

Northpole - 14/8/12 at 10:22 PM

Yes mine does to, but this "clunk" soundI am referring to, comes when driving or moving wheels as the car is not on the floor.

This did not happened before I placed/installed the cable.

Can the gearbox/gears go between gears if for instance the cable does not travel to far/long?

I suspect it stays in between gears. But again, I have not done this kind of a project before.
By the way it is a Triumph Spitfire Mk3 1968 with Busa 2006.

[Edited on 14/8/12 by Northpole]

ReMan - 14/8/12 at 10:30 PM

quote:
Originally posted by Northpole
Yes mine does to, but this "clunk" soundI am referring to, comes when driving or moving wheels as the car is not on the floor.

Can the gearbox/gears go between gears if for instance the cable does not travel to far/long?

I suspect it stays in between gears. But again, I have not done this kind of a project before.
By the way it is a Triumph Spitfire Mk3 1968 with Busa 2006.


Not sure what you mean by "driving or moving wheels as the car is not on the floor.
" ?

Of course it *could* go between gears if there is not enough movement,

Does it move the gear selector shaft as far as it can until it stops?

ReMan - 14/8/12 at 10:30 PM

quote:
Originally posted by Northpole
Yes mine does to, but this "clunk" soundI am referring to, comes when driving or moving wheels as the car is not on the floor.

Can the gearbox/gears go between gears if for instance the cable does not travel to far/long?

I suspect it stays in between gears. But again, I have not done this kind of a project before.
By the way it is a Triumph Spitfire Mk3 1968 with Busa 2006.


Not sure what you mean by "driving or moving wheels as the car is not on the floor.
" ?

Of course it *could* go between gears if there is not enough movement,

Does it move the gear selector shaft as far as it can until it stops?

Northpole - 14/8/12 at 10:57 PM

quote:
Originally posted by ReMan
quote:
Originally posted by Northpole
Yes mine does to, but this "clunk" soundI am referring to, comes when driving or moving wheels as the car is not on the floor.

Can the gearbox/gears go between gears if for instance the cable does not travel to far/long?

I suspect it stays in between gears. But again, I have not done this kind of a project before.
By the way it is a Triumph Spitfire Mk3 1968 with Busa 2006.


Not sure what you mean by "driving or moving wheels as the car is not on the floor.
" ?

Of course it *could* go between gears if there is not enough movement,

Does it move the gear selector shaft as far as it can until it stops?



Sorry I dont have the word for it, but the car is lifted (jacked) from the floor, hope you understand. So the wheels are free and I can try to run the engine and engage the gearbox without having problems in the next traffic signal

IF it goes between the gears, how would it sound? Like "clunk" in all gears?

I tried to measure the movement for the cable, and maybe it has not enough travel, but I just wanted to hear from you guys if you had any experience with that problem?

When checking the clutch inside, all seems fine. I use hydraulic clutch from the car and the "slave" on the Hayabusa engine.

Regarding to the selector shaft and the movement of it, I have to re-check. It is night here now, so I will dismount the cable tomorrow and check the movement on both the cable (again) and the selector shaft.

40inches - 15/8/12 at 08:25 AM

Sounds just like mine when I set up the Accumen. I was convinced that the engine/gearbox/propshaft/diff all or in any combination
where fubared. On the wheels and moving is sweet as a nut, except the almighty clunk into first (normal).
I put up a video in this thread

MakeEverything - 15/8/12 at 08:35 AM

quote:
Originally posted by maccmike
mine clunks from N to 1st. bikes do it too


Bikes do it when either the chain is too slack, or the clutch is dragging. It happens in cars because there is no chain (simulated slack chain), and as the backlash in transmission gets greater, the worse the noise and running the risk of it jumping out of gear.

MakeEverything - 15/8/12 at 08:40 AM

quote:
Originally posted by 40inches
Sounds just like mine when I set up the Accumen. I was convinced that the engine/gearbox/propshaft/diff all or in any combination
where fubared. On the wheels and moving is sweet as a nut, except the almighty clunk into first (normal).
I put up a video in this thread


With the wheels in the air, the whole thing will clatter as the backlash (as in previous post) in the transmission as well as the diff is taken up by the weight of the wheels, backwards and forwards (unless the handbrake is slightly on or the brakes binding). Again, the same happens with bikes, on a slightly lesser scale.

bobinspain - 15/8/12 at 08:57 AM

Northpole.

I'm not a techie, but I can give you my two pen'orth from a users point of view. I have a 2010 Mk2 Busa in an MK. I had never been in a BEC prior to the arrival of my factory-build, so was a BEC 'virgin.'
Check out some of my early posts and you'll find lots of BEC guys took the trouble to reassure me that the 'bag-of-spanners' noise on gear changing in a BEC was normal. The nature of a bike gearbox makes it so.
Some extremely clued-up folk, (eg Andy Bates, AB Performance) recommend fitting a trt propshafft (torque resilient tube) as it can take up some of the 'slack' in the transmission and quieten things down. MK say they've tried them without much success and gave an ballpark estimate of £200 for one.
The noise you get when driving as opposed to spinning the wheels not under load is to be expected. The take up of 'slack' as the load comes on is the main cause of the clunk. When I drive in town, it can be most disconcerting until you get used to it.
I have a Flatshifter fitted, and I get seamless and clunk-free changes when 'giving it beans' that's impossible (for me) to replicate at town driving speeds.
A common comment was that the changes can be smoothed out with practice. With 6 months experience of driving my car, I've found I can be as gentle as a butterfly with chilblains landing on a hot radiator when changing gear in town. It still clunks!

40inches - 15/8/12 at 01:35 PM

quote:
Originally posted by bobinspain
I've found I can be as gentle as a butterfly with chilblains landing on a hot radiator when changing gear in town. It still clunks!


And that's about as gentle as it gets

adithorp - 15/8/12 at 02:33 PM

BEC can and do "clunk" when engaging gear (not always only 1st/2nd).

With the wheels free to rotate off the ground the ground you will get a lot of chatter from the back-lash in the transmission. If it dissapears when back on the ground, it's just that.

The other thing that sounds/feels like you describe is "over throw" on the clutch. The cause is poor ratio of either the pedal leverage or the clutch master/slave cylinder. DanG on here recently had this and we cured it with a pedal stop for now and miht also fit a smaller diameter master cylinder in future. Try changing gears with the pedal not pressed down as far to check if it helps.

ps. add your location to your profile. I suspect you're outside the UK?

MakeEverything - 15/8/12 at 03:08 PM

One thing i mentioned a while back in one of the previous posts on BEC's, is that bikes have Cush Drives on the rear wheel, to dampen harmonic vibration and improve mechanical sympathy. With a BEC, there is no dampening at all between the output shaft and the wheels, so i reckon a dampened drive coupling on the propshaft or output shaft would help.

Northpole - 16/8/12 at 11:07 AM

Well my friends, thanks for all your replays.

I found our what the problem was. The car was lifted up from the floor and when free-wheeling it made a very unpleasant sounds (for motorhead as myself), I did remove the clutch and it was fine. When on load, i.e. on the ground it was fine.

And my first test run ever on my project was amazing! It is so light and FAST.

ReMan - 16/8/12 at 05:21 PM


Great news, take care in it until you get used to it they can bite!