Modern Vespa

I guess good shifting habits vs bad ones can determine how long a shifting cross will last, but is there an "average lifespan" of a cruciform? Xxxx miles = time to change the cruciform, or do you just wait for the tell tale signs?

I'm getting the occasional slip out of then back into gear when I rev it up high in third gear; right before I would shift to fourth. It doesn't do it every time, but seems to be becoming more frequent. It also slips out and quickly back in when I reduce throttle while in fourth gear.

I'm assuming this because of the cruciform.

Hello

I have a cruciform taken from 55,000 mile motor than is slightly worn.

Grumpy

I've experienced that as well on a new cruciform, Astromags. I suspect we might be near the tolerances with the gearstack shim or something. Could also be maladjusted cables, I suppose? But I'm pretty confident with mine.

I've seen reports on here from Grumpy's 55K down to within a few hundred miles of rebuild (those must be due to abysmal shifting skillz or poor gearbox tolerances, presumably).

Hmmmmm. This scooter only has a little over 4000 miles on it. I guess that would have to be some pretty crappy shifting to mess up the cruciform that quickly.


I've fiddled with the gear selector incessantly, I'm pretty sure its cool. I mean, I can shift into a gear, pull in the clutch come to a stop and look at the batwing and it is properly in the groove, for each gear. I assume this means the gear selector is not at fault.

Can you tell me a little more about the gear stack shim?

The shim I'm referring to is kind of like a washer which sits at one end of the gear stack. As things wear in there you sometimes need to put a thicker shim on to keep the gears snugly together. Ensures tighter shifting.

But if it's got 4,000 original miles I imagine you're not in need of a thicker shim yet. Might just be the cruciform's wearing out. I'll have to defer further comment on how many miles = need to change cruciform to people with more experience under their belts. Like I said, I've read a pretty broad variety of numbers on here in the couple of years I've been on the forum. FWIW 4K isn't the lowest mileage to pop up for cruciform replacement (despite being WELL below Grumpy's mark).

Yeah it seemed low to me, but since I'm relative new to these engines, I wasn't sure.

I was trying to avoid splitting the cases until necessary, and would definitely like to do it once, this time, so if anyone has any more suggestions as to what it might be before I do - fire away.

Hello

When you set the nuetral mark to the appropriate indent the mark is on the underside of the gear selector on the bars.

Grumpy

Hello Grumpy,
I appreciate your help, but I'm not quite sure what you are saying could you explain further, please?

Thanks

Hello

look under the handlebar gear selctor there is a mark that is the nuetral and sometimes if the nuetral is set using the dot on top it can lead to jumping out of gear in the higher gears, also has been said the shimming needs to be correct.

Regards

Grumpy

OK I'm closing in on it. I understand, that I could be out of alignment, but I'm not sure what I'm looking for. Is there a mark inside if I remove the headset, or is it something I should be able to see outside? I'm not seeing anything but the usual two dots on top. (they aren't actually perfectly aligned)

Hello

It is outside, of course I may have it wrong or they have been removed.
Although they have been present on all the bikes I have seen.

Grumpy

Anybody have a picture of what Grumpy is referring to?

Hello

Outside and underneath the hand control.

Grumpy

OK. Either I don't have the mark or it got sanded and painted over during my resto.

Whichever it is, I'm glad that tweaking the shifter could solve my problem. I'd much rather fiddle with the adjustments than split the cases.

Hello

I am just a believer that trying the simpler stuff before spending any cash.

Oh and check the actuating rod is not unscrewing itself.

Grumpy

Hello

Pressed the button before I was ready the rod is the part that goes into the gearbox and it operated by the selector arm.

Grumpy

oh, I'm right there with you on that one. I prefer to spend my scooter time riding over repairing. I'll tweak the hell out of it until I'm satisfied there is no other alternative than to split the cases.

i am having this same problem on my p200.

it makes 3rd gear almost pointless.

On one of my Rally's, I was having trouble with keeping it in 2nd gear. A slight tap to the shifter, and it was popping out of gear & into a neutral spot between 2nd & 3rd. Fixed it 75% of the way, using a cable cinch/4th hand tool. Totally manageable now.

I'd advocate messing with your cables, then check the selector arm. The 4th hand tool is your friend!

Just cracked my P200 open after 20K cause I blew the top end. The cruciform was in good shape. Only slightly rounded but I'll be replacing it anyway.

Even on a highly tuned engine you should be able to get 10k out of the shift cross. A lot of it comes down to how the gears were shimmed. If shimmed to the loose side of the tolerance, it will start jumping out sooner.

As a general rule, any time I have the cases split I replace the cross no mater how good it looks.

I discovered that if I twist the clutch hand forward and keep pressure on it after it is in 3rd or 4th, it will stay in gear. I don't know if this suggests anything in particular. I am going to check to see if the actuating rod has come unscrewed.

Also, as a test, I rode over a steep bridge several times, it never popped out. I don't know if this proves anything either.

it could indicate your cables need adjustment.

About 1/4 way down is a detailed process on setting them.

http://www.vespamaintenance.com/engine/select/

They should never be pulled tight with herculean strength and then have the nipples set. There needs to be a bit of slack, but it has to be even.

I've had the same experience. I suspect all it means is we are using a slight amount of extra cable tension to counter a tendency to slip out of gear. Maybe a little more tension in the shift-up cable adjuster could do this for us?

Yeah, this is what I've suspected my problem is... slighly more tension on the downshift side. When the weather clears I'll inspect that more closely along with my airleak safari

As I was riding back to work I was thinking the same thing.

I checked the "upshift" cable for slack before, but I didn't check to see if the downshift cable was resisting. I suppose it could be as simple as that.

That was it. My downshift cable was too tight. I've been tweaking the upshift cable the whole time. I thought the other was good, but I was wrong.

Seems to be working fine.

Thanks everyone.

Sip says 10000-12000km. This is what I found from my transmission after 18000km:





Need replacing I would think.

Your thinking is correct sir! Time for a new one!

Is a hit or miss, sometimes it can last longer than others, it really depends on the type of riding. I suggest looking at how tight the shifting cables are before replacing the cruciform.

Hello

Also depends on the make of the cruciform, genuine ones work well and the quality of the gearbox oil has a big impact on life.
S.A.E 30 was not the recommended oil and a S.A.E 75 was the later recommendation I realise the difference between gear and crankcase rating' but following it the cruciform lasted. 55,000 miles as opposed to much lower mileages on previous scoots.

Grumpy

Really!
Interesting, Where did you find that info? Ive never heard of that before.

Im not doubting it, its just new to me

Hey guys, i dont want to hijack, but im building a px at the moment and its all together, ive raised the wheel and spun it, it changes gear correctly, but im hearing a tick tick, at the same point every revolution, in and out of gear. Wanted to ensure it wasnt the bearing so removed the selector box and its ...gone. Havnt put it back on so im kinda wondering for some assurance.


OP, if this is an imposition ill start my own thread...I feel its bordering on it.



In answer to your original question ive got 27000 k's on my late model px and it changes smooth as silk, no jumping out of gear, im not changing it yet

*edit* sorry mate, i thought you were asking about what kind of milage peeps are getting out of their cruciforms. The above sentence is kind of irrelevant

When I got this scooter, clutch cable wasn't properly adjusted. Clutch didn't disengage well enough. It may have done some damage.

@Trumpy

It is in the riders handbook that came with the scooter.

Grumpy