Sat Nov 20, 2021 1:54 pm

Enthusiast
Joined: 01 Dec 2019
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Location: Tysons (Northern Virginia), USA 22182
 
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Location: Tysons (Northern Virginia), USA 22182
Sat Nov 20, 2021 1:54 pm linkquote
Hello everyone. Question for the gurus, please. What would happen when a shift cross (cruciform) is installed backwards during a rebuild? I mean, what shifting problems would occur? I have a Sprint Veloce engine that is popping INTO gear. I've taken the selector box off and reinstalled properly (multiple times). What I noted is that with the selector box off, I spin the wheel while holding the plunger in neutral, and there is definitely something bumping the plunger (metal against metal) as the wheel spins. I can't tell you if it bumps once per rotation or twice per rotation. I hope I've explained it in a way that's intelligible. What's going on? Thanks all.
Sat Nov 20, 2021 1:57 pm

Addicted
Too Many piles of Junk that need too much work and too much money
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Sat Nov 20, 2021 1:57 pm linkquote
Sounds like the cruciform is backwards, OR the gear stack is not shimmed properly. With gears catching on the cruciform in neutral and others, there is definitely misalignment. Only way to be sure - crack the case and dive in
Sat Nov 20, 2021 2:04 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
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bodgemaster
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Sat Nov 20, 2021 2:04 pm linkquote
Did you remember the spacer/washer that goes on the end of the selector rod?
Sat Nov 20, 2021 2:38 pm

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Sat Nov 20, 2021 2:38 pm linkquote
SoCalGuy wrote:
Did you remember the spacer/washer that goes on the end of the selector rod?
Ahaha - good thinkin
Sat Nov 20, 2021 2:42 pm

Enthusiast
Joined: 01 Dec 2019
Posts: 64
Location: Tysons (Northern Virginia), USA 22182
 
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Sat Nov 20, 2021 2:42 pm linkquote
Thanks. Well, there's the problem. I did not build the engine. I'm just the guy who bought it. Now I'm trying to enjoy it, but can't much because it's no fun to have your scooter pop into gear as you sit in neutral.

So I'm understanding there is a spacer that might be missing in the build. What about the cruciform? What would the symptom(s) of a backward installation of the cruciform be?

Thank you!
Sat Nov 20, 2021 4:31 pm

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Sat Nov 20, 2021 4:31 pm linkquote
Syndrome wrote:
Thanks. Well, there's the problem. I did not build the engine. I'm just the guy who bought it. Now I'm trying to enjoy it, but can't much because it's no fun to have your scooter pop into gear as you sit in neutral.

So I'm understanding there is a spacer that might be missing in the build. What about the cruciform? What would the symptom(s) of a backward installation of the cruciform be?

Thank you!
The symptoms you are describing could be caused by various components within the system. It's really hard to say exactly what the issue is, without knowing exactly what you have inside the engine. You could have a broken gear tooth, backwards cruciform, missing spacer, no shims, broken clip, wrong gears, wrong drive shaft, who knows.... regardless of the actual issue (or issues), it looks like have to open the case to visually see what you are working with. Once you know what is there, you can find the problem and the solution. Good luck!
Sun Nov 21, 2021 2:41 am

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Location: Tysons (Northern Virginia), USA 22182
 
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Location: Tysons (Northern Virginia), USA 22182
Sun Nov 21, 2021 2:41 am linkquote
OK, so I see in my crystal ball that I will soon be splitting the case of a scooter motor. I've never done this, and have never wanted to. Argh! First, I have a question that I hope is easy to answer. Then one that may be hard…

This spacer or washer on the end of the plunger…. Is it a special piece in a single specification, or are there different thicknesses? Is it hard to find one?

Is this a difficult job for a desk jockey to tackle?

If so, is there anyone in the DC area who could do it for me?

Thanks.
Sun Nov 21, 2021 3:14 am

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Sun Nov 21, 2021 3:14 am linkquote
I totally understand where you are coming from. Its tough when not only are you dealing with an issue, but aren't really sure where to start. Thats what this place is for

You know, it could be an issue with your selector box; or the alignment with the selector box + gear stack/driveshaft. Holding the selector rod, while spinning the wheel isn't a really good way to check whats going on. Its definitley misaligned somewhere....ther question is where.

Something to try without needing to dive into the case: add some extra gasket(s) to the selector box. This will shim it out and change the spacing slightly. It just might fix your issue. worth a shot!


This is the washer discussed above, which is inside the gear stack. #12 in illustration below
https://www.sip-scootershop.com/en/product/washer-selector-rod_87600000




The washer is #12

Sun Nov 21, 2021 4:00 pm

Addicted
Old douglas ..smallie with polini 115..super with nasco 177
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Sun Nov 21, 2021 4:00 pm linkquote
when ever a vespa slips into gear from neutral it tends to be a selector box issue,They get a bashing for 50 years and often overlooked .
You can replace the whole part easily (with out a split)..or individual parts.
There is a nice kit from SIP with a new arm. spring and pin....the hole in the arm is notorious for wearing...allowing the arm to move up around 3 or 4mm...and pop into gear (or out)
Sun Nov 21, 2021 4:16 pm

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Sun Nov 21, 2021 4:16 pm linkquote
Bluecati wrote:
when ever a vespa slips into gear from neutral it tends to be a selector box issue,They get a bashing for 50 years and often overlooked .
You can replace the whole part easily (with out a split)..or individual parts.
There is a nice kit from SIP with a new arm. spring and pin....the hole in the arm is notorious for wearing...allowing the arm to move up around 3 or 4mm...and pop into gear (or out)
yes, this is good advice right here - and much easier than the nuclear option of case splitting, and the cost is low as well.
Sun Nov 21, 2021 5:59 pm

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
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Style Maven
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Sun Nov 21, 2021 5:59 pm linkquote
In this case if it turns out necessary, you might be interested in splitting the case while it's still in the scooter. It's not seen a lot here, but it's done in shops all the time. It's easier on a P, but doable on older bikes too.
Sun Nov 21, 2021 7:00 pm

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Location: california
 
Ossessionato
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Sun Nov 21, 2021 7:00 pm linkquote
All good advice above.
Here is a framework to think about it in.
Go after the simplest solutions first to rule things out.

In this case - pulling the selector box off - cleaning all the grease away - and see if the arm is clicking nicely into and out of each part of the bat wing - is probably that step.
If you aren't sure - I like to remove the spring from the arm - to relieve any load on it.
Then if there is slop or play - I can feel/see it.

With the spring still in - it should click positively between each "V" shape in each of the batwing.
Sun Nov 21, 2021 8:03 pm

Hooked
1959 Allstate w PX Engine
Joined: 29 Nov 2020
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Location: Los Angeles
 
Hooked
1959 Allstate w PX Engine
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Posts: 382
Location: Los Angeles
Sun Nov 21, 2021 8:03 pm linkquote
V oodoo wrote:
In this case if it turns out necessary, you might be interested in splitting the case while it's still in the scooter. It's not seen a lot here, but it's done in shops all the time. It's easier on a P, but doable on older bikes too.
And just before that in-frame split he could do a last minute check to see if the selector rod is loose.
Reverse thread. Lefty tighty.
Mon Nov 22, 2021 3:15 am

Enthusiast
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Location: Tysons (Northern Virginia), USA 22182
 
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Mon Nov 22, 2021 3:15 am linkquote
Thanks everyone. So here is where I am right now. I have installed the selector box again, which has positive stops for each gear. Looking at it from the underside, it's clearly engaged with the selector rod. For the neutral position, spin the wheel and it jumps into first gear. If I install the first gear selector cable tightly, I can spin the wheel and it doesn't always jump into gear, but I can see and hear there is something bumping the selector rod on the inside and wanting/trying to pull it into first.

So, my inexpert opinion, based on no knowledge, but only logic, is that something is wrong inside the case, where the gears want to grab and jump into first gear. I'm very unhappy about this….

BUT, I'm very grateful to you for your support and information/ideas. Thank you.
Mon Nov 22, 2021 4:41 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Jet Eye Master
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Mon Nov 22, 2021 4:41 am linkquote
If you take out the plunger rod similar to what Ray8 said you will be able to see more.
Selector box off, standing upright on stand, scooter in 4th gear, unscrew the plunger rod (left hand thread). Take out carefully, if the washer is there it will fall on the floor.
Have a look inside with a torch (flashlight) and see what is going on (which way up it is).

btw; if its jumping into 2nd and not 1st, its a whole different issue.
Mon Nov 22, 2021 10:48 am

Molto Verboso
'64 Motovespa 150S (177) , '66 Allstate SF, '65 VBB, '66 180SS
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Molto Verboso
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Mon Nov 22, 2021 10:48 am linkquote
As RAY8 said, I had shifting issues and found the rod had somehow backed out of the cruciform.
Mon Nov 22, 2021 1:29 pm

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Posts: 64
Location: Tysons (Northern Virginia), USA 22182
 
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Mon Nov 22, 2021 1:29 pm linkquote
Yup. So I will first try seeing if the selector rod is not tightened down. Then I will split the case to see what the issue is. My money is on the cruciform being in backwards. Next, the spacer. After that, shims between the gears. I hope I can stop at step one.

Here, hold my beer…
Mon Nov 22, 2021 3:35 pm

Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
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Location: Rochester, Minnesota
 
Molto Verboso
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Mon Nov 22, 2021 3:35 pm linkquote
Will an endoscope style camera fit in and allow you to see?
Mon Nov 22, 2021 8:15 pm

Ossessionato
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Joined: 26 Jan 2019
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Ossessionato
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Mon Nov 22, 2021 8:15 pm linkquote
reverse thread.
Lefty tighty, righty loosey.
turn it the wrong way....
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