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Rebuild a 250 Alpina 1974 type 115


Divouneh
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Mechanical job is on way, but the clutch retaining nut don't want to come out...

I will need the special tool to hold the hub in place, with an impact wrench I was expecting to get it easily (as the other one in the crank shaft).

What are you using, where could we find the specific tools  (clutch retainer for Bultaco)?

Thank for the help 😃.

 

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4 hours ago, Divouneh said:

Mechanical job is on way, but the clutch retaining nut don't want to come out...

I will need the special tool to hold the hub in place, with an impact wrench I was expecting to get it easily (as the other one in the crank shaft).

What are you using, where could we find the specific tools  (clutch retainer for Bultaco)?

Thank for the help 😃.

 

1803222398_Retainingnut.thumb.jpg.8da31a92a5183a0fc6906010cd37ea44.jpg

I use a socket with the OD machined down to fit onto that nut.

Yes a clutch holding tool is required the way you are doing the work, but if you are going to pull a Bultaco motor apart again, consider loosening the shaft nuts with the motor still in the frame and a chain and back wheel in place.

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I have the socket 😃 

In any case when reassembly I will need the clutch retainer. 

I received the missing seals  and new circlips for the piston:

 

Gearbox sprocket oil seal    (Bultaco part #160-001)    30 x 40 x 7mm.

Gearchange shaft seal        (Bultaco part #160-004)   14 x 24 x 7mm.  

 

 

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Still waiting tool, I am cleaning my cylinder and cylinder head after 40 years 😉.

Did someone used the dish machine 😆?

Steam blasting will be the solution 😒.

 

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5 hours ago, Divouneh said:

Still waiting tool, I am cleaning my cylinder and cylinder head after 40 years 😉.

Did someone used the dish machine 😆?

Steam blasting will be the solution 😒.

 

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Plenty of people have used a dishwashing machine for engine parts. A dishwasher will make the fins bright but only for a short while because they use a caustic solution which will dissolve some of the aluminium and leave it microscopically rough (open to rapid corrosion).

Steam cleaning will not remove the existing oxide.

Dry blast will remove the stains and oxide and will leave it microscopically rough (open to rapid corrosion).

Vapour blast will clean the fins of oxide and stains and smooths the aluminium surface which greatly reduces the future rate of staining and corrosion.

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Yes I will not use the dish washer 😏, my cylinder head will stay with the patina 😘.

However I will paint the cylinder in black....

As I will move soon, I will store my frame in a climate storage. I have still the engine for my lonely evenings 😏.

I am still waiting my clutch tools and the postal services seems to have some issues with the pandemic.  

 

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Tool arrived, I am ready to replace the seals...

I have  a question: I try to change gear  (I feel the motor is in neutral), nothing seems happen ?

For me it was possible to change the gears when the engine was in the bike with the chain 🙄.

 

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When fully assembled and with the motor stopped, the main gearbox shaft usually needs to be wiggled (by rocking the bike) to allow it to change gears.

It looks like you have taken the clutch off. This usually allows the shaft (and the gears on it) to move axially out of their ideal positions, making gear changing harder. The clutch nut holds the shaft in the correct spot.

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Thanks for the help 😃...

I have a bad news, I removed the seals in both sides from the crankshaft. When i turn it I have a light friction noise.

After investigations, i see a small play in the shaft (ignition side), the seal has been removed before and not properly reinstalled 😑.

I need to open the crankcase, but I will not do it myself 😙.

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Every second-hand Bultaco I have ever bought has needed to have the crankshaft bearings replaced. They don't last long. There are a few other things inside the motor that may well also need attention.

I suggest you use someone who has a good reputation for rebuilding Bultaco motors. There are design quirks that catch people out on their first Bultaco motor rebuild.

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I follow the advices: I will drop tomorrow to Bultaco NY my engine , I have a new connecting rod bought from them I will use it.

The bearings from the gear box will be replace too, when open ...😭

 

 

 

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Done this morning, Bultaco paradise in NY state 😊, -7 deg F  (-14 C) ....

I could clean up the pieces at home, reassembly will go fast.

However to adjust the clutch, the engine needs to be in the frame following the the workshop manual  😐 .

But I could set the new ignition in the workbench 😏,

 

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