Hi All , Im looking for some advice on how to sort out an issue with what I thought was a hard seized engine.
I was riding slowly in a quiet back street when the engine starting making some noises that were definitely not normal operating noises. Unfortunately I did not get my hand on the clutch before the engine stopped. Tried to restart but the kick starter was seized solid. Luckily not too far from so dropped it into neutral and pushed and coasted home.
After bit of reading in this forum I worked out it was probably a hard seize in the top end of the motor, with the clutch lever depressed the kick start lever would operate, flywheel would turn.
I live in Jakarta were getting access to a workshop that you can rely on to do the job 100 % is tricky. Indonesians are very practical when it comes to fixing things and they seem to be able to fix any thing with a length of wire and a rubber band. But that's also sometimes the problem too. Things that get a great temporary fix never get a permanent fix, then break again.
I have done a far bit with this scooter since I got it but have not gone too far into the engine.
I have been living in Indonesia for 2 years so I know what you can expect when you buy an old Vespa here. I knew what I was getting myself into. The Vespa is a PX 200 X Arcobaleno, 86. This was not a top dollar fully restored Vespa more an OK runner. Quite unusually I got the full ownership history on this Vespa in the ownership record book, I'm only the fourth owner and the previous owner did a superficial make over to make the Vespa look like a 98 PX 200, ( all of which I have undone ) The last owner kept the bike as a show piece in the front office of their business. I think it is basically a sound bike that is pretty much original. But the maintenance to the bike had been a little patchy .
Mods I have done that effect the engine; new exhaust ( SIP road 2.0), new stock carburetor with upsized jets ( as per SIPS recommendations ), fast flow fuel tap . All replaced because the items fitted were worn out.
So I decided to have a look at the top end myself. I removed the cylinder head and the cylinder. As soon as I removed the cylinder head the piston started to move freely. On removing the cylinder and inspecting the piston and cylinder bore I did not see any scoring or marks on either. The head of the piston seems to me have a lot of carbon for a piston that was only changed 250 KM's ago.
Example of how the local mechanics do things. One of the four cylinder head nuts was in fact an over size nut held in place with a spacer nut ( no, not the one on the inside top which is meant to have a spacer) . The spacer nut was seized on to the shaft bold which was not straight. I doubt a torque wrench was used to tighten any of the four bolts up at all.
So here are a few questions I have after stripping the cylinder down;
1. Is this a lot of carbon for a piston with only 250 KMS. Most likely causes ? ( plug looks Ok )
2. Apart from the gouge marks were someone has hacked into the cylinder head, does this head look like the right one for the cylinder. I don't know why but it doesn't seem right to me. Should I replace it ?
3. The piston head seems to have quite a lot of play ( wobble ) on the top of the crank shaft , should it be tight with no play or not. Same with the crank shaft on the fly wheel. How much play should there be ?
4. As a source of the heat seize , I'm wondering if the autolube pump is operating properly when the throttle is pulled. You can see there has been some sought of mod to the shaft ( see pic ) the arm will go through full range of movement but it gets bit sticky about mid range. The return spring seems OK ?
5. What is the purpose of the small screw under the air box ? ( see pic )
As long as I can get the autolube working and depending answers to the above, I'm thinking I will just clean everything up and put the cylinder and head back together ( new set of gaskets an studs ) required.
Appreciate anyone's thoughts and advice.
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