Oh FFS

coyoteran · Post by **coyoteran** » Mon May 11, 2015 8:38 am

Hi all

So I was riding the P to work today and it started to lose power, make some terrible snappy noises and ultimately died on the side of the road. It kicked over ok but the piston was actually squeaking in the cylinder. Either the oil injector broke (unlikely) or the oil line plugged (slightly more likely). Either way, it looks like I will be premixing in the foreseeable future if...and this is the question mark...I haven't fucked this engine up so bad that it needs a rebuild.

So what say you good people. If the piston still moves should it come back from the dead or is there an overhaul in my near future.

Keep em shiny
T

redbike · Post by **redbike** » Mon May 11, 2015 10:18 am

Huh. Well, you know those Vespas just aren't as reliable as they could be....Someone who actually knows something will be along shortly. I just couldn't resist.

Angelo · Post by **Angelo** » Mon May 11, 2015 10:23 am

It doesnt sound like it was a hard Seized because your rear would have probably locked up...you might have got lucky. You can come back from the dead on a Lambretta with a soft seize, several times....

better let the Vespa PRO pipe up...

jbcollier · Post by **jbcollier** » Mon May 11, 2015 5:31 pm

It will probably run but it would be a good idea to open 'er up and have a look. Doesn't take much to get the cylinder off. Do you have metric wrenches and sockets?

jbcollier · Post by **jbcollier** » Mon May 11, 2015 5:39 pm

Assuming this hasn't happened before, it's also simple to pop in an oversize piston.

Since we're headed that way, do you want me to bring a few tools and manuals?

coyoteran · Post by **coyoteran** » Mon May 11, 2015 6:27 pm

I do have metric tools. I popped open the carb and the top end/float assembly was rattling around on a couple of loose screws. I think it was running WAY WAY WAY lean and the injector couldn't keep up.

If you have the space and you don't mind, some tools/manuals wouldn't be a bad idea. Piss poor timing if you ask me as the bike has been running pretty good of late.

Heading back outside now to keep digging. I am going to add a little 2 stroke to the tank. Cant hurt I suppose.

coyoteran · Post by **coyoteran** » Mon May 11, 2015 8:07 pm

Major update. Head had worked completely loose. and was sitting about 1/2 inch off the jug on one side. I have no idea how it was running.

On the plus side, the piston moves well in the cylinder which does not appear to be too badly scored. On the down side, head gasket is non existant and I think the conrod bearing or some other bearing in that area may be shot. because I can't fully crank the thing around. Is that because of pressure build up in the crank case and no balanced low pressure in the cylinder? Pics to follow.

jbcollier · Post by **jbcollier** » Mon May 11, 2015 8:22 pm

The stock set-up doesn't have a head gasket. I just use a smear of high-temp silicon sealant (Permatex Ultra Orange, Canadian Tire).

jbcollier · Post by **jbcollier** » Mon May 11, 2015 8:23 pm

Should spin around moderately freely.

jbcollier · Post by **jbcollier** » Mon May 11, 2015 8:35 pm

Stop trying to turn the engine over!!!

Most likely crap is jamming the crank right at the rotary pad. Forcing it may toast the rotary pas.

coyoteran · Post by **coyoteran** » Mon May 11, 2015 8:35 pm

Sort of does for a revolution or two and then binds up. Attaching links to some pics.

https://www.dropbox.com/sc/0rvjeyxfzg6w ... Zd1i6fSepa

https://www.dropbox.com/sc/nbmd42nos1is ... PotqM-kZsa

https://www.dropbox.com/sc/n0tk7ur5qc1f ... eojRPrCrUa

https://www.dropbox.com/sc/lks6gl0vnw58 ... 0vlNvz7Yya

jbcollier · Post by **jbcollier** » Mon May 11, 2015 8:38 pm

Photo #3

Is that lower mark on the sealing surface a piece of debris? Or an indentation?

coyoteran · Post by **coyoteran** » Mon May 11, 2015 8:42 pm

Debris

jbcollier · Post by **jbcollier** » Mon May 11, 2015 8:42 pm

Put two nuts on a cylinder stud and jam them together. Use the bottom nut to unwind the stud. Once you have the four out, you can lift up the cylinder enough to get at the piston pin ciclip. Once the ciclip is out, you may be able pull the pin out and get the piston and cylinder off.

If not I have a piston pin puller I'll bring with us.

coyoteran · Post by **coyoteran** » Mon May 11, 2015 8:43 pm

So what do I have to take apart to get to the crank and check out the rotary pad.