A Tail of Two–MS200T–Top Handles & Compression Tests

[billpierce]

I use a thick bit of rubber with holes in to go inbetween the carb boot and cylinder. Then do the carb bolts that hold the carb and the boot to the cylinder up. Make sense? Same on exhaust side.

[spudulike]

Simple, fit the boot and clamp then stick a permanent marker pen down the boot to block it!

[arborlicious]

8 minutes ago, spudulike said:

Simple, fit the boot and clamp then stick a permanent marker pen down the boot to block it!

Simple indeed. Thanks. 

[arborlicious]

Finally found some time today to perform the pressure and vacuum tests...disaster. Would not hold any pressure or vacuum...6 hours later realised I had not installed the plastic plate over the carb boot to seal it onto the cylinder...idiot. Waiting for next weekend for the real test.

[spudulike]

Don't forget to plug the impulse line as well. A suitable nail works for me!

[arborlicious]

I'm using the impulse line to attach the mityvac. Yesterday I made up a blanking plate (10mm flat bar) for the exhaust port which makes it easier to block than using the exhaust itself. Gave it a quick go and at least this time I could build up vacuum and pressure but they did drop down again.

 

What are the expected results with say 10psi? How long should it take to drop down to 0 again?

[billpierce]

If stick a strip of rubber or similar on you blanking plates. Will help get a good seal.

Donnyboy has a good youtube video of a vac test with suggested psi and timing etc.

[billpierce]

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=%23&ved=0ahUKEwirmujtloHcAhWJ-aQKHQJ2AmgQwqsBCCowAA&usg=AOvVaw0VTJzWxrN8ZFOD4xbU2nov

[peatff]

Donny video

 

[arborlicious]

Finally, success!

 

After a couple or nine false starts I'm sure the crank seals are in good condition.

 

I could not seem to get the vacuum or pressure to hold steady (7psi) but in the end traced it to the impulse line itself. The impulse line was quite stiff and I think this was causing it to leak on the crankcase nipple.

 

Impulse line replaced and will hold 7psi all day. Rotated crank shaft and still okay.

 

Can finally start on the re-assembly less base gasket.