Bench Test

[remfanuk]

I want to run my v50 mk2 engine and driveshaft on the bench to check for any leaks in the bevel drive.  As a minimum, what do i need to reconnect to the engine to get it running on my bench?  obviously i will need a battery, starter motor, coils and fuel...anything i might be missing?  thanks.

[guzzisteve]

Don't do it, will fall off onto the floor.

[remfanuk]

could do it on the floor perhaps.

[nc43bsa]

Don't do it, will fall off onto the floor.

I wouldn't try it without the exhaust system.

Is it that big of a deal to install it and the fuel tank in the frame, minus the rest of the body work?

[remfanuk]

I wouldn't try it without the exhaust system.

Is it that big of a deal to install it and the fuel tank in the frame, minus the rest of the body work?

come to think of it isn't a chore.  the frame is sat on a lift at the moment and could refit the centre stand and the bevel drive, as it is only that i want to test for leaks.  apparently, can only be tested properly when pressurised and running on the bike.

[lucian]

I agree, put it back together and ride is the only way to test it. I just rebuilt the bevel on my v50II. After doing the oil passage mod for the pinion bearings, replacing the big bearing and big and small seals and gaskets, I put it all back together and ran it on the center stand in high gear for a couple minutes and no leaks. The next day I took it out on the road for a few miles and got home only to find a few drops on the bottom. The seal journal on the hollow shaft was rusty when disassembled and caused the big seal failure. I had cleaned it up well by hand with some fine emery paper but some pitting remained. Not convinced I did a good enough job I tore it down again and chucked the hollow shaft into the lath and polished the seal land down to a mirror finish with progressive grits down to 600.  Did 40 miles yesterday and leak is gone for good now. I was worried about taking too much material off the diameter but was not an issue. I measured the shaft diameter before cleaning it up at 74.96mm after polishing it was 74.95mm, well within the sealing range of the 75-90-8mm single lip seal.
 Moral of the story is, even if you "bench test" it you wont know if it actually leaks or not until you put some miles on it and things warm up a bit. Easy enough to pull just the bevel off if you need to . 
                                                Clean up by hand attempt #1
 


                                                 Job done right round 2
 

[John Croucher]

Proper crankcase vent.  Install PVC valve.  Proper crankcase vent should be a vacuum.

[remfanuk]

thanks for the replies...it makes sense to fully dry build and sort any issues out before going to paint/cerakote etc.  nothing to be gained by trying to shortcut.  cheers, i will follow your advice.

[Scout63]

If you do Remfanuk, please post a video. I’ve considered it but never tried it.  Sorting after reassembly is always part of the process for me.

[Vagrant]

Thinking out loud here, but unless you get it up to operating temperature for a 1/2 hour or so I don't think you will find most leaks.
If I was worried I'd use a pressure / vacuum tester like they use on two-stroke engines and make some adaptors.

[remfanuk]

am happy to run it for as long as necessary but i run the risk of over heating it i guess if i mock it up on the bike lift.  maybe the only real way of testing it is to take it out for a run. 

[Chuck in Indiana]

am happy to run it for as long as necessary but i run the risk of over heating it i guess if i mock it up on the bike lift.  maybe the only real way of testing it is to take it out for a run.

This.

[Scout63]

I agree, put it back together and ride is the only way to test it. I just rebuilt the bevel on my v50II. After doing the oil passage mod for the pinion bearings, replacing the big bearing and big and small seals and gaskets, I put it all back together and ran it on the center stand in high gear for a couple minutes and no leaks. The next day I took it out on the road for a few miles and got home only to find a few drops on the bottom. The seal journal on the hollow shaft was rusty when disassembled and caused the big seal failure. I had cleaned it up well by hand with some fine emery paper but some pitting remained. Not convinced I did a good enough job I tore it down again and chucked the hollow shaft into the lath and polished the seal land down to a mirror finish with progressive grits down to 600.  Did 40 miles yesterday and leak is gone for good now. I was worried about taking too much material off the diameter but was not an issue. I measured the shaft diameter before cleaning it up at 74.96mm after polishing it was 74.95mm, well within the sealing range of the 75-90-8mm single lip seal.
 Moral of the story is, even if you "bench test" it you wont know if it actually leaks or not until you put some miles on it and things warm up a bit. Easy enough to pull just the bevel off if you need to . 
                                                Clean up by hand attempt #1
 


                                                 Job done right round 2
 

Same problem with my G5. The seal shoulder was rough and caused the same rear end leak.  I have a new one sitting in a box waiting for me to just tear the rear end apart again.  Next time it needs a tire.