no leaks

Just completed a trip from Pittsburg to Erie, Pa. and back on my 72 Roadster. When I got to Erie I parked the bike at my brother inlaws new garage on some pristine concrete. This is how it looked the next morning after a 130 mile ride.



I had rebuilt the engine last winter and took pains sealing the cases with Yamabond also installed a Mikes xs650 pvc valve on the breather hose.
not a drop of oil under the engine, trans or cradle.

Have you checked the oil level?

Its going to start rusting

Seriously. Nice job !

Definitely a note worthy showing off over clean floor too. How fast of cruise did ya reach? About 70 mph throttle worth seems to be point where engine is elastic enough to weep if its gonna. Don't get too smug yet like someone I know and skip the return trip go around on torque holding, so soon.

Pretty easy pace, my wife was following me on a 125 Vino. Don't think I went over 55 mph or I would start to loose sight of her, all back roads with no traffic.
Never thought about the rusting issue, it's always something.

johnm said:

Its going to start rusting

Seriously. Nice job !

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A guy just can't get a break here.

I had quite a laugh over that rusting comment.

You are to be commended for a job well done. Now, if you want to prove something, take out the XS PCV valve and ride for 130 miles and park on pristine concrete. No doubt, a different result. With a pressurized crankcase it's damn hard to keep the oil inside.

Ok then you ain't yet got full bragging rights on oil tightness. Rusting barrel fasteners happened to my 2 Combats while I did have em full oil tight for a season or 2 pressing Combat to 80-90's when ever sane to do so. SS nuts on 1st one stayed nice but the steel studs rusted inside them. I found I can delay this a season or 2 by clear wheel coat but the heat tends to evaporate it off after that, and usually leaks start again by then too so prevents rust, yet also retouching clear coat w/o tedious prep so it sticks around a while. Good advice to check oil after each ride over an hour or more and its still too clean outside, ugh. Tell your wife she gets public notice points with us for taking a chunk out her time to back you up on your time/money stealing hobby from family affairs. Don't forget the case/cradle bolts when going though Commando worship ritual like I did, feeling smug after nil leaks or weeps on 1000 mile away Texas trip and back averaging ~65 mph, which turned out to be rather low oil so got messy again that retorque didn't reseal afterwards, ugh.

I've taken Trixie Combat off line d/t so many little things accumulating and past ring wear blow by spoiling sealing everywhere yet if I stay below 70 and ease on minimal throttle I only get some spittle drops on cases and side covers and no drips on floor but its so so hard on our rural hwys to restrain i creep up over 70 mph/3500+ rpm its so messy I feel ashamed of myself and public impression comments of " I hear they all do that huh"...

Trying to stop oil leaks on the Commando without a reed type crankcase breather valve is like trying to set your watch with your hands behind your back. Can be done, but damn hard and you need some luck.

Huh, a MotoMite brake check valve then later a $100 Dreer Krank PCV worked fine on Peel then Trixie till something else happened like HI over rev or ring wear blow by I doubt even the flapper valves could keep up with. Nothing wrong with having excess sucktion ability but only need so much to be effective.

It's not vacuum as much as it is lack of crankcase pressure. Anything over atmospheric pressure in the crankcase can produce a leak. Ya' hear?

As for Motormite brake check valves, they are best left to check a vacuum in a power assist brake system. They sure as hell don't work as a PCV valve for a Commando. After a few miles you will start developing crankcase leaks. If they (Motormite) were any damn good I'm sure Jim Comstock would not have went through the trouble and expense to make a proper reed PCV valve. Enough of this hokum about Motormite vacuum check valves being a substitute for a reed type PCV valve.

I didn't have much luck with the motormite valve, tried one last summer and still had the weeping problem.
Tend to run this bike pretty easy, It started as a couple basket cases in the 80's and always had a cronic low oil pressure problem that kept me from running it very much. Last fall I finally resolved the oil pressure or lack of and have been riding it more. This trip was actually for my wife to do a little distance riding on her scooter, she wants to do a scooter tour of Tuscany next spring and has never really been more than 20 or 30 miles from home on her Vino.

Frankly, I have never figured out what possible use an add-on valve is for this purpose. The crankcase will exhaust itself through the vent. So what does putting a valve in the way do except restrict the ventilation that the vent provides?

The air goes out but can't get back in I think.

My MotorMht woked but did get heat decays after some seasons so got Dreers Krank which also worked and rather cuter. Maybe my Combat have-had less blow by than most. For sure the reed valve can keep ahead of more blow by that regular PCV's Wes's '71 stays pretty oil tight and I don't think he bot a valve in this at all. Anywho my special will have active exh. extractor so may have to reverse its crank seal.

Hope you wife gets her road and traffic and hazard lesions is safetly. HIGHLY RECOMMEND some low air practice in safe place so she knows when a flat happening and how to control the control reversals pulling to a stop or dicing around a turn when tire goes away. Stopping well is the hardest to get down.

The one way valve would get negative pressure in the cases , theoretically . So it would suck all the oil leaksa IN . :lol: .

It'd shut at tdc ( thereabouts ) as the pressure stopped . Suck all the gaskets in , and the oil'd drop & pool when you stopped . :lol: :x ( just kidding )

It'd shut at tdc ( thereabouts ) as the pressure stopped

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Theoretically, the valve would be closed from BDC to TDC, then open from TDC to BDC. The whole purpose of the reed valve is to keep the rising pistons from drawing air into the crankcase.

Who said "If a Brit bike doesn't leak, it must be out of oil?"

"Who said "If a Brit bike doesn't leak, it must be out of oil?""

Pretty much everybody.

Right! And if tomtietjen keeps breaking with tradition, he is going to upset a lot of people!

Kudos to Tom,....wish I could accomplish the same....going to give the XS reed valve a try. Horrors! A Jap part on a Norton....Oh well, it will just have to coexist with the NGK spark plugs.....

texasSlick said:

Right! And if tomtietjen keeps breaking with tradition, he is going to upset a lot of people!

Kudos to Tom,....wish I could accomplish the same....going to give the XS reed valve a try. Horrors! A Jap part on a Norton....Oh well, it will just have to coexist with the NGK spark plugs.....

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You can get a CNW valve, keeping Norton.