Crankcase Check Valve

[magoconnor]

Hello. 
I bought a valve with these specs would it work on a 90cc 139qmb? 
I just want to make sure, that the engine produces enough pressure to open the valve. 
It will be hooked up to the top crankcase vent, and a tube coming from the oil dip stick. 

Here are the specs: 
Opening pressure: 0.2 bar

Working pressure range: 0.2-6 bar


It is suitable for all sizes of one way valves,non return valves,check valves, oil supply valves, oil pumps, hand pumps and aluminum joints.

It is suitable for all sizes of oil supply joints and hand pumps.

Medium used: Diesel oil, gasoline, water. 

Cheers Mag. 

[GrumpyUnk]

I do not understand. If you connect the top crankcase vent(atop the cam cover) to the dip stick tube, you connect the crankcase to the crankcase. No venting will occur. What's the purpose? Generally you want the crankcase to be able to pulse the pressure caused by the piston pumping(on the connecting rod side, it is STILL pumping air back and forth) to avoid pressure buildup in the crankcase, and the leaking of oil past any seal it can caused by said pressure. Connecting vent to dipstick will do nada.
What did I miss?
tom

[FrankenMech]

That valve takes too much pressure to open it. You need something down in the 0.02 bar or 0.3 PSI or less range.

The crankcase and the valve cover are connected by a large passageway, pick one to vent. The valve cover is a better choice because less oil mist will blow out.

[GrumpyUnk]

Frank, did you make a post a few years ago about a 'reverse trike' on another board?

I have one here to repair and 'upgrade' and searched for a wiring diagram or schematic to no avail. Cannot even find an owners manual. I read a post, with the same user name, and thought it might be you...
Anyway, this reverse trike had no kick start(broken case), no turn signals(flasher), no brake light or tail light(failed socket falling apart and corroeded), and a no-start(wire broken on the switch terminal). It was quite the rabbit-hole journey figuring out who did what to whom without a diagram or hint.

It actually has its cam cover vented directly to atmosphere with no hose or filter. It also has a PAIR system with its output port 'covered' by a melted plastic plug of some sort. I thin it vents directly to atmosphere as it is. Kind of cobbled together from scooter parts and a custom front suspension.
I don't even know what the controls do, and there are some I don't recognize. Not going to trace them out, either.
tom

[FrankenMech]

Grumpy, I could have been on other boards. The mists of time have obscured much. I have used various user names but I don't have exclusive rights. Reverse trikes are strange beasts. I think they all come from the Dongfang motor company in China. They have several design and manufacturing defects. I still see the same defects haven't been fixed. Let me know if you run into problems. I did not get a good wiring diagram  or a user manual other than generic scoot stuff that did not match.

The valve cover vent should go to a port on the air filter assy.

Most of the controls are standard except the suspension lock (SL) below the left hand grip and a rev limiter that is engaged by the SL. The SL cable and mechanism is prone to breakage. The actuator spring is too strong and will shear off the cable end connection. I had to re-engineer the springs and cable. The SL rev limiter works by cutting off the ignition timing pulse from the stator. The kill switch interrupts the timing pulse also.

You are correct about it being cobbled together. The front suspension is a real kluge. The metal to metal shock connections will vibrate your teeth out. The A-arms will bend the tubing they connect to. Someone that was looking at mine thought that the front suspension looked like something from a Polaris ATV? That could be total BS.

I have lots of mods to make on my scoot to solve some defects if I get my hands to work this summer after surgery. The damn heavy front end and drag from the toe-in is way more than the 50cc engine on mine can deal with.