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Pre-unit breathing... #78409
04/06/05 5:58 pm
04/06/05 5:58 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
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scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Hey everyone! I'm a new guy and this is my first post here. Hopefully someone can help smile

I have a '60 TR6 Pre-unit that I'm just getting the motor back together on. I bought it as a basket case so obviously it was missing things...

Here's the question: There is a breather tube on the primary chain case and crank case. I also have a breather port on my oil tank (Mooneyes tank). Could someone tell me what lines (if any) are to be run off these ports and to where? I would appreciate your feedback or at least a kick in the right direction as to where I might find this info. Didn't see it in the manuals I have.

Thanks everyone!


ScooterMcRad
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Re: Pre-unit breathing... #78410
04/08/05 7:11 am
04/08/05 7:11 am
Joined: Aug 2001
Posts: 62
Australia
B
Beeza Geeza OZ Offline
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Beeza Geeza OZ  Offline
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B

Joined: Aug 2001
Posts: 62
Australia
Hi Scoota,
The one on the top of your primary cover needs no line. The one on the crankcase (rear of barrels) you can run a line to oil rear chain.
Just leave the oil tank breather as is. Nothing nasty will happen if you don't run lines on any of them. If you have a late model (solid) inlet cam fitted, you need to either vent your crankcase into primary or vent your timing cover, like the racers do.
Cheerz, Geeza.


'ead down, arse up, flat out!
Geeza.
Re: Pre-unit breathing... #78411
04/08/05 2:30 pm
04/08/05 2:30 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Hey Geeza,
Thanks for your reply and info! I appreciate that.
So, let me just make sure I heard this right... I can leave the primary chain case alone and just leave those vents open. My oil tank I could just run a tube with a screen on it or something (to keep junk out) and the crank case I would technically just run a hose to the ground (or to the chain for lube if I wished)?
This is my first Triumph and pre-unit for that matter. It's a very different animal then anything I've dealth with in the past. I appreciate the help.
Thanks!


ScooterMcRad
Re: Pre-unit breathing... #78412
04/09/05 11:15 pm
04/09/05 11:15 pm
Joined: Oct 2003
Posts: 11,267
North Georgia, USA
RF Whatley Offline
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RF Whatley  Offline
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Joined: Oct 2003
Posts: 11,267
North Georgia, USA
Scoot -
When you built the engine did you install the rotating window at the end of the intake camshaft? If not, I'd put a generic PCV valve off a car on that line with the direction of air travel blowing away from the engine. This will put a negative pressure in the inside of the engine and cut your oil leaks down tremendously.

That same engine line is supposed to run to the oil tank so that the engine doesn't inhale dirt off the road. If you do that you'll need to purcahse a Y-connector to let both the engine and oil tank blow off pressure AND water vapor.

You can run that 3rd line down to the rear chain as suggested.

Hope this helps. bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Pre-unit breathing... #78413
04/09/05 11:52 pm
04/09/05 11:52 pm
Joined: Apr 2005
Posts: 59
Nova Scotia, Canada
S
savageskeeter Offline
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savageskeeter  Offline
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S

Joined: Apr 2005
Posts: 59
Nova Scotia, Canada
Hi all,
I too am working on a pre-unit ('57 6T). I have late cams so I can't use the breather off the inlet cam. I was thinking about using the timing cover option mentioned but was wondering if I should open up the breather ports in the timing case. I am working on a type of Cafe' chop with a 750 top end and want to make sure I have an effective breather. If I run a line below the engine to behind the transmission with a breather filter on the end what diameter tubing should I run? 1/4"? Should it actually run vertically up, down or does this matter for effective breathing?
Thank you in advance,
Matt

Re: Pre-unit breathing... #78414
04/18/05 7:49 pm
04/18/05 7:49 pm
Joined: Oct 2004
Posts: 25
Far Northern California
bitsa110 Offline
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bitsa110  Offline
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Joined: Oct 2004
Posts: 25
Far Northern California
Geeza, Please explain venting the timing cover "like the racers do". Can it be done without punching a hole in the cover for a fitting? Mike


`54 T110 Mild Custom
`56 T110 custom,in progress
Re: Pre-unit breathing... #78415
04/18/05 8:45 pm
04/18/05 8:45 pm
Joined: Aug 2001
Posts: 7,209
Vermont
Jon W. Whitley Offline

BritBike Forum member
Jon W. Whitley  Offline

BritBike Forum member

Joined: Aug 2001
Posts: 7,209
Vermont
RedNeck,

I'm a little confused by your post.I'm not quite understanding to which lines you are referring to and where they are being routed?

Are you saying that the breather tube off of the rear of the crankcase should run a line to the oil tank ? And which line are you talking about running to the chaincase--the one from the top of the oil tank ? beerchug


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project

Re: Pre-unit breathing... #78416
05/19/05 10:48 pm
05/19/05 10:48 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Quote:
Originally posted by RedNeck:
Scoot -
When you built the engine did you install the rotating window at the end of the intake camshaft? If not, I'd put a generic PCV valve off a car on that line with the direction of air travel blowing away from the engine. This will put a negative pressure in the inside of the engine and cut your oil leaks down tremendously.

That same engine line is supposed to run to the oil tank so that the engine doesn't inhale dirt off the road. If you do that you'll need to purcahse a Y-connector to let both the engine and oil tank blow off pressure AND water vapor.

You can run that 3rd line down to the rear chain as suggested.

Hope this helps. bigt
I actually had someone else rebuild the motor because it was so trashed. I'm not sure of the window you speaking of, but it should have been put back stock.
I understand what you mean about the crankcase line going to the oil tank with a Y or T fitting for breathing (maybe to a filter or something). As for the primary chaincase, what about that? I think there may be a middle tube that comes out and down and also a smaller tube at the top of the cover that comes straight out.
Holy confusion Batman! Is there someway to post a sketch on here or could you (or anyone) send me one? A block diagram in MS Word would even be fine.
Does anyone have a photo they could send me showing what they did with their pre-unit lines? Picture's worth a thousand words!


ScooterMcRad
Re: Pre-unit breathing... #78417
05/20/05 2:53 pm
05/20/05 2:53 pm
Joined: Oct 2003
Posts: 11,267
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member

Joined: Oct 2003
Posts: 11,267
North Georgia, USA
Guys -
Yes, I'm saying run the engine breather up to the oil tank to capture the liquid back into the lube system. However, you have to add a T fitting (or the stock Triumph Y fitting) to let the pressure and water vapor out. You can run this second line out the rear fender or to the inlet tube atop the primary chain case.

Hope this helps. bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Pre-unit breathing... #78418
05/20/05 4:48 pm
05/20/05 4:48 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Quote:
Originally posted by RedNeck:
Guys -
Yes, I'm saying run the engine breather up to the oil tank to capture the liquid back into the lube system. However, you have to add a T fitting (or the stock Triumph Y fitting) to let the pressure and water vapor out. You can run this second line out the rear fender or to the inlet tube atop the primary chain case.

Hope this helps. bigt
AHH! That makes sense to run the line off the T or Y to the top inlet of the chain case. What about the inlet/outlet at the middle of the chain case (there's two)? Vent to an air filter?


ScooterMcRad
Re: Pre-unit breathing... #78419
05/22/05 10:34 pm
05/22/05 10:34 pm
Joined: Oct 2003
Posts: 11,267
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member

Joined: Oct 2003
Posts: 11,267
North Georgia, USA
Scoot -
Naw, the one in the middle (at least on mine) had a down-turned tube inside making escape of anything but pressure pretty hard.

Hope this helps.


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Pre-unit breathing... #78420
05/23/05 6:58 pm
05/23/05 6:58 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
RedNeck,
You are correct... the bend is on the inside. Oops! My mistake!
I found a manual that had a diagram in it. It shows the oil tank breather going to the top of the primary chain case. It showed the crank case breathing to atmosphere... I saw a few stockers running just an open tube straight to the ground (drip, drip...). So my thought is to run the line from the oil tank to the primary chain chase and run a small recovery bottle with a drain spicket or cap (upsidedown bottle) with a small breather filter on top to breathe to atmosphere.
Anyone have any thoughts or tried this?


ScooterMcRad
Re: Pre-unit breathing... #78421
05/23/05 7:01 pm
05/23/05 7:01 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum

Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Oops again... I should have proofed that first. The recovery tank and air filter will be just on the breather tube coming from the crank case. The line from the oil tank to primary chain case will be totally independent.


ScooterMcRad
Re: Pre-unit breathing... #78422
07/08/05 8:54 am
07/08/05 8:54 am
Joined: Jun 2005
Posts: 16
Finland
J
JanneK Offline
BritBike Forum
JanneK  Offline
BritBike Forum
J

Joined: Jun 2005
Posts: 16
Finland
Hi there!

Continued this old thread in hope that some of you guys (RedNeck?) could explain a little bit more about how this rotating valve actually should work.

Is the original idea such that the rotating valve should be open when engine pistons are traveling down so that the air compressing to crankcase can "breathe" out? And on the other hand when pistons are traveling up the rotating valve is closed so that dusty/dirty air from outside "atmosphere" is not drawn into the crankcase?

And how about that PCV valve - in case the orginal rotating valve is not installed, does this PCV thing work in the same way as described above?

I'm not sure what I have inside my pre-unit engine since I haven't opened it (yet). But the cylinders are quite "loose" (see my other posting about reboring of pre-unit smile ) and engine is breathing quite heavily resulting also quite a lot of oil coming out from that crankcase breathing pipe. I have only a piece of tube attached to that pipe so that the oil is throwed a little bit further away (and not spilling down making the whole engine outside oily).

So did I get it right if I understood that it "safe" to connect all those three breathing pipes - from engine, from oiltank and from primary chaincase - together with a T-connector? And in case of extra PCV used that should be inserted in that tube leading from crankcase to the T-connector?

To where does that extra pressure and water vapor then "breath" to - I mean how does it get out from system? Does it go into the primary case and then finally out from there via that another pipe (which is down turned inside primary case)?

-JanneK


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