The Jockey Journal

tgb3040 · 10-02-2013, 02:14 AM

Hello,
I just bought a 72 Triumph Bonneville 650 engine. It has an open crank ventilation; open into the transmission that is. I am not used to this since I only wrenched 69 and earlier before. I mounted a new alternator stator. I wanted to make sure everything was alright so I ran the engine without the transmission cover for about 5 minutes. During this, almost a pint of engine oil came through and out on the ground. This seems a little excessive to me, but I don’t know what to expect. Do I need to tear the motor apart in search of a fault, or might this be considered normal?

Best

'59 · 10-02-2013, 02:57 AM

'open into the transmission' ? , do you mean primary chain side.

tgb3040 · 10-02-2013, 03:08 AM

Quote:

Originally Posted by '59

'open into the transmission' ? , do you mean primary chain side.

Yes, into the primary chain side, sorry.
And I ran it without the chain case cover...

Glider · 10-02-2013, 03:44 AM

It's normal. There's no seal on the crank on the later models, there are also a few small breather/oil return holes (I believe).

The primary and engine share the same oil.

zedboy · 10-02-2013, 03:48 AM

Those motorsrun without a drive side oil seal to share engine oil with the primary. tere are three small drillings to allow the oil to drain back to the sum at a certain level. Run with the primary open &it's going to end up on the floor.

'59 · 10-02-2013, 04:07 AM

a pint sounds like a heck of a lot but then a little oil does appear to go a long way. Not saying that there is a problem but i'd just look to make sure there was a good oil return in the tank.

tgb3040 · 10-02-2013, 07:06 AM

Yes, I am starting to think: oil pump.
Now I can't get the motor started to check the return flow. I have a spark and I have fuel, so this indicates to me oil in the crank case.
I have good oil pressure, but the non return valve in the return piston might be leaking... That would give me these symptoms.
Hmmm, now, of to work.

tgb3040 · 10-02-2013, 08:03 PM

Emptied the crank case, got the motor started, good return flow, no problem there. Not nearly as much drainage this time as the last. So things are good. Thanks everybody.
Best

10-02-2013, 02:14 AM	#1
tgb3040 Senior Member Join Date: Aug 2009 Location: Bestorp, Sweden Posts: 128	Question about oil through the crank vent on a 72 Triumph? Hello, I just bought a 72 Triumph Bonneville 650 engine. It has an open crank ventilation; open into the transmission that is. I am not used to this since I only wrenched 69 and earlier before. I mounted a new alternator stator. I wanted to make sure everything was alright so I ran the engine without the transmission cover for about 5 minutes. During this, almost a pint of engine oil came through and out on the ground. This seems a little excessive to me, but I don’t know what to expect. Do I need to tear the motor apart in search of a fault, or might this be considered normal? Best

10-02-2013, 02:57 AM	#2
'59 Senior Member Join Date: Jan 2011 Location: 7th stone Posts: 561	Re: Question about oil through the crank vent on a 72 Triumph? 'open into the transmission' ? , do you mean primary chain side.

10-02-2013, 03:44 AM	#4
Glider Senior Member Join Date: Jul 2009 Location: Earth Posts: 706	Re: Question about oil through the crank vent on a 72 Triumph? It's normal. There's no seal on the crank on the later models, there are also a few small breather/oil return holes (I believe). The primary and engine share the same oil. __________________ When people who should have known better cautioned me about the dangers of motorcycle racing I told them that a fear of death is nothing more than a fear of life in disguise.

10-02-2013, 03:48 AM	#5
zedboy Senior Member Join Date: Dec 2007 Location: Ireland Posts: 300	Re: Question about oil through the crank vent on a 72 Triumph? Those motorsrun without a drive side oil seal to share engine oil with the primary. tere are three small drillings to allow the oil to drain back to the sum at a certain level. Run with the primary open &it's going to end up on the floor.

10-02-2013, 04:07 AM	#6
'59 Senior Member Join Date: Jan 2011 Location: 7th stone Posts: 561	Re: Question about oil through the crank vent on a 72 Triumph? a pint sounds like a heck of a lot but then a little oil does appear to go a long way. Not saying that there is a problem but i'd just look to make sure there was a good oil return in the tank.

10-02-2013, 07:06 AM	#7
tgb3040 Senior Member Join Date: Aug 2009 Location: Bestorp, Sweden Posts: 128	Re: Question about oil through the crank vent on a 72 Triumph? Yes, I am starting to think: oil pump. Now I can't get the motor started to check the return flow. I have a spark and I have fuel, so this indicates to me oil in the crank case. I have good oil pressure, but the non return valve in the return piston might be leaking... That would give me these symptoms. Hmmm, now, of to work.

10-02-2013, 08:03 PM	#8
tgb3040 Senior Member Join Date: Aug 2009 Location: Bestorp, Sweden Posts: 128	Re: Question about oil through the crank vent on a 72 Triumph? Emptied the crank case, got the motor started, good return flow, no problem there. Not nearly as much drainage this time as the last. So things are good. Thanks everybody. Best

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode