Triumph Rat Motorcycle Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter #1
I recently bought a 1972 Triumph Bonneville.For some reason the Oil pressure is all over the place.When I first start it is at 80 psi then it runs for a bit then drops to 60psi then 40psi.At 40psi then roll on the throttle a bit,it will drop to 20psi.With that said,take the bike for a ride around the block once or twice and then it's at just about ZERO psi.Then I rev the engine just a bit, it might go to 20psi.
I've cleaned everything there is to clean,trap,pressure relief valve etc.I know that most of you will tell me that it's the Rod Bearing's. But that's something that I'm afraid to hear.
Thank's Mike.
 

·
Registered
Joined
·
396 Posts
That'd be my bet. Big end bearing wear. Any noises from the bottom end?

Then again, I'd check the oil pressure release valve - that the piston isn't worn or sticking. Check the oil pump. Check that the oil seal in the timing cover (that fits over the crankshaft) isn't badly worn - this will allow oil to seep straight into the sump.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #3
Yes, I will take the Timing cover off and see what's going on.The thing that gets me is that it runs so good,starts first or second kick all the time.It doe's make a little noise when it gets hot,but it sounds as if it's coming from the rocker box.Well I have all winter to fix it.But I really wanted to get my Daytona put together instead.
Thank's for your reply
Mike.
 

·
Registered
Joined
·
970 Posts
I agree, it does sound like rod bearing, but just to be sure what oil are you using? Ideally use 20/50 SG only rated mineral oil. Do not use the modern light weight oils for wet sump bikes ie 10/30
 

·
Registered
Joined
·
29 Posts
Discussion Starter #5
I've been using Valvoline 20/50 racing oil In all of my British cars because it has high Zinc/Phos and with flat tappet camshafts they seem to like it.So being that the bike has a cam with tappets I thought it couldn't hurt.
Mike.
 

·
Registered
Joined
·
970 Posts
I've been using Valvoline 20/50 racing oil In all of my British cars because it has high Zinc/Phos and with flat tappet camshafts they seem to like it.So being that the bike has a cam with tappets I thought it couldn't hurt.
Mike.
This is good stuff to use, stick with it...... any 20/50 with lots of xinc is ideal for these old engines
 
1 - 6 of 6 Posts
Top