Bonneville America Forums Forums Technical Forums General Tech Low Oil Pressure

I'm not going to complain too much about this because I've more than got my money's worth out of this one, but I think my oil pump may be on its last leg on my '04 Speedy. Just shy of 106K miles, and she still runs like a bat out of hell, but idling at a red light, there's not much pressure registering on the British Customs right-side mounted oil pressure gauge. Even at full- tilt boogie she's only getting up to maybe 60 psi. Stopped in traffic, or at a long light, barely off '0', and it doesn't take long for the oil light to try to get my attention.

So, what to do?

I know it's involved, and expensive, and yeah, a Big Bore kit sounds nice. BUT IS THAT REALLY A GOOD IDEA WITH 106K MIKES ON THE ENGINE ALREADY????

For those of you that remember, I have sampled every oil change ever done on this bike at BLACKSTONE Labs, and the last two reports weren't bad, even after puncturing the oil filter and having the motor seize up on me.

I've had 2 back surgeries since then, my home flooded Memorial Day last year, I was released from my position as Service Consultant I'd had the last 16 years, brought home the '09 Speedmaster with only 6K miles on it at the time....so the last two oil samples were from the oil left in the dump when it seized, and an oil change I had done 1K since - but they were both highly encouraging, considering the motor had run dry and seized. (After a new oil filter and fresh oil, it would not crank over - only squealed as the starter motor tried to turn it. Then two weeks later, the day I brought the '09 home, she started and has run fine ever since - in traffic, 90+ degrees in heavy traffic, 2-up...whatever I've asked of her, and I've been intentionally hard on her from the standpoint of "getting on it" all the time, every time, even 2-up, and the only issue I've had is trying to find Neutral after she gets warmed up. But what with the house a mess, and me unemployed and recovering last summer, until this Spring I haven't been riding much. This past Spring though, NCAA Baseball season, I rode a lot, switching from one bike to the other every other day, mostly making the 160 mile round trip to Huntsville, Tx, and back, often 3 days in a row.

So. What to do? Is she worthy of a Big Bore? Worthy of even replacing the oil pump? (Or is even THAT just a matter of installing new pump gears???)

If the consensus is to get after it and fix it, I have no problem committing the resources towards doing just that. I'm just not real sure what to expect when I start down that path...

All things being equal (and they're not), if I had to choose between the two bikes, I really enjoy the '04 more. I like the way it handles and the more nimble steering. And the cams and long TOR's. Both bikes have the same tire's, Progressive fork springs, stock shocks, but the '09 just feels heavier and bigger somehow, while the '04 feels a lot more fun.

Just checking the general consensus here. All thoughts, and most opinions MIGHT BE appreciated.

You may very well need your rod and main bearings freshened up. Low oil pressure is a sign of worn out bearings. A top end job will only speed up the inevitable if that's the case. An oil analysis might be revealing. Oh Snap, I just re read your original post, if your oil isn't showing excessive bearing metal particles, than your oil pumps just might be the culprit for the low pressure readings. You might even throw another gauge on there, just for verification, gauges can go bad, just like any other mechanical device.

I really was hoping to get it to 4K miles then change the oil and sample it. I think I'm close. My commute to work and back is less than a 10 mile round trip, so even if I come home for lunch, it's going to take a long time to put many miles on it. But a 4K mile oil sample would be telling.

My owners manual says 4K mile intervals so that's what I've always done, fortunately able to do that at least 2x/year the first 10 years...

I've only used the SHELL Rotella-T Synthetic 5w40 truck oil (that's why I started sampling the oil from the beginning).

I have substituted a quart of oil with a quart of Polydyn TX7 polymer about once a year, or every 3rd oil change, and I really give the coating a lot of credit for saving the engine when it seized up two years ago. Again, it sat for two weeks, and apparently whatever was "stuck", loosened/freed up...

This next oil analysis is going to be very telling...

Internet guessing game has me on the "test the gauge and then replace the oil pump" team. But, if you wanted to do a big bore at 106K you'd want to replace the big end shells and check the bearings anyway as insurance against damage to the new components so there's that.

I did not read your whole post yet, I will go back and finish it to be sure I didn't miss anything.Small chance the gauge is bad but more likely the plastic pump gears are worn out. Doesn't look too bad to change them and I imagine not too expensive. 60psi is plenty to run the engine but that 0 at idle is not! I would stop running it immediately to fix it! Another possible cause is worse, excessive wear at the bearings can cause this as well as very bad seals. Most likely unfortunately is the worn bearings but I would go for the pump first as it is a much lower cost. Have you seen any signs of metal in your oil? That should be a dead give away for the bearings.

At least when you read the service manual it seems the two pumps are straightforward enough to access and the service limits are easy to measure. Worst case scenario is that you'd be out some sealing washers and a side cover gasket.

My issue is the seized engine. What seized? Transmission? What was the squealing sound? Piston skirt to cylinder wall I'm guessing. The lack of oil would have caused an increase in heat which would have cause the skirts to expand and scuff, also the heat could contribute to the plastic pump gears taking a beating. You would think that the rod and main bearing shells would also see some damage but your oil analysis would have picked this up.

I remember my brother in law forgetting to add oil to the tank for his 2 stroke Johnson 70 horse outboard. He seized the engine. We had to wait a couple of days before it would turn over and then it would run fine. He did this 3 times over 5 years until the engine finally let go. Pretty tough engine. Looks like our Triumphs are tough also.

I haven't researched the oil pump gear replacement, but from what I hear here, it's not as involved as a rebuild, nor as much cost. Sounds like the way to go.

I did see another post on here where someone had a picture of new metal oil pump gears?? Who sells them?

I'm not looking to do a Big Bore unless I was going to have to tear it down to that extent anyway. It doesn't sound like that's the case. And again, I'm more than satisfied with this little hot rod as she is. I just want to make her well again.

As for what seized? Great question, and with any luck at all, I might not ever find out.

Metals in oil sample aren't bad, but bearings might be a concern if it trends the way the last sample indicated.

For what it's worth, I have heard good things about that Polydyne TX7. That surely didn't hurt. It's a coating, and doesn't "wash out" with an oil change, hence only having to use it periodically, and I may be overusing it at that. Whether I used it or not, it was never reflected in an oil change sample. I had a friend that had given me several quarts of it, so I had nothing to lose. I've never bought any, but did see it on the accessories shelf at a Toyota dealership priced at about $40/qt. several years ago.

If I can source the metal pump gears, that sounds like the course I'll take.

Thank you all for the questions and input. This forum has come through again.

Now where again do I pay to support this fine forum?

This bike now has over 111,000 miles on it. Rowdy as all get out, and rides like it’s on rails back and forth across Houston - mostly at night, always 80-90 mph. I found this old post by accident searching for help in changing the oil pressure switch. (I cannot figure out how to get a tool on it.)

It may well have been an oil pressure switch that cured the problem then - I can’t remember. But I’m very satisfied that there are no oil pressure problems on this bike despite the hard use and miles. I can’t help myself but to abuse this fine steed, it’s driving chain and tires every time I get on it. The grin cannot be avoided.

My ‘09 was bobbed and now sports a Thruxton tank and custom paint. Only slightly more civilized.

Splitting time between the two bikes and not really going anywhere the last few years, other than back and forth across town to see a buddy of mine, I’m still managing 6K/year, and riding 120 miles a week or more most weeks just doing that.

If anyone has any kind words about how to get that oil pressure switch off I could sure use it. It’s been changed at least twice before on this old bike but done in the shop and my shop has recently closed.