What are the signs of a faulty oil pump?

[vagabond]

I've been having constant issues with my '79 Special II since taking it out hard onto the road for the first time since restoration. A few weeks ago, it started overheating regularly, along with a growing oil leak coming from the vicinity of the crankcase. I changed the oil, cleaned the oil filter and carbs, checked the points, valves and timing--everything seems to be in order. But it's now having a bit of trouble holding idle RPM and surges/bucks when out on the road. The left side valves/piston is fairly loud as well. Floats are set to 27mm for BS38s, which worked well before the bike started experiencing problems, so I don't think it's that.

So now I'm wondering if its an oil/fuel starvation issue and what the signs are of a faulty oil pump. Unfortunately I over-torqued and broke off one of the screws when changing the crankcase gasket the other day, so I can't check the oil pump directly until I get a new set of screws and get the broken screw out of the thread (if anyone has an extra one of the long screws or is selling/knows where to find a set of screws or crankcase, please let me know!).

Does all this ring any bells for anyone? Thanks!

 

[spanks]

floats should be 24mm +/- 1 mm other than that i have no idea

 

[CDNTX650]

pull a tappet cover off with it running and see if it sprays oil everywhere. Your tach is driven off of the pump as well...if your tach suddenly stops...

 

[retiredgentleman]

vagabond;

Surging motor.................are your points in good condition? If you used feeler gages to gap the points, you may have left some oil on the points. Use some solvent such as contact cleaner on a thin piece of cardboard, and drag it through the points.

If you still have those original 4 position fuseholders (glass fuses), they can cause a lot of grief. Replace them with automotive blade fuses.

What do you mean by overheating? Compared to what?

You said you cleaned the oil filter..............."filter" means you only cleaned one filter There are 2 filters. Don't know which one you cleaned, but there is one at the very bottom of the engine, held on by 6 bolts. Also one on the right side held on by 2 cap screws.

 

[vagabond]

CDNTX650, tappet cover as in from where you adjust the valves?

retiredgentleman, I never thought of that, but you're right it's very possible the points got oil on them. I'll check out that and the fuseholders first thing tomorrow. As for the filter, I only knew about the small filter when I cleaned that and the inside of the crankcase and replaced the gasket, which incidentally still seems to be leaking, unless the leak is from somewhere nearby. I haven't a chance to run it lately to see where the leak is coming from, but it still looks like the crankcase in front. So the big filter is under the engine near the crankcase, accessible from outside the crankcase itself? If so, I'm on that tomorrow.

By overheating I mean suddenly on the freeway losing acceleration, topping out at at most 50mph and dropping little by little, and steam coming off the crankcase when I stop. Then it's hard to start up again until about 10-15 min later, then only holds power for a few minutes after that. I thought it was running lean, so adjusted the valve clearance (two were slightly off), adjusted the points (one was off), and fixed the timing (both were advanced, the right fully advanced)--all this despite that I tuned all of this up two weeks ago and it was running fine. But it loses oil quickly because of the leak, which I think caused overheating the first time due to low oil. The overheating went away for a couple days, then came back 2 out of the next 3 days before finally I had to take it off the road. It's gone 1100 miles in the last month and a half for the first time in 15 years, so I'm assuming there's going to be a lot of garbage released. I put seafoam in the fuel and oil a couple weeks ago and changed the oil a few days ago. Fuel lines seem to be fine, I've the floats adjusted to 26-27mm based on xsjohn's advice in one of his posts--which the bike's run well on for nearly a month so I didn't see a need to change it. Pod filters are a little greasy because the breather hoses exit right above them, but didn't figure this was enough to cause the choppy running.

At the moment it lacks power in low rpm (the carb is as clean as it gets), bucks/surges and has what sounds to me like a dry sound from the engine after around 2500/3000rpm though it does have limited power if I open it up. After which a couple days ago it quickly overheated.

OK, so this is the long and short (but mostly long) of it. It's my primary transportation and joy in life but I'm struggling to find the right answer...

 

[gggGary]

Too many variables. Compression? Hope you haven't cooked something here.
Get the crank vent into a catch can or something.
Clean the pods. Over oiled pods can take you WAY rich like having the choke on. And rich running plus oil can foul plugs.
How does the intake screen look? (bottom filter)
I like the open a valve cover and see if it is spraying oil check.
Low fuel in the bowls can cause a lean condition. Not sure on the XSJohn reference but going far from the correct float level is not sound advice. a mm is far.....

 

[5twins]

XSJohn was running 1980 BS34s with brass floats. They do get set @ 27mm but are the only year that does. All other years are different. Your '79 gets set to 24mm +/- 1mm. Your floats are set wrong, 3mm too LEAN. That's probably the cause of some of your problems (erratic idle, surging, low power). If you don't correct this setting soon, you could damage your engine, if you haven't done so already. The way that it's overheating to the point of having steam come off it, I wouldn't be surprised if you've done some harm already.

 

[xjwmx]

Yes. It's probably pinging like crazy too and you haven't noticed it. Set your floats to 24 and I bet it'll fix your issues. If you still have good compression your motor is probably ok.


Plus, that "dry" sound you hear is the sound of a very lean motor.

 

[vagabond]

xjwmx, I suppose it would be difficult to say whether this lean motor is from fuel or oil starvation?

I am cleaning out the sump oil filter and noticed a thumbnail-sized tear...I'm assuming this is one of the reasons the bike is running so poorly. I'm ordering a new one now.

Could this tear lead to faulty oil pump operation through excessive deposits? What kinds of operational symptoms would you expect with a torn sump oil filter?

 

[vagabond]

I just noticed that, 2 days after cleaning it, the small alternate oil filter has lots of debris caught in it already, including very small small aluminum bits. Could this possibly be a byproduct of a few emergencies where I had to run the bike hot to overheating to get it home. With the new discovery of a tear in the sump oil filter, I'm concerned that something might have gotten in a fried the oil pump.

Any ideas?

 

[xjwmx]

xjwmx, I suppose it would be difficult to say whether this lean motor is from fuel or oil starvation?

Oil starvation won't make it lean. You don't have any real evidence for oil starvation, but with the float setting you have there's evidence that it's very lean. That much off would be on a bs34 at least. To look for oil pump not working just pull a valve cover with the engine running. Also, I would guess that without oil the top end would be making a hell of a racket.

 

[gggGary]

A thumb sized tear is normal operating conditions. By it's self it will affect nothing. It does allow crap through the oil pump, so replacement of the filter is best (needed) How many miles on the bike?

 

[vagabond]

xjwmx: it has been making noise at the top end fairly consistently for a while, but now it's a bit louder.

gggGary: nearly 17000 miles, but only recently back on the road full-time after restore.

I'm inclined to think it's the float level that's causing the issues. It's just funny because it was working fine at xsjohn-recommended 27mm before all the overheating issues began a couple weeks ago.

 

[xjwmx]

It bears restating that the 27mm is for a different carb than you have, one which also used brass floats, for one year, but a different carb.

Has the outdoor temp been going up there over the last two weeks? If so, that might affect your overheating in the last two weeks. Or engine wear could do it.

If you're still worried about oil circulation, remove a valve cover, start the bike, and look for oil.

 

[650Skull]

Going back over your threads i see 5 Twins advised you to change you float heights a couple of weeks ago.

This has to be done. Change the float level

You don't have a tacko.................. The taco drives off the oil pump so if a Taco stops working there is a good chance the oil pump is not as well. Stop and check the Taco cable. If the cable is good, Stop riding and get it Trailer'd home. The Taco is the only thing that can tell you if the pump stops working on a ride. Well that and a locked up back wheel as the motor seizes.

you keep riding even though you think the oil pump is not working

 

[vagabond]

650Skull, no, I haven't been riding at all, not for the last month or so. Terribly frustrating. What do I look for in the taco cable to tell whether it's good or bad? Please fill me in in as much detail as you can.

To recap, the bike was running fine for the first 3-4 weeks since buying it restored and in good running condition. A month or so ago, I adjusted the cam chain adjuster a bit, the bike went a solid 4 hours at highway speeds over the course of 2 days, then the next morning it overheated and began to overheat chronically for a week, then I took it off the road entirely. Opening it up a few weeks back, I found that 2 of the valves were a bit off, the timing advanced on both cylinders, float level had somehow changed drastically, and the points were a bit off.

I adjusted all of these last week and reset the float level tonight to 24mm. I swapped out the sump oil filter for a new one (the old one had a tear but was otherwise ok). The smaller filter was fairly dirty, with small bits of aluminum, so cleaned that and replaced small oil filter gasket. Replaced the clutch case gasket and sump plate gasket. Carbs are clean, synchronized by butterfly valve method for now. Checked the fuel lines--fuel seems to be flowing fine. 20W/50 oil is new. After doing all this, the bike started up fine, held idle well, I readjusted air/fuel mixture. There was a bit of noise coming from the left-side valves and points but everything else seemed fine so I took it out. A bit of hesitation at 0-25% throttle in 1st/2nd/3rd gears but otherwise ok. Took it a bit faster, seemed ok but felt a bit dry in the cylinders somehow. After a good warmup and 5 min on the road at 40-45mph, it backfired loudly I think on the right side, then started losing power, then after that it was hard to start up again and it would die at idle. I'm fairly certain it was overheating based on heat from clutch case. These were all the same symptoms as before I started all the above maintenance.

I'm at wit's end... How do I check the oil compression and taco cable? Any other suggestions? I'm quite frustrated and running out of steam.

 

[5twins]

Since you found your timing advanced, that was probably the main cause of your over heating, coupled with running too lean of course. Advanced timing is one of the major causes of holed pistons on these bikes.

Do a compression test. If you find between 130 and 150 lbs. of compression, the motor is probably still OK. If the tach cable spins while the motor is running, the oil pump is working. The 2 link together so if one turns so does the other.

 

[vagabond]

I'll check out the tach tonight--so you can actually see it spinning? Just to make sure, where exactly do you look and how is this supposed to look?

I'll pick up a compression tester this week--can you find one at standard auto parts stores or it specialized for motorcycles?

The problem is I adjusted the timing a few days back, so that should still be ok, but it was still overheating last night it's first time back on the road. I'm going to recheck the timing, points, valve clearance again tonight to make sure they're all in-line.

 

[xjwmx]

^If the tach is working, the cable is spinning. If you don't have a tach, take off whatever is covering where the cable used to go and look for the little drive thing spinning.

You can borrow a comp. tester at the auto parts store, if you'd rather not buy.

 

[sexybluelady]

didn't read the whole post but is there a way to hook up a oil pressure gauge and see what the pressure is at, haven't done it in a bike yet but I'm sure there has to be a kit out there to do it? all of my experience is in automotive so that is the first thing that we do. That and of course if your vehicle has a oil pressure gauge or dummy light that helps to solve the problem.