IN 2005 the 25tooth Oil Pump gear sheared and head was ruined. Then in 2013 new weisco pistons, powder coat frame...Bike ran super - maybe 500 miles. This spring performance deteriorated, and too late... head was shredded again, and 25tooth gear was bent and 35 tooth Oil Pump Idle cracked in half (I had replaced ALL oil pump parts in 2013 with new parts). Engine is totally apart now. ALL oil passages from crank thru cylinder head were clean. So, I need a new complete head and Oil pump. Will replace CAM tensioners as they may not have been recalled (No punch mark in case). In 2013 I did use assembly lube and HONDA GN4 Oil. I now know to prefill 'cam bowls' with oil, and inspect on occasion and fill with syringe if need be. I will use the Rotella 10w-40 with ZDDP additive. Couple of questions. 1) Does the oil pump flow through thru the tube down to the oil screen, or vice-versa? 2) What forces the oil up thru the small passages, up the cylinder bolts to the head? 3) Does the cam chain bring most of the oil up to the head?. I want to ensure I get it right this time, and need to understand exactly what failed, as I am unsure if the head was oil starved, then the oil pump failed, or was it the other way around? Thanks a million, Bob.
CB360T OIL STARVATION 2 BROKEN OIL PUMPS - NEED NEW HEAD+ Oil Pump+ tensioner
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#1 Oil flows from the screen pickup VIA suction to the pump and then to the rest of the engine.
#2 The PUMP forces OIL up to the rest of the engine. If you look at the base of the left and right REAR Cylinder head studs, right where the stud meets the crank case you should see 2 small holes about 1/2" from the stud. THOSE holes are connected to an oil gallery that runs across the back of the engine which the pump fills with oil. The stud tubes through the cylinders and head deliver the oil from those holes to the top.
IF those holes got plugged or restricted then you would lose oil to the top and fry a head. There should be NO need to fill the bathtubs on top of the engine regularly except for for the FIRST time you plan on starting the bike from a fresh rebuild. Other wise the oil flow from the pump should keep them filled.
#3 NO the oil pump forces all of the oil for the top end up the head bolt oil galleries.
Here is the diagram for the oil flow for the engine from the manual
View attachment oil flow.jpg
AS to why all that broke, sounds like oil starvation from either the wrong type of oil or having to LOW a level or having a plugged pick up. The oil pump is lubed by the oil that flows through it and the gear that drives the pump SHOULD be bathed in oil. Unless one of the galleries in the side cover is plugged or you haven't got the centrifugal oil filter installed correctly I don't see how you could have had that much trouble.
I second all of that. someting has been overlooked here... those oil pumps are bulletproof. not everything on a 360 is, but those usually are . i can't swear to it, but I'm fairly sure ye slinger mates to a passage on the RH cover, and if that's dogged up, you'll bleed off a fair amount of the pressure that ought to head topside. if your crank and trans are not being hurt in these pump failures, id start at that spot
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The pumps have never been a problem. Probably the most reliable part of the bike. Your problem is probably the the pump directly, but something killing it.
Hope you didn't use RTV instead of gaskets. The RTV gets soft and breaks off little pieces. they will clog the pickup and small passages.
Also, a bad side cover gasket will cause loss of oil pressure. The pressurized oil has a little passage at the bottom, under the pump, that is sealed by the side cover gasket. A broken gasket in that area would cause the oil to lose pressure, and flow right back into the sump.
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The pump discharges into that circled area. that is the area I tapped for my oil cooler....If the side case gasket is cracked or missing from that area, the oil will lose most of it's pressure
Hope you didn't use RTV instead of gaskets. The RTV gets soft and breaks off little pieces. they will clog the pickup and small passages.
Also, a bad side cover gasket will cause loss of oil pressure. The pressurized oil has a little passage at the bottom, under the pump, that is sealed by the side cover gasket. A broken gasket in that area would cause the oil to lose pressure, and flow right back into the sump.
The pump discharges into that circled area. that is the area I tapped for my oil cooler....If the side case gasket is cracked or missing from that area, the oil will lose most of it's pressure
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It's an odd set up. That gallery is a blind passage. A dead end.
The other part I should of mentioned is the transfer piece.
The left circle is the other side of the gallery, and the right circle the transfer piece.
As you can see, back in the 80's I had no idea that the RTV Silcone rubber was bad. You can see the rubber bead that tends to break off and clog the passages. I no linger do it, but that rubber was installed, mayb 1987. I know a lot better now. I cleaned a lot of little orange rubber pieces out of the case and bike when I was restoring it.
The transer piece, if it gets jammed, can cause a loss of pressure too. ALL the oil passes through this. If the spring is weak, the piece will lift, and cause a loss of pressure. This is the piece CrazyPJ took a dremel too and widened the passage a little, for less pressure drop. Next time I am apart, I will modify it a little too.
You also can see that I took the oil feed right from the gallery. Immediate to the left of that gallery is the bearing support for the oil pump. Pressurized oil travels through the center of the pump shaft into the passage in the case and to the oil filter. You can see the molded pipe. \
I would suggest the OP check the bearing for the oil pump too. If it is worn, that would also cause a loss of pressure and may be responsible for the pump failure.
Finally, there are 2 oil rings on the pump mount, and a o-ring on the suctin screen mount. If the suction side o-ring is not sealing, the pump would draw air, and the pump would seize after running dry for a while.
In 2013 I used all new gasket set, had machine shop do the new Weisco pistons (now at 368cc - 68.00 mm) and clean up the head. I used (sparingly) Hondabond4 for the cylinder head cover. SO, in the last 2 days - I went thru all oil passages - clean as a whistle.I read thru a copy of the Honda shop manual, and had a Eureka moment, quickly followed by thoughts of either volunteering my beloved Honda for the target range practice, or even perhaps even myself! Per manual, when checking the Oil level "Do not screw in the level gauge in." Like cars, I did screw in the dipstick all the way, then check the oil level. Seems this would lower my oil level by a good 1/4". As painful as this is to ask, can you verify that this error, seems to be the root cause of my calamity.
If oil level was still on the top end of the stick when screwed in, then you are still in the operational area. However, extended running periods on the side stand MIGHT cause the oil pickup to suck air once in a while since it is on the uphill side of the engine casing.
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Since the oil dipstick threads are over 13mm, you would automatically be at least at the minimum level if read screwed in instead of sitting on top of the threads.....
Once started, the amount of oil filling the passages and still draining back from the head would probably be enough to lower the sump level to the cavitation point....especially on the jiffy stand....JMHO....Pilot error....
Once started, the amount of oil filling the passages and still draining back from the head would probably be enough to lower the sump level to the cavitation point....especially on the jiffy stand....JMHO....Pilot error....
Thanks so much frogman - I think the low oil was the cause of oil starvation and fail, as all else was clean. Painful lesson. So am looking for a head, complete oil pump - what type of gasket cement do you recommend for the crankcase and cylinder head - I used Hondabond4 prior?
I've used Hondabond and the grey Permatex with good results. Cost wise the Permatex is my choice.
Just remember to use as little as possible, I also like to let it skin dry before putting things together. You are not really gluing them together so much as you are making a moldable gasket.
Just remember to use as little as possible, I also like to let it skin dry before putting things together. You are not really gluing them together so much as you are making a moldable gasket.
Hi Frogman and other. Bike runs great again. There was an aluminum plug that descended too deep into the oil passage seen in the pic - top notch Machinist (Harry's in Northborough, ma) discovered and ground that out. That plus my low oil issue + not using ZDDP, seemed to all contribute to my prior Head fail. So, I have Weisco pistons at 368cc with k+n pods. Bike pulls strong to 80mph+. Now I need to carb sync....as currently left idle screw at 5 turns, right at 3.5 and am needing to keep idle high - maybe 1800... So I guess a home made manometer and finding 2 6mm vacuum screws?
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I just got my pair of vacuum adapters from crazypj on this site. Also, for the syncing, I just connected the 2 the 2 adapters to a "T" and then to my single vacuum gauge. I use a little vice grip to squeeze the hose near the vacuum gauge just enough to calm the bouncing needle and then I just squeeze the hose going to each adapter with a pair of pliers to measure vacuum for each carb. Its a totally "ghetto" but works well for someone who doesn't need to sync carbs for a living.
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Hondabond4 is fine, just don't tighten it down for about 20 mins. let it get tacky
The oil pump idler is pinned into crankcase, the only time they break gears is when the shaft is pulled out and not re-set properly.
The outrigger is bonded rubber with steel center, it allows for slight missalignment or vibration, never could find out exactly?
If oil pump gear broke, the shaft was probably bent, another 'problem' caused by bad assembly - using screws in clutch cover to pull it into place always breaks things.
Clutch cover should slide up against crankcase.
If it doesn't something isn't assembled properly, either oil pump, oil pump idler or kickstarter shaft. Very rare occaisions, the gearshift shaft has moved
Oh, there is also an updated oil pump pick up. Standard on all CJ's forget when they started using it on CB. It was also a replacement upgrade if clutch cover was removed by dealer
You'll have to find Trek97 blog for details, I sent him the info
Oil flow diagram is also pretty sketchy about flow in and out of centrifugal filter. It flows 'in' through the center 'tube' in clutch cover and 'out' around the periphery, through the transfer piece.
I think the 'reservoir' is also to acts as an area where particles can accumulate before getting to the filter?
The oil pump idler is pinned into crankcase, the only time they break gears is when the shaft is pulled out and not re-set properly.
The outrigger is bonded rubber with steel center, it allows for slight missalignment or vibration, never could find out exactly?
If oil pump gear broke, the shaft was probably bent, another 'problem' caused by bad assembly - using screws in clutch cover to pull it into place always breaks things.
Clutch cover should slide up against crankcase.
If it doesn't something isn't assembled properly, either oil pump, oil pump idler or kickstarter shaft. Very rare occaisions, the gearshift shaft has moved
Oh, there is also an updated oil pump pick up. Standard on all CJ's forget when they started using it on CB. It was also a replacement upgrade if clutch cover was removed by dealer
You'll have to find Trek97 blog for details, I sent him the info
If you check the crankcase, the 'blind passage' is just transfer reservoir where oil comes in from pump then goes back up to the idles shaft then into the clutch cover gallery. It isn't shown on the oil flow diagram.
Oil flow diagram is also pretty sketchy about flow in and out of centrifugal filter. It flows 'in' through the center 'tube' in clutch cover and 'out' around the periphery, through the transfer piece.
I think the 'reservoir' is also to acts as an area where particles can accumulate before getting to the filter?
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