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[Bulleteer51]

Hi guys,

It seems my 1951 Bullet has a bit of an oil problem. She wet-sumps a lot (probably more than what could be considered “normal”) but the pumping oil out of the breather ceases after a bit when she warms up a little (or else she’s then pumped out whatever has drained into the case I guess!). Once she’s completely warmed through (so after a couple of miles) there seems to be a fairly constant fine mist of oil out of the breather and she is also then burning a fair bit of oil (blue-smoke-syndrome).

The furthest I’ve ridden in one ride is therefore only around 15 - 20 miles as I’m obviously concerned that the breather could be blowing oil on the tyre (not ideal…..!) or as she's obviously burning oil etc something needs to get sorted. After buying her this time last year I had the mag reconditioned (starts 1st kick now), new brake shoes, tyres, cables, clutch, exhaust valve and top end checked and did a few other jobs like carb cleaning, new fuel tap etc etc so I spent a fair bit just after purchase when in theory she was all good to go with nearly 112 months MOT....... The guy who did most of the work (Enfield specialist) reckoned that the main phosphor bearing needed replacing as oil was perhaps passing through it and not properly being pumped-back to the oil tank.

Unfortunately I’m in no way competent to do a bottom end rebuild myself unfortunately ("A man's got to know his limitations" as Clint Eastwood would say) and he thought it would be around a further £800 job (so I’m thinking £1k after a few “extras” are found to be done as the always are) although he did say he’d do a reduced labour rate for me over a winter. Some advice please from all you all would be really appreciated. Does that sound like the likely problem and solution? If so, does the cost sound about right too? Incidentally, when hot she does seem to run pretty fast too – manual advance/retard of course so I’m wondering if this is currently over-advanced?

Thanks for any thoughts!

[Mark M]

Oil burning can be a result of over filling the oil tank, ideally the level needs to be about halfway between high and low marks, although if it's a 51 you won't have any marks! Also, rings can take some time to bed in, use cheap oil while running in not expensive modern stuff, it slows down bedding in of components. Replacing the timing side bush is a possible wet sump cure but is a pain, a lot of work for a cheap component. Can't say if £800 is cheap or not, it depends on his labour rate. Racing when hot is usually worn carb or too lean settings.
REgards, Mark

[Bullet Whisperer]

I am currently repairing a 1953 350 engine which had been wet sumping heavily. In this case, somebody had drilled two holes through from the timing side, coming through behind the timing side outer race, to aid removal. unfortunately, they also allowed lots of oil in from the timing chest. They had also omitted the hardened thrust washer that fits between the timing side main bearing and the housing in the crankcase - this had allowed the inner race of the timing side main bearing to randomly float around and merrily chew its' way through the crankcase, breaking through behind the exhaust cam. If you remove the timing cover [and maybe the cams] you might find an explanation. Sadly, the Bullet engines are pretty easy to work on, inviting all sorts to 'have a go' and probably end up with a 'runner'.
The engine would have to come out and be split to change that bronze bush, unless by some miracle it is loose in the crankcase, but then a new one would probably be a loose fit as well. That said, I have seen some badly worn bushes in engines that haven't smoked much, if at all. A bent [sideways] conrod can be another cause, as it will make the ring gaps try to line up and when they do, you will get blow by and oil consumption. I have seen some very worn valves and guides in Bullet engines and they don't use that much oil as a result. All of this assumes your crankcase scavenge filter is clean and your oil pumps are in good order. Cheers, Paul.

[Norm]

I have to do the same to an early one that was crated to India. I have pushed it to the back of the shed for the moment till I get a chance to get to it. Piston on TDC makes no difference and when being ridden it is pumping oil out of everywhere because it is constantly wet sumped. Scavenge pump seems ok but can't keep up. My plan is to split the cases and machine it to take an oil seal and just leave what is left of the bronze bush in there

[PeteF]

Not that I know my early Bullets very well but.....you haven't got the oil filler cap down tight have you? Certainly some of the 50's Bullets have two positions and it needs to be half off (so to speak) as it acts as a breather.

[Leon Novello]

Try what Pete F says; also try Castrol Edge 25/50 mineral oil; it slowed down the oil consumption and wet-sumping on my Bullet. As Confucius say,`Try easy way first.`

[Norm]

Hi Leon, or you could try filling the motor with grease, then it won't wet sump. I just pulled a 4 speed gearbox to bits to convert it back to right shift. The box was stuffed full of multi purpose grease and I mean full. Problem was the only thing suffering from a lack of grease was the bearings because it had been flung away. Sad part I have to admit is that it was owned by an Aussie and he had obviously read somewhere to fill the box with grease and that is what he did

[PeteF]

Norm should have mentioned that he's joking about filling the engine with grease.
There are people who read this forum without the technical knowledge to realise this.

[Bulleteer51]

Thanks for everyone's thoughts and a few bits : The oil I try to use a thicker grade and also run low following other advice and have had but thanks Leon - shall get some of the Castrol and try that as well.

Pete F - I now put the oil filler cap in the higher of the 2 positions during running (although didn't at first and this did improve things!).

Paul - I've put in a new filter and the a couple of chaps who had a look seemed to think the oil pumps were operating fine (but how could I check this?).

Thanks Mark M for thoughts on the "racing" - I'll try a little adjustment work next weekend!

It's been sugested elsewehere that it could be that the bore is quite worn and hence oil is passing down the sides of the rings and re-bore could be an easier fix. I don't really want to bore her out though as I'd like to keep it as original as possible.

[simon]

I found that my 51 Bullet would self sauce if I used modern synthetic or multigrade oils. I used straight mineral 50 grade (all year round in Auckland NZ) and found it much improved.