Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: DaveB on April 07, 2017, 02:59:46 PM
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... junk, ... problems, ...any other word
On returning from a 20 mile ride I saw the following... Please watch one or both videos...
https://vimeo.com/212262790
https://vimeo.com/212262907
I'm pretty sure this is condensation, not smoke, and the white liquid is either emulsified oil or condensation with a little oil from the breather. Is this normal? To be expected? or have I bought a whole heap of trouble? I'm just surprised it there could still be so much condensation in the engine after 20 miles.
I thought when checking the oil level the other day I saw a little emulsified oil on the dipstick but then ruled it out immediately because it's not liquid cooled. Never thought about condensation and I don't remember my CB 550 K3 ever doing this back in 1980.
Sorry, I know I'm asking a lot of questions but I'm sizing up what I've bought.
Thanks.
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Buy some fresh oil and a filter then take it out for another decent ride them change oil immediately you get home, probably get better with regular us. 550 has oil in engine case so oil stays warmer
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Water could have sneaked past the dipstick O ring. If there's water in with the oil, then you're going to get steam coming out of the breather. As Brian says...fresh oil, and a fresh O ring.
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I would change to oil and flush through as per previous posts. Might just be that the bike has been standing and condensation formed due to hot and cold changes in temp. There is certainly no mechanical cause but the issue is to get any water vapor out before it does any damage
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As the others have posted, I don't think it's too bad. If it's been run much recently on choke and not brought up to full temperature then it will have an excess of water vapour in the oil. I'd not expect it to stop steaming given those circumstances until something like 50 to 100 miles of running. In 20 miles it just hasn't had enough time at decent heat to evaporate much.
Try doing this, smell the oil on the dipstick and compare it to new oil. I'll have a bet that it reeks of petrol. If so, Bryan's advice to change it is even more relevant.
As a comparison to more modern engines, the choke system on these is really crude and amounts to not much more than stuffing a rag into the intake. There is no corresponding throttle lifting connected to the choke operation and it literally just stops the air going into the motor. It runs very rich to start it and you're best to get it off choke ASAP which requires you to moderate engine warm up with the throttle. It really is that manual.
You get alot of unburnt fuel in that situation and quite a bit of it will pass the rings and just mix with the oil. That's how water gets into oil on any of these old aircooled engines.
The 550 K3 was also a lean burn setup I believe, so far less likely to do this. Although looking similar, they are fundamentally better (nobody likes those carbs though) for running and engine without excess fuel being used and not entirely combusted.
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My 500 was like that, I re-routed the breather pipe over the chain and had a permanently oiled chain..... for 30 years, riding to work and back. As said, its just water in the oil from short journeys and the engine not being warmed through. Change the oil and filter. It may take a couple of changes to get all the emulsion out of the engine.
I had an old push rod engine Escort that was terrible for it, doing the tappets (often on the old Kent engines ::)) had the rocker cover off, it was thick with white sludge that when cleaned out was full of water. And that engine did 120,000miles.
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Blimey Tomb, 120,000 miles out of an Escort, that's about five times what I got with oil changes every 2000 miles. Mind you I was only 18 so it was maxed out most of the time.
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It was using a bit of oil, best thing was the Escort had perfect sills when it went for banger racing, boring car but bloody dependable, which is all I ever want out of a 4 wheeled tin box.
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120,000 out of a Kent engine if used and serviced right----20,000 from the little old ladies version
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My heap was a 1972 Escort 1.3L in horrible brown colour. Thought it was a Kent engine but may be wrong. Fantastic fun car for an 18 year old, went everywhere sideways. You could virtually rebuild that engine whilst your mum made your tea. Cant do that with a modern car, but that said you dont need to. Cant complain about the old girl though, I treated it to a very hard life and it stood up pretty well. Kids, bless em.
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Back in the day I ran a number of Renaults. Very ugly as the 16 version but liked the 17 coupe. Engines were pokey for the day and reliable - whilst I rarely remember any servicing! However when the bodywork rotted out it didn't matter if the engine ran!
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1972 1.3 escort definitely a Kent, hate to think how many I have rebuilt. V6 3.0 was an Essex and the 2.8 a Cologne 1.6 and 2.0 ONC was a Pinto and the later OHC Escort a CVH built in Bridgend
OK I used to be a Ford nut as well as Honda!!!
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Wasn't the CVH very similar to the 750 SOHC Honda's in layout? In that the cam and rockers are broadly similar in concept.
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Except for the fact that the CVH had hydraulic tappets yes