Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Martin6 on September 27, 2023, 02:03:49 PM
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I've got to the point where i will start to address my leaking head. Before I remove the engine I wanted to check the compression. I started on a compression test yesterday. My battery gave up and again today after all night on a battery tender. In fairness, it has a manufacture date of 2005!
Are the replacements from David Silver good? Any other recommendations?
Thanks, Martin
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If you can afford it fit an Advanced Glass Mat Battery (AGM) they hardly ever need charging, even on the winter layover. Plus an extra benefit is there's no acid to leak on your paintwork. Got them on all my bikes, can't recommend them highly enough.
I think the batteries at Silvers are Gel type. Not the same thing as AGM.
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Found this company excellent
https://www.tayna.co.uk/
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I second tayna batteries and the numax is fine, the 500 Ted had off me say for 8 months and started fine
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Thanks, used the link and ordered an AGM 14Ah, 200CCA for £37 delivered. Not bad.
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That's a very good price for an AGM battery. Nice one.
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If my head was leaking, I'd go see a doctor Martin. Last thing you want is brain cells coming out of your ears.
Bit late to advise but all batteries are not the same, even of the same type. Check CCA figures for Cold Cranking Amps, the higher the figure the stronger the battery.
For the 500/550 the standard battery was the Yuasa 12N12A-4A1, the wet cell battery has about the same CCA as an AGM, the Exide has the most of any of the replacements at 165 CCA, however you get what you pay for. If you want an AGM (and who wouldn't, no battery acid spilling all over your new paintwork and chrome) then the cheapest is the Powerline at £30, it's a 150 CCA battery, the slightly more expensive Numax at £41.95 is however less powerful at 135 CCA, so I'd avoid that, the best is the Motobatt at 160 CCA but it's a lot more expensive at £63.03. Given the choice you can buy 2 Powerline batteries for less than 1 Motobatt, it's slightly less powerful but not that much. I'd buy that one I think.
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I always use a battery pack for more power when running a compression test post a picture of your leak only in Totham if you need a hand
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Oddjob, I bought the Powerline. It Quotes a CCA rating of 200A. https://www.tayna.co.uk/motorcycle-batteries/powerline/yb14l-a2-agm/
Be a bit annoyed if that's inaccurate.
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Oddjob, I bought the Powerline. It Quotes a CCA rating of 200A. https://www.tayna.co.uk/motorcycle-batteries/powerline/yb14l-a2-agm/
Be a bit annoyed if that's inaccurate.
Thats what we use on all our 750/4's Martin, from Tayna😊😊😊
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I always use a battery pack for more power when running a compression test post a picture of your leak only in Totham if you need a hand
👍
The front head bolt, just in front of the head cover, visible in-between exhausts 2 and 3, has sheared, by the look of it. It's too long to pull out without removing the head cover. Also, the head bolts that can be checked inside plug holes 1 and 4 were a bit loose. I think the previous, previous owner had the head off (and possibly went further) for new rings. But didn't torque it up properly, putting too much force on that bolt.
I'm not burning oil, but the head join is generally oily and misting the bike nicely. There's a few drips as soon as I stop and put it on the sidestand, as it runs off the fin. Plug no.1 is sooty and I think it's probably the leaky head.
I've been putting off dealing with it, to enjoy the bike this summer, but also dreading getting the motor out of the frame. Never done it before! Also, undecided how far to go. A 40,000 mile motor with no history. I probably ought to check the condition of everything, but it seems to run fine until no.1 plug soots up. So I'll probably limit it to a visual inspection of the bores and cam and a de-coke as needed. Then do my best to put it back together oil tight.
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Oddjob, I bought the Powerline. It Quotes a CCA rating of 200A. https://www.tayna.co.uk/motorcycle-batteries/powerline/yb14l-a2-agm/
Be a bit annoyed if that's inaccurate.
Thats what we use on all our 750/4's Martin, from Tayna😊😊😊
👍
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Different battery Martin. I did say for the 500/550 as the variants in the 750 range could mean that different types were fitted to different models, like between the F and the K for instance. If it says 200 it will mean 200. Reading between the lines it looks like Powerline may be a decent battery. Not sure who makes them though, looks to be Tanya itself.
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Battery arrived lunchtime, less than 24hrs after the order was placed, with 'standard' delivery. Impressive.
Bike strip down has commenced. I feel like I'm committed now!
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Different battery Martin. I did say for the 500/550 as the variants in the 750 range could mean that different types were fitted to different models, like between the F and the K for instance. If it says 200 it will mean 200. Reading between the lines it looks like Powerline may be a decent battery. Not sure who makes them though, looks to be Tanya itself.
I fitted a Powerline to a previous car as it had the highest specification (Ah & cca)for the casing size at a competative price.
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Of course, if you have loads of spare cash, you could fit an Odyssy battery. They are very good but expensive. Also take up a lot less space than conventional (like most AGM batts)...
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I have found a bit of a problem with AGM batteries in that they are slightly taller than standard and the leads aren't quite long enough to reach. Most of my leads did fit after a bit of rerouting but on the 350 I had to replace with slightly longer leads.
I thought it may just have been Motobatt so I tried a different brand this time and that's the same. I'm told it's because they have a circuit board on top so that adds height. Never opened one up so don't know if that's true.
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Hi Martin
When I lifted my cb750 engine out I made a platform just in bit higher than bike frame the put jack under engine with a piece of wood on jack and then slid it out I did it on my own but if you got help even better I left on platform to work on
Paul
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They are truly heavy engines. Well done doing it on your own.
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Not sure if it applies to motor cycle batteries, on cars many but not all manufacturers specify a casing type such as Type 019 that applies to two of our vehicles. This dictates the layout & type of connection lugs, battery height, width & length in mm.
When looking for a replacement battery I search by casing type, Ah & cca I then double check the dimensions as there seems to have been a drift for selling some 019 types that are not quite the original dimensions. I suspect that manufacturers are looking to make batteries that fit a wider range of vehicles by ignoring some of the fine details.
I bought a replacement Varta battery for a BMW Mini some years ago from Eurocarparts - it was very cheap at the time compared with everything else. When I came to fit the battery it was not tall enough - it was impossible to fit the connections due to the battery location as it would have shorted on the bodywork of the battery well. I managed to make it fit by standing it on a thick peice of Polystyrene sheet. Far from ideal - the battery failed a few months out of warranty.
Below video shows AGM technology.
https://www.youtube.com/watch?v=u2QwntIO4Mk
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I tend to try and find the original battery as fitted by Honda, see what's it's measurements are then see what available in replacements. In the 500/550 range the AGM batteries are 1mm taller, 161mm as opposed to the standard 160mm. I doubt 1mm would cause any problems. Width and depth are the same.
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All mine have been specified for the relevant bike and have been between 6 and 8mm higher.
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Looking at Ted's link, this associate one came up
https://youtu.be/8CxFpIoKwy0?si=p__DBh2uaozMN8L7 interesting just to see the process.
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Looking at Ted's link, this associate one came up
https://youtu.be/8CxFpIoKwy0?si=p__DBh2uaozMN8L7 interesting just to see the process.
Interesting video - I have read about how to de-sulphinate lead acid batteries previously the video method looks as though it can be dangrerous.
On later smart chargers like my C-TEK there is a Reconditioning mode that they advise you only use once a year on a battery - I belive it uses pulse charging at higher voltages to reverse the effects of sulphination.
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Hi Martin
When I lifted my cb750 engine out I made a platform just in bit higher than bike frame the put jack under engine with a piece of wood on jack and then slid it out I did it on my own but if you got help even better I left on platform to work on
Paul
Neat idea. I have a couple of mates offering to lend some muscle. I'll remove the ancillaries, including the exhaust flange fixings (the parts that screw into the head). But I'll leave in the stator / dynamo, clutch etc. and see how we get on.
Your idea, plus with some 4"×2" strapped to the barrels, to lift it each side, should work. It doesn't matter if I scratch the frame getting it out, as I'm planning to strip it and paint it up. Getting it back in though...!
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Re the height of batteries, I think some, maybe my Motobatt AGM, (which has proved excellent) had a section that can be removed making it less tall. I didn’t spot it initially when struggling to fit it.
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Very good experience with Motobatt also. Over 4 years in use without any issue. Cold storage during winter with trickle charger attached.