Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Matt_Harrington on November 10, 2023, 09:19:58 AM
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Should one be able to dismantle the advance/retard unit? My spare unit is really stiff and the cam section seems to be reluctant to withdraw from the plate.
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Pretty sure they come apart when the springs are off much like the Lucas car type.
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Yes, they do come apart easily, starting with the springs, but mark the position of the cam first, it can fit 180 degrees wrong on reassembly.
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Thanks. It's going to need persuading!!
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Might need soaking overnight in Evaporust or similar.
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Now apart! It required some effort and now needs a serious clean....
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You could copy what I did with mine Matt, paint in the markings so they stand out when your timing the engine. I did the T marks in red and the F marks in white so they'd really shine under a strobe for instance.
(https://i.postimg.cc/W4g0vFY6/IMG-3269.jpg) (https://postimg.cc/WDpdm3vh)
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Excellent idea Ken, I'll be doing that as trying to see timing marks in daylight with old eyes and wearing glasses is a pain.
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You could copy what I did with mine Matt, paint in the markings so they stand out when your timing the engine. I did the T marks in red and the F marks in white so they'd really shine under a strobe for instance.
(https://i.postimg.cc/W4g0vFY6/IMG-3269.jpg) (https://postimg.cc/WDpdm3vh)
That’s a good idea, works very well. What paint did you use for that?
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Ken, I did see that a while ago when you posted it. Excellent idea and I'll do something similar, depending on which Humbrol paints are to hand....
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I would avoid just siliver.
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You could copy what I did with mine Matt, paint in the markings so they stand out when your timing the engine. I did the T marks in red and the F marks in white so they'd really shine under a strobe for instance.
(https://i.postimg.cc/W4g0vFY6/IMG-3269.jpg) (https://postimg.cc/WDpdm3vh)
That’s a good idea, works very well. What paint did you use for that?
I always use the small pots of Humbrol modelling paint, they last, have a great range of colours and aren't all that expensive. I do the writing on the handlebar switches as well. Also done the seat lock arrow and the black on the rotor cover badges. It lasts and is quite resistant to heat and UV.
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You must have a very small brush Ken or do you use one of those blunt syringes?
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I always use the small pots of Humbrol modelling paint, they last, have a great range of colours and aren't all that expensive. I do the writing on the handlebar switches as well. Also done the seat lock arrow and the black on the rotor cover badges. It lasts and is quite resistant to heat and UV.
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Cheers, I will get some ordered
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With engraving like that on the switchgear and the advance/retard unit for example I just drop enough paint into the engraving to completely fill it plus a little extra as it shrinks as it dries. I wait a day or so and then either scrape the excess off with my fingernail or a cloth soaked in thinners, thinners is easier BUT if the paint underneath is soft it will take that off a well, ceramic coating is unaffected by thinners, powder coated also resists it but try not to press on hard, just lightly brush the top of the excess is best in my experience. If it's soft paint, like rattle can etc then the fingernail is generally best, just be careful. The problem with the thinners is that it can and does wick down and remove paint inside the engraving as well, which is what happened on my 500 rotor cover on the Made in Japan writing.
Sometimes it's trial and error, find what works best for you. If you don't like having long fingernails for instance ask the wife if she has some spare acrylic nails, they may work.
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just curious, are all the CB four cylinder points plates/advance units the same from that era? IOW, can the 400/550/750 components be interchanged? Pics look the same to me...
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Points plates yes, advancers will vary on advance curve but will physicaly fit
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Bryan , when you say advancers, does that mean the cam AND the weights/springs?
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Yes the complete unit, inadvisable to swap parts between advance units
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Does the points cam index mark on an ND advance unit point to the 1-4 or the 2-3 markings? (it can be assembled either way so wondering which is correct.)
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Does the points cam index mark on an ND advance unit point to the 1-4 or the 2-3 markings? (it can be assembled either way so wondering which is correct.)
There's some really good images on here of the correct position.....but I can't readily find them.
It won't run if fitted backwards...giving crude analysis to confirm :)
Finding out...install it however fitted, turn the crank to F on 1&4 (as that's indexed to crank) the cam should now be starting ramp to lift points of 1&4 set to fire those piston at the top of stroke.
The other, wrong way, it will be just starting to lift 2&3 with those piston at the bottom of stroke.
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here you go, cam position notch
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Thanks! I had found some images of the TEC unit and ASSumed it would be the same but wanted to be sure. The pics I found of the ND were too low resolution/grainy to see, including those in the service manual.