Honda-SOHC

So a 1mm pitch thread then .. perfect - many thanks.

Hi Bodd,

My 400-4 came with the Boyer Bransden unit already fitted (installation instructions attached for info).  The unit is specifically : KIT00089 (BOX00035)   Micro-Digital ignition system for Honda "4" S.O.H.C. motorcycle (210k) if you look at their website.

I have found it excellent.  I have had the engine apart and refitted - and all works well still.  Your battery needs to be in good condition - but that aside I'd rather not rely on points these days (had far too many issues in the past!).  Sorry - dont know price or how it compares to others.

Then 12 it shall be .. many thanks Trigger.

Hi Drew,
Just to add my penny's worth from my recent 400 engine overhaul (which is also to have an easy retirement) - I figured I'd replace what was needed (and from advice sought from the gurus here).  My cam chain adjuster (the U shaped thing) was jammed and beyond mending .. so I plumped for a nice new shiny one from DS (which is expensive - but has a proper pivot - I have previously posted a pic here) - plus the 2 blades as they were very scored (prob due to the adjuster being jammed).  I didn't replace the springs. On reflection perhaps I should - but then on adjusting a gentle press down through the removable screw seems to be pretty standard for these anyway.  I did also replace the cam-chain (you would wouldn't you).  If the adjuster still worked I would have left it; if the blades were within tolerance I would have left them too.  So - my take is as others here - replace as needed - but don't go mad if you don't need to. For example my main and crank bearings looked pretty good to me - so I saw no point in shelling (to pinch your pun) out £100s for those.  Rings were clearly worn - so they had to go (and lo and behold the eye watering aroma of burning oil when ticking over in my garage (door open is long gone).  And also as documented elsewhere the primary chain was wrecked - so that went (along with the rubbers as advised by OddJob I think - they were indeed old and solid - and relatively cheap anyway).

Good luck Drew .. I'm sure the rebuild and subsequent riding will bring you the immense pleasure it's brought me.  If anyone spends any time around and over exmoor, around Lyndon and lynmouth and surrounds and sees a red 400-4 being ridden by a middle aged bloke with a massive grin .. that'll be me     

I wonder if anyone has any tips for repairing a small gash in my (400-4) seat cover.  The seat is original and I'd like to keep it if possible (I have replaced the strap and buttons as they were quite corroded).  Any hints and tips gratefully received.  Many thanks.

Thanks both - Pete I am indeed, and Mick I hope the first press of that starter (or swing of leg) is as satisfying as mine was.  My better half (and daughter) insisted on witnessing that first start-up.  I warned them it may be a disappointment ... but after a heart stopping whirr of starter motor and no firing - one started, then three ... then all four.  Not smooth then (I hadn't done the dynamic timing at the stage and the carbs weren't balanced) .. but a beautiful sound that I hadn't heard for some 8 months.  And my better half and daughter clapping and saying stuff like "we knew you could do it!".  Fan tas tic   

Hi,

With the invaluable help of members of this forum I have completely stripped and rebuilt my 1976 400-4 engine - and she lives again! It all started with some weird grinding noises (not to mention cam chain chatter and primary chain slap) and the urge to remove all the horrible paint/lacquer that was peeling and  generally looking a right mess.  So she was stripped right down (and soda blasted) and the primary chain replaced (along with the cushion rubbers as advised on this forum) plus the cam chain was replaced together with the adjuster arm (a new one from DS as mine was completely seized and worn away),plus the slippers.  All the engine seals were replaced, but the bearing shells all looked fine so they have stayed.  At the top end I replaced the piston rings (all were well outside tolerances despite being 1mm o/s rings - so clearly at least one rebore in its time (indeed it was clear that the barrels have been off - but I dont think the bottom end has been touched in its 38 years). I also replaced all the valves as virtually all were hammered - literally.  They looked as if they had been ground, but I suspect in doing this the hardened 'crust' have been removed meaning that the tappets have been slowly wearing into them (I replaced the tappets too) -so they looked pitted.  And valve seals of course.  Something I spotted when putting the rockers back in (and not mentioned in the original workshop manual that I am fortunate to have) was where the springs that keep the rockers apart should go.  If you get them wrong the tappets dont quite line up properly with the valves - I noticed that the way around that they had been mean that was indeed the case and I wonder whether that too lead to undue hammering of the valve stems (perhaps an expert can comment on that?).  I just looked through my photos of the strip - and annoyingly didnt take a pic so cant show you which way around I have them now!  I have just balanced the carbs (I did also strip the carbs and cleaned them, one float was 'sticky' due to the hinge pin being slightly bent and this meant I used to pour fuel over the floor if I forgot to switch off the fuel tap - not any more!) - and she's running sweet as a nut.  So - ready, I think, for an MOT next week.  I have to say I am well chuffed having never done more engine fettling than replace a GT380 piston many, many years ago when I inadvertently holed it after fitting expansion pipes without re-jetting!).  I have absolutely loved it.  Yes there have been frustrating moments - but I've said before (and I wont stop saying it -so tough!) that this forum has helped me no end.  Its so good to look at (and listen to) a sweetly running engine and to think I have stripped it right down, replaced stuff that needs replacing, rebuilt it .. and it works!  I plan to do more over the years - but this one will always be the special one.  And to celebrate I attach a gratuitous shot of said bike as she is now and a few of the many, many in progress shots.