400-4 Tappet Adjustment using thread pitch?

[DayvW]

Hi,

I rebuilt my 400-4 engine last year - with much advice from many off this forum - and she's still running sweet as a nut (took her out for a first proper 2015 run yesterday - fantastic).  Well - my battery is duff I think (she cut out eventually and I had to turn the headlight off to kick her up and get home - will be testing the charging circuit later) ... but that aside all was excellent .  But I digress. 

I want to check my tappets - and thought I'd try the technique I read about somewhere that sounds really neat - ie. knowing the pitch of the adjuster thread, simply turn the required number of turns - or fractions thereof).  But I can't find where I read this - and importantly what the thread pitch of the adjusters is.  So - has anyone tried this?  Would you recommend it? And what is the pitch of the adjusters?

Many thanks.

[Bryanj]

One full turn of the adjuste is 1mm or 40 thou so 1/8 turn is 5 thou

[DayvW]

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

[mike the bike]

It's finer than 1mm, don't know what exactly.   It's a sound idea is that though.

[Clem2112]

I once had the SPQR ?  tappet adjustment tool that used x clicks of turn for the common thread pitches on BMC and Fords. Really good for minis.

The thread on the Honda is quite fine.... Think I measured it at 0,7 mm ?
Sounds like it should work ..... Maybe if the threads are new?

When I tried the same approach described here for my 400/4 using the Honda adjuster and a ring spanner I found the slack or wear in the threads (even with new tappet screws) left me with a bigger gap. You need to back off to the angle required and hold it there while tightening the locknut and it isn't easy !
What I find works for me after many go's  is to lightly tighten onto the .002" feeler then lock up the nut lightly and re check.
Then turn the screw in whatever direction by a fraction and lock up the nut fully while resisting the torque with the adjuster tool.
Trial and error really.

[DayvW]

Well .. in the end I resorted to the old tried and tested approach as I found it most accurate - though I did try based on a .7mm pitch (which seemed pretty close - perhaps .8?).  I did replace all the tappets last year (along with almost all the valves .. and some point they had all been doing battle it appeared!).  It is tricky getting it right - I tend to use 2 thickness gauges and judge it when the correct one goes in fine but the other (a tad larger) wont.  But I almost always get caught out by the fact that its best to just give the rocker a nudge each time to make sure its pressed against the valve .. found this by trial as I kept going up and down thinking I was going mad until I realised that sometimes I was testing the gap with it kind of hovering on the spring .. if you get my drift. 

Anyway tappets now fine ... my charging is  another story - I've found that the alternator is getting no power hence not generating a bean.  I have found the dodgy connection in the cable right close to the alternator - but not sure how to fix it .. and found that to replace the cable is an eye watering £60 odd (from DS).  So - I'm going to see whether I can repair it .... if anyone has any experience or tips on this .. I'm all ears ....

[mike the bike]

I don't know how your soldering is but that's the best way to repair it.

[DayvW]

The wires just werent making contact with the plus .. really odd - so I pulled them apart and want to try to re-afix them.  My soldering isnt bad but I'm going to see whether I can find a new spade and bullet connectors that fit .. bullet may not be too bad - but the spade is actually a part of the white connector block ... some goolging needed methinks!

[Green1]

The Hitachi blocks are simple enough but I wont recommend which one to get as I always get it wrong
pm BigAl he can supply them.

Mick 

[mike the bike]

Google Vehicle Wiring Products,  they sell spade connectors (for connector blocks, get the spades with latch), jap bullet connectors etc.  I've used them for years

[Lobo]

The 400F rebuilt blog in Classic Bike mag recently quoted the tappet thread @ 0.5mm (/ turn); or 0.02"

Given all 400F tappets are set to 0.002" it implies 1/10 of a turn to set them.

Not saying its correct - just saying I've read that!
Simon

[DayvW]

Many thanks .. I have taken a look and found an ebay shop (Autostar) that seems to have what I need (6.3mm 8 way connector - I can either use the whole connector or use bits I think) and what look likes the right bullet connectors (3.9mm) .. we'll see.   I also ordered some PVC loop tape and stuff which is more heat resistant too (currently re-building another bike .. sorry .. not SOHC but a smelly 1975 2-stroke (my other love!) so I needed tape for that too.  Hopefully I can get the cable repaired with this, get power to my alternator and hopefully all will be well and I can put some miles on the 400 without running out of juice .. or will my RR let me down .... we'll see .

[DayvW]

The 400F rebuilt blog in Classic Bike mag recently quoted the tappet thread @ 0.5mm (/ turn); or 0.02"

Given all tappets are set to 0.002" it implies 1/10 of a turn to set them.

Not saying its correct - just saying I've read that!
Simon

Ahhhhhh .. THAT'S where I read it ... doh .... of course .. and I was using the article on electrics to suss my alternator problem ...

[Lobo]

Ah... and its a pain, but the bullet connectors are 3.5mm. Bloody hard to source: if you find them in the UK can you post their address here... I've always had to use the 'States...

Simon

[DayvW]

Ah indeed - thanks Simon.  Well .. I need just the female part this time - so I may be able to adapt them .. but I'll have a hunt for 3.5s .. thanks for the warning.

Cheers,
Dave