JAPton blog

[JackyJoll]

Maybe a blind person could help you find the source of the click. They are well known to have good directional hearing.

[Buckaroo]

Didn't see that coming

On a serious note : would a lack of pressure between the roller and can lobe cause this? Push rods too short and not maintaining optimum pressure.

Probably a rubbish thought but I'll blame heat exhaustion.

[Rockburner]

Didn't see that coming

On a serious note : would a lack of pressure between the roller and can lobe cause this? Push rods too short and not maintaining optimum pressure.

Probably a rubbish thought but I'll blame heat exhaustion.

Push rods are definitely not too short...

[Rockburner]

Back in the shed of prevarication....

Well, actually.... progress has been made.

As promised, I tested the cam lobes by the simple mechanism of throwing the cam shaft into the pillar drill and setting up my magnetic stand for a dial gauge.

i tried the digital gauge first, but it was just too hard to follow, so I dug out the needle gauges.


First try, but then I realised that the gauge wasn't being held very well, so there was a hiatus of sorts while I fecked about with the gauge clamp on the stand...

And eventually gave up and used the other needle gauge which isn't as reliable... but should be ok for this.

Here's a couple of lovely little videos...

Ignore what I'm wittering on about in the video re which lobe I'm looking at, I got confused.
This is for the exhaust lobe


And this is the inlet.


It might LOOK like the inlet would be the first lobe that's activated when you look at the camshaft... but note that the cam followers are not inline with each other, they're either side of the camshaft, so as the camshaft rotates, the exhaust follower is actually the first one that's actuated.


Anyway - the cam seems good.

I also rotated the timing chest with some oil drizzled over the actual gear-teeth of the camshaft and half-time pinion.... which I realised that I hadn't done yet! the click-clack was definitely reduced when I did that... so I think it's just the backlash that is inherent in the system, and I'm being way too anal about it*.

So i also checked the backlash again (at a point where both valve springs are partially compressed), and it's no more than a degree, if less. Which is inline with expectations, so I pondered while I took a drink, (Fever Tree Mexican Lime Soda if you're interested), and thought.. fuck it.

So I assembled the timing gear for the final time and also decided to make a new timing cover gasket, because the one I'd been using had got very oily and I wasn't sure if it would take the 3Bond very well.

So - here we go again:
Cut the a blank bit.


Leave it under something heavy for a short while to ease the bend .


Basic outline and as many screw holes as I could get the pen to work with.


Half way through the dinking.


So - new gasket.

I also remembered a bit of advice I'd seen and found a short length of "wire" to make sure that the oil-feed quill is inline when the timing cover is fitted.


(yes, I spotted that bit of gasket paper...)

Fitted the push rod tubes



Fitting the cover, making sure everything is aligned



Timing cover buttoned up tight. New gasket was fitted with 3Bond. The gasket is so thin, I just spooged out an excessive amount of 3Bond from the tube and brushed it onto the gasket paper thinly with my fingers.



remember to pull out the guide wire.... do NOT want that to wander down the crank shaft....


Then placed the Magneto, fitted the sprockets and chain.


There's no keyways on either of those sprockets, they're held solid by the nut pushing the sprocket onto the taper. I messed around for a bit getting the camshaft sprocket done up - eventually got it done up "tight" by putting the plug into the head and working against the compression, but it wasn't ideal. So once the Mag was tightened down with chain tension, I had another go at it, working against the locked mag spindle.

Mag chain in and tensioned.


With some movement, but not too much.


The combined backlash between the timing disc on the crank output, and the locked magneto spindle is about 10 degrees!! So ignition timing will be approximately correct at best....

I timed it to 34degrees before TDC, which... according to one of the books, is correct for a 350 at 15:1.... but this bike is about 400cc... running a much lower compression (estimated 9:1) so none of the ignition timings mentioned in any book will be correct, so I've chosen a starting point and will work from there.

This is the "drive plate" for the Pilgrim Pump.


It drives that little thing there.


Don't forget to cover over the Mag's spindle lock hole



Just showing here that even with the chain cover on, I can still get at the mag spindle to make ignition timing adjustments.


And the little cover in place


I didn't bother trying to seal the chain cover, I expect it might come off again reasonably soon....

Fitted the upper valve covers.


And, while I was at it, the return tube for the sump-return pump. (I expect that would be a pain in the arse to fit once the engine is mounted.)


I also, luckily, remembered to fit the mag-platform brace.

The next thing I need to do is sort out the Rocker box oil feed union, which really is absolutely knackered, not only are the hex-flats nearly gone for fitting it, but the thread for the nut that holds the banjo fitting on is absolutely fucked.

I managed to talk to another JAP expert the other day, and got a bit of a dressing down for not being pro-active enough, eg not having my own lathe, to be working on old bikes and engines. He also said that I was making a mountain out of a mole-hill with this banjo post business.

Which I thought was a tad harsh, but he did have a valid perspective at least, so I need to find localised "mate down the pub" for some of the more engineering-ey work. With any luck....


One other thing he suggested though was taking the 1/8" BSP 28tpi oil union and running a 3/8" BSC 26tpi Die down it. His thinking was that the thead is only about 3/8" (if that) and over that short distance, the thread-form is close enough that the die won't destroy the BSP thread, but will cut a usable BSC thread-form. I'll hold that thought and if I can't find a BSC union then it's an option to try with a new steel post from the suppliers (who are adamant that they only have the BSP unions).

[Rockburner]

Well, they say you never know until you look....

So today I took a spin in down to Selsey, where I'd seen a large JAP branding on one of the small garage-type buildings. What do you know, right by the sea there's a guy who builds and raced JAP grass-track bikes and Formula 500 cars.

I'd spotted the place when we first moved here, but today was the first time I'd actually walked through the door. Face to face really does make a difference. Lovely guy, very very knowledgeable and he pulled a oil union from one of his old rocker boxes and let me have it! In turn I gave him my details with a promise that if he needs a pair of hands in a rush, I'm only 10 minutes away.

Turns out the union was still BSP, but i was able to adapt it, running a die down the thread does seem to have worked (and I needed to clean the thread in the rocker box too, obvs), but the union has fitted beautifully now.

Seeing as I was on a roll, I fitted the oil line from the pump to the head while I was at it.

(yes it needed 3 copper washers....)



Pump end.


Then I removed the two large bolts that hold the rocker box down, and fitted the head-steady, this is why I needed the oil union before I could get much further - you can't fit/remove the oil union with that head steady in place.


My Dad never learned to weld....

(mind you, I haven't yet either! )



I even got as far as wiring up the Mag to see if there was any sparks!


And there were!

but they were pretty small and weak... so it could be a shite plug, or well, we'll see...

Took the timing wheel off and put the primary gear cog in place, but haven't done anything up yet.



Next time I'm in here... it's just a case of bolting on the front engine plates, and doing that nut up TIGHT (with Loctite)....

And....

I can put it in the frame....

Well.... first I have to figure out where the bits I still have left over should have been fitted.... worryingly... one of them is a rather large diameter, but shallow, nut. IE it seems like a specific use-case nut.... oooo-er...

[Ian]

I can't wait to see it run

[Rockburner]

I can't wait to see it run

Fingers crossed....

I'm fitting the Concentric, but I have no idea what jet/needle/slide combo it needs, so it'll be trial and error for a while! (Not too mention the "best guess" ignition timing!)

[Rockburner]

So... er... another installment.

This is how I left the engine:


I started the evening by fitting the front engine plates:


Nice and easy.


I then remembered I wanted to safety wire the sump plug


Not my finest work, but should be good.


Then I fitted the output nut


Can you say "f****** tight" on air?


So far so good - the bits I have left...


Managed to fit the needle into the carb (middle position of 3 for now)


Had to disengage the other end of the cable to do it though! I've a nasty feeling that I may need to make/buy a new cable to be honest.


Because there's an extra ferrule at the twist-grip end to allow the cable to fit snugly into the adjuster for the quick-action twistgrip (why a quick-action?? why not!)
But with the ferrule fitted, the slide doesn't drop all the way to the bottom.
I ended up removing the extra ferrule for the time being.


I then tried the clamps on the rear engine plates again...


And took the legs off the engine...



Can you tell where this is going.....

Can you??

In the immortal statement the actress said to the bishop....


"IT'S IN!"



Took me a only a short bit of sweating and straining, with some liberal swearing for good measure, then some fiddling about to get the engine bolts into place after they all had a good brass-brushing!
The thing is fugging heavy, and I've just remembered i was going to weight the thing before I fitted it.... ah sod it.


Started to re-fit all the other little bits: this is the new coil:


I wasn't happy with it sitting right over the exhaust, so after some faffing about looking for a spacer:


I fitted it on the other side of the head steady


nyloc


Primary chain


little fishy swimmy swimmy!



The oil pipes: eventually I want to fit transparent ones here so I can see the oil flowing, but they do tend to go foggy rather quickly... so.. maybe.



I WAS tempted to leave the exhaust off... but decided that would be childish.




Carb is on too....
Note to self - those nuts are a bit of a git to fit - you need to hang the carb at the very end of the studs and work it down because the studs are so close to the body, the nuts can't be spun down if the studs are protruding all the way through, ie if the carb is "in situ" right up against the manifold..


Cable routes, again - not brilliantly happy, but we'll see - the throttle cable might be better off OVER the frame rail... then then it might bash on the tank underside... we'll see. The slide does seem to be free to move.


The plug wire seems a bit long... that may be trimmed a bit and the old NGK cap fitted.


The coil in situ



Routing for the mag-coil loom, again TBC


Did the plug up tight


That slightly long engine bolt at the bottom left IS used, and not just for to hold the cases together - the primary chain case has a bracket that is mounted to it (IIRC).


Kill switch wiring, again, TBC.


The only things left to fit are the tank, seat and chain cover.

Then... err.. it's time to kick it, I suppose....

I tried rotating it by hand... and I CAN get it over compression by hand... soo... that could mean it's lower than I thought (or maybe I'm heavier than I look??)

I'm not sure what to think at this point... it could be an abject failure, it could fire up straight away....

[cvilla]

Can't wait for the big reveal....

[Rockburner]

It's a nice Thursday afternoon - I really ought to be enjoying the sunshine.

Hey ho, back to the shed.

First thing I did was have another go to see if the mag was producing sparks: It was, they're not huge, but they're there.



So I pulled down the tank, after pondering which needs to be fitted first - seat or tank.
It's a bit easier to fit the tank first.
Here's the first problem...


Petrol hose is about 2-3 inches too short now.

Luckily I had grabbed Dad's filthy bag of filthy hoses last time I was at the old folks home.


Found some nice unused braided fuel hose, which matched what was already in use, and there's plenty of it.
I still trimmed it a short as I thought I could get away with.
(The whole bike is built up "as if" it were a race bike, lightweight, minimalist etc, so I may as well carry on that theme where I can).


Re-fitted the oil lines.


I then tried to get it spinning enough to check the oil was flowing, which proved a thankless task. I even pulled the feed off the pump to check there was flow from the tank, which there was.

So, I stood looking at it for a bit....

Then realised I may as well give it a kick, so splashed some 98Ron E5 into it...

Spoiler

HOLY FUCKING SHIT!!! IT'S ALIVE!!!!

MUWAAHAHAHAHAHAHAHAHAHAHAAH!!!!!!

I genuinely swear to any deity you choose, that was the 2nd time I kicked it with the plug in!!

I will admit, the first kick was promising.... there was a "crack" of a very definite ignition, it just didn't catch.

I am SOOOOO fucking chuffed right now!! When I stopped the video I was laughing manically and couldn't stop myself for a minute!



I still can't believe it fired up so easily!!

There's still a fair bit to do before it's road-ready, but most of it is tinkering, then tuning the carb a bit and making sure it's the ignition isn't "too" advanced - but fuck me... I am gobsmacked.

[Lutin]

[Count Steer]

You star.

Legend.

[Rockburner]

And so begins the teething issues....

This damn banjo union will not stop weeping.


I have pissed about with it for a couple of hours now, and discovered something.

The bloody filter plastic has a partial lip in it! I have a spare one and it has it too!
You should be able to just about make it out on this macro shot:


It "keys" to this area of the mating faces where the filter plastic overspills from the float-bowl body:


You can't make it out, but in this shot it's slightly skew and so sits proud a bit.


I don't know if that lip is enough to prevent a petrol-tight seal... but I do know I can't get the fecker to seal, no matter how tight I get the banjo bolt. I was getting worried I'd strip the thread in the (new) float bowl!

It's definitely coming from the upper part of the banjo union.


FFS

I may head over to the Ardingly AutoJumble on Sunday (if I can), the AMAL specialists are normally there so I can ask them about it in person (with the community of old bike geezers face to face tends to get you more information).

If that reveals nothing, then I'll have a go with Hylomar or something like I did with the Monobloc reservoir cover, it might help.

And I figured I'd stick the end-can on too.
(after a quick polish )

[Buckaroo]

Brilliant video!!

[mangocrazy]

Well done, that man. Perseverance pays! The exhaust sound with no silencer was enough to wake the dead. What's it like with the silencer?

[crust]

Fantastic!!!

What an excellent reward for all your hard work and perseverance

[v8-powered]

Excellent result! It sounds an angry old thing.....

[iansoady]

I see you're using my trick of 2 crocodile clips to hold the plug! This is a brilliant rebuild and makes some of mine look trivial.

[ajlog]

Love your youtube thumbnail, sums this up.
Fantastic, what a milestone for the project after the hours of work, head scratching and perseverance.
A very well deserved congrats.

[JackyJoll]

I have never found those nylon bases prone to leak, so it should be fixable, maybe with a replacement gauze.

Any piece of Hylomar that comes off downstream of the gauze will roam around the float bowl like the Flying Dutchman, until it causes trouble.

I mounted a small resin-filled coil too close to an iron cylinder head and the coil cracked.