Friday, 10 October 2025

FH - shaking down

 Well, the Huntmaster is back on the road and very lovely she is too. When I last rode her a couple of days ago I sensed that she wasn't starting quite as easily as normal and back in the workshop I had a look at the points - they were a little bit closed up and on adjusting them back to 12 thou, her usual immediate starting returned. I'd also weakened the idle a little bit and speeded up the tick over. 

Today she's back on form, going really well, starting very easily and on arrival at my destination showing no oil leaks other than a slight weep around the base gasket and the usual drip from the chain case.

Back at the workshop, I tightened up the base gasket and it occurred to me that maybe I could thicken up the felt pad in the oil tank to reduce the oil going to the chain case. 

Looking around the bike I noticed there was a slight weep from the oil feed to the inlet rocker box. 


It turned out that the acorn nut on the other side was very loose. 


What you have to do is slacken the banjo nut completely and then tighten the acorn nut such that the rocker shaft is tight against the inside of the rocker box and then when that's done tighten the banjo bolt.

I have some 3 mm felt sheet that I bought for the W/NG air filter - I'll see if I can roll up a bit of that into a cylinder of about 12 mm diameter and cram it into the Huntmaster oil tank chain case feed. Maybe I'll wait until I change the running-in oil (SAE30) to the normal oil (SAE40) - that might make a difference.

More later.

Sunday, 5 October 2025

W/NG - Small Jobs

 A bit of workshop time this afternoon gave me the opportunity to complete some long-standing jobs on the W/NG.

This first is quite a simple one. There's been a leak from the rocker box oil feed for years - actually ever since I've had this bike. It's never had an acorn nut and in all the time I've been running it it's had a plain nut in this position which obviously won't seal the banjo. This afternoon I made a new acorn nut using a piece of suitable stainless steel hexagon bar finished with a specially ground form tool. 

Hopefully this will stop the leak!


Next up, a part that I didn't even know was missing until a chance post on the AOMCC forum. This little bit of bent sheet stops the field stand from moving upwards too far - it means that you can grab the stand with one hand whilst sitting on the bike and fit it neatly into its spring clips. Essentially the little bar guides the field stand into position and all you have to do is push it into the spring clip. 

It's made of a bit of 3 mm sheet, drilled for 7/16 and bent to shape.


Here it is, painted and in position.


Next is the new Lucas U39 switch - I have the proper one at last, including the 'T' position which illuminates only the tail lamp.

This is a picture of the underside of the existing switch, showing the position of all the wires.

I didn't get to finish this part of the job, so more of that later.

Thursday, 2 October 2025

FH - dishonourable discharge

 So after a few weeks on the bench, dealing with the wet-sumping and the fact that I seem to have forgotten how to start the Huntmaster, it now seems to run ok. Only problem is that it won't charge.

First suspicion was some wiring problem, or a failed regulator - crazy really, as in all the years I have used these regulators and wired my own bikes I have never had a problem. With the bike idling I had a look at the dynamo to see if there was anything coming out of it. I saw nothing. Zero volts. Nada.

I had a bit more of a poke around with the multimeter and eventually realised that the problem was a bit more fundamental than even the wiring of the dynamo - it wasn't actually turning! If I turned the armature by hand from the commutator end it was clear that there was actually no resistance - mechanical resistance I mean.


Next step is to turn to the other side and have a look at the drive chain. Normally this is suspended between two sprockets, one on the idler spindle and one on the dynamo - it's not supposed to be lying in a heap at the bottom of the timing case.


I poked around in the grease and pulled out a chain which still had the broken link on the end. Fortunately a bit more poking around found the side plate so I could be satisfied that I had all the broken bits and nothing was going to disappear into the engine and cause some monumental failure.


I bought this chain from Draganfly - and of course I mailed them to say that it had broken after 250 miles. They were excellent and had a new one in the post the same day.

The expert opinion from the AOMCC FB pages is that the chain was probably too tight. There is a recommendation in the Owner's Guide that it should have an 1/8" to 3/16" play - I've always had a bit of a problem with determining chain play and thinking about it I am undecided as to whether the measured play is stretch, with the links tight, or play with the links loose. I am going to try and fix this with that play being given by looseness in the links rather than by forcing the chain to deflect by the given amount. 


The little puller makes short work of removing the idle pinion dynamo sprocket, and attempting to replace the chain without moving the dynamo suggests the chain was way too tight.

It's charging merrily again now and we'll see what happens - if it fails again I might buy a belt drive kit from SRM.


Monday, 29 September 2025

W/NG - on the bench

 With the Square Four away it's time for the Huntmaster to step up and become go-to bike. The W/NG is going on the bench for a bit of a look around and some little jobs .

It's quite oily and I know that the decompressor is still leaking. What I didn't expect was to see that the leak appears to come from the main decompressor body and not from the spindle - it appears that the Dowty washer isn't doing its job and perhaps that is because the mating surface isn't as flat as it might be. I've cleaned up the nut and mating surface and relaced the Dowty washer with a new one, as I don't have a fibre washer of the correct size.

I've also replaced the (missing) gasket in the exhaust inspection cap - see that drip?


On a club run a couple of years ago, the horn fell off and it's retaining bolt was replaced by a 5/16 screw from the spares kit. I've replaced this with the proper 3/8 screw and I've also moved the horn bracket a little bit so that the terminals don't touch the engine plates and the horn body doesn't press the cable against the frame. The horn is now free to vibrate properly.


I've taken the opportunity to reroute the cable as well.


There are always tiny little things that bug you about a bike, particularly one which is in patinated condition like this. The washers under the headlamp bolts were very large and unsightly being chromed. I've replaced these with some rough old washers of the right size which look a lot better.


I've stripped the carburetter and cleaned the idle ports, but I didn't really find anything.

In other news, the Huntmaster has most definitely wet-sumped. There's probably a pint of oil here in this pan which I drained from the sump, being unable to start the bike. You could feel the oil in the crankcase being churned up when you kicked it over.



Saturday, 27 September 2025

W/NG - it's home!

 Well, it's home!

Today I took the SQ4 down to my son's house for a holiday, and brought the W/NG home - a round trip of about 60 miles with a bit of extra lane-thumping. I'd forgotten what a laugh it was.


For some reason it's refusing to idle, and the decompressor is still leaking...