Friday, 21 April 2017

Sorting the front brake rod

Two brake levers: the top one is a Drags repro and very nice it is too; the bottom one is the original one from my bike, which has a fully round hole for the brake rod. This obviously allows the brake rod to spin when you are trying to adjust the brake, which is irritating.

This hole is not supposed to be round...

This is a very dodgy picture, nicely illustrating the problem of focusing on small subjects while confusing the auto-focus with a confusion of adjacent objects. It shows the brake rod with a small weld, partially closing the hole on each side. I use MIG wire as a filler for jobs like this. 

After welding, I filed the hole back to shape to fit the brake rod. Here it is in place:

Job done. Now I can adjust the brake easily.

Trip to the City

An eye test gave me an excuse for a trip to the city yesterday: not a particularly nice day, but the SQ4 has not been out for a bit so it was time to stretch her legs.

I chose an A-road route outward, with 60 mph stretches for several miles and she is flying along; a mixed A & B-road route back gave me more of the same with some twisties and peaceful roads at the end:

At the start of the trip, the early morning starting ritual revealed the carburetter flooding: switching off, starting the engine, and switching on again, the flood did not repeat itself - I think the float sticks occasionally.

On the road, my 28/24 psi front/rear tyre pressure combination may be questionable. The front end feels light and not terribly planted - I may need to reduce the pressure on the front. The bike wants to drift to the side of the road so I think I will look at the wheel alignment.

In town traffic, in the morning, you can feel that she's not happy. She gets hot, and the carburation appears rough - not too bad to be called a misfire but not relaxing either. Arriving home, I noticed the same arriving in our small seaside town, and you can see oil on the HT leads so perhaps this is not carburation at all. The clutch also starts to drag a little, so maybe some adjustment there.

Stopping to pick up some Argon on the way back (The TIG welder is hungry again) I noticed a slight clonk when moving the handlebars - this may not come from the front end, but needs investigating.

I also noticed a little oil leak, two in fact - both from the primary drive, one at the clutch and one at the front. The chain is also not getting any lubricant.

I had the LED headlamp on all the way back - it's nice to see the bike balances charge in town with this fitted. Not so nice was the flickering rear lamp apparent with the bike idling, when I took these pictures. I also noticed that I had lost one of the 4 BA screws that retain the ammeter/switch panel to the headlamp. More fool me, for not fitting shakeproof washers!

So, a few little jobs (including the perpetual speedo fault) but generally a grand day out. I must have been going some, because my shoulders ache this morning!

Friday, 14 April 2017

Kickstart Jamming - Properly this time...

So, excessive use of the kickstart while evaluating a magneto probelm eventually made a permanent situation of the jammed kickstart. The lever got very stiff and it was clear the kickstart case had to come apart. The strip is fully explained in one of this blog's most popular posts 'Spend a night in the box', and is documented here for the W/NG.

I leave the gear lever in place when I pull the kickstart cover off, and push both the selector shaft and the kickstart shaft to make sure they stay in place. With a soft mallet, pulling on the gear lever, this is what you see when the cover comes free:

Close inspection of the spring revealed that the 90 degree bend on the end, which hooks to the kickstart shaft, had fractured though it does not look like it here. After 70 odd years of use, the spring has suffered a brittle fracture across about 75% of its width:

It was also apparent that the kickstart quadrant bump stop was missing. I suspected that this had been deleted from the design when the rubber footrests & other parts were deleted in 1942, but a look at a 1941, 1942 and 1943 parts list revealed the bump stop present in all three.

The CP gearbox has a 1/4" wide kickstart spring, unlike the BA whose spring is 3/8" wide. There is not much room for the spring, which chafes on the inner case:

Using a small gas torch, I could re-bend and temper the spring, which was handy as Draganfly were out of stock. Here it is in position again:

I took the opportunity to replace the kickstart quadrant bump stop with one from stock.

When you replace the kickstart, you have to wind the spring up significantly to avoid it binding on the case.

You can see the witness marks where the spring has been in touch with the kickstart case.

Wednesday, 5 April 2017

Kickstart Jamming

Since the beginning i have had persistent and intermittent problems with the W/NG kickstart jamming. Until now, this hasn't been much of a problem since it hasn't been going anywhere but since it is almost ready for the road, the problem needs a dose of thinking about.

Questions on the forum revealed suggestions about excessive end float in the kickstart quadrant, so I have turned the bike in the workshop preparing to take the gearbox end cover off. Looking at it from the outside I have realised the lever is somewhat loose.

Tightening it all up, I've realised the lever clamp nut fouls the clutch lever pivot on the gearbox end cover:

Tightening that up, the jamming problem goes away. Another schoolboy error.

I'm told I had a lucky break and that I should put the bolt in the other way around. Apparently if that nut comes loose and you give the lever a hefty kick, the clutch lever pivot will break off...