What have you done with your bike/s today?

[Worty]

My modern Bantam has nice pop-pop-pop on over-run

If yours does it GB, I'm not going to worry myself any more.  Although I do suspect mine makes a more anti-social statement at times.

[CheeserBeezer]

I've just come in from the workshop and succumbed to the impending festivities....and it's bl@@dy cold outside! I'm making a bit more progress with the 2026 project. I made some bushes for the centre stand so there she is, on her own two feet for the first time!

[CheeserBeezer]

An update on my previous post of 13/12/25 in this thread, regarding the nuts and bolts which hold the flange to the brake drum (54-55 models). I have proceeded as described and used 'Unbrako' 10mm x 20 mm button heads and flanged nuts. I've ground a flat on the bolt heads, as per the originals. I've had to skim the edge of the flange off the nuts to avoid a contour in the rear brake drum, but other than that, all good. The flange is very hard steel so it is necessary to drill it out with a solid carbide drill which can be purchased for about £6. I'm much more confident about this arrangement than the pattern nuts and bolts which, in my experience, are absolute cr4p!

[CheeserBeezer]

I've fitted a centre stand spring to the 2026 project. Then I robbed the battery off it for my 'Holmfirth' A10 so that I could get the charging system working. I've just fitted a 12v dynamo and a new, 12v, regulator. I checked the wiring over and all seems OK. The PO must've been having a bit of an issue as the ammeter had been wired the wrong way round. All OK now and charging like a good 'un.

[Catz]

Nice one, getting there, though i always thought you were a strict 6v man, don't know why.
BTW, if you come across an email from me please discard as i'm now sorted.

[CheeserBeezer]

Nice one, getting there, though i always thought you were a strict 6v man, don't know why.
BTW, if you come across an email from me please discard as i'm now sorted.

....all my bikes are 12v

[Worty]

6v for me still.  My occasional riding at night on the GF is a bit like navigating by the stars with a candle.

[BagONails]

Hi RD and Worty
The usual cause for backfiring on the over run is an air leak on the exhaust system 
even the tiniest leak will suck in air which ignites fuel residue in the exhaust

John

Cheers John.

The thing that confuses me is that I'm bound to have an exhaust leak on the GF, especially where the down pipes meet the silencer, but never any decel popping.  The Kwaka, on the other hand, is sealed up the best I can get it but still pops away.  Maybe this is the reason the W650, as stock, had a fully sealed, integrated exhaust with a clamp only on the balance pipe - to avoid leaks.

The bike has reasonably balanced carbs and a stock air filter.  It runs on the lean side, but I think most Japanese bikes do.  Popping is usually worse pottering through traffic/built up areas, or long descents.  A shut off after a prolonged, wide throttle opening ( ) is usually fine.

Hi Worty, don't know if your 650 carby version is the same but my 800 with fuel injection deliberately bleeds air from the intake side into the exhaust manifold area to help clean up (burn) any unburned fuel. This is generally the cause of overrun popping noises which are fairly mild on the original exhausts.  When I fitted an aftermarket exhaust I dispensed with this system altogether and blocked up the air supply. It still occasionally pops a little bit on the overrun but is much reduced now. 

[Worty]

Cheers BoN.  Yes, mine's the carby version and, yes, it had one of those 'systems' as you describe.  On mine, it used to be a pipe that ran from the airbox to a setup on the front of the cylinder head which did exactly as you describe.  All that has been removed, and suitable bungs put in place to seal the old holes.  However, I still get the full rice krispies on decel quite often, and it can be hard to quieten it down.  It's possible I could have an air leak somewhere, but it's not obvious.

One thing I did wonder about was that mine still has the reed valve assemblies on the front of the cylinder head where the old 'environmental control' air pipe was connected to.  This has been blanked off where the pipe used to fit, but I'm wondering whether dispensing with the reed valves completely and just putting a plain blanking plate on may change the situation?

[CheeserBeezer]

I've made a bit more progress on the replacement engine for the 'Holmfirth A10'. Barrels on, and made a breather pipe which threads into the crankcase.

[berger]

cheeser i hope the lock washers on the barrel base are better than the ones i first fitted on betsy 2 the berger build because they settled and settled and settled again they were so really soft

[CheeserBeezer]

cheeser i hope the lock washers on the barrel base are better than the ones i first fitted on betsy 2 the berger build because they settled and settled and settled again they were so really soft

Yes, i've come across that. I think these are OK.

[chaterlea25]

Hi All,
Those serrated washers are a pain in the you know where
I have always fitted flat washers and I never had any trouble 

John

[Greybeard]

I will not be riding my bike for a while because the roads have been salted. Down 'ere in Cornwall the weather does not usually get seriously cold but overnight we've had sleet and hailstones and a light dusting of snow. It's 'orrible out there ❄️❄️❄️🌨️🌨️🌨️😕

[Worty]

I will not be riding my bike for a while because the roads have been salted. Down 'ere in Cornwall the weather does not usually get seriously cold but overnight we've had sleet and hailstones and a light dusting of snow. It's 'orrible out there ❄️❄️❄️🌨️🌨️🌨️😕

You're not kidding GB, the 'feels like' temp up in Yorkshire was around -8C.  Unlike the bike, I don't function well in the cold, so I won't be on the road just yet.  I also have my son's house to fix up, but that's on hold at present too.  As I get older, life seems to get busier - don't know how I found time for paid work.

Christmas is gone, the New Year has begun, I'm eyeing up my first riding day now.  Unfortunately, given the jobs I have to do on the GF, the first is probably going to be on the Dubya!