[GUNR]

Hey Gizzo, how many of those air 'traps' did you put in your line before the final one which has the vent hole? Did you route the line along your chain guard and manage to aim the delivery head of the Loobman at the inside run of the chain?

[GUNR]

While testing out my newly installed Ace 'Big Gulp' air box kit, I took in the corners on the road to what we refer to as 'up river'. The ravages of the recent bushfires sit in stark contrast to the beauty of our local Macleay River. The black at the base of that tree is not a shadow but charring by flame; the black 'soil' under my bike is actually ash.

I discovered yesterday that one of my friends had never been on a motorcycle in her life and I  realised immediately that in her travels she hadn't really 'felt' the road texture, felt the rain, smelled the country odours or experienced that wonderful thing which is being atop a living, breathing monster which can be controlled by the 'twist of a wrist'. We, the initiated, are so much more alive as a result of our riding bikes (especially thumpers!).

[gizzo]

Hey Gizzo, how many of those air 'traps' did you put in your line before the final one which has the vent hole? Did you route the line along your chain guard and manage to aim the delivery head of the Loobman at the inside run of the chain?

The only airlock is the one with the hole, just before the dripper thing, per the fitting instructions. Same goes for the ones I've fitted to my other bikes. The dripper deposits oil on both sides of the sprocket via the cable tie wicks thence to be centrifugally flung into the chain as the sprocket goes around. It doesn't need aiming at the chain at all. All it needs is the wire that holds the delivery head to be on such an angle that the oil runs out and down onto the sprocket.

I've secured the hose to the swingarm with cable ties, leaving a bit of slack at the pivot end to allow for suspension movement. Don't zip them up too tight though, or you'll crimp the hose shut.

[GUNR]

I finally got my velocity stack installed but will have to wait until the morning to see if I can notice any difference. A couple of days ago I received my new compression tester and discovered that after several attempts all the readings were 60PSI; not good. The quickest solution for me was to buy a standard barrel and piston set from our host, that way I'll have a spare barrel on hand if I ever need to do a +10 thou rebore and get the matching piston that is in the 'online store'.

I have the crankcase gaskets, head and base gaskets, kickstart seals, new oil pump plastic drive cog, new primary (Renold) and drive chains, front and rear sprockets, cush drive rubbers as well as the rocker cover seals and O-rings. I hope I haven't forgotten anything.

To change over the primary chain, does releasing the tensioner provide enough wiggle room to slide the chain off or will I have to remove either the crankshaft sprocket or clutch basket to do this?

My Haynes manual mentions a special tool required to remove and install the head nuts. Is it required, or will my 3/8" or 1/4" drive sockets set fit the bill?

I like to be prepared before I start to operate so that I on't have any surprises that will mean the bike's guts will be subjected to humidity changes in the carport when it lives.

[GUNR]

Is the barrel and piston swap as straight forward as removing rocker covers, head, barrel and piston and the reversing the order to reassemble? The head, for example , doesn’t need rocker removal?

[gizzo]

You'll never get a good compression test on your bike because the decompressor is doing it's thing at cranking RPMs. You eed to disable that if you want to do a compression test. It's built into the exhaust cam and need the engine cover taken off to access.

You don't need a special nut holding tool for the head nuts.

Yes you'll need to take the rocker blocks off to remove the head. Can't withdraw the pushrods otherwise. It's only a few screws, easy.

Can't remember 100% whether the chain comes off easily. Ben and Taurim probably have better info.

You bought the oil pump gear from H? Might get one to keep in the spares box. Don't lose the O ring in the engine cover behind the filter housing!!
Good luck!!

[GUNR]

Once the cover is off, how do I go about disabling the decompressor?

[Beeza]

You have to take both the clutch and crank sprocket off with the chain, not enough slack otherwise. Given that you need to loctite the crank bolt and clutch nut anyway, no real extra work. I use a tapered wood block to jam the chain to hold the shafts. Just take the tensioner, as likely as not in backwards anyway, off before wailing on the fasteners.

The o ring on the pump/cover deserves some study. I use a dab of silicone to hold it in place during assembly. It is crude, and a bit scary frankly, but seems to work. H’s sells an ‘approximately 10mm’ o ring which is slightly oversize. I prefer an actual 10mm which seems like what would happen in India. It seems like you must use a gasket on the timing side because of the o ring squish factor, but the clutch side can be silicone.

Keep us posted…

[GUNR]

Thanks Beeza. I saw H’s special tool to lock the teeth of the crankshaft sprocket and teeth of the clutch basket, but thought a small wooden wedge might suffice. I haven’t ordered new washers for either of those or the 2 washers for the long head bolts. Can I safely reuse them? It’s quicker to receive a delivery from the other side of the planet in the UK via DHL than from 1,500km away in Melbourne.

[gizzo]

Once the cover is off, how do I go about disabling the decompressor?

Remove the exhaust cam and pull out all the bobweight and spring crap. Reinstall the cam. There's a YouTube that one of our members here posted that shows how.

You can reuse all the washers.

[GUNR]

Thanks Simon👍👍. A new barrel and piston is coming now anyway, so I’ll have some options in the future. Did you stick with the standard valve sizes when you changed to stainless or did you get the larger inlet valve? I suppose I won’t know what condition the valve guides are in until I buy a valve spring compressor and test the valve stem play in their guides. I’m only presuming as I haven’t done this before.

Anyway, it’s a nice day so I’m off to test the velocity stack and to play Irish tunes with a mate 50km away😁

[Beeza]

Thanks Beeza. I saw H’s special tool to lock the teeth of the crankshaft sprocket and teeth of the clutch basket, but thought a small wooden wedge might suffice. I haven’t ordered new washers for either of those or the 2 washers for the long head bolts. Can I safely reuse them? It’s quicker to receive a delivery from the other side of the planet in the UK via DHL than from 1,500km away in Melbourne.

The washers on the crank and clutch are reuseable. I haven’t done the head yet, but I think the same applies. One nice thing about the Enfield design is that the cylinder is long but the finned part is short so there’s not so much expansion so easier on the head studs.

A wedge of wood (Wedgewood?) worked fine for me. Be sure to clean all oil off the threads, use red loctite, and prime the blind hole in the crank well so the air doesn’t blow all the loctite out as you screw the bolt in.

I think a large part of the problem is that the splines aren’t super snug and the sprockets work a bit with the reversing loads. The crank spacer washer probably shifts a tiny bit but the loctite keeps the bolt from migrating. Splines can be like that, either a press fit or needing a locking tab washer like at the output sprocket.

It’s possible that the primary chain has been replaced. The Renold is blued steel, Iwis is edge staked and the OEM is center punched with a brownish master link.

[GUNR]

Remove the exhaust cam and pull out all the bobweight and spring crap. Reinstall the cam.

If I can temporarily disable the decompressor without draining the oil, it would indicate whether or not the barrel and piston need to be replaced at the time.
I was thinking of grouping some of my many tasks concurrently. If the oil needs to be drained to remove the RHS CC cover for;

temp. disable decomp.
front sprocket
kickstart seals
oil pump plastic cog etc.

how can I then check the compression without some sort of lube in the bore? If it is possible to disable the decomp. without draining the oil, can the compression testing be done with the RHS CC off?

[GUNR]

Anyway, it’s a nice day so I’m off to test the velocity stack...

I haven't been on the bike for a few days, but for some reason it felt like the 'megaphone effect' was now kicking in at 2,500 instead of 3,000rpm. There seems to be much more 'tow' in the mid-range and this extends to at least 5,000. Surely this feeling can't be due to the combined addition of the Ace big gulp air box mod and the recently added velocity stack? Wow what a difference and she is now even more fun than before!

[gizzo]

If I can temporarily disable the decompressor without draining the oil, it would indicate whether or not the barrel and piston need to be replaced at the time.
I was thinking of grouping some of my many tasks concurrently. If the oil needs to be drained to remove the RHS CC cover for;

temp. disable decomp.
front sprocket
kickstart seals
oil pump plastic cog etc.

how can I then check the compression without some sort of lube in the bore? If it is possible to disable the decomp. without draining the oil, can the compression testing be done with the RHS CC off?

Maybe you could do a compression test once you've removed the rocker cover, exhaust rockers and pushrod. But leave the inlet in place. That sounds like it should work. IDK if it'd upset anything down below if you spun it over with the side cover off. If you're going to rip into the decompressor mechanism you need to let the rocker up anyway, to take the load off the lifter and get the cam out. Win, win. I'd try that before doing it with the side cover off. Just because I'm confident it's safe.

I would have no problem doing a compression test with no oil in the engine. It's a roller bottom end. residual oil will be enough to lubricate it for the short time it's spinning over.

Before you go removing the cam, make note of the gear backlash between the cam gear and the driving gear. There needs to be some, but not too much. If there's none, the gears or cam bushes flog out (I don't recall which it was). Some guys have eliminated the backlash to get rid of the rattle but caused other problems. The cam runs on an eccentric shaft that can be turned to adjust gear backlash.

The GT comes with a 1mm oversize inlet valve and 500 size exhaust valve. I left them both as is. Just got the 1 piece exhaust valve.

It's good to hear your butt dyno likes the airbox mod. Mine does too. My benchmark was the way my bike pulled up over a particular railway overpass. It went up ok before but romps up with the airbox mods. I bet your bike has tons of compression.