1974 XS/TX650 rebuild

[Floradawg]

A beautiful bike! What are the cylindrical parts mounted at the top of the rear shocks?

[tonyfoale]

A beautiful bike! What are the cylindrical parts mounted at the top of the rear shocks?

Air or nitrogen sealed pressure chambers. The gas pressure is to stop or reduce the tendency for cavitation in the damping oil. This is very common with any quality shocks but some incorporate the gas chamber within the body of the shock and some do it in a remote cylinder connected by a hose.

[th62]

And some of the cheaper ones are BS, just for show. Fortunately, mine are real.

[tony_hill]

Very well done! Your design concepts, even if they didn’t work still benefitted us all. I certainly learned a bit from your hydraulic clutch attempt!
Thank you for sharing your beautiful project!

[th62]

I made a fuel distributor a while back, its function was to level the fuel when the level in the tank dipped below the level of the tunnel and also to neaten things up. ,I had two online filters feeding fuel into the distributor.

The filters just kept cracking and leaking, so I decided on a combined fuel filter/distributor and this is what I came up with. The unit sits between the manifolds I made a while bike and is mounted in rubber grommets on a bracket attached to the cam chain tensioner.

The filter is sintered bronze and the body 6061. The bore is 18mm at the top to seat the filter and O ring, then expanded out to 23mm. There are three 6mm brass barbs pressed into the lower section, two for inlets for fuel, the third for purging debris. The top cap is retained by two M4 screws and is a push fit over the lower body, an O ring sits in a recess around the filter for sealing the top cap to the lower body.

Two 8mm brass barbs were pressed into the top cap and they feed the carbs via short fuel hoses. The cap is drilled 10mm underneath leading to a 5mm cross drilling which lead to the two brass barbs.

[tonyfoale]

Very neat.

[th62]

Problems, problems, problems. Bike was going fine, shut it down and next morning it wouldn't start. I've had the engine out 3-4 times and stripped it down trying to find the problem: Bore is well within spec as are the pistons and rings. Valves have been leak checked - no problems, Head gasket is also fine, no leaks from there but compression test revealed 75psi, a squirt of oil in the plug holes brought the compression up to 130psi.

Once again I stripped it down, honed the cylinder and then measured bore and pistons again, perfect. Checked valves for leaks, prerfect. Checked head gasket for leaks perfect, checked stagger of ring gaps, perfect, but compression still 75psi, jumping to 130 psi after a squirt of oil. This just isn't making sense. SoI checked the gauge on the compression tester, perfect. Aaaargh!

So today I made this leak down tester, yes I know you can buy them for a few bucks, but I make stuff, its what I enjoy doing. I had to turn down a 1mm jet to press in the three way adapter, otherwise it was simply made from air fittings. I have a Jamec fitting on it at the moment, but most of my Jamec fittings leak a little, so I may have to change it to a Nito fitting. Basically the same as the commercialy available ones except there is a hose between the two gauges, the first gauge being fitted to the compressors regulator.

Tomorrow I'll test for leaks, there's has to be something I'm missing. I'd pull my hair out if I could, but that's long gone.

[tonyfoale]

Is the compression loss equal on both cylinders?

[th62]

Yep, within two or three psi.