Johansson´s Pocketbike

[Johansson]

Ok, to get this thread back in order I´ll post the video of the last and successful run of the bike.

The engine idled for 3 minutes without any problems with an EGT of slighly below 500C. When I attempted to throttle it a gasket blew inside the safety pressure valve leading to some diesel getting spilled onto the exhaust, so at the moment the bike is apart for some modifications.

Since I have just started working 200km away from home I will have less time to spend on the bike from now on, but I will try to spend a couple of hours each weekend on it so I can road-test it before the snow comes...

//Anders

[Johansson]

I have fixed the leaks in the fuel tank and fitted a second bleed nipple on the combustor so the P2 gauge won´t have to be connected to the same hose as the bleed air for the bearings.

I have also decided to redesign the throttle, after doing a closer check on the pressure valve I found that the spring couldn´t take the pressure and has been compressed. It will be difficult to repair since the valve was never intended to be disassembled, and it is also too unreliable since it will spill fuel all over the engine in case of another spring failure.

I will first try to remove the pressure valve and run the system without any restriction on the outlet to see how much fuel the main nozzles flow with the throttle valve set to full recirculation back to the tank, since the system pressure at idle will be very low there will not be much fuel going through the spray nozzles.

//Anders

[Johansson]

Today I bought a length of 6mm air hose and a neat pressure valve which will replace the broken one I use now. No pics unfortunately but I will upload a bunch as soon as I have gotten some more work done on the bike...

//Anders

[Johansson]

The battery box is made and fitted and the tank, combustor and tailpipe are painted. I think that the frame modifications are finally finished so I can start assembling the bike as soon as I get the gasket material that I´ve ordered.

In the combustor picture you can see the T2 probe and the second pressure nipple that I fitted last week.

//Anders

[Johansson]

I´ve started to assemble the bike today. The silver heat-resistant paint matches the golden tone of the fuel connections and exhaust nozzles really nicely I must say, but as always it looks better in reality than on a picture...

A friend just sent a picture of me with the bike just after the last run when the combustor problems was solved, I was just as happy as the picture describes! *LOL*

//Anders

[Johansson]

Ahh, two wonderful weeks of vacation is almost over. Not much done in the garage but a couple of 1000 km on the big bike and some serious drewling over a big turbine at a tank museum.

I found some time last week though that I spent on fitting the air connection nipple to the frame instead of on the handlebar, it looks better and gets the air hose out of the way. No pics yet but I will post some soon...

//Anders

[Johansson]

Here are the pics. I really must get a better camera since it is very hard to get a good shot with the one I use now...

//Anders

[skyfrog]

Nice work, Anders.

One quick question, don't you need a screen on the front of the intake to prevent FOD ? The intake is so low, just above the ground maybe 15 cm, and is so close to the back of the front wheel, be careful of the FOD, dirt, pebbles etc.

[Johansson]

Thanks!

On one picture higher up on the page you can see the bike with fairings on, the intake will be protected with both the fairing and extra FOD shields under the engine and higher up behind the front wheel so it should be well shielded from gravel and fingers.

I will not fit any kind of filter to the intake, the shielding should be enough and offer less air restrictions for the engine.

//Anders

[Johansson]

Today I have wired up the idle system, fitted and tested the ignition module and found a suitable oil tank for the bearings. I have also made a gasket for the combustor lid out of an old sheet containing asbest so it should not have any problems with the radient heat.

Left to do before the long endurance test on idle is to fit hose connections to the oil tank and fit it to the frame. If I can keep myself from being too social tomorrow I just might have time to test it before I head off for work on Sunday...

//Anders

[Thedon]

nice W123's in your video..(sorry i own one and its kind of an obsession)

[Johansson]

W123? You mean the lawn-mover?

//Anders

[Johansson]

Some more hoses are connected and an ignition problem is solved, the tank fairing is fitted with a spacer at the front to get some distance to the CC. If I can get some hose clamps tomorrow it is ready for a long test run at idle.

There is no use in posting pics of the bike at the moment since you couldn´t tell the difference from earlier pics, just imagine a bunch of hoses and cables pointing in all directions... ;-)

(I would have had time to do more this weekend, but I have just started to turbocharge a Suzuki GSX750 -84 that I bought this week. It became boring to only have 2 big projects going. *LOL*)

//Anders

[Johansson]

A last the bike starts to look like a bike again, it is ready for another test now but it will have to wait until next weekend since I haven´t got time to do a long test run today.

If it wasn´t for the FOD-shield and gauges I would keep the bike like this and fit two small headlights a´la Triumph Speed Triple, with the tank fairing raised a couple of centimeters it looks pretty brutal... :-)

//Anders

[Nick]

love the sound of the little beast,looks great too!

Next project, a full size speed triple!
Go on, you know it makes sense :-))))


Nick