Most 2 stroke twin cylinder petrol engines have both cylinders firing at the same time. You could therefore use two of these ignition units. one connected to cylinder 1 and 4 and the other connected to 2 and 3. two hall sensors and two magnets would be needed , one at. 30 degrees before top dead cen...

Static timing for Rcexl ignition is 28 degrees Before Top Dead Centre. The ignition unit has built in auto advance so you don't want to set it more advanced than this stationary. If you find that the engine kicks back too much when starting you can retard it a bit but it should be OK

You can use SIROFLEX trade strength Red High temperature Heat resistant silicone sealer. It is recommended for up to 300 degrees C but it doesn't deteriorate on petrol engine exhaust joints. It has the advantage that it helps to keep the bolts secure because it seals the threads and there is no gask...

When you go to the print shop don't quote a percentage - tell the operator how long you want the sheets to come out eg; enlarge from 40" x 20" to 60" x 30" or whatever the relevant dimensions should be. Otherwise you may get something you don't expect !

Electric starter has to be the best bet! But it will be useful to check the spark plug if engine won't start. If dry, fuel is not getting through so you will have to prime the fuel lines and carb. If wet, engine is flooded. Dry it out completely with gas ring or gas torch until all the wet oil and f...

Hi Carey, I know this has nothing to do with Ian's enquiry but your calculations from Bob Clowes seem to present some problems. The exhaust port area of 20 sq mm seems awfully small to need a tail pipe diameter of 12.55 mm. This 12.55 mm diameter then changes without explanation to 12.55 sq mm area....

Octopus RC also list a good range, I've had good service from them. But stick with the RCEXL brand
(not the XYZ ignition ).

You could try r.w.woodhead@btinternet.com He makes oleos to order at a sensible price but I don't know if he would do anything that big.

Thanks for your advice Nick - I'll follow your recommendations.

Can anyone advise me of the best way to retain the screw which holds the throttle butterfly to the shaft to prevent loosening due to vibration. I would normally use Loctite but don't want it to get into the bearing surface . There is nothing in the Walbro manual so I assume this is not normally dism...

I don't think you are going to get an honest answer on this John, but based on past experience in engine manufacturing industry it will probably as follows. Champion would have had an agreement with Zenoah to supply spark plugs in which case they developed a plug ideally suited to the engine - the 8...

I seem to remember that some of the old two stroke motorcycle engines did not have the flywheel keyed. I suspect the keyway is only provided for ease of assembly on a production line. The key is only likely to shear if it experiences a high shock load or serious backfire. Go easy on the Loctite - a ...

Suggest you obtain a diaphragm kit for the carb - If Gashanger can't supply you could obtain a Walbro equivalent ( I suspect the DLE carb is a copy ) from Rowena Motors . The Walbro equivalent carb is WJ 71 and the diaphram kit for that is D10-WJ . Their address is on Google. Also try Googling WALBR...

The Windsor propeller website gives useful info about changing from two to three blade props but they don't cover 4 blades.

Used copies available from Amazon for less than £10

What is to stop you having the join in the fuselage just rear of the wings with the servos just rear of this joint ? This would avoid the servo weight in the tail and any complication in the linkages. With no joint at the tail end the tail itself would also be lighter.

In the absence of any precise 3W figures 0.020" ( 0.51mm) would be appropriate. The main concern would be to avoid setting them too wide which might put strain on the ignition system, but 20 thou. is safe enough.

These problems sound like ignition timing faults. I don't know how you would check this on Zenoahs. Petrol engines will kick back badly if too far advanced - running backwards could be retarded. ( Early BSA Bantam motorbikes would set off in reverse at traffic lights until they fitted a long delay c...

See ' Help required making 50cc silencer ' by Paul Hill on page 2 of Technical Help of this forum. Chris Lane provides details of a download from Model Engineer 15th March 1956. Excellent starting point ! My effort was made ( from the next door neighbour's rotating washing pole) approximating Fig 3 ...

Hi Hugh , I can't visualise the bearing you are looking for but a good starting point is the on line catalogue of Simply Bearings ( at Leigh in Lancs). Tel 01942 269837 . From this you will be able to describe and dimension your bearing the way the bearing suppliers list it. They supply from bargain...