Hi Everyone :)
Yatto (Dave)in Oz here.
Help!!!
Has anyone had problems with the piston "jamming" (getting caught)at the top of the cylinder liner when the liner is in fully in place (down as far it will go). The piston will not move down freely.
The piston moves up and down freely without any problem before inserting the liner.
Is it me??........have I done something wrong?......lol.

The outside of the cylinder liner has no major tolerances to contend with and any scratches are there due to the manufacturing process so will not effect the movement and performance of the piston.

Regards

Spencer

a very small lecture is required here, from memory of my r/c flying days many moons ago, this type of engine was known as an abc engine,the abc meaning alloy bronze liner. and as others have said there is a fine taper up the lining,and made to a very fine tolerance,this helps keep the compression high,but because of the material of the liner,it expands when hot, thus freeing the piston slightly and allowing very fine particles of oil to lubricate the liner,as it has no compression rings or oil rings to do the job. this type of engine was considered high performance and long lasting.

interesting information...learned something new

You can pick up some afterrun oil from a local hobby shop or maybe even a Mr Toys store if they have a Radio Control section. The after run is really just to keep things lubricated and protect the bearings from corrosion while the motor is sitting. A brand new nitro engine will be really tight when new and even after some running in, so at this stage it would be near impossible to turn the motor over via the crank shaft and that's fine 'cuz that's how it should be.

As previously mentioned people here are jumping the gun.

It is not a problem and you should not be looking for a fix. That said after run oil will be essential to keeping your engine well maintained so it would be advisable to get some.

When its time to break in your engine it will get lubricated when you first run your fuel mixture through it.

Hi Senorita87


First of all double check the assembly of the crank arm and that it is in the correct position and in line with the cylinder lining. Make sure you have added the after run oil before attempting to recoil the piston, make sure you are giving it a good pull as you would starting a petrol engined lawn mower etc so that the piston does a few good rotations when pulling. Once or twice is enough and further pulling of the recoil cord should be avoided until your RB7 is ready to run.

If you still think you have a genuine fault with the recoil kit then there are contact details on the magazine that come with your parts. Either give them a call or email customer services.

You could also request another copy from your news agents where you get your copies from but you will have to pay for this but it will at least allow you to continue your build.

Any faulty parts may/will have to be returned.


Regards

Spencer

The groove should indeed face towards the counterbalance/towards the inside of the engine, and also not visible when you remove the pull-start/engine back plate. Otherwise the conrod/piston will jam at the bottom stroke.