Jawa 4 Valve help needed!

[Mick22]

Let me start by declaring I have never worked on oa speedway bike and am well out of my depth on this one!!

I have a mates FT500 Jawa which he believes is the first 4 valve model (he knows less than me about speedway bikes), he wants me to get it going for him so he can have a try on it.

It appears to be in good overall condition but has been sitting for over 10 years.

I have done most of the usual checks that you would do on a bike that has been sitting for a while, but the main thing I am not sure about is the oiling system. I have experienced castor oil gumming up and going hard on 2 stroke race engines, does this happen to the internails on a speedway bike?
Will I need to disassemble the engine & oil pump and clean everything?
Will the oil tank need to be cleaned out?

Also for one really stupid question...I understand the oil goes from the tank in the top tube down to the oil pump/dripper on the right side of the engine. But where does the oil end up??? does it drip on to the track, go out the exhaust, catch tank??

Thanks in advance
Mick

[Bamford#69]

Hi,
where does the oil go?, some will be burnt,but under the engine is a flap valve the drops it on the track,  it will be fitted now with a plate that has a hose going to a catch tank behind the engine between the rear engine plates , you will need to drain this regularly ,maybe 2  races will be full depending on your pump flow settings .
check this when you drain it when racing it will leave tell tale bits of metal in the oil , a warning on which bits are wearing out !
If you dont know its workshop history you  should strip  it down first
Bean oil is a great lube , but it will gum up when left in an engine and in a "Pilgrim" pump
good luck
cheers

[Mick22]

Thanks mate, where the oil ended up has been doing my head in!

Looks like its coming apart for a clean, everything looks basic enough so shouldn't be too bad to work on...except for the cam chain tensioning not sure how thats done but I'll do some more googling and try and find a description. I'm guessing you just have to keep the 2 tensioners even

[jimg1au]

the cam chain tensioners are easy its the shims under the buckets for valve gap is the bugger.

[Bamford#69]

Hi,
mine was an 897/3 single cam 4 valve , ie, early  total loss bottom end,  later model top end, great motors , last of the "clean oil" motors, went to recirculating oil in sump for the later 898 motors . still plenty of parts available ,
cheers