Forum

[555]

Hello there ! I have a 2004 500cc 65 and I would like to know can I swap in any 500cc engine from a similar year? There is no gear box on the newly found engine, is it a simple case of nuts and bolts and lots of time?? And tea of course , and swearing ! Thanks

[Chris Tindal]

You can swap in any 350/500 Redditch or pre EFI Indian bullet engine.

[555]

Thanks , a good start , what about the gearbox? Mine is the 5 speed left side change.

[Adrian]

The five-speed box will complicate things a little bit with regard to the rear brake. You can either get the right-foot shift conversion and go with a left-foot brake pedal, or if not you will probably have to weld the necessary lugs on the frame for the right-foot break pedal. A rear-set footrest kit might get around this, anyone here know?



A.

[stinkwheel]

Surely if it's just a short-engine swap, retaining the original gearbox and chassis, the foot lever arrangement will remain unchanged?



The clutch splines are different between the 4 and 5 speed gearboxes so you will need to use a 5-speed clutch centre with a 5-speed gearbox.



If one is electric start and one kick, this could potentially cause a small amount of faffing. Depends on if you are retaining the sixty-5 primary drive componants or the one from the donor engine.

[stinkwheel]

Ahh. Looking at pictures I see the gear shift passes through the primary drive on the sixty-5. So yes, the degree of faffing will heavily depend on if you are retaining the original primary drive.

[555]

Ok, so not just a few nuts and bolts then! I think its now getting beyond my capabilities. Will revert to plan A of having my engine rebuilt. Thanks for the pointers and faffing level!!!

[stinkwheel]

Hold your horses. The amount of faff depends on what exactly you are doing. So what exactly are you doing?



There are effectively three big lumps to these engines. They attach separately. There is the engine itself (what I referred to as a "short engine". There is the primary drive case which is the oval bit on the left hand side that your gear lever is sticking out of and there is the gearbox which is the bit on the right hand side with the kickstart attached.



When I assemble a bike, I put the three bits in separately. So I bolt the engine into the frame then I attach the gearbox to the back of the engine (you can also do this with the engine and gearbox joined together but I find it easier separately). This part is just giant mechano although some of the afore-mentioned swearing can come into play when it comes to getting them lined up with the holes. Finally I bolt the primary drive case and its contents to the outside of the engine and gearbox, this contains the clutch, alternator and the chain joining the engine to the clutch. Slightly more of a fiddle but still not hugely complex. Any reasonably competent home mechanic should manage it.



So, if you are looking at retaining your original primary drive and gearbox, any old engine will fit.



Also worth noting that if you are going to have the engine out, you will need to take the primary off anyway because you won't get the engine bolts out.



So engine in:








Gearbox fitted:






Ready for primary drive:






Primary drive on:

[stinkwheel]

Also worth mentioning that the unit construction 500 engines are becoming increasingly hard to come-by so depending on what's wrong, rebuilding it is probably a good idea anyway. I spent AGES looking for a set of late 500 crankcases for my project bike and landed up paying a stupid amount of money a basket-case bike as a donor for the project. A blown-up 2004 motor with intact crankcases could go for several hundred pounds to the right buyer because they have additional webbing that makes them good for use in a highly tuned engine. Even if the whole top end and crank were scrap.

[stinkwheel]

That should say "pre-unit" not unit construction.