What mods for 433


EXCITER bottom end!....but then if you're gonna go that far..lol

That's always the first thing that I think of with those engines due to the spline clutch. Better clutching is high on my performance-list though. Other than that, for cost I would look for a cheap set of reed cylinders. Run some Honda 50 cages, flat-slides, whee!!!!

None of which answers your original question. Other than the standard ignition, intake/exhaust improvements those are the biggest bang for the buck mods I know of.
 
Stroke is the same from 338 all the way through the 485. This is all the same family. If you happen across an EXCITER bottom end, your jugs should drop right on there to my knowledge. There are some different jugs, I don't know which ones are the best though, Nutz would know. There have been guys flycut the top half of the case to accept 485 jugs and build a sleeper 485! The 485 pistons go right in, no need to change the rods. The big change from the spline clutch engines, which I call the GP engines from the EXCITER is the taper end crank which allows upgrading the clutching. You also move from points to CDI with the EXCITER. They also changed the case to set two bearings on the PTO end instead of just one as on the GP engines, which is why personally I would not attempt to go crazy with the 73 and opt to start with an EXCITER 433 instead...depending on the mission. It can be done though, like Nutz says, depends on how much you want to spend.

You can even have the PTO end welded and machined to a taper end, but you're still stuck with the single PTO bearing in the case.

The stock spline clutches don't work too bad, depending on what your mission is for it. The 433 is a good reliable performer in just about any form. Don't forget, your engine is virtually the same architecture as the 71 that won the WC! But the 433 EXCITER engine is the best of the lot as it has everything already. The ultimate evolution of this engine family though is the 485. With the right mods they can really sing in true form to their heritage as a giant killer. Though their axial fan doesn't fit the early chassis very well.
 
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to do the phazer top end on the Exciter bottom the top case needs to be bored to accept the larger diameter skirt bores of the phazer and then yes they fit ...depending on which route you go cylinders studs need to be replaced with phazer studs then you can either run the phazer heads or the exciter heads but the domes will have to be recut to match ....i just finished one of these hybrid motors and had a Aaen phazer pipe fitted to the exciter chassis

The reed 433 cylinders are all pretty close throughout the years .... best bet would be to use a exciter bottom end for the cdi and better crank design.
 
Thanks for all the info. Lots to think about now. I appreciate your knowledge and sharing it!!! Have a good X-Mas!!
 
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