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300ex qustions.Need tips/tricks also!
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Posted by: jarfly

Ok I deleated my old post cause it was very vage on what I need to know.
I have some qustions about a 94 300ex I picked up for 400 bucks.
I have been bord out to 330cc's. Needs piston.
I dont care much about the elct start(it dont have a starter at the moment.) I want to do away with it and go kick start but still want lights I do a lot of night ridein and I dont want theme to dem out like my old shee did.
So heres my qustion.
1.Could I use a 250x bottom end? and use my 330 head? if so will it still be a 330cc engine? I was goin to do a stock 350x engin swap but the 330 should be just as good should't it?
2.If i use a 250x bottom end and the ex head I should't need custom header pipe?
3.400ex arms? are they wider? and on shocks what would I need to put 400ex shocks on?
4.swing arm? could I use a 400ex swing? or what is a good cheap swing arm?
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Thanks for the help and if you have any info/tips on any thing I would like em

Posted by: honda300EXtreme

ok let me try to help you out

1. a 330 (80mm bore) on a 250x bottom end does not equal 330 cc's because the 250x has a shorter stroke then the 300ex, but if i recall correctly, the 300ex and the 250x pistons do not interchange because if different wrist pin diameters, but im not positive

2. no you will not need a custom header, simple as that

3.400ex a-arms are about 3 inches wider i belive, and you need to run a shock relocator bracket, which will allow you to run a variety of shocks, and youll also need 400ex tie- rods

4. i tried a 400ex swing arm it was a pain in the ***, the 450r swingarm will work but you need to mount a bracket on the frame, to accept the linkage for the new shock you will need

hope this helps

Posted by: Dr89

^^^ everything he said.

i'll only add that if you have the means to properly do a 350x engine conversion you'd be a lot better off than you will be with your 330....it will be quite a bit more powerful. you will need a custom exhaust for that. oh and just replacing the starter would be a lot easier and more convenient than going to a kick start...they're only like 30 bucks or so.

Posted by: 2muchquad

The 250x and 300ex have the same wrist pin diameters.You could use the 300ex piston in a 250x for slightly lower compression because of the wrist pin location.A 250x piston in a 300ex will have higher compression.The wrist pin locations are slightly different because of the 250x and 300ex have different strokes and rod lengths

Heads cams exhaust etc will all interchange though