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ajp pr3 zongshen engine info/help

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Friend has a 2014 ajp Pr3 which has an electric start zongshen 233 cc 5 speed engine in it,he loves itespecially the low seat height for his short stature. Only bitch is its slow as hell. Can he use top end performance honda crf230 topend parts,or rev box,carb,??? No room for bigger carb i am told as gas tank is behind engine. I have not seen bike as he lives 200 miles away,but would like to speed it up over winter[Northern Vermont winters are verrry long] Any input or info would be greatly appreciated.

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My friend bought the 223cc version for a replacement in his 200.  There are two diferet stud patterns out there. One is the same as the honda and the other is wider spacing.  The one we have has the honda spacing and it sure looks like honda parts will fit, top end wise.  If its the wider stud pattern on your friends you wont be able to use honda cyl, or head. I think the wider spacing would be great to allow for a bigger max bore size.

user name GREENHUMAN has extensive experience with the parts interchange and has built some impressive motors.

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Unfortunately, you will find that most CRF230 top end parts won't fit the PR3 with the 233cc engine. The stud patterns are different (69mm piston), and the PR3/PR4 gudgeon size is 17mm versus 15mm for the CRF.

Having said that, with some modifications, you can use CRF performance camshafts. There is a bush on the non-sprocket end of the AJP camshaft, just like the old XR200 used, so either a different bush needs to be made up, or a suitable bearing found to fit. The standard CRF bearing has a larger O/D than the O/D of the AJP bushing.

The CDI unit (rev box) will work too, but needs an adapter plug to suit the different connecter style. I guess you could chop the existing plug off and fit a CRF style one if you wanted.

It would be interesting to see if a PWK carby would fit...

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You would have to be very careful with the performance cam as the ZS uses a 34 mm inlet valve and a bigger exhaust valve than the crf. Not much space between the valves.

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Send Thumper racing and email and see if they have any thoughts about your problem. I hear they are very good at what they do. With these AJP engines especially the PR3 and 4`s being more popular, maybe they have tinkered with one and could help.

Here is the website http://thumperracing.net there is contact info on one of the pages.

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