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Engine differences

2143 Views 6 Replies 6 Participants Last post by  mac102004
Is there any differences in the early model trx300 fourtrax engines compared to a later model trx300's? I have a friend needing an engine for his '95 trx300 4x4 and he has found a parts bike that looks like an early model, '88 to maybe a '91. looking at the pics of the parts bike, I can tell right off hand the exhaust is different.
Will the early engine bolt up to his later model frame?
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Jeep is correct, as a whole an early motor will swap right over to a later model/frame. Notable Parts differences are the Cam, CDI and Carb. You can run any carb, any cam and any CDI on any year engine so you don’t need to be concerned about sourcing other parts.

One thing I’m not 100% on between the years is the front drive shaft, I know when folks fit a 4x2 lockout to an 88-92 300 they have to modify it, not sure if the shaft length is different or not. Pretty sure Fishfiles or retro will know this though.
1988-1992 had a different harness plug for the regulator vs. the 1993-2000. other then that they will swap over just fine.
Manny, chatting about harness and cdi interchange in a thread of mine, funnily enough the exact same thing you have mentioned.
However, I have 88-92 & 93-97 CDI’s and harnesses, I can switch them around all I want and they work great, I have heard exactly as you say though that they don’t fit.
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