I have 7 of the good old baja wilderness 400s that were sold at Canadian tire. I've made a small collection over a few years. People love to call them pieces of crap and yes they are right but I have been able to get every single one I've bought running and driving good. I have about $2000 invested in 7 running and driving quads. Anyways I put 10,862k on one of the bikes and it developed an oil leak. I ignored it until the rod started knocking 2 days ago from me not putting any oil into it. I'm only 15 but I really want to keep that bike because it was my first bike. It's a 2007 baja wilderness 400 and to my knowledge they are a pretty close clone to the 2004 kodiak 400s. The only problem is that the bajas are an oil cooled 386c with fins on the cylinder while the kodiaks are all liquid cooled 401cc. Anyone know if I can swap the top end out when I put in a new crank, rod, piston etc...? A liquid cooled big bore would be pretty cool. Also these bikes share the same diff as the 04 kodiaks. Does anyone know if you can fit one of the newer locking diffs in the older kodiaks? These bikes have been good to me so I don't want to give up on them. Let me know if you have any info or you can just tell me I'm way to ambitious for a kid. Thanks all.

 

I don't think that the Kodiak cylinder will fit. Even if it is the same mountings there will be a water pump in the crankcase on the Kodiak. Air cooled engines usually nip up on bore and/or gudgeon (wrist) pin too, leaving bottom end with just enough oil to survive without damage.

On the diff lock front, this website https://www.501parts.com/product-cat...-servo-motors/ is dedicated to Yam front diffs, and sells lots of special stuff to upgrade, convert to cable, etc.

 

Cool I'll check out the link! Do you think there are any other top ends out there that would fit the 386cc Chinese motor? I'm not sure exactly what it's based off but I can show a few pictures. I have a crank and rod to go in but no top end and it's only showing 89 psi compression. The current one is obviously shot. Thanks for the info!

 

Don't go stripping it and fitting a new rod if you don't need to. 89psi isn't all that bad, I would guess at it being a light seizure if it is knocking, so take the cylinder off and check bore and piston for scores, and big end for "lift". Trying to find a bigger bore for it will be a waste of time unless Baja themselves made a bigger version by increasing bore, and you won't get that much of an increase in power anyway, My advice is find out what standard parts you need first, then try to get them.

 

I took your advice and the top end is very scored. I ordered a new one from hisun (the company that makes them) I fitted it and it runs with no knock now. I did the entire top end, piston rings bearings valves, cam. 130 psi compression. Thanks for the help!