300ex Engine Problems

My 300EX is blowing blue smoke out of the tail pipe and I am pretty sure its burning oil. Does this mean I have to replace the rings? If I do can someone help me out and tell me how much it would cost yo get this fixed and what all I would have to do to it? Also if I have to bore it when I get the new rings should I go to 330? Thanx! PLEASE HELP!!!

[hondaracing 79]

when that happend to mine they told me i needed new rings, i ended up with a new topend and preety much new everything and it cost about $800 , and if u dont know what u are doing let someone who does do the work for u it is a ***** to work on 300's

[stevengates45]

Originally posted by hondaracing 79
when that happend to mine they told me i needed new rings, i ended up with a new topend and preety much new everything and it cost about $800 , and if u dont know what u are doing let someone who does do the work for u it is a ***** to work on 300's

I just rebuilt my 300. wasnt hard at all. Didnt spend anywhere near close to 800. I put a new wiseco piston & rings in it. Costed me about 125. Thats the cost of gaskets too.

[rbm300ex]

Steven,
Did you go larger on the piston size or just replace w/stock? I just bought another 300ex that i'm tearing into the top end to cure what insaneryda86 described and am considering going to a 305cc while I'm at it and was curious as to what you did? I was figuring about 200.00 with bore/machine work, thanks for your info. on what you spent.:)

[stevengates45]

I didnt go to a bigger bore size, I just stayed stock size but put a higher compression piston in(11:1). The main reason I stayed stock is because I ride the river alot & alot of times when I see people on the river I sortof show out alot on my bike & I constantly stay on the gas, Im just scared i'll push my motor a little bit too far & blow it up or something.

[330EXman]

hey you should just buy a new wiseco piston after al if you wore away your rings then your piston must have some hours on it. a wiseco can be installed in the same sleeve. just hone it and go for it. i got my new wiseco and rings and wrist pin for $50.

if you just get rings make sure to replace the wrist pin and bearing too that is something that should be done every time the piston or piston rings are replaced!

o ya if you have a good shop manual and have some good mechanical know how you can do this jod your sely. you will need soem special tools but that all. after you do this stuff and get the engine in you make sure to check valve spring clearence befpre starting.


later man

What is a good piston of the same stock 300ex size that would give me more power but without making me change anything?

[330EXman]

buy a wiseco. you can get a higher compression and at the same time get serious HP gains. this can be installed right in the same sleeve and comes with its own rings and wrist pin. its simple to install if you have the right tools and a good mechanical knowhow.

a new wiseco piston and rings and wristpin come all together for $75-$100

later man Jay

Thanx Jay...and if anyone else has any suggestions let me know!