Engine Qs

[reconmaster]

ok i have decided what i'll probly be doing this winter to my ex 1st is get a header, a parkingbrake block off, graphics, maybe new fenders, and a bumper.
foe the motor i have been thinking about doing some stuff but i don't think i'll go with the 330 kit cause it wouldn't rev enough for mx purposes for most tracks in my area and boring out tends to causeproblems for reliability. other wise i 'm pretty sure i'll get an oversized piston (high compression), cam(i think what you consider a stage from webcams is), and port n polish.
what is a 300s stock compression?
can i get 12:1 compression piston
i do have a limited budget so can you guys please give me any other ideas i could and some advice or words of wisdom thanks

[kd5sfq]

If I remember right stcok compression is 8.9:1

If you go over 11:1 compression, your starter motor may have trouble cranking it. Some have problems and others don't... Go figure.. Even so higher compression give you much gain in power for the cost... You will need to run race gas though.

For MX I recomend staying under 300cc just in case you want to run a national event. With the right cam and carb it can really scream... My sons is at 289 right now and it is fast around the track.

We used a big bore sleeve to keep the walls thick. We ran it all season.

An oil cooler is a good idea... An all around cam does good...

Don't forget about you suspension. It's more important than motor work... On an MX track you can only go as fast as your suspension will allow you to. A stock bike with no motor work can out race a quad with motorwork and poor suspension.

[reconmaster]

i got suspension dealt with so 11:1 is fine with out race gas? btw the classes in canada are open cc

[Cody_300ex]

I wouls still just go with a .080, less money and enough power for MX. If your wantin to spend big money then I would go with a stage 4 web cam, kibblewhite h/d springs, hardened rockers, shortened valve guides, Shave/deck the head .020 to get a little more compression, 4 angle valve job, Port & poilsh, 400ex carb and you will have a hell of a MX motor. Now If you don have a lot of money go with a stage 3 web cam, Kibblewhite valve springs, Shave/deck the head, 400ex carb if you have a dremal, clean up the ports, and poilsh the exhaust side, keep the intake rough for fuel atonimization(sp). A local machine shop should bore your cylinder out, and shave the head alltogether for no more than 120-130. I hope I was a help, I know people running both these set ups and there both pretty stout I know of a few others that are good too.

[reconmaster]

the problem with .080 is you can't bore it out if you blow it up i was thinkin the 2nd or 3rd cam that webcam shows on there page
i figured jetting the carb would be good enough or if had $$$$ get an edelbrock .020 gives enough compression and doesn't throw away much reliabilty

[kd5sfq]

If you go .80 over with a big bore sleeve and there is still lots of room grow...

I suspect that there may be less than a 1 HP gain between a well build 282cc and a 298cc.

[Cody_300ex]

On a stock sleeve you can go all the way out to a .120 which is a 305cc. I regret only going with a .040 piston.

[reconmaster]

me and my neighbr were talkin and the 11:1 ratio would kill my durability he said go with a 10:1 or could i get away with 10.5:1 wdoes honda make does kinds of pistons

[Cody_300ex]

Originally posted by reconmaster
me and my neighbr were talkin and the 11:1 ratio would kill my durability he said go with a 10:1 or could i get away with 10.5:1 wdoes honda make does kinds of pistons

lol, you need to find some new neighbors. No it wont, I have been running well over 11:1 for about 9 months now and mine is still runnin strong.

[reconmaster]

what kinds pistons can i get 0.020 besides wisecoe?