whats the difference between big bore and stroker

[REPOMAN]

is a stroker better than a big bore? i just dropped a valve yesterday on my 440. i am thinking about getting a stroker but dont know anything about it. its either that and keep my bike or i am parting it out after i get a 450r. i truely dont want personal opinions just facts if available. thanks guys

[DementeD]

bore = diameter of the cylinder
stroke = the length the piston has to travel


so when you bore your cylinder to 89mm it gives you the 440
now..when u change/modify ur crank to give your piston more travel up n down you increase the stroke..

both increase displacement

[vAnS_77]

Stroke = no realibtly AFTER you have bored to 440 is asking for a blown engine imo.. For MOST** people.

[drew416ex]

If done correctly, a stroker is just as reliable and faster but also costs more than a big bore. Also, many say a stroker revs slow. Not true. If you built say a 440 stroker (+4 crank and 87mm piston) it will rev just as fast as a non stroker. I know because I have had a big bore and now have a stroker. Now if you do a 460 (+4 crank and 89mm piston) It will rev a little slower but haves gobs of low end torque which means you could gear it higher and not really sacrifice any low end. I really wouldnt want a 460 because I like quick revs and I dont know how reliable they are, but my 440 stroker has no problems whoopin some pretty modded 450's.

I have ridden both 440 big bore and 440 stroker. Now I thought the 440 stroker had way more power, pulled through the gears like it was nothing. But both had different exhaust. The 440 stroker had a HMF and the 440 big bore had a Dr. D which is pretty crappy. I dont know if the pipe made that much more of a difference but the 440 stroker killed in drag races too against other 440 big bores not just the one with the Dr. D that I rode.

[REPOMAN]

sounds like i will just get a 450r. i just killed my second 440 and i am tired of working on it. so i will just get the bigger motor and keep reliability. so if anyone wants parts off my bike i will post a list asap

[jomama]

are you kidding me?!!! a stroker motor is ten times more reliable then a bigbore! A bigbore will be 10 times more likely to wear out rings. For example look at the ol quadzilla 500s, they had a huge piston. theyd go like hell... for about 5 days. Im not dissin the zillas im just explaining their nickname. piston eater

[DementeD]

well..that depends on the engine

in this case we are referring to the 400ex
stock bore/stroke is 85x70(1.21) which makes it an oversquare motor
which..runs a little hotter then undersquare..requires higher octane at the same compression has better reliability..faster and higher revs then an undersquare..
now..if u increase ur bore to 89 and stroke it 4mm thats a bore/stroke of 89x74 which is a 1.2 ratio..which is STILL an oversquare motor..
so the 460 is .01 difference in the ratio ..which makes that pretty damn good..

now if u just stroked the motor 85x74(1.14) would still be considered oversquare...so regardless of ur stroke or bore..ur still ending up with a very close bore/stroke ratio that really wont effect the reliability of the 400ex maybe ...and stroking the motor vs boring actually helps the motor to run cooler..
the stroker does cause more stress but overall the ratio is still considered an oversquare engine and should have any problems at all..

[DementeD]

Originally posted by jomama
are you kidding me?!!! a stroker motor is ten times more reliable then a bigbore! A bigbore will be 10 times more likely to wear out rings. For example look at the ol quadzilla 500s, they had a huge piston. theyd go like hell... for about 5 days. Im not dissin the zillas im just explaining their nickname. piston eater
that is just misinformation....the zillas are not the same bore/stroke as the 400ex so therefore that information has no bearing here..

[Wheelie]

This is my 3rd season on my stroker, it has been as reliable as a stocker. Fast machine, revs very quick and rock solid.


The Quadzilla aka LT500 has a 85mm piston stock. A 400ex has a 85mm piston stock. Just an FYI for those that don't know.