Stroker/big bore

[teamexileracing]

Ok ive herd the word stroker been thrown around he for quite a while, What is the difference from the stroker and a big bore?

 

[dte825]

A stroker increases your displacement (cc's) by making the stroke of the piston longer. A big bore increases displacement by making the diameter of the piston larger.

 

[teamexileracing]

ok gotcha now.

 

[dave76]

Yeah they basically just move the crank pin up a bit, popular stroke increases is +7mm, +10.5mm, +8.5mm. This is the distance they raise the crank pin.

 

[jasonp]

Also most of the time you gain more from a stroker then a big bore by the same displacement.

 

[fredybender]

Stroke will give torque, as compared to bore that will give you HP...
Picture that longer stroke will give more leverage (moment) , as compared to bore size, that will give more surface, thus more force on the piston (pressure X surface area)...
But we must remember that stroke & bore are relative to each other: (Long, square, or super square engines) ... Bore realtive to stroke... Making them either "peaky" or "torquey" ...

Just my 0.02$
Fred

 

[97warriorrider]

most of the time with a stroker u also have to bore your cylinder

 

[imtarnished]

most of the time with a stroker u also have to bore your cylinder

or atleast rehone the cyl. wall.
~Bill

 

[93warriorridr]

Ok, but could you run a stock bore size or close to stock bore like maybe .020 over with a stroker crank and not have any problems? Also what does the stroker do to your reliability compared to a larger bore?

 

[97warriorrider]

stroker's are alot better..if you bore your motor and you have say a .40 over bore then u blow it up and need to bore again your just punching your motor even more..and then you might need to get a new cylinder..or a new sleeve pressed

 

[93warriorridr]

so you can use a stroker without an overbore

 

[imtarnished]

so you can use a stroker without an overbore

that depends on the condition of the current cylinder wall. If it's in good shape, a rehone should be fine. And the stroker design itself nicely compliments the the warriors natually "torquey" motor.

Now, keep in mind, Any motor, especially a stroked one, will see the most benefit from a motor that has been spec'd out to work with the riding conditions that you will encounter the most. And also while keeping in mind what you will be riding most. Check out this thread for more info as far as cams go. http://yfm350.proboards31.com/index.cgi?board=tutorials&action=display&thread=1173385110
For the rest of it you should be able to work out compression, gearing, and a pipe (which is somewhat preference, somewhat actual differences).
---For those just joining the boards, as far as pipes go, and effect the warrior motor. It's pretty much any high end pipe, Yoshi, White Bros, FMF, and few others, will all yield similiar results, total power output. Though some will place the power in different places of the power band, the yoshi is a more mid-high end pipe, as opposed to a White Bro's E series, or FMF which are more low-mid pipes (for the most part).

Good luck, and keep us informed.
~Bill

 

[dave76]

Ok, but could you run a stock bore size or close to stock bore like maybe .020 over with a stroker crank and not have any problems? Also what does the stroker do to your reliability compared to a larger bore?

Believe it or not but a stroker engine will probably live longer then a stock Warrior engine because the longer stroke actually slows the crank speed down, enabling slower piston speeds also, which all cut down on the wear factor. The biggest impact of a stroker is the torque and power come on a lot earlier in the RPM band, enabling you to relativly stay in one gear while trail riding instead of say shifting 3 to 4, 4 to 3. It becomes more luggable.