+5 Crank on a 727??

[socalrappy700]

I think your being too modest Troy....I'll bet that thing hauls the friggen mail and there's not but 1mm of difference between your +5mm stroke 105mm bore  and my +6mm 105mm bore. I'm sure you would give me all I can handle in a race 

Plus your old.

[Troy]

I think your being too modest Troy....I'll bet that thing hauls the friggen mail and there's not but 1mm of difference between your +5mm stroke 105mm bore  and my +6mm 105mm bore. I'm sure you would give me all I can handle in a race 

Haha, I doubt that Randy.  At least at this point.  I will tell you my goal now is to start paying attention to all of the things you are and I know there is a ton of power left in my setup.  It's very rare that anyone does all of the racing secrets and all of the small details that I'm sure your doing, that will keep these little cc bikes running with the big dogs.  Hopefully in time though I can get this setup optimized and get all that it has to offer, I know there's alot of power I'm leaving on the table right now.

[RaptorRandy]

I think your being too modest Troy....I'll bet that thing hauls the friggen mail and there's not but 1mm of difference between your +5mm stroke 105mm bore  and my +6mm 105mm bore. I'm sure you would give me all I can handle in a race 

Plus your old.

  True dat.....

[Colorado700R]

so since HP is a function of RPM, would a shorter stroke (IE shave the jug) with a Big bore produce more total HP and less torque?

Aaron

[RaptorRandy]

I think your being too modest Troy....I'll bet that thing hauls the friggen mail and there's not but 1mm of difference between your +5mm stroke 105mm bore  and my +6mm 105mm bore. I'm sure you would give me all I can handle in a race 

Haha, I doubt that Randy.  At least at this point.  I will tell you my goal now is to start paying attention to all of the things you are and I know there is a ton of power left in my setup.  It's very rare that anyone does all of the racing secrets and all of the small details that I'm sure your doing, that will keep these little cc bikes running with the big dogs.  Hopefully in time though I can get this setup optimized and get all that it has to offer, I know there's alot of power I'm leaving on the table right now.

You'll get it there Bro. It took me a while to get mine to where it ran to it's full potential and when I compare it to bikes like Grant's & Subs I'm still not where I need to be if I want to hang with them on the hill. One things for sure, once you get there you'll want more  


Randy 

[RaptorRandy]

so since HP is a function of RPM, would a shorter stroke (IE shave the jug) with a Big bore produce more total HP and less torque?

Aaron

Shaving the jug won't change the stroke just the deck height. Having said that, it's all in the combination of parts IMHO but from what I have seen I would tend to agree that the all bore motor will make less TQ than a Bored and stroked motor with all other things being equal.....but there is no hard and fast rule IMHO

[Colorado700R]

so since HP is a function of RPM, would a shorter stroke (IE shave the jug) with a Big bore produce more total HP and less torque?

Aaron

Shaving the jug won't change the stroke just the deck height. Having said that, it's all in the combination of parts IMHO but from what I have seen I would tend to agree that the all bore motor will make less TQ than a Bored and stroked motor with all other things being equal.....but there is no hard and fast rule IMHO

Thanks Randy, but i was thinking like a shorter stroke plus a shaved/bored cylinder to achieve less overall piston travel with a similar deck height to standard + higher compression to achieve higher RPMS/HP 

Or would this end up a zero sum gain ?

Aaron

[theshee]

I still say that troy is getting the majority of his added power from the stroke... There are several 727s up here that are not stroked but bored, and neither are a challange for troy or myself  (and Im still on stoke bore and stroke)... From my experiences on banshees, you gain way more power on stroke then bore.  After riding troys bike and my bike, they both rev about the same, I noticed no loss on the top end on troys bike.

[preddy08]

I still say that troy is getting the majority of his added power from the stroke... There are several 727s up here that are not stroked but bored, and neither are a challange for troy or myself  

At least when I'm not in Colorado...LOL.

Boring is just a stepping stone in getting you more power. They all build on each other.

[theshee]

I still say that troy is getting the majority of his added power from the stroke... There are several 727s up here that are not stroked but bored, and neither are a challange for troy or myself  

Boring is just a stepping stone in getting you more power. They all build on each other.

Id agree with that 100%...

[Troy]

I agree with both of you 100%  And hopefully that story isn't the same when I come to Nebraska tomorrow Preddy.  I can't afford to have anymore bad luck on motors right now.  If I don't get you racing, it will be because my map is off and can't adjust to the altitude,LOL.  Aaron, my jug is shaved also, not right at zero deck like the last setup but it will be soon and I'll end up shaving around .020" off of the head as well to tighten things up a bit.  As far as the shorter stroke goes, your piston is actually traveling faster both up and down before and after top dead center with a longer stroke than it would with a stock stroke.  That and your added stroke is only on the down stroke.

[Colorado700R]

I agree with both of you 100%  And hopefully that story isn't the same when I come to Nebraska tomorrow Preddy.  I can't afford to have anymore bad luck on motors right now.  If I don't get you racing, it will be because my map is off and can't adjust to the altitude,LOL.  Aaron, my jug is shaved also, not right at zero deck like the last setup but it will be soon and I'll end up shaving around .020" off of the head as well to tighten things up a bit.  As far as the shorter stroke goes, your piston is actually traveling faster both up and down before and after top dead center with a longer stroke than it would with a stock stroke.  That and your added stroke is only on the down stroke.

Piston is traveling faster to cover more distance in less time correct? but overall crank RPM is similar?  but if the stroke was shorter than stock the travel distance is less, piston speed is less and could allow for faster crank rpm?

I'm just thinking out loud here but here's my basic thoughts.  I was just thinking about Big block Chevy (Raptor) vs Small block chevy (450).  BB builds torq faster and HP on lower RPMs,  SB Chevys build HP faster and can run higher rpms.

Was just thinking maybe a split between the advantages might be intresting.

Aaron

[Troy]

You're going to find this hard to believe Aaron, I've built 3 or 4 big blocks and about half a dozen small blocks in different hotrods that I've had.  My big block 396 with a custom grind solid cam and closed port heads and a few other goodies would pull over 7000 rpms consistently.  I had an extra set of push rods in the glove box but all of my big blocks bent even the 7/16" push rods when rodding on them.  My smallblocks didn't rev and make power any higher than that big block did.  They wound up faster, but not higher.  Check this out, my Raptor engine is basically one cylinder of a small block 377 stroker motor if you look at the bore and stroke, pretty much 350 stroke and a 400 bore.  Pretty cool stuff right there.

[Troy]

Hey Aaron, are you going to race Pike's Peak this July?  Me and my buddy plan on signing up and paying as soon as they allow us to, I understand it is first come first serve.  I'm hoping it's a pretty simple deal cause I'm jonesing to rip up that mountain.

[Colorado700R]

You're going to find this hard to believe Aaron, I've built 3 or 4 big blocks and about half a dozen small blocks in different hotrods that I've had.  My big block 396 with a custom grind solid cam and closed port heads and a few other goodies would pull over 7000 rpms consistently.  I had an extra set of push rods in the glove box but all of my big blocks bent even the 7/16" push rods when rodding on them.  My smallblocks didn't rev and make power any higher than that big block did.  They wound up faster, but not higher.  Check this out, my Raptor engine is basically one cylinder of a small block 377 stroker motor if you look at the bore and stroke, pretty much 350 stroke and a 400 bore.  Pretty cool stuff right there.

Cool beans, I like learning/ or disprove what I thought I knew.  But I think one of our biggest hindering factors in the the Raptor top end power is total rotating mass.  I know a few folks here have lightened the crank/counterbalancers and had awesome results, just thought that keeping the stock displacement via boreing with a smaller stroke might be avantagous to that.

THanks for the great info Troy