firebanshee Posted November 20, 2008 Report Share Posted November 20, 2008 I am thinking about have the bottom of my cub cylinder shaved off and my domes re cut has anyone had this done to there bike and if so did you like the outcome?I have been told you can squeeze a little more power out of these cylinders by doing this. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted November 20, 2008 Report Share Posted November 20, 2008 I'm definitely no porting/engine expert, but won't that lower your ports and decrease port timing? I don't see how you would get more peak hp out of it; maybe a broader hp curve, and peak at lower rpms. Quote Link to comment Share on other sites More sharing options...
firebanshee Posted November 20, 2008 Author Report Share Posted November 20, 2008 I'm definitely no porting/engine expert, but won't that lower your ports and decrease port timing? I don't see how you would get more peak hp out of it; maybe a broader hp curve, and peak at lower rpms. I was thinking along the same lines as you but i just got my bike off the dyno and the motor builder was talking to me about doing this to my cylinder to get alittle more out of it and was trying to figure out how this would give me more power.I trust the builder hands down, i will ask him alot of questions if i decide to do it.I was wondering if anyone on here has done this. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 20, 2008 Report Share Posted November 20, 2008 I woudl think lowering the port hights woudl make for more midrange wich would "feel" like more power. I think if I was going to try that running a stock stroke crank, I would have a 4 mill cub cylinder and have 2 mm decked off the bottom and not have to mess with the head. Or if I was running a 4 mill crank take a 7 mill cylinder and have 1.5mm milled off the bottom. Wonder how 10mill cylinder would run with 3mm shaved off the bottom and have a 4 mill stroker crank? Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted November 20, 2008 Report Share Posted November 20, 2008 If you are trying for more of a broad power curve you can deck the bottom. This is what it will do. Lower all port heights. This will move the power band lower but kind of give the same curve. After decking I like to bring the transfers back up and leave the exhaust down low. This makes for a broader power curve with less peak. I think any kind of crank changing is too drastic. You will leave the rings exposed in the exhaust port at BDC. I would think that would be excessive heat. Plus the port durations would get crazy, no Quote Link to comment Share on other sites More sharing options...
firebanshee Posted November 21, 2008 Author Report Share Posted November 21, 2008 If you are trying for more of a broad power curve you can deck the bottom. This is what it will do. Lower all port heights. This will move the power band lower but kind of give the same curve. After decking I like to bring the transfers back up and leave the exhaust down low. This makes for a broader power curve with less peak. I think any kind of crank changing is too drastic. You will leave the rings exposed in the exhaust port at BDC. I would think that would be excessive heat. Plus the port durations would get crazy, no Your explanation makes sense to me and this sounds like the kind of power i am after.I want it to pull hard through the power band and not just have peak power.I am a 260 lb rider so i think that would probably work good for me.Thanks. i Quote Link to comment Share on other sites More sharing options...
Darthwall Posted November 23, 2008 Report Share Posted November 23, 2008 Your explanation makes sense to me and this sounds like the kind of power i am after.I want it to pull hard through the power band and not just have peak power.I am a 260 lb rider so i think that would probably work good for me.Thanks. i I was wondering the same thing about using stock drag ported 7mill cylinders on a 4mill build im doing wouldnt the larger ports of the 7mill give it alittle extra flow and by shaving 1.5mm off the bottom put the timing at where it should be for a 4mill? Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted November 23, 2008 Report Share Posted November 23, 2008 I was wondering the same thing about using stock drag ported 7mill cylinders on a 4mill build im doing wouldnt the larger ports of the 7mill give it alittle extra flow and by shaving 1.5mm off the bottom put the timing at where it should be for a 4mill? That might work. Will the rings come out at TDC with that much taken off the bottom? Quote Link to comment Share on other sites More sharing options...
Darthwall Posted November 23, 2008 Report Share Posted November 23, 2008 That might work. Will the rings come out at TDC with that much taken off the bottom? no they still sit inside about 1+mm im using blaster pistons which I think the rings sit farther down than banshee pistons Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted November 23, 2008 Report Share Posted November 23, 2008 That should get the ex timing way down. Should be a good mid motor once the tranfers are taken back up. Quote Link to comment Share on other sites More sharing options...
Darthwall Posted November 23, 2008 Report Share Posted November 23, 2008 ya I really dont know I sent K&T an email explaining what I want to do so hopfully I will hear something back soon i just want to get this shee back running so I can play in the snow Quote Link to comment Share on other sites More sharing options...
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