elwilliams13 Posted May 7, 2008 Report Share Posted May 7, 2008 I got a set of cylinders that where ported a while back. It was a recreational port I measured them and got: 26.75mm fron the top of the exhaust to the top of the cylinder and 41.30mm from the transfers to the top of the cylinders. The intake was cleaned up but look the same size. port Quote Link to comment Share on other sites More sharing options...
endofitall9 Posted May 7, 2008 Report Share Posted May 7, 2008 that intake is definately not the same size and those have boost ports cut in them..who done the porting? i think that the porting is set up for stock stroke. dont quote me but i think if your port is above 24mm you have to have them adjusted for 4mm..someone correct me if im wrong...also those dont look like no recreational port ive ever seen... Quote Link to comment Share on other sites More sharing options...
blowit Posted May 7, 2008 Report Share Posted May 7, 2008 (edited) I got a set of cylinders that where ported a while back. It was a recreational port I measured them and got: 26.75mm fron the top of the exhaust to the top of the cylinder and 41.30mm from the transfers to the top of the cylinders. The intake was cleaned up but look the same size. port Drag race specs or at least timings. sounds like it is not well matched if nothing is done to the intake. After looking at that pic, they seem to be cut for speed, not comfort. We would probably seek to do more work in the intake but it looks pretty good so far. Brandon Edited May 7, 2008 by blowit Quote Link to comment Share on other sites More sharing options...
elwilliams13 Posted May 7, 2008 Author Report Share Posted May 7, 2008 These were done by TDR and It is his recreational or stage 1. Any other measurements you might need let me know. I am trying to put together a low to mid motor and looking around my parts bin. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted May 7, 2008 Report Share Posted May 7, 2008 Yeah, its about 195 degree duration. I dont really see anything recreational about it. The duration on the exhaust is about where a drag bike would be setup. I run 187 degrees exhaust duration on my dune port 350. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted May 7, 2008 Report Share Posted May 7, 2008 what pipes do you run 187 exhaust with? Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted May 7, 2008 Report Share Posted May 7, 2008 pro circuits. Quote Link to comment Share on other sites More sharing options...
elwilliams13 Posted May 7, 2008 Author Report Share Posted May 7, 2008 What would be ideal duration or port height for bottom end? What needs to be done to wake up the lowend? Is the stock porting better than what I have? Plan on running PT mids. Quote Link to comment Share on other sites More sharing options...
wesw Posted May 8, 2008 Report Share Posted May 8, 2008 187 deg isnt much above stock ports i think 195 exh setup 4mm would be a decent dune bike but for stock stroke yeah it would be a agg duner-drag port. lot of stuff to do can go wide exh to make good torque with not as much exh duration to a limit. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted May 8, 2008 Report Share Posted May 8, 2008 What would be ideal duration or port height for bottom end? What needs to be done to wake up the lowend? Is the stock porting better than what I have? Plan on running PT mids. stock port timing would be far better for a bottom end motor. The cylinders you have should come on strong in the upper mid range and build a lot of topend power with very little on bottom. I run similar port timings on my stock stroke dune motor (196 deg), it will run with most builders drag ports but I have some tricks to maintain some of the bottom end so it is still very rideable on the trails an in the dunes. Quote Link to comment Share on other sites More sharing options...
elwilliams13 Posted May 8, 2008 Author Report Share Posted May 8, 2008 What would cleaning up the intake and exhaust, and widening the exhaust do for the motor? Quote Link to comment Share on other sites More sharing options...
wesw Posted May 8, 2008 Report Share Posted May 8, 2008 (edited) widen the exh makes more torque while not making it all top end. but you can only go so wide. too wide will eat rings. i wouldnt worry about those intake they look good enough not like you will get 15 hp from the intakes. if its already ported you cant change too much or it will throw the characteristics out of range. call that tdr and find out what its setup for and what to run. or buy some stock ports and start from scratch with a mx port. Edited May 8, 2008 by wesw Quote Link to comment Share on other sites More sharing options...
elwilliams13 Posted May 8, 2008 Author Report Share Posted May 8, 2008 Think starting over will be best. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted May 8, 2008 Report Share Posted May 8, 2008 you could run a thinner base gasket that would lower the durations a little bit. I think they make a .12 base. That might get it down to 192ish and then you can raise the transfer ports to 130. They widen the exhaust to 70% of the piston size and let it rip. You could go a little higher on the transfers to give it even more midrange but you will loose top end. Its up to you. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted May 8, 2008 Report Share Posted May 8, 2008 187 degree duration is the port basically being lifted to the point were the tunnel matches the port. It is higher than stock which is 30mm. Its roughly around 28-28.25mm. 26.75mm is around 195 degrees. Basically 187 degree duration is tuned to the area of about 9k rpm for maximum power. My pipes sign off at about 8700 rpm, so its about perfect. My bike will also run with 4 mills and other decent built weekend warriors on the drag strip, but I can turn around and ride a hole or a sandy trail with it. Quote Link to comment Share on other sites More sharing options...
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