Quote from: Sublunacy on August 04, 2015, 09:16:54 am

Quote from: 92lt250wannabe on July 29, 2015, 02:16:49 pm

Subluncay I don't think u know what your talking about half the time.

Get ahold of Carl bud aka iceracer.

My cylinder is heavily ported and the stock 34mm carb was just fine man.

 your missing out on some power maybe. raising the exhaust port makes the pipe peak earlier because of increased blowdown. widening the exhaust port makes a bit more torque and optimises for larger carbs to make torque.

porting the transfers gets tricky because it could lower the primary compression wich would lower the torque and increase the blowdown


milling the head to get a good squish and compression is as responsible for a modern running engine as the ports.

Raising the exhaust port does increase the blowdown time/area but in the majority of the case makes the pipe peak later or at a higher RPM not earlier or at a lower RPM.

Transfer port modifications are tricky.  There is not a particular modification that works best on every engine.  The only way we learn about any of these modifications is to try it, then run the engine in the field and or on the dyno to evaluate whether the modification was beneficial.  Real port development usually requires some cylinders to take one for the team and end up in the scrap pipe

If the transfer port modification involves raising the transfers, it decreases the blowdown time/area of the exhaust port.  It does not increase the blowdown. 

---------------------------------------------------------------------------------------

 SUBLUNACY REPLY-

no. the pipe would peak earlier and have more over rev.

no. if the transfers are raised the primary compression lowers period.

---------
nobody is making more torque on any build unless the pipe acts like a torque pipe on the cylinder.