PV TRI Z question

[cumminstroker]

Hi, I am finally in the process of PV my Z. I have an 83 yz250 cylinder and all related parts, my question is if anyone has added boost ports to the intake side of these cylinders similsr to the wrench report mod to the stock cylinder or if you think I should do it. I believe the 84-88 yz250 cylinders have at least one boost port. Also, I am using the stock z flywheel now but if I was to use the yz pvl style would I also have to use the yz coil and cdi? Any input would be appreciated, I know there are a couple of tri z experts on here! BTW, I will post some pics of my sweet 85.5 Z once it is done!

[NOS_350X]

To use the Yz ignition setup you have to go to the yz crank also. The flywheel wont fit on the shaft. There is a port on one side already.

[cumminstroker]

That answers my flywheel question, thanks. But my 83 cylinder dosent have any boost port but I know the 85-87 does have one, I am just wondering if I add one or two to my cylinder if it will help anything.

[NOS_350X]

IMO the gains arnt worth the work to add the added port,and port it properly, At least on the banshee cylinders. Just get the SOB ported and GET IT RAG

[tecat-z]

Anyone who ports your K cylinder will add the "Boyesen sub ports". The cylinders are very thin in that area, so they will be fairly tall and narrow in width. Honda had many placement constraints in place on engine design in both mx and atvs at this time. This left the other oems to make some design compromises in their production engines. Many of the deficiencies can be improved upon by crafty porters. 84 L cylinders had 1 sub port, but those cylinders come with other obstacles to overcome when setting up intake properly. 84 up cylinders have the potential to create much more power however due to a triple port exhaust and more meat in critical areas for "adjustments" I've done this exact build a year ago, and the end results are good. It's by no means the fastest machine out there. But it is one of the most unique machines in many areas and built right, with respectable all around performance.

[cumminstroker]

Well I went ahead and added the 2 "boysen sub ports" tonight and it all went ok and yes the area to work with there is very thin! Tecat-z, did you use the stock z head and flywheel and if so would you recommend lightning the flywheel and or milling the head? All the input is appreciated!

[tecat-z]

I used a complete 84L ignition. Which requires the use of yz stator side crank wheel. I sent the crank, oem rod kit, and piston assy to crankworks for a balanced rotating assy. The 83-84 yz rotor is very light due to it being a inner rotating design. It's almost too light for atv use, but works well once a feel is reached. The oem Tri-z stuff is very heavy. I have a few lightened flys on hand that were spun by the legendary Ronnie Hopkins. I honistly only need one. If you are interested at some point, holler......