tri-z motor and the yz 250 motor??

[mike from long island]

i had a brain storm this morning on the crapper lol does the intakes and reed cages from the later year yz dirt bike motors fit the tri-z??? i am trying to get a bigger carb for my Z now that i have gotten a nice motor together. the stock intake boot doesnt fit any of the carbs i have. what do you guys think?? thanks mike

[Billy Golightly]

Mike,

I've got a 85 YZ250 cylinder and head that i plan on some time or another mating onto a Tri-Z bottom, so maybe I can help you a little bit. On my 85 Cylinder, the intake is VERY larger. Its probably the size of a Tri-Z intake, and then half again. What you could do though I believe from the Tri-Z Wrench report posted at the quad pit is that you can use an IT250 intake boot. I'm not sure of the year but I believe it said 83(?) Might want to check it out for sure your self, http://www.quadpit.com

[GreenBoy]

I will use the cylinder of a 87 YZ 250,the sleeve and the YPVS has to be modified,bore and stroke are the same,bottom part as well.The inatake is completely different from the Tri Z intake.
I think the best solution for you is to use a Boyesen Rad Valve,if it has the same bolt pattern (look at Bikebandit.com) you can use one of either the YZ 125 or YZ 250.It will easily fit a larger carb and the stock intake.That´s what I did with my other Z engine (and with my Tecate).The Rad valves are available for about 30$ +++ at eBay,I got mine there.With a little luck they are even new :-)
If you cant find one,send me a mail I might have one left for you.

[mike from long island]

ok greenboy. i understand how the rad valve will work. but i am not sure why i am looking at bikebandit?? should i be looking for the bolt pattern?? about what year rad valve should i use?? thanks for the help mike

[GreenBoy]

Yes,you should look up the bolt pattern at bikebandit.com . The radvalve I will use on my bike has the number 34,but the letter to determine the exact year of construction is missing.The ´97-´98 (34D) YZ 250 radvalve will not work on the Tri Z,I guess mine is from an earlier modell.
The radvalve I have will fit on a 44mm carb flange (like on a 38mm Keihin PWK),it makes a little turn to the left so you must use another airfilter too.When it´s done it will look like on my Tecate --> http://www.3wheelerworld.com/remotepictures/HagenTecate/TecateMotorLeft.jpg
You can find more infos at http://www.boyesen.com/catalog/MCRadValves.pdf
Once in a while the radvalves are really cheap on eBay,try to get one with carbon reeds,you can search for "Rad Valve".
Hope this helps
GreenBoy