Recent content by mopar1rules

I have a mikuni tm35mm carb for sale if interested. Everything works and there is nothing wrong w/it. Pm me w/an offer.

It most likely just identifies a newer or old casting and/or which foundry poured the cylinder. There is a similar thing like this with banshee heads.....early banshee heads say something like "GUY-1" and them were on like the first 2 yrs or so and then the casting number changed to "GUY-2". The...

you really can't judge what octane of fuel to run, based off of a cranking compression reading from a tester. you need to know the UCCR (uncorrected compression ratio) and CCR (corrected compression ratio), to accuratly determine the proper octane for your motor. the reason your cranking...

I've got a namura piston in my kx250 and so far so good. I also like the coated skirts. I can't recall if the piston crowns were coated at all.

i'm sure he's talking the "bowl" or "bell" of the head.

My guess is 162psi is going to be closer to 12:1 to 12.5:1 UCCR.

Not sure why everyone is so negative towards cast pistons. I have no issues w/cast pistons at all. I run pro-x pistons in my banshee. I don't see the wisecos being all that they are cracked up to be. My buddy runs them in his banshee and when you inspect the pistons, the skirts have collapsed...

Your piston is clean for a few reasons....probably the seafoam some, but most likely you're just too rich on the jetting. You see, the clean area on your piston crown, is what tuners and engine builders call "piston wash". It is a way (and most accurate) in watching jetting. I bet your plug is...

I'm assuming you are rebuilding the top end from a lean meltdown, w/stock jetting and aftermarket exhaust and air filter?? What pipe you running and what air filter? I don't trust jet kits. I like to jet the atv w/my own selection. You would be better off and have more $$ in the wallet most...

Exactly. Depending on the build and pipe being ran, you need to know if you even need more duration/port area. If you don't need more area or duration, then no sense in raising the exh port and taking away from the bottom end.

180 grit is too fine IMO. don't go over 120 grit. 80 grit is good enough for intake and transfers. guys, only polish the exhaust port!!

DO NOT GET THE WISECO CRANK!!! they are made in china and my buddy ran a wiseco crank this year in his '08 yz250 and the rod snapped, wrecking the crankcases, cylinder, and vforce reed. just get your japan made yamaha crank rebuilt, w/oem components, for all out reliability. if you really are...

It seems to me that "knife-edging" the crank on a banshee, would cause a reduction in the primary crankcase compression ratio?? More "material" that's not "there" to fill in that amount of "volume" down there. You know??

You can still get a crank rebuilt, once it has had its pins welded. It just takes a little more time for the crank rebuilder, as he has to grind away the weld bead. They pretty much just use the tig torch to melt part of the crank pin and counterweight together. They may add a little filler...

anytime you raise the exhaust port, you're gonna wack away some bottom end. your blow down time might have gotten a little long now, and create a peaky/pipey feeling engine.