blueshee Posted January 28, 2007 Report Share Posted January 28, 2007 On my last dune trip I noticed more smoke coming from my right cyl. and also a slight lack of power. When I got home I did a compression check and found 125 on the left and barely 100 on the right. So, I decided to tear it down before going out again. When I bought the bike about a year and a half ago, It was a completely fresh motor (Crank Up) The person I bought it from gave me the reciept from a local dealer that did the job. On the reciept I saw a machine shop sublet leading me to believe they punched it out a bit. So before Ordering parts, I decided to mic out the cyls and pistons. I came up with 2.558" on both cyl. w/ max .001" taper and out of round, so I figure I can just hone it and it will be fine. My pistons measure 2.551" leaving me w/ .007" clearance. My clymer manual says I Should have .002" clearance. What do you guys think of that. Should I get the same piston size or go a little bigger if they even make them. Also I am debating between wiseco and vertex pistons, any suggestions? I am also thinking of getting a mild dune port done. What do you guys think of D&M racing out of Phx, Az work? And If i decide to mill the head, when do I need to start thinking of welding the crank. Sorry for such a long post, but Im trying to be as detailed as possible. I appreciate any oppinions and advice. Quote Link to comment Share on other sites More sharing options...
yamaha04 Posted January 28, 2007 Report Share Posted January 28, 2007 well i havent done any of these mods yet but i do have my parts sent away to get some if it done, and iv been around long ehough to know some stuff. i would say get your crank welded now before you decied to go with any more hp, also i would get your cylineders bored just so you know the size and what size of pistons to get makes things easyer and its nice to know they arnt out of round at all i think. also for the porting iv never heard anything about there work but porting is a very good way to make more hp. its a noticable difference apperantly from what iv been told. oh yeah and about your head being milled if your going to do that your upping your compression and therefore i would get the crank weled since you have it half way apart. just my .02 cents Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted January 28, 2007 Report Share Posted January 28, 2007 You might be able to get a way with just new pistons. New pistons could bring you back in to spec. What kind of pistons are in it now? Just OEM Yamaha pistons? 2.551 in = 64.7954 mm. I would say your current bore size would be a 65.00mm bore. But I would deffinatly make sure before you just go throwing in pistons. For pistons I would go with Wiseco Racers Choice HP Sereis that are Electra Coated. The HP sereis pistons are supose to have larger windows in the skirt to help with air flow. I believe that the Electra Coated ones have a anti friction coating on the skirt. Here is a link to Wiseco Pistons Yamaha Pistons. Wiseco Piston LINK Quote Link to comment Share on other sites More sharing options...
blueshee Posted January 28, 2007 Author Report Share Posted January 28, 2007 In mm my bore is 65 mm, pistons 64.8. Im guessing this size piston is advertized as 65?. I guess Il just order 65mm pistons and hone the cylinders and call it good. What do you all say about vertex pistons, are they any good? Or should i just stick with wiseco. Thanks for any replys and suggestions Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted January 28, 2007 Report Share Posted January 28, 2007 I would run wiseco if it were mine. That is what 90% of peopel are going to tell you too. Quote Link to comment Share on other sites More sharing options...
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