ap3x Posted December 4, 2011 Report Share Posted December 4, 2011 Bike is in great shape. Alot of upgrades. Only like 80-90 pounds on each side though. I'm not sure on the bore size, I'm going to have to measure that when I pull it apart. Guessing that it has the stock bore, or maybe slightly larger than stock, can I just order that size top end kit with pistons, rings, gaskets, etc.? I think I read somewhere that pistons for a stroker crank are different than the normal ones, in which case, could I just order a set of rings and gaskets and get some decent compression? Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted December 4, 2011 Report Share Posted December 4, 2011 (edited) The stroker has nothing to do with the pistons. Weather it is a long rod or not does. Both a 4mill long rod, or a stock stroke long rod crank require Wiseco 795 series pistons. The stroker requires a cut head, custome cut stroker domes in a cool head, or some kind of spacer (ethire under the cylinders or between the head and cylinders). So if you have a long rod 4 mill then you need both 795 series pistons, and a cut head, cool head with stroker domes, or a spacer plate. You best bet is to tear it down to see what you have. If your compression is low then the cylinders will need to be meaured to see if you need to bore it or if you can get by with running a new set of pistons the same size. Edited December 4, 2011 by jbooker82 Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted December 4, 2011 Report Share Posted December 4, 2011 The stroker has nothing to do with the pistons. Weather it is a long rod or not does. Both a 4mill long rod, or a stock stroke long rod crank require Wiseco 795 series pistons. I disagree with this. Thers isn't such a thing called a 4mil stock stroke long rod crank. It does matter if it's a 4mil long rod or 4mil standard rod. If he has a 4mil standard rod (110) it will require a standard banshee piston 573 series. If it is a long rod crank (115) it will require a 795 series piston. Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted December 4, 2011 Report Share Posted December 4, 2011 Rod length is what you need to know to order pistons, that and what bore u have. 110mm rods require 513 piston not a 573. Long rod or 115mm require a 795 series or a 573 (if the bore is big enough). The 795 piston is is a banshee long rod piston the 573 is a blaster piston which uses a 115mm rod as well but only avail in bigger bores. And yes stroke does not matter it can be 4mm 7mm 10mm or stock stroke with a 110 rod and still use a stock piston. But he said it was a 4mm so best to tear it down and see what u got have ur cylinders measured and order what u need. Andy Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted December 4, 2011 Report Share Posted December 4, 2011 I disagree with this. Thers isn't such a thing called a 4mil stock stroke long rod crank. It does matter if it's a 4mil long rod or 4mil standard rod. If he has a 4mil standard rod (110) it will require a standard banshee piston 573 series. If it is a long rod crank (115) it will require a 795 series piston. Thanks Andy, I meant 513 series for 110 rods. had my 421 cub on my mind when I said 573 series Quote Link to comment Share on other sites More sharing options...
ap3x Posted December 5, 2011 Author Report Share Posted December 5, 2011 Thanks for the numbers guys. I won't have time to tear into it and start measuring until this weekend and I'll be sure to post up any questions, pictures, etc. I've got another quick question. When I take a look at my top end, will the pistons have any kind of marking on them that could help me identify what brand/series they are? Quote Link to comment Share on other sites More sharing options...
vulvafan537240 Posted December 5, 2011 Report Share Posted December 5, 2011 Thanks for the numbers guys. I won't have time to tear into it and start measuring until this weekend and I'll be sure to post up any questions, pictures, etc. I've got another quick question. When I take a look at my top end, will the pistons have any kind of marking on them that could help me identify what brand/series they are? if they are wiseco's Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted December 5, 2011 Report Share Posted December 5, 2011 (edited) I disagree with this. Thers isn't such a thing called a 4mil stock stroke long rod crank. It does matter if it's a 4mil long rod or 4mil standard rod. If he has a 4mil standard rod (110) it will require a standard banshee piston 573 series. If it is a long rod crank (115) it will require a 795 series piston. Read it again slower. The +2mm stroke has nothing to do with what piston to run. If it is a long rod or stock length does deterimine what piston you have to run. If you read it says. 4mill Long rod crank, and a stock stroke long rod crank both require Wiseco 795 series pistons. What deterimes the series of pistons run is determined by the rod lenght, not the stroke. Hot Rods #4001 Stock stroke, stock rod lenght = 513 Series Pistons Hot Rods doesnt make a +4mill stock rod crank any more. There are others that still do. = 513 Series Pistons and one of the following (cut stock head, cool head with cut stroker domes, spacer plate under the cylinders, spacer plate between the cylinders and head). Hot Rods #4011 Stock stroke 5mm long rod crank = 795 Series Pistons Hot Rods #4105 +4mill Stroke 5mm long rod crank = 795 Series Pistons and one of the following ( cut stock head, cool head with stroker domes, spacer plate under the cylinders, spacer plate between the cylinders and head) So the determining factor on what series of pistons you need to order is the Rod Length, not the stroke. Edited December 5, 2011 by jbooker82 Quote Link to comment Share on other sites More sharing options...
ap3x Posted December 10, 2011 Author Report Share Posted December 10, 2011 Okay heres what I've learned. I checked my compression with my own tester before pulling it apart. I've got 125 in the right, 120 in the left. Not near as bad as I was told, but that explains why it started up first kick every time. Pulled in apart. Pistons are in marked with ".50" on the tops. That's all she wrote. Crankshaft is marked "29L". Then I mic'd my bores and pistons The right side: 2.539 and.534 (clearance of .005). And the left side: 2.537 and .532 (clearance of .005). Those numbers in metric figures are just a hair under 64.5mm, which puzzles me as I thought they would have been exactly 64.5 brand new and probably a hair bigger now. Don't know what I'm gonna do now. The bores and pistons are in spectacular physical shape if it wasn't for the .005 clearance. Any input here would be appreciated. Quote Link to comment Share on other sites More sharing options...
FASTOYS Posted December 10, 2011 Report Share Posted December 10, 2011 .005 Clearance is TOO loose.. Sounds like you have a worn bore or collasped piston skirts.. I would take them to a machine shop or send them to one of the site sponsors who can bore them to next size. Quote Link to comment Share on other sites More sharing options...
ap3x Posted December 10, 2011 Author Report Share Posted December 10, 2011 Yeah I'm just going to do the whole top end the next size up. From what I read, the '29L' crank is the stock yamaha crank after all, so the guy I bought it from who said it's a 390 stroker, either didn't know what crank he put in there, or was just fullof it... But either way, this crank gets the 513 pistons (or whichever brand non stroker pisotns I choose)? I'll need to find a shop to bore them out. The only one I've found so far quoted me $320 for the pair. Sounds about twice as much as it should be, right? Quote Link to comment Share on other sites More sharing options...
tedd1 Posted December 10, 2011 Report Share Posted December 10, 2011 Find a builder you like that sponsors this board and send the cylinders to them. They will take care of you. Hell, you got 2 of the best answering your questions! Quote Link to comment Share on other sites More sharing options...
vulvafan537240 Posted December 10, 2011 Report Share Posted December 10, 2011 $320 to bore a pair of jugs? !?! My local shop charges $30 a cylinder. Quote Link to comment Share on other sites More sharing options...
mpd579 Posted December 11, 2011 Report Share Posted December 11, 2011 Like they said use on of the sponsers on here. Jeff at fast & Kevin at HJR are both great. Should be around 100 bucks Quote Link to comment Share on other sites More sharing options...
ap3x Posted December 11, 2011 Author Report Share Posted December 11, 2011 Dropped them off at the local Yamaha dealer. 80 bucks a hole. I've done a lot of business there, I just never realized they did their own machine work. Should be ready to go this week some time. Quote Link to comment Share on other sites More sharing options...
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