03DMshee Posted May 1, 2012 Report Share Posted May 1, 2012 Rebuilt top end using vitos super stock pistons. Jugs were bored 20 over. Head was shaved 20 thousandths. Put together with all new gaskets that were supplied with the vitos kit. Torqued everything to factory specs. Proper break in period and retorqued after break in. Roughly 5 hours after rebuild had small amount of coolant push from over flow hose. This happened a few times but coolant was checked and it had not dropped all that much. Noticed after cool down quad took 3-4 kicks more than normal to start, normally it starts on the first kick. Quad was running well then lost all power and shut off. Judging by the pictures i feel as if compression leaked into cooling system and boiled coolant. Is this something anyone has heard of? Or does anyone have any insight as to what might have occurred. Below is bike specs 20 over Head shaved 20 thousandths B8ES plugs Timing 2 degrees Pickup set at 18 thousandths gap Trinity 2 into 1 Prodesign foam filter with airbox lid on Dmc 916 exhaust Vf3 Pwk35 carb 175 main 48 pilot DEK needle Center clip Klotz supertechniplate 36:1 Air screw 1.5 turns After roughly 10 hours on rebuild Link to album https://picasaweb.google.com/103182486397669436026/BansheeGoBoom?authkey=Gv1sRgCLjRzfCN8cGgAQ Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted May 1, 2012 Report Share Posted May 1, 2012 Yikes......that's pretty impressive. I think your onto something there.....especially as seeing how one of your pistons seems to be coolant washed as if it was hot when the coolant went in and cleaned the piston crown. However also looking at your dones in your head it appears that you had some serious detonation going on there. What fuel were you running and what elevation are you at? Quote Link to comment Share on other sites More sharing options...
mk2dubbin Posted May 1, 2012 Report Share Posted May 1, 2012 That's pretty gnarly. Quote Link to comment Share on other sites More sharing options...
Dahl87banshee Posted May 1, 2012 Report Share Posted May 1, 2012 Same happened to my super stock pistons after 12 hours. Propped break in and everything. I wasn't impressed with them.. Quote Link to comment Share on other sites More sharing options...
shakar Posted May 1, 2012 Report Share Posted May 1, 2012 Yikes......that's pretty impressive. I think your onto something there.....especially as seeing how one of your pistons seems to be coolant washed as if it was hot when the coolant went in and cleaned the piston crown. However also looking at your dones in your head it appears that you had some serious detonation going on there. What fuel were you running and what elevation are you at? that sucks i agree ......what oct was you runing? did you leak test?maybe your wp failed?? goodluck Quote Link to comment Share on other sites More sharing options...
Banshee Bitch Basket Posted May 1, 2012 Report Share Posted May 1, 2012 I haven't heard good things about the super stock pistons but i can't seem to find what exactly goes wrong with them. The water pump works fine, that was what he first thought had happened so thats the first thing he checked Leak test i dont think he did. I know he did a compression test before he tore everything down. Octane is 93. I thought i typed that in last night but i guess i didnt He doesn't need his wife answering for him either haha. Thanks for the replys though! Quote Link to comment Share on other sites More sharing options...
03DMshee Posted May 1, 2012 Author Report Share Posted May 1, 2012 haha..thanks babe... waterpump checks out fine octane is 93 elevation roughly 900 im gonna check trueness on jugs and cyl head tonight.... shop that decked head used a mill to do it...could that have been a no no? Quote Link to comment Share on other sites More sharing options...
Coupelx Posted May 1, 2012 Report Share Posted May 1, 2012 check that head to make sure its straight and then the cylinder too. what i see is scuffing from overheating since it was obviously using coolant. Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted May 1, 2012 Report Share Posted May 1, 2012 Same happened to my super stock pistons after 12 hours. Propped break in and everything. I wasn't impressed with them.. I haven't heard good things about the super stock pistons but i can't seem to find what exactly goes wrong with them. The water pump works fine, that was what he first thought had happened so thats the first thing he checked Leak test i dont think he did. I know he did a compression test before he tore everything down. Octane is 93. I thought i typed that in last night but i guess i didnt It's called being too lean. Not the pistons fault. Detonation will destroy every brand and style piston. When you are making 8 more HP, you have to feed it more fuel. This is why that style piston has gotten a bad rap. People drop them in like is a basic rebuild, yet don't re-jet. You need to go bigger on both your main and your pilot. Your making a lot more power and have to spend some time doing plug chops and tuning for the new set-up. You can't shave a head and install pistons that simulate porting and not spend some time starting with the motor jetted fat and working your way down from safe to a solid tune. I would have at least started with a 50 pilot/180 main/CEL or DEK needle, and I'm not sure what your kicking compression is, but with your mods I would be running 110 race gas or a 50/50 mix with premium. I'd also be running a #9 plug. Sorry to pile on......but I have LOTS of experience with these pistons on many peoples motors and can routinely get 80 hours out of them. I've run 2 into 1 intakes with them as well as twin 28's and stockers, and I've dyno tuned them all, so I think I'm pretty close on what these do to your overall power and how to jet them accordingly. You WILL make a solid 8 more HP with them alone. Quote Link to comment Share on other sites More sharing options...
registered user Posted May 2, 2012 Report Share Posted May 2, 2012 you say it ran well but if water is introduced into one of the cylinders you would think it would run alittle strange. im thinking it just leaned out on the one side. look at the difference in the wristpins. the one with blue heat marks appears it got hot. check underneath the pistons also. the scuffed one will probly have black death. means the crown temp got hot enough to cook the oil past its limits. at that point its all over but the crying Quote Link to comment Share on other sites More sharing options...
03DMshee Posted May 2, 2012 Author Report Share Posted May 2, 2012 The head hadn't changed at all...look like that before I put it on...I would imagine if I had any detonation that it would also be on the pistons...I did change jetting and I did work my way down from a 185...I guess I didn't do my homework on the pistons because if I can only get 80 hours on Vito's and 7 GOOD years on factory then I should should just back off and go back to basics...thank you for all the input... Quote Link to comment Share on other sites More sharing options...
03DMshee Posted May 2, 2012 Author Report Share Posted May 2, 2012 And compression is 145 Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted May 2, 2012 Report Share Posted May 2, 2012 I wasn't implying that you can only get 80 hours out of a Vito's piston. I was just making a point that they are clearly not a 10 hour piston. (2-3 seasons on a Vito's piston I have done...not 7) But if you want to run the same piston for 7 years.....stay stock and don't worry about making more power. As you get into the 60's and 70's for HP, you'll find stuff naturally wears out faster. I'll re-ring a piston if compression drops by 25PSI. If the piston had no more machining grooves on it...I'll just change it. Quote Link to comment Share on other sites More sharing options...
rodneym Posted May 2, 2012 Report Share Posted May 2, 2012 So if you just keep it stock with bolt ons the motor will last that much longer??? When mine was stock i bet it had over 500 hours on it Quote Link to comment Share on other sites More sharing options...
03DMshee Posted May 2, 2012 Author Report Share Posted May 2, 2012 It also comes down to what you do with your quad...I like to have power but I also enjoy gas mileage and all around fun..over here in PA we have nothing but hillclimbs and trails so we do a little differant riding than the dunes guys do...so thinking about it I guess everyone's ambitions are a little differant...I did however find my problem as far as I know and it comes down to the milling of cylinder head...pics to follow...thanks for all the input..just keep in mind everyone has a differant riding condition and not everyone can ride from the truck to a dune a quarter mile away and rip hills...we have to ride 10 miles to fetch a hill sometimes...thanks again Quote Link to comment Share on other sites More sharing options...
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