slothman Posted March 16, 2012 Report Posted March 16, 2012 Well got a banshee for cheap- I knew the motor didn't seem all there- so I did a compression test got 80 psi in both cylinders. Also- it lags/bogs when I first rev it, even on a warm engine. Can this be caused by the low compression? I did notice the parking brake cable has been removed- not sure about the TORS. If I rebuild the top end it will be my first two-stroke project (I am pretty mechanically inclined as far as car engines). But what Wiseco kit should I buy? Do you have the heads checked first and then decide what bore to go with ? Any help is appreciated ! Quote
Motooutcastxxx Posted March 16, 2012 Report Posted March 16, 2012 I was always told as a rule of thumb, and I'm not sure how accurate it is but, anything under 100 psi and it's time for a top end, 80 is definitely not good. Pull the cylinders off and have them mic'd, hone or bore, then find a top end kit. If you need a service manual there's one on here somewhere you can download. Quote
slothman Posted March 16, 2012 Author Report Posted March 16, 2012 I was always told as a rule of thumb, and I'm not sure how accurate it is but, anything under 100 psi and it's time for a top end, 80 is definitely not good. Pull the cylinders off and have them mic'd, hone or bore, then find a top end kit. If you need a service manual there's one on here somewhere you can download. Ya...I have heared anything 110 and below should be rebuilt. Forgive my ignorance, but what is the difference between a hone and a bore? And does either one increase the engine power ? Which company do you recommend to inspect and hone/bore the jugs? Quote
Larry's Shee Posted March 17, 2012 Report Posted March 17, 2012 It only has one head and you check the bore of the cylinders. Any good machine shop can measure the bores. They need to measure in six spots, top, middle, bottom, front to back and side to side. If the shop doesn't know this find another. Then if the bores are within service limit you mic the pistons to check clearance. If clearance is out of spec you should bore it for new pistons. Personally the bores would have to be damn near perfect before I would put new pistons in old holes. If everything checks out good you can hone it and just put new rings in. As to the comp test. Was the hole adapter same length as spark plug threads? Did you hold it wide open throttle and kick until gage stopped moving? Also keep track of which piston goes in which hole so if you re-use them they go back same. Always use new pison pin circlips. All of this is covered in Clymers manual, probably in download also. Quote
Larry's Shee Posted March 17, 2012 Report Posted March 17, 2012 Your bog could be dirty plugs, carbs, air filter, or all three. Quote
Poolman Posted March 17, 2012 Report Posted March 17, 2012 Could also be the Bike was never jetted properly to begin with. Quote
Motooutcastxxx Posted March 17, 2012 Report Posted March 17, 2012 Yeah what they said. ^^^ but any reputable shop will hone/bore the cylinders and match up a set of pistons, all though it'll probably cost you an arm and a leg.... possibly a testicle. Check out one of the site sponsors maybe, they offer some decent deals for full top end kits but you would need to send them your cylinders. Here's the link to the service manual, always good to have. http://bansheehq.com/forums/index.php?showtopic=150327 Quote
Poolman Posted March 17, 2012 Report Posted March 17, 2012 Yeah what they said. ^^^ but any reputable shop will hone/bore the cylinders and match up a set of pistons, all though it'll probably cost you an arm and a leg.... possibly a testicle. Check out one of the site sponsors maybe, they offer some decent deals for full top end kits but you would need to send them your cylinders. Here's the link to the service manual, always good to have. http://bansheehq.com/forums/index.php?showtopic=150327 This is exactly what I had to do a month or so ago. Sent my cylinders to Jeff at Fast. Got them Bored .020, Honed, Chamfered, New Weiso Pistons, Rings, Cylinder Base Gasket, Head Gasket, 4 Reed Gaskets, Shipping both ways. She runs like a top. I already had an MX Port Job so didn't need any porting. I think the whole thing ran me including shipping both way's a total of $415.00 Hey Bro, How you liking those Shocks ? Quote
Motooutcastxxx Posted March 17, 2012 Report Posted March 17, 2012 This is exactly what I had to do a month or so ago. Sent my cylinders to Jeff at Fast. Got them Bored .020, Honed, Chamfered, New Weiso Pistons, Rings, Cylinder Base Gasket, Head Gasket, 4 Reed Gaskets, Shipping both ways. She runs like a top. I already had an MX Port Job so didn't need any porting. I think the whole thing ran me including shipping both way's a total of $415.00 Hey Bro, How you liking those Shocks ? Just sent you a PM actually... Quote
slothman Posted March 17, 2012 Author Report Posted March 17, 2012 It only has one head and you check the bore of the cylinders. Any good machine shop can measure the bores. They need to measure in six spots, top, middle, bottom, front to back and side to side. If the shop doesn't know this find another. Then if the bores are within service limit you mic the pistons to check clearance. If clearance is out of spec you should bore it for new pistons. Personally the bores would have to be damn near perfect before I would put new pistons in old holes. If everything checks out good you can hone it and just put new rings in. As to the comp test. Was the hole adapter same length as spark plug threads? Did you hold it wide open throttle and kick until gage stopped moving? Also keep track of which piston goes in which hole so if you re-use them they go back same. Always use new pison pin circlips. All of this is covered in Clymers manual, probably in download also. Yes adapter is the same length. I held it WOT and kicked until the gauge stopped moving. When I rode it I could tell it something was wrong...it didn't feel like my KTM 250 smoker at all. So what shop should I send the head to? Honestly I don't want to spend more than $300 for the top end rebuild. Quote
Overdose Posted March 17, 2012 Report Posted March 17, 2012 At 80psi I'd definately say it's time for a rebuild but just to add a little to this conversation don't forget that a persons elevation plays a part in there compresion as well. I'm at 5500 ft above sea level and ride at 6500ft. A new top end at this alltitude in right around 100-105 psi. We require the use of smaller domes in a cool head just to get up to stock compresion at this altitude. Good luck with your bike and welcome to HQ. Quote
Motooutcastxxx Posted March 17, 2012 Report Posted March 17, 2012 Yes adapter is the same length. I held it WOT and kicked until the gauge stopped moving. When I rode it I could tell it something was wrong...it didn't feel like my KTM 250 smoker at all. So what shop should I send the head to? Honestly I don't want to spend more than $300 for the top end rebuild. Honestly, you might want to plan on spending a bit more than $300 but if you're on a real tight budget I would pull the cylinders to see what you have to work with before anything. I sent my cylinders to Herr Jugs Racing and Poolman sent his to F.A.S.T. but I've read thread after thread on here and pretty much all the sponsors are top notch, you can't go wrong with any of them. I'm not sure where you're located so who knows maybe you even have a decent shop (or maybe a sponsor) that's fairly local. I would definitely keep in mind what Overdose said also... http://www.bansheehq.com/yz-banshee-specs-sponsors.html Quote
slothman Posted March 17, 2012 Author Report Posted March 17, 2012 At 80psi I'd definately say it's time for a rebuild but just to add a little to this conversation don't forget that a persons elevation plays a part in there compresion as well. I'm at 5500 ft above sea level and ride at 6500ft. A new top end at this alltitude in right around 100-105 psi. We require the use of smaller domes in a cool head just to get up to stock compresion at this altitude. Good luck with your bike and welcome to HQ. i MIGHT be at 1000ft above sea level, lol Quote
slothman Posted March 17, 2012 Author Report Posted March 17, 2012 Honestly, you might want to plan on spending a bit more than $300 but if you're on a real tight budget I would pull the cylinders to see what you have to work with before anything. I sent my cylinders to Herr Jugs Racing and Poolman sent his to F.A.S.T. but I've read thread after thread on here and pretty much all the sponsors are top notch, you can't go wrong with any of them. I'm not sure where you're located so who knows maybe you even have a decent shop (or maybe a sponsor) that's fairly local. I would definitely keep in mind what Overdose said also... http://www.bansheehq.com/yz-banshee-specs-sponsors.html ya times are tough these days. If I can get away with a $300 build that would be awesome, but I know it's not gonna happen lol. But I know I can find a Wiseco top end kit online for about $200....so if I can have the heads inspected and bored at a local shop for $100 that puts me right where I want to be. Quote
Poolman Posted March 17, 2012 Report Posted March 17, 2012 ya times are tough these days. If I can get away with a $300 build that would be awesome, but I know it's not gonna happen lol. But I know I can find a Wiseco top end kit online for about $200....so if I can have the heads inspected and bored at a local shop for $100 that puts me right where I want to be. All True if can be done locally without shipping but forgot one thing Gasket set. So I could see it getting done for about $350.00 locally. Quote
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