dezrik Posted April 2, 2013 Report Share Posted April 2, 2013 I just bought this banshee, The guy told me it had a fresh top end (I heard this before). Its been running pretty strong the last week. I installed a adjustable timing plate and set it at +4 degrees and I went for a little putt on some trails next to my house. I was in 6th gear and had it pinned and all of a sudden it wouldn't take any fuel and was bogging at 1/2-full throttle and eventually died. I pushed it up a pretty big hill and rolled it down and got it started by popping the clutch in gear. Still wouldn't take any throttle but I got it home with 1/4 throttle and choke out (10-15mph). As soon as I got home I pulled the plugs and they were wet of course. I took a quick compression test and The most I got was 80psi After 4 kicks and both cylinders read pretty close to the exact same. Im at 7100ft but Thought it was a pretty low reading and it needs a top end. Anyway I pulled the top end today and I don't know which direction to go the cylinder looks pretty good other then some light scratching but the piston looks pretty bad, rings are thin too. What would you guys do? Quote Link to comment Share on other sites More sharing options...
Finch Posted April 2, 2013 Report Share Posted April 2, 2013 if the cyls arnt to worn you can hone and slap new pistons in need to be checked with a bore gauge prolly be better off just bore hone and new pistons tho some porting and welding the crank while your at it! Quote Link to comment Share on other sites More sharing options...
dezrik Posted April 2, 2013 Author Report Share Posted April 2, 2013 Yeah, I don't plan on running these pistons, I will get new ones for sure. Quote Link to comment Share on other sites More sharing options...
04_blu_shee Posted April 2, 2013 Report Share Posted April 2, 2013 Junk cast pistons, your lucky you didnt scatter a piston skirt....I also say bore hone forged pistons and weld that crank! Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted April 3, 2013 Report Share Posted April 3, 2013 if you dont feel any scuffing with your finger nail etc.. and bore is still within spec.. a hone and new pistons will suffice.... if you feel nicks with your finger nail and or bore is worn out... go next size up... This is Steven's official home version of a "Feeler Gauge". Quote Link to comment Share on other sites More sharing options...
troyzstang Posted April 3, 2013 Report Share Posted April 3, 2013 If you're going to replace pistons get a fresh bore and do it right. Just my opinion Quote Link to comment Share on other sites More sharing options...
04_blu_shee Posted April 3, 2013 Report Share Posted April 3, 2013 X2... what troyzstang said. Do it right now or pay more after a catastofic failer. Quote Link to comment Share on other sites More sharing options...
Nightmare Posted April 3, 2013 Report Share Posted April 3, 2013 Hold on a second, you only kicked it 4 times for the comp test? And you Installed an adjustable timing belt? Sent from my SGH-T679 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
04_blu_shee Posted April 3, 2013 Report Share Posted April 3, 2013 Nightmare im gonna give ya a "Ya Buddy" on that clairifacation on the "Timing Belt"....I think I forgot to install that 4yrs. ago on my last build Huhhh Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted April 3, 2013 Report Share Posted April 3, 2013 Hold on a second, you only kicked it 4 times for the comp test? And you Installed an adjustable timing belt? Sent from my SGH-T679 using Tapatalk 2 Someone is missing out on some big power Quote Link to comment Share on other sites More sharing options...
blowit Posted April 3, 2013 Report Share Posted April 3, 2013 This is where people either waste their money or waste a good bore, or blame casted pistons because your bore clearance is not right. The ONLY way to verify a bore is with a bore gauge. Having it bored for the hell of it is not advisable. True that damage you can feel may warrant a bore, but just because it is smooth does NOT mean the bore is good and it is also possible and likely that the bore is perfect. I recently inspected an ORIGINAL 1987 Banshee engine for a family member. I was shocked that she was well within spec. I told him to put it together and ride it a few years and go from there. There is a reason there are dimensions in the book. Looking at a bore just does not tell the story. Regarding cast pistons, they get a bad rap and if you read back to some of my previous content years ago, I explained that casted or hypereutectic pistons DO have their place and WILL last longer than forged pistons compared side by side. The casted piston contains much more Silicon and is a harder alloy that resists wear and thermal expansion. They also expand more uniform thus require much less bore clearance. Don't sell casted pistons short. Forged do have their place but 90% of Banshee engines will do great with cast pistons. Brandon Mull Engineering Quote Link to comment Share on other sites More sharing options...
dezrik Posted April 3, 2013 Author Report Share Posted April 3, 2013 Hold on a second, you only kicked it 4 times for the comp test? And you Installed an adjustable timing belt? Sent from my SGH-T679 using Tapatalk 2 Fixed, I don't know wtf I was thinking. Yeah kicked it over 4 times to get 80psi, then I kicked it 6-7 more times but the compression didn't get any higher Quote Link to comment Share on other sites More sharing options...
possum Posted April 3, 2013 Report Share Posted April 3, 2013 Your gauge is junk Quote Link to comment Share on other sites More sharing options...
dezrik Posted April 4, 2013 Author Report Share Posted April 4, 2013 Decided to send the cyls over to wildcardracing and have them inspect them and tell me if they need bored or honed. and have them put me together a top end kit, and while its there some trail porting. Quote Link to comment Share on other sites More sharing options...
Starwriter Posted April 4, 2013 Report Share Posted April 4, 2013 Split the cases and send them the crank too. Quote Link to comment Share on other sites More sharing options...
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