Blowtie316 Posted October 31, 2014 Report Share Posted October 31, 2014 (edited) I have been chasing a vibration for a while now on my banshee. When I bought it I didn't really notice it, was my first banshee, but upon riding other banshees I figured out mine was pretty bad. I removed the stator cover and flywheel and checked crank rounout and found it was .008", pulled it further apart and found a loose rod bearing. So I called up FAST and they hooked me up with a welded 4 mil hot rods crank, new pistons and a spacer plate (due to not having time for the proper port job). Runout on new crank was around .001". Put it all together and it vibrates the same. I did some searching and found that the motor mounts are supposed to have 2 dampers, so I bought new ones and installed them per the book, also torqued mounts per manual. No change. The flywheel had some idiot marks so I bought a mint used one off of ebay. It looks perfect, same as old one except it doesn't have what looks to be 8 balancing holes drilled into it from the outside radius. Are drilled holes normal? Anyway, I tried the mint one and it didn't help. I installed the clutch clocked the way the manual calls it out, am I missing something else? Where should I look from here? Thanks for any help. Edited October 31, 2014 by Blowtie316 Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 Quote Link to comment Share on other sites More sharing options...
Phelps Posted October 31, 2014 Report Share Posted October 31, 2014 what kinda handlebars do you have vs other bikes? fixing a vibration on a banshee is like trying to tighten up a vagina on a prostitute. aint gonna happen.they viberate. higher compression, pipe choice etc can also amplify it. pipe hanger choice can also increase vibration. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted October 31, 2014 Report Share Posted October 31, 2014 What bars do you have? Any anti-vibe stem will drastically reduce vibrations to the bars. I think a better test is with your feet on the foot pegs. Does yours vibrate at the pegs the same as the others? Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 Stock stem with pro taper bars. But we've been using the pegs for comparisons. The bars seem to take some of the buzz out but the pegs will make you numb. I think this is more than normal banshee vibration. Sent from my SGH-T679 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 For comparisons, I have ridden or felt 3 other banshees here local, one high compression trinity ported t5 pipes, one stock with lrd pipes, and one other ported with 18c heads and t5s. Mine has easily 2-3 times as much vibration as these others. Also, my other ride is a big bore (330) trx250r, and it doesn't vibrate as much as this banshee. Should I take another look at the clutch? Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 Could have a detonation issue Could be a tuning issue and it isn't running smoothly. Hard to tell over the computer. Yeah I'm just looking for ideas. It has 21cc domes, cranked 165-170 compression, squish was right around .045. I have tried 110 and 91 pump gas with no change. It runs good, sounds clean, doesn't bog or miss, idles fine, etc. 27.5 pilot and 300 main. Quote Link to comment Share on other sites More sharing options...
Atomic Monkey Posted October 31, 2014 Report Share Posted October 31, 2014 I'm just putting this out there because I just went to the Hotrods L/R 4mil from a shortrod 4mil, and I noticed a big change in the amount of vibration. I just figured its a balance issue with the crank, longer rods, and the pistons. I know for sure the crank was never balanced with the pistons I got. Can't say for sure if they even balance the crank and rod assembly. Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 (edited) Not really anthing else done to it. 4 mil long rod hot rods crank, welded 65.5 pistons, no porting Spacer plate 21cc domes-coolhead 170 compression .045 squish Stock carbs with 2-1 k&n type filter CT racing/power pros midrange pipes +4 timing Engine runs quiet, no rattles or pinging. Edited October 31, 2014 by Blowtie316 Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 31, 2014 Report Share Posted October 31, 2014 Is this felt at idle, or when riding? You're sure it's the motor, not loose hubs, loose chassis bearings, junk exhaust hangers, sloppy axle, etc? Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 I wonder if the crank is not trued up? Did Jeff say he checked the trueness of the crank? I didn't talk to Jeff, but Cody said they check them all, and won't send them out if they are not within spec which I think was .0015 or .002. I checked the stator side of this one only and it was real close to .001, maybe just a little over like .0012 or something. Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 Is this felt at idle, or when riding? You're sure it's the motor, not loose hubs, loose chassis bearings, junk exhaust hangers, sloppy axle, etc? It is most noticeable Idling and revving, but it does it during riding too, probably just masked by all the other bumps and vibes. I think Atomic Monkey may be right, I have read that the stock 350 cranks are balanced for 250 pistons and it gets worse with longer strokes, longer rods, and bigger pistons. I'll call FAST and see what they say. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted October 31, 2014 Report Share Posted October 31, 2014 Where the bolts go through the case there are dampners not the little d shaped washers but pressed in peices I have replaced them on a few bikes could be issue or the bottom dog bones are worn out Quote Link to comment Share on other sites More sharing options...
Blowtie316 Posted October 31, 2014 Author Report Share Posted October 31, 2014 pipe choice etc can also amplify it. pipe hanger choice can also increase vibration. I am going to experiment with this, my silencers are mounted directly to the frame, no rubber bushing, grommet or anything. Thanks for the idea. Quote Link to comment Share on other sites More sharing options...
Phelps Posted October 31, 2014 Report Share Posted October 31, 2014 i'd just ride it. find a buddy with a big cc alky bike with direct peg mounted pipes so you can see how nice and smooth your bike really is lol Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.