LoveThePolice Posted March 20, 2017 Report Share Posted March 20, 2017 Hi, I have a 2011 Yamaha Banshee with a list of (mostly airflow related) mods. You can read about her in my previous posts, but it will suffice to say that I have FMF fatty pipes and Powercore 2 silencers, vForce 4 Reeds, a Toomey 2 into 1 air filter, +4 timing, etc. Anyway, I have never had her jetted quite right. Not well enough to start perfect from cold at least (which I hear is a common issue). Once she warms up she's always been spot on. I'm running 320 mains with 27.5 pilots. The problem I am having is as follows: I turn the fuel petcock to on with fresh, 32:1 mixed 98RON fuel, flick the ignition switch, and turn the key. I kick 3 times softly, then with full force. This pretty much always does nothing, so I put the choke out to max. After 15-20 kicks, she will splutter up for a few seconds, struggle to reach 1/3rd throttle, then splutter down and stall. Occasionally I get her working for long enough to get a ride in. When I do, I leave the choke out for 5 mins. After this period she runs pretty perfectly. A few notes which might help to diagnose the issue: She runs better when hot. Pretty damn well. When I go to low throttle when the engine is warm, she still struggles to stay operating, and I never used to have this problem. I recently installed the vForce 4 reeds. The bike has never idled comfortably warm or not. I have to feather the throttle. I recently did as the Clymer manual suggested and turned the air screws to 2 turns out. Didn't help. A few ideas I've had, if you can throw me on the right track I'd appreciate it: Maybe the jetting at low throttle was slightly on the lean side to begin with, and the reeds installation maybe I've pushed it too lean. But reeds are meant to make your bike richer, so this doesn't make much sense. Maybe I didn't get the seal correct and there is an air leak in the reed assembly. This would presumably make it leaner. I have heard of issues with interchanging the float bowls from each carb. Perhaps I inadvertently switched them over when I cleaned my carbs? Help! I am heading out on a trip soon. A recon trip with the purpose of getting her running perfectly. I have a long 5km stretch of flat road to plug chop on, and I have a few spare pairs of spark plugs. I would like to get her starting fairly okay before I go on the trip, so that I don't get down there and realize that it's something other than jetting. Thanks for any help. Quote Link to comment Share on other sites More sharing options...
STRIBZ Posted March 20, 2017 Report Share Posted March 20, 2017 where you from? temps and elevation? Still have tors? Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 20, 2017 Author Report Share Posted March 20, 2017 Western Australia. Still have TORS. It's about 25-30c here this time of year Quote Link to comment Share on other sites More sharing options...
STRIBZ Posted March 20, 2017 Report Share Posted March 20, 2017 i'm from Perth wa.. I would start by getting a tors delete kit. You are rich on your main to. i was at 300main 27.5pilot with your mods and was still bit rich. Are your carb slides in correct carbs? half moon out? tube in between carbs connected? Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted March 20, 2017 Report Share Posted March 20, 2017 Most thoroughly written post ever. Have you done a plug chop? Sent from my LGMS210 using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 20, 2017 Author Report Share Posted March 20, 2017 How can I be rich when the choke helps? When it runs better when hot? I have not done a plug chop, but will on sunday Quote Link to comment Share on other sites More sharing options...
Ducman Posted March 20, 2017 Report Share Posted March 20, 2017 second on the try a 30 pilot. Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 22, 2017 Author Report Share Posted March 22, 2017 I've never had a 30 pilot before and it has run pretty damn well in the past. I tried sticking pilot screws in and then out a turn with no change in either circumstance. I have ensured that the float bowl with the choke jet is on the right carb. I don't really know what else it could be :/ Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 22, 2017 Author Report Share Posted March 22, 2017 (edited) Just an update lads: Compression: as suggested by the Clymer manual by putting my thumb on the empty spark plug socket and kicking it. My thumb is pushed out indicating sufficient compression. Going to get a gauge tomorrow for an accurate reading. Spark: having the spark plug out of the cylinder, I kick the engine and sure enough, a spark is emitted. Fuel: took the carbs apart and there's fuel in the float bowl. Jetting: put the pilot air screws at 2 turns out, needle jets at middle clip, 320 mains, 27.5 pilots (cannot get 30's before I go away, plus it was working fine before). Syncing: Synced the carbs as per Clymer instructions. Throttle valves rise at identical time. I have literally no idea what else could be wrong. Looks to me like it's got all the foundations for combustion. Any suggestions? Edited March 22, 2017 by LoveThePolice Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 22, 2017 Author Report Share Posted March 22, 2017 Put a fucking 30 pilot in there. Will go to the store and see if they have any tomorrow. I don't see how that could be the problem if it's run fine on 27.5's before at equivalent temps and altitudes. Quote Link to comment Share on other sites More sharing options...
RIPPIN' IT UP Posted March 22, 2017 Report Share Posted March 22, 2017 Will go to the store and see if they have any tomorrow. I don't see how that could be the problem if it's run fine on 27.5's before at equivalent temps and altitudes. Had a 27.5 pilots with vforce 4 reeds, it is to small, it would just run with the air screw out at one turn & it took a fair few kicks to start. Run the 30 pilots, I have a pair I could send you, from Far North Queensland, depends on how soon you need em. Sent from my ZTE T84 using Tapatalk Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 22, 2017 Author Report Share Posted March 22, 2017 i'm from Perth wa.. I would start by getting a tors delete kit. You are rich on your main to. i was at 300main 27.5pilot with your mods and was still bit rich. Are your carb slides in correct carbs? half moon out? tube in between carbs connected? Had a 27.5 pilots with vforce 4 reeds, it is to small, it would just run with the air screw out at one turn & it took a fair few kicks to start. Run the 30 pilots, I have a pair I could send you, from Far North Queensland, depends on how soon you need em. Sent from my ZTE T84 using Tapatalk Alright, I will go to the shop tomorrow and get some 30 pilots and 300 mains. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
Ducman Posted March 22, 2017 Report Share Posted March 22, 2017 It sounds like your not getting enough fuel on the pilot jet. A rich pilot should make starting easy. Turning the airscrews out makes it leaner, so you probably need to screw them in to make it run richer. You should try to turn them 1/2 a turn out from seated and see if this makes any improvement at all. If it does then the 30 pilots should improve it even more. Quote Link to comment Share on other sites More sharing options...
LoveThePolice Posted March 23, 2017 Author Report Share Posted March 23, 2017 (edited) It sounds like your not getting enough fuel on the pilot jet. A rich pilot should make starting easy. Turning the airscrews out makes it leaner, so you probably need to screw them in to make it run richer. You should try to turn them 1/2 a turn out from seated and see if this makes any improvement at all. If it does then the 30 pilots should improve it even more.Thanks for the advice mate, I've been rather busy today: 1. Installed 30 pilots, the 27.5s were slightly sandy but not clogged. Cleaned em better than I thought I had before. 2. Installed 300 mains. No clogs. 3. Ran a compression test. Only makes 90 psi. Seems like it's time for a rebuild, does it not? 4. Air screw at 2 turns out, needle at middle clip. 5. Fixed a small leak in the right exhaust manifold. 6. Inspected reed cages for damage, all clear. 7. Push started once, now she will start from kick, albeit not very reliably. I will tinker with the jetting down south to see if I can get it Mickey Mouse. Thanks a lot guys. I don't know what I'd do without you. Is that 90psi a good indication that a rebuild is warranted? She still screams along... PS: whoever put the left carb air screw on the inside side of the bike needs to be fired. Means I have to take the air filter off to adjust :/ wish I could do it while it's running. Edited March 23, 2017 by LoveThePolice Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted March 23, 2017 Report Share Posted March 23, 2017 90 pounds of compression is definitely about the end of life for a motor. Verify with another gauge to be sure. 2 Quote Link to comment Share on other sites More sharing options...
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