bikerbill2021 Posted December 13, 2017 Author Report Share Posted December 13, 2017 Even my boss ran AVGAS on his brand new banshee right out of the box and had no issues I can grab some 91 and try for sure tho Quote Link to comment Share on other sites More sharing options...
Keno Posted December 13, 2017 Report Share Posted December 13, 2017 I've ran lots of avgas. It isn't your problem. The 120 psi with a cut head is definitely a clue though. Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 13, 2017 Author Report Share Posted December 13, 2017 46 minutes ago, Keno said: I've ran lots of avgas. It isn't your problem. The 120 psi with a cut head is definitely a clue though. Werd, gonna try these leaner jets (carefully mind you) and see if there is any change, if not, ill give HJR a call and see if maybe I got the wrong or a bad head or something Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted December 13, 2017 Report Share Posted December 13, 2017 (edited) 120 psi is stock compression. ill tell you what it is NOT. its not from you not having a ground from your engine to frame or paint on your frame with your ground unless its thick af id look into that compression. even once broken in doubt it would raise more than 10 psi. u sound pretty mechanically inclined im assuming u are doing the test properly with a decent gauge. Claude was having some funky issues too with his running av gas till he closed his plug gap to 18 or 20 I think Edited December 13, 2017 by Ayesully810 Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 13, 2017 Author Report Share Posted December 13, 2017 2 hours ago, Ayesully810 said: 120 psi is stock compression. ill tell you what it is NOT. its not from you not having a ground from your engine to frame or paint on your frame with your ground unless its thick af id look into that compression. even once broken in doubt it would raise more than 10 psi. u sound pretty mechanically inclined im assuming u are doing the test properly with a decent gauge. Claude was having some funky issues too with his running av gas till he closed his plug gap to 18 or 20 I think Hmmm interesting, I could try re-gapping to 18 or so on the plug and see if that makes And yea the frame was just rattle canned, nothing special, and I cleaned off all the ground points and points where the coil bolts to the frame, but the compression is making me question things, ill have to contact HJR and double check with him. Quote Link to comment Share on other sites More sharing options...
Canadianshee Posted December 13, 2017 Report Share Posted December 13, 2017 Your set up seems pretty much the same as mine. I to also have HJR MX porting with a chariot heat with 20cc domes, but with FMF fatties. Your compression does seem a bit low as I have between 155 to 160 psi and our elevation is pretty much the same. I started out with the jetting recommendations which are the same in your post from builder. I was running into the same issue that you are describing, of falling off or not reving. After some jetting trials and chops I ended up with 27.5 pilots, AC one turn out, 340 mains, clip in 3rd groove if running oem needle. Plug gapped at 20.Did you check the squish when you assembled top end and leak test. Sent from my LG-H831 using Tapatalk Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 13, 2017 Author Report Share Posted December 13, 2017 29 minutes ago, Canadianshee said: Your set up seems pretty much the same as mine. I to also have HJR MX porting with a chariot heat with 20cc domes, but with FMF fatties. Your compression does seem a bit low as I have between 155 to 160 psi and our elevation is pretty much the same. I started out with the jetting recommendations which are the same in your post from builder. I was running into the same issue that you are describing, of falling off or not reving. After some jetting trials and chops I ended up with 27.5 pilots, AC one turn out, 340 mains, clip in 3rd groove if running oem needle. Plug gapped at 20. Did you check the squish when you assembled top end and leak test. Sent from my LG-H831 using Tapatalk I did not check the squish gap, the jugs were new and ported fresh by him, as well as the head cut, so I just threw it together thinking he had everything spec'd right, may have been a mistake on my end... I just put the 270 mains in, needle #4 position as recommend by my local shop, no change, still the same. After riding it and warming it up, I wanted to check compression with it hot, to my surprise it was less then when it was cold, maybe 100-110 on both banks. I took a vid of me riding it and free reving it, as well as some pics ill upload in a bit when I get home here in a bit, at work now Thanks for the input so far fellas Quote Link to comment Share on other sites More sharing options...
Canadianshee Posted December 14, 2017 Report Share Posted December 14, 2017 Does it sound like a hollow bog when it starts acting up past 1/4 throttle with no acceleration Sent from my LG-H831 using Tapatalk Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 14, 2017 Author Report Share Posted December 14, 2017 42 minutes ago, Canadianshee said: Does it sound like a hollow bog when it starts acting up past 1/4 throttle with no acceleration Sent from my LG-H831 using Tapatalk h/o ill post the vid here in a sec so you guys can see Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 14, 2017 Author Report Share Posted December 14, 2017 Ok heres the vid of it acting up. from 27 secs and up is a full throttle pass in second gear Here is a vid free reving it, as you can see, it has no problem reving up, perhaps a bit smokey if anything, but seemed more or less normal to me this is the right bank after that run left bank and a crappy pic of the plugs, seemed drier, but i cant do a proper chop with it acting this way So this was with 270 mains and the needle on #4, with no change, which in a way, I'm a bit relieved, as this seems stupid lean to me and from all Ive read/experienced with these bikes. I have dropped it from a 330 to this 270 with little, if any, difference. As you can see the compression numbers are lower then one would think for a fresh top end and milled head, so something internally may be amiss. However, there is one last thing I did not check, reeds. I bought brand new V force 4 reeds and installed them right out of the box, so maybe I did not orient them right if they need to be in a certain way, or maybe there is like tape holding them closed from the factory or something. I will remove them tomorrow and inspect, and I'll install my old stock reeds to see if that makes a difference. If no go on that, I'll fab up a leak tester and see if its holding pressure, then from there, most likely tearing the top end apart. Any more input is welcome Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted December 14, 2017 Report Share Posted December 14, 2017 (edited) If it were me I would have kept that fat jetting and leaned the needle all the way out to see if it would rev. Sounds like you have swapped every electrical thing for a working one off the parts bike right? That compression still aint right tho you should be around 160, I would get a better tester and retry then call kevin cause your comp is low. pistons facing the right way right? arrows towards xhaust ports Edited December 14, 2017 by Ayesully810 Quote Link to comment Share on other sites More sharing options...
Canadianshee Posted December 14, 2017 Report Share Posted December 14, 2017 Was hard to tell exhaust smoke looked a tad white, have you looked in your rad to see if your coolant has dropped.I had some issues syncing carbs with the peep windows and the lock jam nut turning. If you have access to a sync tool, sync carbs with it to be sure. Sent from my LG-H831 using Tapatalk Quote Link to comment Share on other sites More sharing options...
bikerbill2021 Posted December 14, 2017 Author Report Share Posted December 14, 2017 18 minutes ago, Ayesully810 said: If it were me I would have kept that fat jetting and leaned the needle all the way out to see if it would rev. Sounds like you have swapped every electrical thing for a working one off the parts bike right? That compression still aint right tho you should be around 160, I would get a better tester and retry then call kevin cause your comp is low. pistons facing the right way right? arrows towards xhaust ports I attempted that as well, i think I had 310s in it at that time, but I dropped the needle in to see if there was any change, sadly nothing. For the most part yea swapped everything from a known good bike electrically, making me put that at the bottom of my list Pistons are installed correctly with arrows towards exhaust ports 7 minutes ago, Canadianshee said: Was hard to tell exhaust smoke looked a tad white, have you looked in your rad to see if your coolant has dropped. I had some issues syncing carbs with the peep windows and the lock jam nut turning. If you have access to a sync tool, sync carbs with it to be sure. Sent from my LG-H831 using Tapatalk I haven't checked the rad to see coolant level, however I have inspected through the plug hole and kicking it over with the plugs out to see if there was any coolant, all dry, no coolant in chambers. Aside from syncing the carbs with the window on the side, thats all Ive done, def something to consider tho if I cant track this down. Quote Link to comment Share on other sites More sharing options...
Canadianshee Posted December 14, 2017 Report Share Posted December 14, 2017 Did you have your pod filters on when you made the video. Have read in a different post of filters with outerwear that were over oiled was a cause of not reving out under load. It's not much help other then something to check. Sent from my LG-H831 using Tapatalk Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted December 14, 2017 Report Share Posted December 14, 2017 (edited) carb sync def aint that culprit here lol that thing wont rev for shit, jmo. I have no other tips for you but ill be spying on here to see what it might be. Im sure sleeper will chime in at some point with some og knowledge Edited December 14, 2017 by Ayesully810 Quote Link to comment Share on other sites More sharing options...
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