Crnr2Crnr Posted February 3, 2023 Author Share Posted February 3, 2023 after several hours of thought and deliberation... I'm down to the coil and wiring which I did move that were touching the muffer, OR the power valves which I haven't torn apart YET. based upon what I saw with a borescope the pistons have excess carbon build-up which means not enough spark or not enough exhaust getting out. compression is solid on both jugs. y, pipe and muffler are clear... checked them immediately after finding the mouse nest in the airbox. this needs to see max rpm before I load it onto his truck next week... bit frustrated atm. Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 3, 2023 Author Share Posted February 3, 2023 Coil tested good. going to back track... ordered new mikuni fuel pump, going to check the lines for kinks and pull the jets to see if something broke free in the old pump and plugged us up again. knew I should have put a new pump on it right away... Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 7, 2023 Author Share Posted February 7, 2023 (edited) Bam, got you Bro! Happy Birthday 🎉 Edited February 11, 2023 by Crnr2Crnr 1 Quote Link to comment Share on other sites More sharing options...
Sled_Hed Posted February 7, 2023 Share Posted February 7, 2023 We're you able to figure out your low RPM issue? Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 7, 2023 Author Share Posted February 7, 2023 10 hours ago, Sled_Hed said: We're you able to figure out your low RPM issue? waiting for the new fuel pump... 🤞 1 Quote Link to comment Share on other sites More sharing options...
mnstang Posted February 10, 2023 Share Posted February 10, 2023 Carbs can run for a while just off the fuel in the float bowls without a fuel pump even connected. Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 11, 2023 Author Share Posted February 11, 2023 (edited) sadly, here's where we're ending the story for now... compression 128mag and 130pto and cylinders were borescope checked from multiple angles. everything in the entire fuel system was either replaced or cleaned. reeds removed, inspected and gasketed. new airbox foam, intake tube cleaned and sealed. all exhaust removed, inspected and resealed with new gaskets and springs. power valves removed, inspected and cleaned. power valve cables adjusted to specification. voltage regulator replaced. starts on first or second pull and idles perfectly at 1500 rpm. where the problem lies... on a track stand it revs to about 5800rpm, then just falls flat on it's face and the sled won't move under it's own power. we loaded it on my brothers truck last night and it's going to Joe next before anything else gets touched on it. we're all thinking it's something electrical at this point. can't thank young gun Jake for helping me with this project and our mutual meticulous nature of doing things. after covering all the bases we had time to we were both disappointed and yet strangely a bit happy to see it leave last night. will update when we know... on the bright side, his 21 RXC is going to live here for me to dial in for him. Edited February 11, 2023 by Crnr2Crnr 2 Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 13, 2023 Author Share Posted February 13, 2023 around 3am this morning I remembered something that I never took apart, checked or looked at because we were so focused on everything else. the previous owner mentioned it wasn't backshifting properly the last time he rode it before I came to look at it. I never removed the belt once and we always had the belt guard down when running it. my thinking at the moment is the secondary spring is broken, the belt is getting sucked into the sheaves which isn't allowing it to rev out. on the track stand at idle (1500 rpm) the track is spinning quite a bit to the point you need to apply the brake. when on the ground we had to push it up the ramp to get onto the truck. it won't move on the ground under it's own power. So... I ordered a stock spring from Country Cat and am shipping it to his house. Also sent him a YT video (this one) to learn how to take the clutch apart, inspect, clean and assemble it with his son's. feeling a bit dumb right now for not thinking about this until it's 1000 miles away. Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 13, 2023 Author Share Posted February 13, 2023 (edited) I have no idea which helix and spring are in there. Black magic? Edited February 13, 2023 by Crnr2Crnr Quote Link to comment Share on other sites More sharing options...
mnstang Posted February 13, 2023 Share Posted February 13, 2023 I think you'd be burning the shit out of the belt if that is the case Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 13, 2023 Author Share Posted February 13, 2023 7 minutes ago, mnstang said: I think you'd be burning the shit out of the belt if that is the case I think it was... In hindsight. We were just so focused on all the other sin I found. Quote Link to comment Share on other sites More sharing options...
Cat45 Posted February 15, 2023 Share Posted February 15, 2023 On 2/13/2023 at 10:31 AM, Crnr2Crnr said: I have no idea which helix and spring are in there. Black magic? Sure looks like a black magic helix Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 15, 2023 Author Share Posted February 15, 2023 15 minutes ago, Cat45 said: Sure looks like a black magic helix any idea which spring they used? stock green is what I ordered to check it. Quote Link to comment Share on other sites More sharing options...
Cat45 Posted February 15, 2023 Share Posted February 15, 2023 if i remember right mine had a gray titanium spring, no idea on rate. But it's been 20 yrs since i sold the sled and my memory sucks Quote Link to comment Share on other sites More sharing options...
mnstang Posted February 15, 2023 Share Posted February 15, 2023 5 hours ago, Crnr2Crnr said: any idea which spring they used? stock green is what I ordered to check it. If you're putting a stock spring in you might as well put a stock angle helix in otherwise you're just mish matching clutch calibration parts which is obviously a bad plan Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 15, 2023 Author Share Posted February 15, 2023 (edited) 5 minutes ago, mnstang said: If you're putting a stock spring in you might as well put a stock angle helix in otherwise you're just mish matching clutch calibration parts which is obviously a bad plan just to test when he gets the old spring out he's supposed to send me pics or the whole spring. we have a lot of time until next February do you have an old black magic catalog by chance? Edited February 15, 2023 by Crnr2Crnr Quote Link to comment Share on other sites More sharing options...
mnstang Posted February 15, 2023 Share Posted February 15, 2023 2 minutes ago, Crnr2Crnr said: just to test when he gets the old spring out he's supposed to send me pics or the whole spring. we have a lot of time until next February do you have an old black magic catalog by chance? Yeah I have a couple of them Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted February 15, 2023 Author Share Posted February 15, 2023 27 minutes ago, mnstang said: Yeah I have a couple of them Cool, when he gets it apart we'll see if there's any numbers on the helix and spring. Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted December 28, 2023 Author Share Posted December 28, 2023 it was a sticking oil pump... of all things. full oiling, all the damned time. even you know who couldn't believe it and just happened to see it stick when the air box was off. Everytime we ran it here the air box was on it. VID_20231228_131846.mp4 1 Quote Link to comment Share on other sites More sharing options...
joe_zrt Posted December 29, 2023 Share Posted December 29, 2023 Dam, that's a tough one to diagnose Quote Link to comment Share on other sites More sharing options...
Crnr2Crnr Posted December 30, 2023 Author Share Posted December 30, 2023 On 12/28/2023 at 9:03 PM, joe_zrt said: Dam, that's a tough one to diagnose it's not over... hitting 6800 and falling on its face... next up, check stator and test with another one... pull the jugs, run cylinders and a set of rings. he just did a new compression check and it dropped to 110ish from 130ish. this sled is f'ng possessed and a thousand miles from me Quote Link to comment Share on other sites More sharing options...
joe_zrt Posted December 30, 2023 Share Posted December 30, 2023 Electrical gremlin I bet. You probably end up making your way back to the stator. And you pulled the reeds, so you know those are good. Quote Link to comment Share on other sites More sharing options...
Not greg b Posted January 2 Share Posted January 2 On 12/30/2023 at 1:02 PM, Crnr2Crnr said: it's not over... hitting 6800 and falling on its face... next up, check stator and test with another one... pull the jugs, run cylinders and a set of rings. he just did a new compression check and it dropped to 110ish from 130ish. this sled is f'ng possessed and a thousand miles from me “They don’t build them like they use to” Ass drag life 1 Quote Link to comment Share on other sites More sharing options...
mnstang Posted January 2 Share Posted January 2 Should have got a Z Quote Link to comment Share on other sites More sharing options...
Not greg b Posted January 2 Share Posted January 2 On 2/15/2023 at 2:44 PM, Crnr2Crnr said: just to test when he gets the old spring out he's supposed to send me pics or the whole spring. we have a lot of time until next February do you have an old black magic catalog by chance? I may have that information. I took some pictures of a bm catalog when I was at the hall of fame. I just have to fire up my old ass naked lady machine to find them. 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.
Note: Your post will require moderator approval before it will be visible.