bansheeryder21 Posted January 3, 2012 Report Share Posted January 3, 2012 I just got a 421 cub 4-mil built by Kevin @HJR motors. It is fully ported and I'm running 34m PJs. My sig lists all my mods. I took it out this weekend for the first time and it runs well until it warms up. I would do about 2-3 runs down the drags and then it would not rev out. When I give it gas (full throttle) it would just bog down and wouldnt not rev any higher. Low rpm's are okay as well as idle. If the bike cools down then it's okay for about 1 more run and then bogs out again. Plugs are brand new. Jetting is 172 main, 152 pilot, air screw 2 turns out. Plug color is light grey and bike is not overheating. I've read that this could be my plug wire caps and that the resisitor goes bad after awhile. It is an 04 and they have never been changed out. I played with my jetting 170, 172, 180 mains and it does the same thing all around. 170's feel the best but plug color is very light grey and I don't want to run that lean. This is a brand new cub motor with zero hours. Can someone please help me and explain why this is happening? I have not changed out my plug caps yet. Just got back from Gordon's yesterday. Not that it matters but I am running Maxima K2 fully synthetic esther blend oil at 40-1 with AVGAS. Air filters are brand new. I have an allumunim oversized radiator with an oversized impeller and water wetter w/distilled water. I am going to use engine ice instead to keep it cooler. Compression is at 135psi in each cylinder but I believe my tester is bad because I bent the hell out of a copper fitting and the o-rings are worn. I will use a different compression tester to get true reading but do not believe that compression is an issue due to it being a brand new motor built by HJR. My squish is .050 which is perfect. Any help will be appreciated thanks! Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 3, 2012 Author Report Share Posted January 3, 2012 (edited) i had the same issue almost as you with my engine (stock ported cyls) Turns out It would go down to 1 cylinder after a bit. test your plug caps, check pick up gap, ext... test your coil / stator. and if all that still doesnt change anything i would try swapping cdi's. (mine was either the coil / caps or the flywheel) my flywheel had loose magnets so changed it along with the coil) and it cleaned up But im confident its a simple electrical issue your having... test your caps / coil first. I hope it's just a simple electrical issue. thanks for the help. Can you break down how to test the coil, stator, and caps? Procedure and readings? Two weeks ago I was running a 350 ported duner (HJR) and had no electrical issues at all. The cub is a new case with a stator and flywheel off a 2001 banshee. But the same flywheel and stator was also running on a stock 350 two weeks earlier as well. I'm wondering of the cubs are sensitive to electrical spark. My ported 350 was fine but now I'm having issues with my cub. I wonder if the caps need to be new because the way the cubs run. Edited January 3, 2012 by bansheeryder21 Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 3, 2012 Author Report Share Posted January 3, 2012 problem, the 152 pilot. should run a 52 pilot. typo... it is a 52 Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted January 3, 2012 Report Share Posted January 3, 2012 Just call Kevin. I had my motor ported by him. When I got it back I was on the phone with him for an hour just picking his brain. Not once did he seem to get annoyed. He should be able to point you in the right direction. Quote Link to comment Share on other sites More sharing options...
beez33 Posted January 3, 2012 Report Share Posted January 3, 2012 It happend to me. Mine was a spark plug boot and coil. Avgas sucks dick. Quote Link to comment Share on other sites More sharing options...
2004LEBanshee Posted January 3, 2012 Report Share Posted January 3, 2012 Just so you know some parts can test good but still be bad. Had numerous ricki stators that did that and one cdi Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 3, 2012 Author Report Share Posted January 3, 2012 I've been in contact with Kevin all weekend. He is helping me as much as he can. The thing that sucks is i have to ride it in order to trouble shoot. I cant ride it at my house. I can put it on jacks and do it that way but dont know if it will work under no load. I will start by checking and testing everything as listed above and will post results. Thank you everyone for all your help so far. I am confident that along with all your help I can resolve this issue. Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted January 3, 2012 Report Share Posted January 3, 2012 These are all good answers. You just have to get to work. No easy way around it. You’re lucky that I'm just a drive down the street if you need me. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted January 3, 2012 Report Share Posted January 3, 2012 Pick up the flywheel and shake it...if it sounds like things are broken up inside, replace it. Cubs don't need any more spark than a stocker...but since you had it all apart, it's possible something either broke or wasn't put together properly...don't overlook or take anything for granted. Did you measure the squish before firing the bike? What is the timing set at? (Sorry if any of this is answered...I just parsed this thread) Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 3, 2012 Author Report Share Posted January 3, 2012 These are all good answers. You just have to get to work. No easy way around it. You’re lucky that I'm just a drive down the street if you need me. Yeah i am lucky! Thanks for all your help since October Kevin. I appreciate it more than you know. Thats why I will always rep HJR. its been a rough season so far! Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 3, 2012 Author Report Share Posted January 3, 2012 Just tested my compression with a auto zone tester. It read 150 psi in each cylinder cold motor. My cub is fully ported cases and all. Is this okay? Also did a test on my caps and one read 4.7k and the other 13.8k. I may have found my problem. Check all the wires and grounds and everything connectes tightly. Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 4, 2012 Author Report Share Posted January 4, 2012 Bought a NGK plug cap p/n LBO5E. someone who has changes theirs, what ones did you buy? Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 4, 2012 Author Report Share Posted January 4, 2012 Bought a NGK plug cap p/n LBO5E. someone who has changes theirs, what ones did you buy? I got the wrong one. I tested it and it was 5.5k out of the box. Can someone please tell me what kind they uses to replace their caps? Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 4, 2012 Author Report Share Posted January 4, 2012 I got the wrong one. I tested it and it was 5.5k out of the box. Can someone please tell me what kind they uses to replace their caps? I also tested coil, stator, and cdi. All are good. Im pretty sure its the bad cap. Just need to know which ones to buy??? Quote Link to comment Share on other sites More sharing options...
bansheeryder21 Posted January 5, 2012 Author Report Share Posted January 5, 2012 I founf out the right NGK plug caps to buy. TB05EMA. I replaces them and got the bike running. Since I cant ride it at my house I plan on taking it somewhere on Saturday morning to test it out. I will post how everything goes. Quote Link to comment Share on other sites More sharing options...
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