Docsl98 Posted April 15, 2005 Report Posted April 15, 2005 OK, So I'm rebuilding my Brother's Girlfriend's Banshee. It refused to start, so I took it apart and it threw a circlip and the wristpin ate a huge groove in the cylinder, so we got a new cylinder and had both bored out to 65 mm. I got everything back together and it fired on first kick. I started it on six occassions after that for the next day with the air cleaner off and it started first kick. I then rode it around on my street with the air cleaner off and it ran pretty damn good although it was a little rich down low. I went to put everything back together and when I put the semi-dirty air cleaner back on it started first kick and within 3 seconds started dying. I gave it gas and it started to rev higher then it started popping and backfiring. It would not start after that and it consistantly backfires while trying to start it. This is with or without the air filter again. I ripped the whole bike down and took the head off again, the piston rings are still seated, I retightened everything down hooked up ALL carburetor connections securely and still no start. I have tried gas in the cylinder, starting fluid and nothing, we tried towing it behind my SUV and at about 17 mph it tries starting but just backfires the whole time. I have been working on and building race motocross bikes for the last 13 years and I have never EVER seen anything like this before from merely putting an air filter on. The only thing that concerns me is when you put the carbs on the clamps tighten all the way down, meaning I can only get them as tight as that, will new clamps help this or do I need new clamps and new boots? Could that even be the problem? I also replaced the carburetor connectiing tube with a brand new one, just to make sure that was not it. This has been going on into a 2 week project and it's really starting to upset me, Please Help! Quote
bigboybanshee Posted April 15, 2005 Report Posted April 15, 2005 I know this sounds simple but have you cleaned the semi-dirty air filter yet? If it started running shitty once you put the air filter on, that's the first thing I'd clean / check. If you're running an outerwear on it (and it's dirty) I bet you're choking it for air Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 Yes cleaned thoroughly with K&N kit and reoiled, but it won't even start without the air filter now either. And I've tried three sets of new spark plugs. Quote
NitroTate Posted April 15, 2005 Report Posted April 15, 2005 You may have already thought of this but something similar happened to me a long time ago when I was new to banshees but are you absolutely positive the carb slides are in the correct side? It's possible to put them in backwards and then the shee runs like shit, if at all. It will backfire and sometimes run on one cylinder etc. Make sure you sync the carbs, there are little windows on the sides of each carb and as you roll on the throttle you will see a ping mark appear in the window, both marks should appear at the same time, if you don't see a ping mark at all the slides are in the wrong carbs. Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 Also it has FMF pipes and removed tors, I have disconnected the tors box also and it's jetted with 300 main jets. Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 I only take the slides out one at a time when I'm working on the bike. They are in right and are in sink. I've also pulled both carbs completely apart and cleaned out all ports openings and jets with carb cleaner. Quote
NitroTate Posted April 15, 2005 Report Posted April 15, 2005 Crap I don't know then, sorry man. Do you have an adjustable timing plate that may have come loose?? Quote
ledofthezep Posted April 15, 2005 Report Posted April 15, 2005 Since you've already went over the carbs again, I'd check for an air leak, cracked reeds, incorrect timing and/or bad stator....in that order. Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 Just switched them to rule that out. Before I saw a line in the window right near the top, now it looks like there is a metal casting hole that is visible through the hole, still wont start. I don't see anything pink on either carb slide when I pull them out. Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 Already removed the ignition cover thinking the exact same thing, all stock , stock locations. Why would the air filter have triggered a stator failure? Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 Reeds are beautiful, look brand new, and a crack would probably cause more top end flutter than hard starting wouldn't it? Quote
ledofthezep Posted April 15, 2005 Report Posted April 15, 2005 Yes, a crack would cause you more issues when on the gas since it's sucking more air...I have never found anything that's sure-fire as to why a stator goes bad. I've been through some myself, had them go bad just sitting there, and after riding & never have I had one slowly go bad or anything like that. If you have a clymers & an ohm meter; you can check the specs on the stator....or just swap it out with another from another bike if you can. I'd definately be checking for leaks, but 90% of the time when backfiring on a shee occurs it's timing related. Make sure the stator & CDI connector is good & no prongs got bent when you connected them together. Quote
NitroTate Posted April 15, 2005 Report Posted April 15, 2005 Yes, a crack would cause you more issues when on the gas since it's sucking more air...I have never found anything that's sure-fire as to why a stator goes bad. I've been through some myself, had them go bad just sitting there, and after riding & never have I had one slowly go bad or anything like that. If you have a clymers & an ohm meter; you can check the specs on the stator....or just swap it out with another from another bike if you can. I'd definately be checking for leaks, but 90% of the time when backfiring on a shee occurs it's timing related. Make sure the stator & CDI connector is good & no prongs got bent when you connected them together. 355735[/snapback] Agreed, I had the same issues with a stator before too, that's why I mentioned it also. They're moody like my wife was last night, one minute she was joking and timing was good with my comebacks, next thing I knew she was ripping my head off, guess it's time to go play with the shee for a week... Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 I have an ohm meter, but what is a clymers? Quote
Docsl98 Posted April 15, 2005 Author Report Posted April 15, 2005 (edited) Will new clamps, new boots, or both create a better seal around the carbs, because like I said I can't tighten down the clamps any more. My dirtbikes never had this issue because there was always plenty of room for more tightening of the clamps. All gaskets have been replaced on the top end with a metal cometic gasket kit. Would liquid gasket possibly help, because the old gaskets were not metal. Edited April 15, 2005 by Docsl98 Quote
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