copemech Posted March 18, 2014 Report Share Posted March 18, 2014 (edited) Seems to me you at least have a clue at what you are after here and how to get there! I am guessing the CDI unit is FU if all else is good. Something with the stator winding? Then you can get into other weird stuff like a cracked magnet in the flywheel! All else fails, you might want to call rising sun or possibly Adrian at Lewisport or someone to see if they will allow you a return on a tester CDI if there is nothing else close to you. Not that it makes sense, but I suppose to changed the plug? I have seen enough weird stuff to know how this goes, unfortunately. Edited March 18, 2014 by copemech Quote Link to comment Share on other sites More sharing options...
b40rt Posted March 18, 2014 Report Share Posted March 18, 2014 Are you sure the reeds are ok ? This might not be your problem, but damaged reeds WILL stop it running. Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted March 18, 2014 Report Share Posted March 18, 2014 Climberevan, Welcome first off. My buddies 2001 txt 321 will start in reverse every time i bump start it backwards. I have even had his starting when pulling back on the bars in gear putting the thing on the trailer. These bikes start very easy unlike the pro models. I had this problem on my 2000 280 and i think the problem i had may be yours. The kick start gear, when worn out will stay engaged to the idler gear, and as the kick start returns it will actaully stop the the engine and spin it backwards. Sounds weird but it can happen. Here is what i would look for. Have the flywheel cover off and pull the plug. Kick it down to the foot peg and watch the direction of the fly wheel. If you are wondering if thats forward or reverse then just put it in gear with the clutch out and you will find out real quick. If the bike rotates backwards when kicking down then.... ummm i dont know how that can happen. If the fly wheel rotates one direction down it should not rotate in the opposite direction on its way up right? Well go look for that.... If the idler gear is worn out the bike will run like the brakes were on and from what you were saying before the thing started doing this that might be the case. Pay attention to number 8 and 11 if this is the case. To the forum I broke reeds on a gasgas and it will run. Poorly but it will run. Carbon build up causes a back fire and my reeds imploded. Both on a gasgas and once on an old ty350 i had. keep in mind that early two strokes didnt have reed valves. --Biff Quote Link to comment Share on other sites More sharing options...
tltel Posted March 18, 2014 Report Share Posted March 18, 2014 Hi If the blue marks were on the bike when you got. This is an old problem and probably why it was sold. I would guess CDI control box is at fault. Good luck TLTEL Quote Link to comment Share on other sites More sharing options...
copemech Posted March 19, 2014 Report Share Posted March 19, 2014 Climberevan, Welcome first off. My buddies 2001 txt 321 will start in reverse every time i bump start it backwards. I have even had his starting when pulling back on the bars in gear putting the thing on the trailer. These bikes start very easy unlike the pro models. I had this problem on my 2000 280 and i think the problem i had may be yours. The kick start gear, when worn out will stay engaged to the idler gear, and as the kick start returns it will actaully stop the the engine and spin it backwards. Sounds weird but it can happen. Here is what i would look for. Have the flywheel cover off and pull the plug. Kick it down to the foot peg and watch the direction of the fly wheel. If you are wondering if thats forward or reverse then just put it in gear with the clutch out and you will find out real quick. If the bike rotates backwards when kicking down then.... ummm i dont know how that can happen. If the fly wheel rotates one direction down it should not rotate in the opposite direction on its way up right? Well go look for that.... If the idler gear is worn out the bike will run like the brakes were on and from what you were saying before the thing started doing this that might be the case. Pay attention to number 8 and 11 if this is the case. To the forum I broke reeds on a gasgas and it will run. Poorly but it will run. Carbon build up causes a back fire and my reeds imploded. Both on a gasgas and once on an old ty350 i had. keep in mind that early two strokes didnt have reed valves. --Biff Now that is some good info Biff! That is what we pay you for! Ha! Possibly it is normal, if properly induced? No ides if the CDI has any protection against it, although I was under the impression that most do, and that backward running was not possible, although I get things running through the old head, such as on a pulse coil setup, how does it know? I think the pulse polarity would change with direction of rotation, a simple diode may control it, yet if that diode is shorted, the system would not know. The newer stuff has hall effect stuff, and I cannot explain just how it all works either, so all just theory! My Theory! Hey, it works for me! Ha! That is why they call them black boxes and I hav not found any info on any of them! Quote Link to comment Share on other sites More sharing options...
climberevan Posted March 19, 2014 Author Report Share Posted March 19, 2014 Yes, the blue marks didn't inspire confidence. I did some more dis-assembly today and found no faults with the piston, stator wiring, exhaust (not blocked), etc. While the header was off I kicked it and it started and ran like a banshee, but I killed it immediately since I wasn't sure if it was OK to run without the header. I then re-assembled everything and...nothing. I took off the exhaust and tried again, but no dice. Now it seems to fire a little, and backfires sometimes when I've been kicking for a while, but the most it's done is a couple of fires. I moved the stator in its slots to retard it as much as possible (which corresponds to about 13-15 deg BTDC), but it changes nothing. The guy at Lewisport didn't have any suggestions, but he seemed confident that it wasn't the CDI ("They almost never fail.").He said that 20 degrees of advance was WAY too much, though. He thought it should be about 4. I, however, am really starting to think this is it. It's not cheap, nor returnable, so I don't want to buy one if there's any other explanation. Arrgh. Quote Link to comment Share on other sites More sharing options...
copemech Posted March 19, 2014 Report Share Posted March 19, 2014 You should be able to email Steve at Motoplat UK(Bradford ignitions) He may have suggestions, as with Mr Jim Snell at Rising Sun imports. Possibly they have run across this? The other answer, What have you not done? Well, try that! That is the way this stuff goes if you don't have any known good stuff to work with. Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted March 19, 2014 Report Share Posted March 19, 2014 Getting back to what i was refering to. When kicking it over does the engine drive the bike forward or reverse? If it kicks it forward does it remain rotating that direction when releasing the kick starter? --Biff Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted March 19, 2014 Report Share Posted March 19, 2014 You should be able to email Steve at Motoplat UK(Bradford ignitions) He may have suggestions, as with Mr Jim Snell at Rising Sun imports. Possibly they have run across this? The other answer, What have you not done? Well, try that! That is the way this stuff goes if you don't have any known good stuff to work with. Yea cope this is all pickup coil and not hall effect. I think there is enough charge and capacitiance in the system that even with timing being off it will still push the fly wheel enough to keep the thing running. I agree that CDI is highly unlikely. These ignitions were built like a tank. Dont worry Climberevan we will get you sorted out. Just check the rotation of the engine as you are kicking and releasing the kick starter. Another thing that popped into my head was exhaust back pressure. It could be building up and pushing the piston in the opposite direction after a few rotations and that would also make the bike have no power. Unlikely but also possible. --Biff Quote Link to comment Share on other sites More sharing options...
climberevan Posted March 19, 2014 Author Report Share Posted March 19, 2014 Thanks guys! The kickstarter definitely does rotate the engine in the correct direction (confirmed by rotating it in gear with the rear wheel). Plug out, it keeps turning for bit after the lever is released. It does feel like it has a missing tooth or something and seems to skip a bit about every 20th kick, but I just figured it was catching strangely. I thought about the back-pressure thing as well, especially after it started with no exhaust. I am able to blow freely through all 3 sections of the exhaust, though, so that can't be it. While it was running it was quite powerful--I was actually pretty surprised by how strongly it pulled in 4th and 5th up to speeds that were beyond what I wanted. I'm going to do a compression test today to rule that out. Quote Link to comment Share on other sites More sharing options...
b40rt Posted March 19, 2014 Report Share Posted March 19, 2014 (edited) "Keep in mind that early two strokes didnt have reed valves." --Biff Early 2 strokes were piston ported, so your comment is not relevant. (They didn't have cdi' s or hall sensors either ! ) Edited March 19, 2014 by b40rt Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted March 19, 2014 Report Share Posted March 19, 2014 "Keep in mind that early two strokes didnt have reed valves." --Biff Early 2 strokes were piston ported, so your comment is not relevant. (They didn't have cdi' s or hall sensors either ! ) Touche... --Biff 1 Quote Link to comment Share on other sites More sharing options...
copemech Posted March 20, 2014 Report Share Posted March 20, 2014 ("They almost never fail."). I seem to recall Dougie loosing a SSDT on that principal! Ha!But that was a Beta I think! Quote Link to comment Share on other sites More sharing options...
climberevan Posted March 21, 2014 Author Report Share Posted March 21, 2014 Compression test results: 130 psi throttle closed, 140 throttle open. Stabilizes after 4-5 kicks. So...I guess we can rule that out. Quote Link to comment Share on other sites More sharing options...
climberevan Posted March 22, 2014 Author Report Share Posted March 22, 2014 Thanks to a very helpful and generous fellow trials-er, I had the opportunity to swap in a known-good CDI. Still no starting. It will fire once or twice, then dies, just like before. I'm really starting to suspect the fuel delivery, but I took the carb off and attached it to a vacuum to confirm that it's delivering fuel, and it is. This thing is driving me CRAZY. What's next? Stator? How do I test it? Quote Link to comment Share on other sites More sharing options...
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