death star Posted September 19, 2007 Share Posted September 19, 2007 Hi everybody, I am a newbie to this forum. Need some helpful advise please. Just bought a 83 TT600 that had a seized piston. Got everthing back together and now have no spark. Have gone through all wiring and tests that I can do and everything seems to test ok. Is there a way of testing the CDI box so I can know for sure if that is the issue. I find it hard to swallow that the spark box went tits up since the piston seizure. The previous owner did not mention any ignition issues, just the top end. Any help with your past experiences would be greatly appreciated. It's been over 30 years since I have had a kickstart dirtbike and trying to spin the motor over and check voltages is a pain in the rear, I'm used to bikes with starters! Thanks again for any help. Link to comment Share on other sites More sharing options...
Bruce Posted September 20, 2007 Share Posted September 20, 2007 I take it you have correctly connected the loom and checked resistances. I would agree the coincidence of a faulty CDI unit is unlikely. Last check I'd recommend you try is check the HT lead to sparkplug suppressor cap. Trim 2mm off HT lead, re-insert the cap and try again, as the HT Lead was known to be susceptable to corrosion in these models. Likelihood is pulling it off the plug was the last straw. Link to comment Share on other sites More sharing options...
death star Posted September 21, 2007 Author Share Posted September 21, 2007 I take it you have correctly connected the loom and checked resistances. I would agree the coincidence of a faulty CDI unit is unlikely. Last check I'd recommend you try is check the HT lead to sparkplug suppressor cap. Trim 2mm off HT lead, re-insert the cap and try again, as the HT Lead was known to be susceptable to corrosion in these models. Likelihood is pulling it off the plug was the last straw. Thanx Bruce, will give that a try. Reinstalled the spark box tonite and reconnected all wiring, kicked her over and I swear I did see a weak spark at the grounded plug. When tried to start with plug in tho, no go. Your suggestion could very well explain this development, will try and advise, thanx again Link to comment Share on other sites More sharing options...
death star Posted September 25, 2007 Author Share Posted September 25, 2007 Thanx Bruce, will give that a try. Reinstalled the spark box tonite and reconnected all wiring, kicked her over and I swear I did see a weak spark at the grounded plug. When tried to start with plug in tho, no go. Your suggestion could very well explain this development, will try and advise, thanx again OK, thanks Bruce, tried your idea and lo and behold I got the beast started. Sure is hard to start tho. I can't count the number of kicks it took. Now it is still hard as heck to start cold. Have adjusted the valves and I know the valve timing is spot on. Have taken primary carb apart and adjusted float level and cleaned all jets and orifaces. Low speed needle is 1.5 turns out per manual and have tried another 1/2 turn out with no effect. Have pulled the plug and it is not wet at all after repeated kick tries. Any thoughts? Link to comment Share on other sites More sharing options...
Bruce Posted September 25, 2007 Share Posted September 25, 2007 OK, thanks Bruce, tried your idea and lo and behold I got the beast started. Sure is hard to start tho. I can't count the number of kicks it took. Now it is still hard as heck to start cold. Have adjusted the valves and I know the valve timing is spot on. Have taken primary carb apart and adjusted float level and cleaned all jets and orifaces. Low speed needle is 1.5 turns out per manual and have tried another 1/2 turn out with no effect. Have pulled the plug and it is not wet at all after repeated kick tries. Any thoughts? Early kickstart TT's have a weak kick over spark. ... you generate the current for the spark on kick over not via battery. Make sure all lights etc are off. Have you got the kickstart technique right? A seemingly stupid question, but if you are new to these old 600 thumpers, they will start a dream if you kick them over right and be an absolute bitch if you get it wrong. ... feel for the near TDC compression by gently pushing down on the kickstart lever. When you reach it come back up on the kickstart and kick all the way through to the end of the stroke with firm pressure. Failing this have a look at the following to make sure you have a clean circuit: Side stand switch (if present of course) Kill switch Check all earthing points are clean and make good contact especially on any repainted surfaces Check the neutral cable (blue if memory serves) these go into the crankcase and can deteriorate and break under heat Recheck coil resistance remember a cold engine takes more electrical current to start than a hot one. If all these check out, then you need to make sure it is indeed an electrical problem. Remove the plug from the head so you have no compression when you kick her over, then remove the suppressor cap from the HT lead and make sure a bit of wire is poking out. Ask someone brave to hold the ht lead close to a exposed metal earthing point on the bike and kick her over with gusto. If the spark is orange = weak. Blue = OK. Now try it with the suppressor cap and plug in on the same grounded surface. Link to comment Share on other sites More sharing options...
Bruce Posted September 25, 2007 Share Posted September 25, 2007 Oh, you dont want a wet plug. Dont use that as your yardstick. Rather look at the plug after running for a while to judge mixture. Remember these bikes run notoriously rich anyway. Are you using the correct amount of choke on cold starts? Link to comment Share on other sites More sharing options...
yoda Posted September 25, 2007 Share Posted September 25, 2007 For kick starts you need a very clean plug of the right grade and good ground (earth) to the engine/, engine/frame. This ensures an electrical path. Kickover start voltage will be low so anything you can do to enhance this will be good. Link to comment Share on other sites More sharing options...
death star Posted September 26, 2007 Author Share Posted September 26, 2007 For kick starts you need a very clean plug of the right grade and good ground (earth) to the engine/, engine/frame. This ensures an electrical path. Kickover start voltage will be low so anything you can do to enhance this will be good. Okay, thanks guys will double check all of the above and make sure. Also will play around with the technique, have been using full choke and also no choke trying to find the sweet spot. Will play around with 1/2 choke and see what happens. I remember my old DT400 (still wish I had her) took some TLC to start. Link to comment Share on other sites More sharing options...
death star Posted September 28, 2007 Author Share Posted September 28, 2007 Okay, thanks guys will double check all of the above and make sure. Also will play around with the technique, have been using full choke and also no choke trying to find the sweet spot. Will play around with 1/2 choke and see what happens. I remember my old DT400 (still wish I had her) took some TLC to start.It lives!! Fired up on 3rd kick tonight and seems to run like a dream. Thanks to all who gave input on this issue. It seems the problem was a leaking oil supply oring in the side cover allowing oil to migrate into the stator/rotor area and shorting out the signal. Replaced the oring and cleaned out with carb cleaner and let air dry overnite. Of all the unexpected stuff to find. I hope this issue is permanetly fixed, however I still don't understand how the LH side crank bearing is sitting there exposed with no seal to keep oil out of the side cover. Have found no reference to a seal in the parts breakdown or in the factory service manual. Don't know a whole lot about these dry sump systems yet. If anyone has knowledge on this I would appreciate the education. But hey, at least I know now what to do if I don't have fire again. Thanks again everyone. Link to comment Share on other sites More sharing options...
Bruce Posted September 28, 2007 Share Posted September 28, 2007 Glad you sorted it out. Oil seal leak eh? That's a new one to remember. Link to comment Share on other sites More sharing options...
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