1985 CR 500 starts cold; won't start warm

[moabrules1]

I just got an '85 CR 500 for a restoration project that is difficult to start. I did some electrical checks on the ignition coil based on the Clymer manual and it failed 2 out of 3 so I replaced it. So after sitting for two weeks, I slapped the new coil on and did the rock back and forth thing. The bike fired in two kicks. I shut her down without warming the bike up, finished putting some plastics and seat on and tried to fire her up again with no success. I pulled the plug and it was all wet, so I figured it was flooded and let it sit for the night. While the plug was out, I checked the spark condition in my dark garage. I was able to accomplish a spark by kicking the bike with my hand. The spark seemed o.k. but I wouldn't call it blue, instead I would characterize it as purplish (is this good). Tonight, I reinstalled the plug, did the rock back in forth thing in gear and she fired in about three kicks. I rode the bike around the neighborhood and the bike seemed to run pretty good, it revved cleanly and barked hard! So, after making sure the bike was good and warm, I shut her down and tried to start the bike again. I held the throttle wide open and, it took about twenty kicks until I got it lit again. I took the bike for another run around the block. After that little jaunt, I tried to start the bike again with no success. Is something wrong with the CDI/stator on this thing? The resistance measurement on the stator was lower than the spec in my Clymer manual. It seems weird that the bike has such a hard time starting when warm. Any help would be appreciated.

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[Crazyced]

Ever tried to kick it with the trottle closed?

[Slowmotion426]

Too much gas man...

[xylicon]

I held the throttle wide open and, it took about twenty kicks until I got it lit again.

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Don't do that, little to no throttle at all and it should start.

[Tyayo420]

Ever tried to kick it with the trottle closed?

haha im pretty sure if hes restoring a bike, i think he knows or anyone in their right mind wouldnt always hold it wide open to start lol...i hope atleast..sounds to a person such as myself with hardly any mechanichal expertise, that its flooding out after it starts, and or before or during

[moabrules1]

haha im pretty sure if hes restoring a bike, i think he knows or anyone in their right mind wouldnt always hold it wide open to start lol...i hope atleast..sounds to a person such as myself with hardly any mechanichal expertise, that its flooding out after it starts, and or before or during

Do any of you guys own a CR 500? I haven't been away from 2 smokes too long to know the difference between the carbs. On a 4 banger, of course I'd flood the thing cracking the throttle wide open when starting. That's because the 4 stroke carb uses an accelerator pump. The CR 500's carb doesn't. That means gas doesn't squirt into the engine every time you crack the throttle. In my past experience with a two stroke, kicking with a WOT was a good way to unflood the thing. Since the a higher vacuum signal = more gas being sucked out of the carb, holding it wide open should accomplish exactly what I just said due to the lower vacuum produced by the engine when kicking it over combined with the larger venturi created by the WOT. At any rate, I figured it out. The damn thing just requires a special starting drill compared to any other bike I've ever experienced.

[jbird710]

All 3 of mine start the same way. Ensure the gas and choke are on, slowly kick through 3 TDC strokes, bring the bike to just before TDC, get the kick starter engaged at the very top of the stroke, and kick it through fully. If they don't start on the first kick, they will usually light within 2 more. After warming up, I do the same thing, except for leaving the choke off, and they will all start with out ever cracking the throttle.

[joshwfl]

Same here:

http://video.google.com/videoplay?docid=-3766243873321372979

[evo125]

my cr125 starts first kick warm or cold w/ no throttle and its an 1985 with a skinny purple spark. purple is not bad but if the spark is thin and purple you could loose your spark at upper rpms as well as hard starting. it can also make jetting a nightmare. my cr also failed the tests in the manual but it was a connector not a component giving me greif. weak spark does make it hard to start period, but worse warm than cold. when warm you don't need the extra gas in the mix to light er off and lean mixtures are hard to light. try checking the two connectors onto the coil, they seem to go west and weaken your spark before the bullet connectors from the stator/trigger to cdi box. if they unplug from the coil with a small amount of force they are prone to arcing and forming porosity on the terminal, just give the plug an ajustment by squishing the bugger lightly to get a firmer connection. just a slight amount of voltage drop on primary circuit can make your life miserable.

good luck and be sure to tell us if you fix the problem

[moabrules1]

my cr125 starts first kick warm or cold w/ no throttle and its an 1985 with a skinny purple spark. purple is not bad but if the spark is thin and purple you could loose your spark at upper rpms as well as hard starting. it can also make jetting a nightmare. my cr also failed the tests in the manual but it was a connector not a component giving me greif. weak spark does make it hard to start period, but worse warm than cold. when warm you don't need the extra gas in the mix to light er off and lean mixtures are hard to light. try checking the two connectors onto the coil, they seem to go west and weaken your spark before the bullet connectors from the stator/trigger to cdi box. if they unplug from the coil with a small amount of force they are prone to arcing and forming porosity on the terminal, just give the plug an ajustment by squishing the bugger lightly to get a firmer connection. just a slight amount of voltage drop on primary circuit can make your life miserable.

good luck and be sure to tell us if you fix the problem

Now that's a good, helpful post. When I first starting messing with this bike, it carburated poorly like it was too rich. It wouldn't take full throttle, backfired, etc, and I had to push start it. I stripped the carb down cleaned all passages with compressed air and was surprized to find the properly sized main for my elevation (according to my chart) however, the pilot was too rich, so I jetted that down. Reassembly of the carb yielded nothing good, so I looked into the electrical system next. Upon removal of the gas tank I was glad to see that the negative to the ign coil was barely on. I plugged it in,fueled up the carb and was able to kick start the bike! I was thinking that I found the problem. I left the bike sit for the rest of the week and had a really frustrating weekend when I could get the thing lit anymore. I mean, I tried kick starting the bastard over a three hour period with nothing. That's when I did some resistance checks on the ign coil, stator, etc. The coil failed 2 out of 3 tests so I replaced it (and the cap) with a new unit. Installation produced a cold start but, I couldn't get it lit warm. So I did some reading here and on cr500riders.com and through that, I discovered a "drill" for starting the bike. I am now pretty much able to fire the bike up when I want. My warm technique is to find TDC by hand and push through the two tough spots (by hand). I then let the kicker return to its fully upright position and kick with bad intentions. I've been able to start the bike consecutively this way. Oh yeah, and that's with or without full throttle. Thanks.

[evo125]

glad i could help. my negitive electrode on the coil acually had pit marks from the plug arcing on the tab! adding further resistance to the tab.