AM6 losing spark

[Machinist]

Hey guys,

I have a 2001 AM6 that starts very easily cold, but once it gets over ~150F it dies (loses spark). Before it completely dies it will generally come back to life for a few seconds. When it happens the tach instantly drops to 0, and I'm sure its getting fuel. So far I have checked the stator and the wire resistances seem to be within range. I just put in a new cdi and it still has the exact same problem. Any ideas? Seems like maybe something is shorting when it heats up, but I don't know where to start looking.

[chrism15]

something is shorting when it heats up.

answered ur own quistion

if youv already checked the stator and cdi is replaced then you can rule them out, you have checked the spark plug right?

make sure all the wires are routed correctly and are not able to short out anywhere (maybe cable tie them to keep them away from things and neaten them up), wires coming from the staor (as you said), cdi wires ect

[RS_Patrick]

Did you try a new sparkplug??? and wich Sparkplug are you using?

Are you sure you got the mixture right on the carb?

What is your bikes setup?

[Machinist]

The problem started while using a BR10EIX. At that time I thought it might be the spark plug so I put in a B10EGV and the problem continued. I just pulled the latter plug (electrode was black) and put in another BR10EIX but havent tried it yet.

Not sure that the carb is setup right, although It was running perfectly before. Are there any good reads on how to tune the carb right?

I'm running a malossi 80cc top end, doppler endurance ER1 crank and delorto 21mm carb, premixed fuel (usually ~30:1)

[RS_Patrick]

30:1 is a bit rich mate, and what Malossi 76cc (theres is no 80cc) kit do you have exactly? did you read the manual what plug it needs? because some of them need a B11EGV.
Try 35:1 with a Fully Syntetic oil thats ment for Premix only like Motul 800.


What CDI unit do you have on there? the stock ones dont like running over 9000rpm to much and can fail from that or start to act crazy, maybe it starts to "leak" internaly wen it gets warm, like the high voltage coil arcing internaly or one of the capasitors leaking wen it starts to get warm.

I do think its an elecronic isue with the CDI, as i know recall your the guy with the Naked RS50 with the Digital dash, im guessing the Tach on it takes the signal from the HT lead? in that case it has to be the CDI unit or the Stator, my guess would be the CDI like i just mentioned above.

[Machinist]

I dont remember off hand what kit it is so all I can tell you is Malossi. I also dont have the manual.

CDI is the stock unit. I did notice before it started giving me trouble that it didnt like going over 10k sometimes, but I just put on a new one and it didnt change the problem at all. Where can I find the appropriate cdi?

You are right about the bike and I am running the digital dash. The tach is just a wire zip-tied to the spark plug wire, so I also thing that the problem must be before the spark plug. If it helps, here are my stator wire resistance measurements both cold and after the bike shuts off when hot:

White/Red: 121 cold/ 134 hot
White/Green: 765 cold/ 854 hot
Red/Green: 886 cold/ 988 hot

[chrism15]

think you need something like the top performances cdi unit like patrick had/has - yellow

[Machinist]

link?

[chrism15]

try and find one now

found this and it says for minnerelli am6:

http://www.easyparts.nl/showarticles...formances.html

im new to easy parts really and cant seem to find the yellow top performances unit but maybe there not being sold anymore, patrick will know so wait for his reply.....

[RS_Patrick]

http://www.easyparts.nl/showarticles...arelli_6v.html

[Machinist]

Thanks Patrick! I do have a question though. It doesnt make sense to me why my bike would run fine for months and then all of a sudden would start having this problem. If the stock cdi wasn't sufficient, why would it work for awhile and then quit? Also, wouldn't the new cdi that I put on work for awhile also instead of just having the same problem?

Why would putting on a bigger top end affect the cdi? The stator is the same and shouldnt the cdi put out the same amount of power to spark?

[Machinist]

Okay potential new breakthrough. Swapped in the BR10EIX and was able to run the bike to a higher temp, although this time when it stalled i tried starting again and noticed that with the engine turning over the lights came on and my digital read out gave me an RPM value. I believe this must mean the problem lies with the fuel and that I am fouling the plug? Does anyone have a good walkthrough on how to correctly tune the carb?

[RonneBear]

http://www.scribd.com/doc/9726341/Tw...ormance-Tuning

Good tuning info.

[RS_Patrick]

Mate, but did you actualy try an 11 grade sparkplug yet? i ran an 11 during the summer in my bike.

And electronics can just die from one momend to the next.
I dont really get the dash, it didnt read anything before if the bike died, and now its reading rpm wen your trying to start it? but with the lights on?

p.s. the value on White/Green should be 700 Ohm +-20% so thats a bit higher in your case wen its hot, keep in mind they just give the values for White/Red and White/Green as they would be at room temprature i asume.

im a bit short on time latly so i readed over that the first time, but i dont think its a reall problem.

[Machinist]

Haven't tried the 11 grade yet, Ill look for one to order

My dash gives me rpm readout from spark plug wire. When the problem first started I would notice that right when the bike died the rpm would drop to 0 and would remain at 0 when trying to restart. Yesterday when turning the engine over the lights would come on AND the rpm would read ~1000-1400 meaning stator and cdi working, correct?