OzVMX Forum

Clubroom => Tech Talk => Topic started by: brent j on October 18, 2015, 09:44:35 pm

Title: Testing a Yamaha stator
Post by: brent j on October 18, 2015, 09:44:35 pm: Is there a way to check the stator on my YZ80J ignition?

I think the low speed coil my be playing up as the motor misses badly and sometimes cuts out if I let the revs drop once the motor is up to temp

I'd like to be able to eliminate this if possible
Title: Re: Testing a Yamaha stator
Post by: TT5 Matt on October 18, 2015, 10:27:32 pm: take the whole system off including the rotor and send it to Steve at betta bikes in SA where he will test the entire system and repair whats needed,saves alot of head fork on old bikes ;)
Title: Re: Testing a Yamaha stator
Post by: Lozza on October 19, 2015, 01:30:29 pm: I should have another stator Brent. You can make a simple rig to test the strength of the ignition.
Title: Re: Testing a Yamaha stator
Post by: matcho mick on October 19, 2015, 03:05:54 pm: Brent,i have L model specs?,charge coils brown to reds 505ohms +-10%,pickups red to red/white 10.4ohms +-10%, :P
Title: Re: Testing a Yamaha stator
Post by: Viper666 on October 19, 2015, 11:18:37 pm: Mick,

Are you sure about the specs? If the pulse coil is 500 ohms (Or thereabouts) I would expect the source coil to be 1400 or 1440 (1437 ohms) + or -?
Title: Re: Testing a Yamaha stator
Post by: brent j on October 20, 2015, 11:52:20 am: Thanks for the replies

Matt, I’ve sent an ignition to Betta Bikes before with good results but I’m not going to have time to do it.

Lozza, I’m interested if you have another stator, PM on the way
Title: Re: Testing a Yamaha stator
Post by: matcho mick on October 20, 2015, 11:58:10 am: Quote from: Viper666 on October 19, 2015, 11:18:37 pm
Mick,

Are you sure about the specs? If the pulse coil is 500 ohms (Or thereabouts) I would expect the source coil to be 1400 or 1440 (1437 ohms) + or -?

yep,pulse coil (trigger/pickup/whatever) is only 10.4,the charge coils 505,this according to the genuine yam L book
Title: Re: Testing a Yamaha stator
Post by: Lozza on October 20, 2015, 01:24:37 pm: A fault like that isn't going to show up in a static test, needs to be tested under dynamic conditions
Title: Re: Testing a Yamaha stator
Post by: Daryl Jones on October 21, 2015, 01:21:01 am: Quote from: Lozza on October 20, 2015, 01:24:37 pm
A fault like that isn't going to show up in a static test, needs to be tested under dynamic conditions

Erratic faults can be tricky.
I once had a Suzuki RM with a stator wire that was broken inside the resin.
It would start & run just fine...'til it got really hot. Then it would run erratically for a bit & then stop dead.
Would not spark again until it cooled down. Heat was expanding the stator and separating the connection.
I dug the hair width wire out and after a couple of attempts was able to solder it back to the main wire.
Covered the repair with araldite, worked fine for years.

Cheers Daryl.