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Does anyone know if the stator for a 80cc/100cc the same as in the minis?

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So my son was racing the CRF100 Sunday and out of nowhere it died. I thought for sure the new revbox I bought pooped out. We put the good stocker back in and still no spark. Only other thing I can think of is the stator. I can find them for $75+ all do or find them for about $20 for the 50cc/70cc I have found that they are the same type, but are these a direct swap from 50cc up to 100cc? Thanks everyone

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check the resistance. measure between the black wire with red stripe and ground (the engine). it should read about 400 to 800 ohms. if you have unlimited resistance (open circuit, aka, broken wire inside exciter coil), the stator is bad. if not, you have another problem. check the whole wiring harness for unplugged wires. unplug your kill switch and make sure it is not the problem.

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You my friend are a wealth of knowledge when it comes to the electrical on these bikes. I am going to do exactly that tonight.

check the resistance. measure between the black wire with red stripe and ground (the engine). it should read about 400 to 800 ohms. if you have unlimited resistance (open circuit, aka, broken wire inside exciter coil), the stator is bad. if not, you have another problem. check the whole wiring harness for unplugged wires. unplug your kill switch and make sure it is not the problem.

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You my friend are a wealth of knowledge when it comes to the electrical on these bikes. I am going to do exactly that tonight.

thank you. i dont consider myself an expert, but i have an understanding of how it all works and of electricity/electronics in general.

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Also make sure the green ground wire for the harness is secure to the frame. If the bolt vibrated out while riding, and the contact is lost, it won't spark.

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Also make sure the green ground wire for the harness is secure to the frame. If the bolt vibrated out while riding, and the contact is lost, it won't spark.

very true. take the gas tank off (first step to seeing all the electrical) and there is a little 8mm bolt that has a few wires bolted to it. this is (i think) the only ground connection on the while bike, so if you loose it, all circuits are open.

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Here's a little guide to where all the electricals plug in, the green circles are the harness ground wire and bolt, as mentioned above.

I can't say for sure if the stator from an XR/CRF50 or 70 will work for sure, but I did use a wiring harness and electricals from an XR50 to power a '95 XR100 engine in my '91 frame, with no issues whatsoever.

XR-CRF100electricals.jpg

Edited by dirtbkr188

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you can eliminate the stator from the picture like i mentioned with the continuity test. you can also eliminate the kill switch by just unplugging the kill button. the key switch can be eliminated by unplugging it, and wiring the two plugs together as to complete the circuit that the ignition key used to make (i think this is how the key works. it might be open circuit for ignition, and shorting out to kill the engine, in which case just disconnecting it would rule it out as a problem. i need someone else to confirm which way the keyed switch actually works. )

once you take all those parts out of the picture, you are left with the cdi, ignition coil, and wiring harness. it sounds like you already tried a new cdi. you can do a resistance test on the ignition coil, or get a battery with at least 6 volts, put a spark plug in the boot, wire the body of the plug to the green terminal on the coil, run the - battery to the green terminal, and put a wire on the + side of the battery. strike the other terminal on the ignition coil real quick with the + of the battery and see if you get a spark. you just made a "breaker point" ignition.

though i recommend doing the resistance test.

Edited by MCRIPPPer

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Well I am going to figure this all out tonight. I have all the plastics off and the tank off. I am going to use a multimeter and get a buddy to come by and see if he can shed some light on the electronics. I wish you guys lived in Northern California. HAHA If I cant figure it all out, off to the mechanic it goes I just hate wasting money on something simple I should be able to figure out. I want to again thank you all for the help.

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In answer to your original question...

I imagine this is the style of the stator you're thinking of 403649348_o.jpg

If it is, it won't work as a bolt on. The backing plates are different. They are radially smaller, meaning less voltage produced utilizing your original flywheel (magnets further away from windings). You could install an appropriate flywheel, however now the pickup would be too far away from the flywheel (radially smaller than the stock unit).

Same goes for this style style

76265030_o.jpg

TT User StorminNorman07 has setup a bolt on CRF50 style inner rotor for the XR80/100... $250ish. Pricey but the engine will rev like hell.

Liberated from factory service manual... with a little extra info from me.

If there is no spark at plug, check all connections

for loose or poor contact before measuring each

peak voltage.

- Just like Dirtbiker188 said...

Disconnect key switch (locate "bullet" connectors at end of switch harness, disconnect bullets (Black / white wire and a green wire)

Disconnect the kill switch (follow harness from switch, disconnect it at "bullet" connector - Black / White wire).

Spark plug gap 0.6-0.7 mm (0.024-0.028 in)

All voltage readings are AC, with respect to good clean ground on frame.

Spark plug must be installed. Setup your meter leads, set DMM to AC Volts, if available use the Min/Max function to get the best reading (Most Digital Multi Meter screens don't refresh quickly enough to use an 'unsecured' reading reliably) - You MUST disconnect each plug containing the indicated wire prior to taking the reading!!! Do not check readings by back probing the harness! give the bike a good healthy kick and record results.

Alternator exciter coil peak voltage 100 V minimum (Measured at Black / Red wire @ CDI: If voltage is less, you may have a break in the harness. Recheck reading at plug coming out of magneto cover. If it's still too low, you've got a dead stator or magneto - possibly someone has hit the magneto with a hammer trying to remove it?). If the reading is acceptable 100V AC or more, continue on.

Ignition pulse generator peak vo ltage 0.7 V minimum (Measured at Blue / Yellow wire @ CDI : - If you're using an auto ranging meter you may have to change the working range of the meter to get an accurate reading here; Again, if the original reading is poor; check Blue / Yellow wire coming out of the Magneto cover. Also note CRF/XR 80/100's are real chain chuckers. If your bike has recently tossed the chain, there's a good chance the pickup coil is damaged (under magneto cover, small black box at 2 O'clock position with respect to magneto - just look for cracks.). If the reading is acceptable, continue on.

Ignition coil peak voltage 100 V minimum (Measured at Black / Yellow wire @ coil, a low reading indicates bad CDI or damaged harness/plugs) If the reading is acceptable, remove the spark plug cap (hold cable, turn cap to left - may have to give it a final tug to get the boot free of the wire), set your meter for resistance and measure from the Black / Yellow wire at coil to the spark plug wire (jam lead into exposed end of spark plug wire). Reading should be about 5-20 Ohms - This value is from my general experience. It is not law. Generally, read with a good quality DMM {I use a Fluke 187} 5 - 20 Ohms is good. More is bad. Dead short (0.00 Ohms) bad.

Edited by theraymondguy

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My friend did the same thing for his kid but if you put the smaller one in it will work but they work harder and die out way faster

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My friend did the same thing for his kid but if you put the smaller one in it will work but they work harder and die out way faster

why would it work harder??? the ignition on the 50-70-80-100 are all pretty much the same. i think they use the same cdi, coil ect..

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So I ended up dropping the bike off with my mechanic before jumping the gun. I had did everything all you recommended and still no spark. He came back and told me it looks like something got caught between the crain and the ignition cover. Broke the cover and center case. knocked the pickup off the locating tab and bent the mounting bracket. got everything lined back up and we have spark. Ordered a new cover and going to check gap to see what we can do about the center case. While it is there I had a box full of stuff I gave him. My son is racing the bike and was clearly in first when this happened so I want to give him the edge this weekend. Get this all fixxed, installed a complete BBR big bore kit with cam, etc..., Pro tapers, BBR exhaust, AVS levers, the new CDI, and if it shows up in time a new rear spring to firm it up a bit. He primarily rides a RM125 but loves to race the CRF100 because he can man handle it and is fast on it for what it is. The bike is actually my wifes cruiser so I really bought the mods for her. I will give you guys a before and after of the bike once I get it back. Thanks for all the help.

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glad you got it fixed. that didnt even cross my mind as to be a possible problem. there was another guy on here that has the same problem, but water and dirt got in there and corroded all the flywheel and electrical. make sure to plug the hole back up with jb weld or get new case.

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So we ended up with a new case, cover, and all the mods put on. We had races last Sunday in Stockton, Ca and my son took 2nd after dumping the clutch at the gate and running with the bike and eventually laying it down. He was in dead last by a bit and ended up 2nd in a 12 bike heat. In the main he took off in 3rd gear of a CRF100 and was in 2nd from the whole shot. By the first lap he was in first and never looked back. That BBR kit rocks

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