Posts
1237
Joined
11/8/2011
Location
Ascot Park, CA
US
Edited Date/Time
5/22/2014 4:10am
So when I bought this little bastard it didn't run and the guy said it was running 6 months previous to that....blah blah blah we've all heard that bullsh*t!!
So far I've soldered in a new condenser, replaced the points and gapped them, cleaned any rust on the flywheel and I've had good ohm readings on the coil and everything seems to be in working order. With the plug in the cap grounded to the cylinder head, I've kicked it over a zillion times and I get nothing.
The recommended plug is a B8EV, would a B8ES make a difference?
Would should I look for? I've eliminated the old kill switch to simplify my troubleshooting. I also order a new condenser as I'm assuming the one I soldered in might be bad...it came in a NOS "ND" brand tune up kit.
Thanks guys!
So far I've soldered in a new condenser, replaced the points and gapped them, cleaned any rust on the flywheel and I've had good ohm readings on the coil and everything seems to be in working order. With the plug in the cap grounded to the cylinder head, I've kicked it over a zillion times and I get nothing.
The recommended plug is a B8EV, would a B8ES make a difference?
Would should I look for? I've eliminated the old kill switch to simplify my troubleshooting. I also order a new condenser as I'm assuming the one I soldered in might be bad...it came in a NOS "ND" brand tune up kit.
Thanks guys!
One of the best things you can do is to keep your eye out for a late model DT100MX - RT100 CDI system. They bolt right on .
The Shop
First thing is to check the lobe that breaks the points for wear. If the points open and close as you rotate the flywheel, you should be ok in that area.
Is the flywheel marked with a "T" and an "F" mark that aligns with the case mark? It should be. You want to make sure the points are breaking as the T mark aligns with the case marks. The F mark is too late. Use a piece of celophane cut into a strip with a bit of duct tape on one end for a handle, slid between the points while closed, as the T mark on the flywheel starts to align with the case mark , you will feel the celophane release as the points begin to open. Snug the point set screw down.
This should get it close enough to make fire, with good components. A new source coil can probably be had for relatively little money on Evil Bay. With a new condenser,points, and ignition coil, probaly have $100 in total parts, that thing should make spark.
It's just a future resto waiting to happen, so I'm happy to let you use the stuff.
So I have two spark plug coils I've been using while trying to get spark. The first is the original that came with the MX100. The second is a newer spare I bought for my MX360.
While looking up spark plug coil part numbers, I noticed the MX100 part number is different than the part number for an MX360 spark plug coil.
Would this make any difference? I'm wondering if the original MX100 spark plug coil I have could possibly be junk and the new MX360 spark plug coil might not work for an MX100 for some reason?
Am I onto something? Haha
Not sure if any of the things I replaced possibly helped, but one of the problems was the wire that solders to the condenser and makes contact with the return spring of the points was accidentally grounded to the backing plate of the points. OPPS!!
Now I'm trying to get this thing to kick over and I'm wondering if any of you MX 100 specialist have any recommendations? "Project Racer"?!! The carb is the stock mukuni, I've gone through and cleaned it very meticulously, the main and pilot jets are stock and clip on the needle is on the third slot from the top. I've also got the slide height adjusted so that when I turn the adjusting screw in, the slide just starts to rise up.
My MX360 fires on the first or second kick cold with the choke on. I'm trying to do the same with this 100, but it seems like I'm fouling plugs...maybe no choke?
I've also replaced the stock reeds with boyesen, the cylinder was bored and a new piston, rings and etc were installed.
Wish this damn thing would just fire right up!!
I played around with the carb for awhile and though I'd pull the tank to connect the kill switch into the connecter near the ignition coil. I had disconnected it while shaking down the stator problems I was having. I thought I'd also bolt back in the original ignition coil just to see if I still had spark with the original coil. I kicked the bike over with the plug up against the cylinder and I realized I had a lot more spark than the re-pop china ignition coil I had bought off of evilbay. I threw the tank and seat back on, said a little prayer to the gods of motorcycles and on the second kick, the little bastard fired right up!! A quick carb adjustment and I went for a cruise down the street at 9:30PM! Haha! I'm sure my neighbors hate me even more, that 100 is louder than my 360!! I might have to throw an one of those DG generic retro silencers on it. Or not!! Haha!
I'd also like to say THANK YOU for all the help guys!!
Cheers,
Zeke
I'm sure the poor thing could probably use a new clutch, but what other things would you guys try changing? The gearing and jetting are stock so maybe I could make a change there to wake the thing up?
I really have to rev it out to get it to accelerate decently.
Any ideas?
Yes, it's going to sound like your wringing it's neck to make it go, but that's what a 100cc motor does....just do it and hang on!
Oh, and one tooth smaller CS is a must....
Pit Row
Thanks guys!!
Also...sometimes when I start it, (it likes to start without the choke) the idle runs up and I have to adjust it down using the slide height screw. After a few turns of the throttle the idle settles down too low and I have to adjust the screw back in. I'll then do a few laps around the block and when I'm ready to slow down and stop, the idle is so low, the bike wants to die.
Any ideas?
I dropped the front sprocket one tooth and replaced the pilot jet. The bike starts up and idles fine and it really accelerates well now!!
I'm looking forward to restoring this little beast and beefing up the front end.
Post a reply to: 1974 Yamaha MX 100...No Spark!