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Looking for help on my recent purchase...

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I didnt see an XL category, so I decided to post here. Hopefully I didnt post in the wrong place...

I recently picked up a 1975 Honda XL100. It needed some help but I got a fair deal on it.  Ive ordered a Clymer manual, but am waiting for it to arrive. Anyway Ive been trying to get it to fire. The points were all out of wack, but I think I have them timed properly now. I can kick it over and all I can get it to do is backfire, very inconsistently. Theres no battery in it. I went to buy one today, but the local powersports parts place didnt have the correct one in stock. Are these bikes battery dependent for ignition?

 

Cheers, David

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Hi David.

I know the earlier bikes were battery dependent--1970 to about 1974--but somewhere around the '74-'76 years I THINK, the battery was no longer needed for ignition. I'm sorry but it has been a long time since I messed with those bikes and can't remember the exact year the change happened.

I had a '72 SL125 in the late '70s and can remember trying to get it to run with no battery. It would actually start and idle but if you tried to rev it up, it would bog and not gain any RPM--almost like the magnets in the rotor were energized and trying to pull the stator along with them. I know that sounds weird but that's what it felt and sounded like. Strange. Almost like if you were riding with the brakes on and attempting to accelerate.

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Fuel tank is bone dry, petcock and carb are spotless. The backfiring I got was just with brakekleen sprayed in the carb. It should have atleast fired once, but all I got was backfires. Sparkplug and boot are new. I found some wiring diagrams on google and it looks like it is battery dependent. 

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Is the advance mechanism cam in correctly? The points cam part can be installed into the plate either way. One is correct, the other is 180 degrees out. If it's 180 out, you'll get backfiring but no start.

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Thanks for that, I had that suspicion but wasnt sure if it was possible. I was going to check that next after my manual shows up.

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My first test was brake kleen sprayed into the carb throat. Cam tension is ok.

My Clymer manual showed up today so I did some work on the bike. The wiring diagram for 1975 shows that it is NOT battery dependent. zrxer hit the nail on the head, the points cam was 180 out. While I was in there I set the valve clearance, they were a bit tight. I put some gas in it and it didnt take long to fire up. Rode it up and down the driveway but didnt run it long as the petcock developed a leak. 

I also have to repair the kick starter. At some point it striped the splines and somebody welded it on. Then what looks fairly recently is someone needed to get the right side cover off. Instead of simply grinding the welds flat and pulling the lever off, they cut off the end of the shaft and lever clean, about 1/4" into the shaft, and jammed pieces of wire in it to try to hold it. I noticed this shortly after I bought it, and since both pieces were already butchered I drilled through both and hammered a roll pin in them. But that roll pin didnt last longer than maybe 10 kicks before it sheared.

Im not sure if I want to split the case and replace the shaft, and rebuild the motor at the same time, or drill my roll pin hole slightly bigger for a 1/4" bolt, or find a Lifan engine of slightly more displacement...  But thats for another day.

 

Cheers

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Well a used but good condition CB100 engine came up on Craigslist, I paid $100 and the seller delivered it so I couldn't complain. By the time I buy a new kicker shaft and the gaskets and seals I'd need to replace while the cases are apart, it ended up being cheaper.  Spent today swapping it over, I used my stator windings as well as points and advance mech. It started first kick, sounds awesome, tons of compression. 

Unfortunately it won't shift. It doesn't feel like the shifter mech isn't engaging with anything, just moving back and forth. I just hope it's nothing deeper than the right side cover.

That's my $100 cb engine on the left, my old one on the right

IMG_20170430_142415_zpsamjxmm2t.jpg

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I recently repaired my neighbors XR70. It had the same issue as what you're saying about the shifting. Turned out the shifter drum stopper end with the roller broke off. The shifter drum stopped rotating and was stuck between gears or neutral or something but it wasn't in a gear. Never seen one of those actually break before.

Hopefully your repair is as simple.

Edited by zrxer
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I'm hoping so too. I won't have a chance to rip it apart untill wendsday. 

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Well I ripped it apart, I found that the shift shaft wasn't lined up, it was missing it's return spring, and the stopper/arm that engages with the drum was missing. 

IMG_20170503_163613_zpscb31ue2o.jpg

I pulled all the needed parts off of my other engine.

IMG_20170503_163617_zpsx1a0hrfu.jpg

 

Once all back together, I was able to cycle the drum through all gears via the shifter, but unfortunately all of the gears except for either 2nd or 4th(not sure which, going off position if the drum) acted like neutral. No engagement whatsoever. Something is either very broken or missing completely. Not sure why someone would pull parts out of a case and slap it back together, but there are some shady people out there.

I decided to walk away at that point. It was pretty clear I got a little bit screwed, on both the bike purchase and the second engine purchase. Once I calmed down I focused on how to make things right in my own head. I found a 1982 Honda XR200 parts bike for a decent price. The motor and all wiring are there and it cycles through all gears. 

If I'm going to be putting as much money as I already have in this bike, it sure wasn't keeping it's 100cc motor.   This 200cc is finding it's way in this frame one way or another...

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Well I ripped it apart, I found that the shift shaft wasn't lined up, it was missing it's return spring, and the stopper/arm that engages with the drum was missing. 
IMG_20170503_163613_zpscb31ue2o.jpg
I pulled all the needed parts off of my other engine.
IMG_20170503_163617_zpsx1a0hrfu.jpg
 
Once all back together, I was able to cycle the drum through all gears via the shifter, but unfortunately all of the gears except for either 2nd or 4th(not sure which, going off position if the drum) acted like neutral. No engagement whatsoever. Something is either very broken or missing completely. Not sure why someone would pull parts out of a case and slap it back together, but there are some shady people out there.
I decided to walk away at that point. It was pretty clear I got a little bit screwed, on both the bike purchase and the second engine purchase. Once I calmed down I focused on how to make things right in my own head. I found a 1982 Honda XR200 parts bike for a decent price. The motor and all wiring are there and it cycles through all gears. 
If I'm going to be putting as much money as I already have in this bike, it sure wasn't keeping it's 100cc motor.   This 200cc is finding it's way in this frame one way or another...

Do it, it'll be a sweet bike. I just put an xr200r engine in a cr125.. I love frankenbikes.IMG_1550.JPG

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Awesome bike! I like frankenbikes too. Is the stator in the xr200 motor capable of running lights, or is there a stator from another bike I have to swap in for that?

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Perfect, I guess an 82 will be a 12v system too. I'll have to buy a regulator and a battery

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Ive found some conflicting information about the electrical system on the XR200. Maybe someone can help me confirm if some of its correct. The bike is at my girlfriends parents place so I cant go look at it. 

Basically I thought an 82 would be 12v, but Ive found some information saying that 81-83 used 6 volt. That would be ideal, since I could keep most of the existing electrical on the XL100 frame. Ive also found info saying that it is 12v, but more people are saying 6v...

And in whichever case, sounds like there is a pink wire coming from the stator that goes up under the gas tank area and loops back down to the stator. Will I basically have to take this wire and run it to my regulator/rectifier?

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Well, the XR is dismantled and the 200cc heart is hung in the XL frame

IMG_20170505_195756_zpsqdc11v1y.jpg

 

It will have to come out so I can clearance the frame, as the case on the right side hits the frame, keeping me from installing the lower rear mount bolt

IMG_20170505_195751_zpsmz5i2fji.jpg

I think I will also have to flip the intake around, as right now it's pointed straight at the XL's frame

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Ive found some conflicting information about the electrical system on the XR200. Maybe someone can help me confirm if some of its correct. The bike is at my girlfriends parents place so I cant go look at it. 
Basically I thought an 82 would be 12v, but Ive found some information saying that 81-83 used 6 volt. That would be ideal, since I could keep most of the existing electrical on the XL100 frame. Ive also found info saying that it is 12v, but more people are saying 6v...
And in whichever case, sounds like there is a pink wire coming from the stator that goes up under the gas tank area and loops back down to the stator. Will I basically have to take this wire and run it to my regulator/rectifier?

Yes, the looped pink wire is your lighting coil wire.

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