Honda Motorcycles - FireBlades.org banner
1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
So I have a 1975 Honda XL100 that I got for my first bike going on two years ago now. It's been a great learning experience for sure! I'm trying to get the thing on the road, but problems have arose and I'm still green at this so I'm trying not to make things worse... But it's not running well at the moment. Starts up first kick which is nice, but I recently there was oil leaking out from behind the points and I had to replace the oil seal that sits behind the points and the spark advancer.

My Clymer manual describes the following abbreviated procedure of setting the points -- when the timing mark on the stator lines up with the notch, then the points shoud be "just starting to open". So they describe using a circuit test light that will dim when the points contact opens. Then once you get that, you set your maximum gap (not at the timing mark..) to 0.3 - 0.4mm .. with the same adjustment procedure as setting at the timing mark.

So I went to try this, and it didn't quite work out for me.

First time setting points and when I opened up the alternator cover to reveal the markings I found the seal to be .. So I ordered it and it came in. My brother in law, the guy I bought the bike from and has owned bikes for years came by the other night and I asked him to give me a hand setting it up.

The way he did it was lining up the timing mark, and setting the gap to the available feeler gauge wideth of 0.38mm. Seemed to run alright once he did that, rode it around the parking lot here but didn't get it out of first. After they left, I took it out the engine is missing at higher revs.

So then when I got back I tried to set the points like it has in the book but to no avail.... Now it's missing more than before.

Any pointers or direction you may have are welcomed!
 

·
Premium Member
Joined
·
32,034 Posts
So I have a 1975 Honda XL100 that I got for my first bike going on two years ago now. It's been a great learning experience for sure! I'm trying to get the thing on the road, but problems have arose and I'm still green at this so I'm trying not to make things worse... But it's not running well at the moment. Starts up first kick which is nice, but I recently there was oil leaking out from behind the points and I had to replace the oil seal that sits behind the points and the spark advancer.

My Clymer manual describes the following abbreviated procedure of setting the points -- when the timing mark on the stator lines up with the notch, then the points shoud be "just starting to open". So they describe using a circuit test light that will dim when the points contact opens. Then once you get that, you set your maximum gap (not at the timing mark..) to 0.3 - 0.4mm .. with the same adjustment procedure as setting at the timing mark.

So I went to try this, and it didn't quite work out for me.

First time setting points and when I opened up the alternator cover to reveal the markings I found the seal to be .. So I ordered it and it came in. My brother in law, the guy I bought the bike from and has owned bikes for years came by the other night and I asked him to give me a hand setting it up.

The way he did it was lining up the timing mark, and setting the gap to the available feeler gauge wideth of 0.38mm. Seemed to run alright once he did that, rode it around the parking lot here but didn't get it out of first. After they left, I took it out the engine is missing at higher revs.

So then when I got back I tried to set the points like it has in the book but to no avail.... Now it's missing more than before.

Any pointers or direction you may have are welcomed!

I haven't played with points in more than twenty years but one trick to know when they're _just_ opening is to bite a cigarette paper between them and gently pull as you wind the crank over. As soon as it releases you know it's opening.
When you say you set "the gap to the available feeler gauge width of 0.38mm" is 0.38mm the specified gap or is that just what you had handy?
Missing at higher rpm could be several things unrelated to the timing, but does it have a mechanical advance unit?
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #3 ·
Hey, thanks for the reply. The specified gap is 0.3mm to 0.4 mm and the feeler that we had handy was a 0.38mm. so it's between the specs.
 

·
Premium Member
Joined
·
32,034 Posts
Hey, thanks for the reply. The specified gap is 0.3mm to 0.4 mm and the feeler that we had handy was a 0.38mm. so it's between the specs.

That should be fine then.
Is everything else good? Is the advancer working okay?
New air and fuel filters, new oil, new spark plug and lead, new points, valve clearances set, no rust in the tank, fresh fuel and disassemble and thoroughly clean the carb would be a good start and then do a compression test. I'd highly recommend replacing the intake manifold and all fuel and vacuum hoses as well.
I had an '81 XL500 for a short time but it was for dirt only with YZ forks and shocks.

Parts fiche:
1975 Honda XL100K1 OEM Parts, 1975 Honda XL100K1 OEM Motorcycle Parts - BikeBandit.com
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
Carb was just cleaned, fresh oil last weekend.. new air filter.. Fresh plug to be put in tonight, But I still would like to know the correct procedure for the points.
 

·
Registered
Joined
·
89 Posts
I believe that Honda used the same procedure for setting the points gap on those early bikes as they did for their small engines that were equipped with points. First, and most important, there were two marks on the flywheel. One was marked "T" and one was marked "F". The "T" indicates top dead centre, so that position is used when setting valve lash. The "F" is for setting the points. So line up the "F" with the mark on the case. Slightly loosen the points clamping screw. Now move the points just until they touch the cam piece that opens and closes them. Then tighten the points clamping screw. Now the points will open at the exact number of degrees before top dead centre. Be careful that the flywheel remains still while doing all this and be sure that tightening the clamping screw doesn't cause the points to open-this is why the clamping screw should only be loose enough to allow you move the points with a bit of effort. Good luck
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
Thank you!! That helps immensely -- I was using the T mark :rolleyes: I will try that tomorrow.


I believe that Honda used the same procedure for setting the points gap on those early bikes as they did for their small engines that were equipped with points. First, and most important, there were two marks on the flywheel. One was marked "T" and one was marked "F". The "T" indicates top dead centre, so that position is used when setting valve lash. The "F" is for setting the points. So line up the "F" with the mark on the case. Slightly loosen the points clamping screw. Now move the points just until they touch the cam piece that opens and closes them. Then tighten the points clamping screw. Now the points will open at the exact number of degrees before top dead centre. Be careful that the flywheel remains still while doing all this and be sure that tightening the clamping screw doesn't cause the points to open-this is why the clamping screw should only be loose enough to allow you move the points with a bit of effort. Good luck
 

·
Premium Member
Joined
·
32,034 Posts
I believe that Honda used the same procedure for setting the points gap on those early bikes as they did for their small engines that were equipped with points. First, and most important, there were two marks on the flywheel. One was marked "T" and one was marked "F". The "T" indicates top dead centre, so that position is used when setting valve lash. The "F" is for setting the points. So line up the "F" with the mark on the case. Slightly loosen the points clamping screw. Now move the points just until they touch the cam piece that opens and closes them. Then tighten the points clamping screw. Now the points will open at the exact number of degrees before top dead centre. Be careful that the flywheel remains still while doing all this and be sure that tightening the clamping screw doesn't cause the points to open-this is why the clamping screw should only be loose enough to allow you move the points with a bit of effort. Good luck
Excellent stuff, PM!
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top