Author Topic: Honda Cl100 wont start, after running the night before.  (Read 1928 times)

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Offline dylanw

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Honda Cl100 wont start, after running the night before.
« on: August 05, 2020, 01:57:53 PM »
I have a 1973 Honda CL100 which hasn't been running the best but still starts. but today i couldn't get it to fire at all. i check for spark it was good, i checked compression and it is good as well. and i just put a new carb on only a couple days ago. the first couple kicks i tried it would backfire very loud. I then tried starting fluid and now nothing was happening at all. after this i thought the ignition timing was off maybe so i used a test light and set the points so when it went over the F mark on the flywheel the light would turn off like it says in the manual. i also attempted to make sure the valve timing was set properly. i lined up the t mark on the flywheel and the O mark on the cam looked to be off very slightly so i moved it over one tooth and checked again but now it was even further off so i assumed how it was before was correct and switched it back.
Any help would be greatly appreciated. Thanks

Offline bryanj

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Re: Honda Cl100 wont start, after running the night before.
« Reply #1 on: August 05, 2020, 02:11:43 PM »
The light should come ON when the F mark lines up rotating engine the correct way. Points gap first at 0.35mm 14 thou
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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Offline WhyNot2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #2 on: August 05, 2020, 02:40:13 PM »
How's the battery?

I had to install one of these to get mine to run.
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #3 on: August 05, 2020, 08:29:05 PM »
How's the battery?

I had to install one of these to get mine to run.
i got the battery new around a month ago and what is that in the pic?

i will try and adjust the points gap. but later today when i was messing with it some more and it started to backfire again but not as load.

Offline WhyNot2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #4 on: August 06, 2020, 11:34:38 AM »
That's the rectifier.

The one on the bike is square and red, down by the battery.
« Last Edit: August 06, 2020, 11:39:22 AM by WhyNot2 »
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #5 on: August 06, 2020, 06:32:10 PM »
So after i adjusted the points the bike sound like it wanted to run but never quite got there. So i decided to try and bump start it and it started up. but it didn't want to rev up very high it was like it was hitting the rev limiter.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #6 on: August 07, 2020, 10:12:12 AM »
Ok so after it ran yesterday and let it sit over night i doesn't want to start up again even when i try to bump start it. what would cause it to be extremely difficult to start when its cold. Thanks

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #7 on: August 08, 2020, 10:05:43 PM »
I got the bike to run and idle the best its been since i have owned it. It was a combination of the ignition timing being off and the points gap was off as well. Even though i set the timing with a test light and when it hit the F mark the light came on i still had to move the base plate of the points clockwise about 15 degrees and then it fired right up.

Offline WhyNot2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #8 on: August 10, 2020, 07:11:40 AM »
Good going, glad to hear you got it running.

Can you post a picture of it?

I'd like to see it. I really like these little things.
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #9 on: August 11, 2020, 03:02:49 PM »
it pretty rough

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #10 on: August 11, 2020, 03:13:50 PM »
After i got it running good i wanted to see the top speed. But it didn't want to rev out in 4th gear and in 5th gear i was actual losing speed. it was also hesitating at WOT when i was in 4th gear. I think it might need a larger jet but i am not for sure.

Offline WhyNot2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #11 on: August 11, 2020, 04:23:02 PM »
Looks purdy good..........haven't been able to put mine on the road yet.

Right now, it's a back yard toy.

I'm really thinking that rectifier might need to be changed out.

But, that's my opinion, not an expert, by no means

Mine:::::
« Last Edit: August 11, 2020, 04:35:39 PM by WhyNot2 »
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #12 on: August 12, 2020, 09:00:53 PM »
I guess i forgot to tighten the lock nut. I believe this is why it wasn't wanting to rev out in higher gears.

Offline WhyNot2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #13 on: August 13, 2020, 02:51:43 AM »
I guess i forgot to tighten the lock nut. I believe this is why it wasn't wanting to rev out in higher gears.

Oh, wow........did it mess anything up?
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline dylanw

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Re: Honda Cl100 wont start, after running the night before.
« Reply #14 on: August 16, 2020, 08:51:13 PM »
Lucky i don't think so, i think it got caught at the bottom of the oil pan near the filter.

Offline Bodi

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Re: Honda Cl100 wont start, after running the night before.
« Reply #15 on: October 16, 2020, 06:57:11 AM »
Too many years ago on my '65 CB77 (around 1971?) I was quite far - 250km or so - from home when a tappet I had apparently left too loose dropped into the oil pan. I hadn't yet been brave enough to open the cases and limped home on one cylinder (and a LOT of clacking) to my mechanic/guru who dropped the oil pan and retrieved the parts. Nice (but tense) tour on back roads of the countryside I had bypassed via the highway. No serious damage done except to my pride, a quick look into the tappet cover would have found the problem.
Unlike the e-z-strip case bolts going into alloy, those tappet nuts need to be tightened securely... to where you thing the wrench is about to bend.

Offline grcamna2

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Re: Honda Cl100 wont start, after running the night before.
« Reply #16 on: October 16, 2020, 10:23:54 PM »
Glad to see you found those.How's the condition of your ign. points ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
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