Topic: CL100: Episode II

[foutuframboise]

I'm a youngster from Arkansas, thinkin' he can tour the country on his lil '71 CB100.
Found this girl down in Roswell, New Mexico . .

[foutuframboise]

I brought her to my friends' home just East of Albuquerque. Gave her some Tender Lovin' Care . .

w/ only a 4000-mile lifespan and a depressingly puny 200 miles between the last 2 owners . . She Bucked to LIFE!

. . gooood girl.

Loving the road , and a good challenge . . and appreciating the significance of her tenor, she bowed her head graciously to accept her charge.

Rue, myself, and the Girl . . locked and loaded

(this is rue:
that's him down there at the bottom]

[foutuframboise]

I've probably ridin' her about 1300 miles since I got her, and I should mention briefly that it Has been a challenge . . I'm pulling a massive load along behind me, and we catch wind like crazy. Handling, Is Fine (for the most part, probably post some specific issues later on) , as in we ride pretty safe and secure; the load is hefty but well balanced, so its not so bad. the difficulty has been riding into strong winds; it holds us back like crazy every now and then . . Riding with the wind, or even just perpendicular . . is awesome in comparison.

We've been over some amazing roads . . Incredible stuff, we've seen.

The High Road to Taos:
absolutely gorgeous . . we happened to meet this really bubbly, way down indian dude, that was just tooo cool. he suggested I get my behind out of the Crap traffic that I was really looking to avoid . . and Take the High Road. I didn't quite understand the details of his directions, but we went for it . . dipping into the New Mexican countryside. there were Spanish-style churches, very old. the culture was radiating a very unique vibe . . all the homes had been very lovingly decorated w/ sculptures, marked by a very luscious history . .

we slept in the mesa of Taos . . out under the moon
with the coyotes . . bathing in mineral springs

onward, north into colorado . . the Valley of San Louise,

Poncha Pass launched us down highway 50 East to ride alongside the Arkansas River as it cuts through an amazing stretch of canyon  .. and when the canyon opened up again , we ran north through hills and mountains of Colorado, through San Isabel National Forest, i believe .. past Florissant Fossil Beds , Pikes Peak , Cripple Creek . . and down , SouthEast through the pass into Colorado Springs . .

that's pretty much, the vague synopsis of my CB100 travel adventure , Episode I.

more to come . .
(by the way , she's in the repair shed now ..

~justin

[tomkimberly]

Looks like you're have a great time!


Tom

[foutuframboise]

Truly. I've got a bump in this road, though . .

:Here's the story of my mechanical issue:
I've been staying as on top of maintenance as possible, and I have been trying to keep her good and tuned up as we climb in elevation. she's been running pretty great. except I've been hearing this clicking sound (it may have been very faint before, but by the time I got to CO Springs it was getting fairly narley-sounding), and its not the sound of valves clacking, I do not think --I've been looking for an experienced mechanic around the CO Springs area, who knows about these early honda single-cylinders and would be willing to listen to it and give me some advice; no luck in the help desk department-- I was pretty sure that it was a loose valve chain, because it was making this sort of sporadic metallic clattering sound, especially amidst changes in RPM. I attempted to tighten the cam chain tensioner on the crankcase, as advised, by turning it counter-clockwise . . unfortunately, before I did this correctly, I turned it in clockwise for a few turns. THEN I checked the manual . . (that was dumb) when I screwed it in, clockwise (the wrong way) I never heard or felt anything fall out of place (though it certainly could have, I am guessing). And I never felt any tension either way I turned it. turning it back counter-clockwise, wayyy out . . never a bit of tension within the reasonable range . . so I put it back somewhere in the middle, a little on what should be the tense end of the spectrum.

so I looked around town. haven't really found any helpful and friendly mechanics that have intimate knowledge of my bike . . so I go about my business. get a little temp job about 15 miles north of the city. And yesterday when I'm coming south . . the bottom fell out.

I'm riding along just fine, and out of nowhere: I lose all torque . . all RPMs and she sputters to sleep . . the electrical system was fine; horn, lights, everything still worked electrically. I go to give it a light kick . . and i just hear:

Click, Click, Click, Click, Click, Click, Click . .
like a chain had fallen off its sprocket or something . .

so as I said, she's in the repair shed, or rather the parking lot beside my friend's house, who is a great asset and help being a very skilled mechanic himself. He's just busy with work, and I'm trying to fix this myself and not to garble up his free time.

Sooo: today, I've gone through and stripped the engine . . as described in the manual. I've also removed the points plate, advancer, and base, in order to check on the cam sprocket . .

and I was expecting the chain to be broken, or off the sprocket . . or something, but its secure and tight.

I'll keep everyone posted, as I gently dissect the old girl . .

[WhyNot2]

I also have a cb100...........curious to see pics.

[foutuframboise]

I got the engine pulled.
I'm curious to see what this thing looks like on the inside.

[HondanutRider]

I got the engine pulled.
I'm curious to see what this thing looks like on the inside.

Pretty much the same as my SL100 that I rebuilt a few years ago.

[foutuframboise]

Awesome. I'm very open to advice . . this is the first engine I have opened up ever, and I'm a little nervous.

When I was stripping my motor yesterday and draining oil, I found that it was fairly low on oil; although, I had checked my oil levels with satisfaction several times while on the road . .

I'm a little bit worried about her . .
pictures to come, soon

[foutuframboise]

this might sounds silly, but according to the Shop Manual I'm at the point where I "Do not loosen the cylinder head bolts."

I'm not sure which are the cylinder head bolts .. The Honda manual is very adamant about not loosening them. I imagine the four 8mm cap nuts can only be the four on top . . dunt see the cylinder head bolts i'm supposed to leave alone . .

[foutuframboise]

Okay. This isn't so scary after all! Crazy to see inside this thing, makes me feel a little guilty about the last 1300 miles, though . . I want to take care of her . .

Anybody want to help me with nomenclature here?

I removed the 'top-end' ? is that right? from the 'cylinder head' ?

and now I can see the top of the piston, which looks Burnt up . . and smells pretty narly . . lot of oil in there

[HondanutRider]

Sounds like you have removed the cylinder head if you now are looking at the top of the piston.  If its oily then the oil has either come from the head (e.g. likely the valve guides), or an oil passageway between the head and the cylinder top (e.g. there are guides and seals at the head gasket that maybe have leaked), or from below (e.g. maybe broken rings/scored cylinder).  You likely should next remove the cylinder to expose the piston and its rings, and also to look at the condition of the cylinder.  You may need the next overbore size of piston and rings and get the cylinder re-bored, if they are damaged.  At any rate, you will likely need a new gasket set.

[Kevin D]

FWIW the picture is a CL100, a "Scrambler", not that the engine parts are any different.

top of the piston, which looks Burnt up . . and smells pretty narly . . lot of oil in there

Did the engine have compression after it quit? got a picture?

[foutuframboise]

Kevin D, good point. She's most definitely a scrambler . . its just her love of the pavement . . gets me thinkin' I'm on a CB

she'll probably be un-scrambled as the build continues, Episode III perhaps . .

Hondanut, Thank You for clearing up that matter of vocabulary . . I was sort of guessing . .

. . I have pulled the cylinder now. And she's fairly rough. the top of the piston and the bottom of the exhaust valve both have a crust of tanish/orange crap . . the exhaust valve is especially bad. I just got back from the store, picked up a #3 driver for my crankcase covers . . and a CLR derivative, the Bath & Kitchen variety. Will this be okay for cleaning purposes? Probably rinse with gasoline or diesel?

also, the piston (is it the wrist-pen that it swivels on?) well, its swivel function is really rough . . lot of friction. Looking very much forward to fixing that.

What looks to be a sleeve within the cylinder, it is a little bit etched, but doesn't seem to be too bad -- this engine, only has about 5000 miles on it. I am faintly considering an over-sized piston and a bore job. On the other side of the coin, I think I may do well to just hone the cylinder, clean the piston, new wrist-pen perhaps, install fresh rings . . and Yes, there are a couple of gaskets that need replacing, for sure.

again, I'm wide-open to friendly advice
that's what I'm here for 

~
Thanks everyone for this amazing forum!
I will certainly continue to dig through the archives, to try to solve as many mechanical puzzles as possible. This my first time ever opening up an engine! Thanks for the support, cool guys.

-justin

[foutuframboise]

These photos are pretty low resolution . .
perhaps someone may gain some info by seeing them.

[HondanutRider]

A bit difficult to tell from your photos, but it looks to me that the head gasket (the main/thick one between the head and the cylinder at the top of the piston) has failed and let oil leak and enter the cylinder.  (Was the motor smoking when running?)  The oil is under pressure to reach the top valve mechanism by traveling up passageways around one of the cylinder studs (which have a collar and maybe a small o-ring to seal further at the head gasket), and there appers from your photos to be some leaking there.

Your valves and piston top don't look too bad to me, and should clean up with some careful scraping.  If the cylinder walls aren't scored/scraped and the original rings and piston are intact, then a light hone and new rings would be a good idea.  Also, you could check the valve seats for leaking by inverting the head and filling it with a thin liquid like thinner/varsol.

You described how the wrist pin (its called a "pin" not "pen") has a lot of friction.  It shouldn't.  The easiest fix is a new piston which should also include the pin and the retaining clips as a set, along with new rings.  If the original isn't rotating freely then it may have been damaged or scored - something you can see by removing it from the piston and connecting rod.  Hopefully the small end of the connecting rod (where this wrist pin goes though) hasn't been damaged, otherwise it would likely need replacing.  If the oil level gets low, these parts (which rely on oil splashing up on them from below) wouldn't get properly lubricated and that might cause failure.

[foutuframboise]

Thanks for your advice.

Also, I heard using CLR would be bad for my engine and that I should use something like naptha or mineral spirits, to chase with penetrating lubricant and wipe clean. All good advice. I haven't really considered a new piston all-together, though it sounds like a good plan. Do you think that the end of the connecting rod that attaches to the piston might be worn as well? How might I help to refinish that surface? I also really like your thoughts on checking valve seats. Thank you. I was wondering how to examine the cylinder head and valve mechanism. I guess that's also a good means of adjusting the valves perfectly? so that they perform their duty of maintaining compression, and without a racket and unwanted wear . .

[foutuframboise]

FWIW the picture is a CL100, a "Scrambler", not that the engine parts are any different.

[. . .]

Did the engine have compression after it quit? got a picture?

I changed the name of the thread to reflect the fact of the matter . .

annnd, Yes. The engine did have compression after. And it was running quite nice before . . I was thinking that it was the Cam Chain/Sprocket/Tensioner that had caused the problem, but actually all was good in that department. Right after the bike lost power and died when I tried to kick it over, it just made a clicking sound . . Now, I'm thinking it must have to do with the transmission somehow. The piston isn't in the greatest shape, but I haven't discovered anything in the top-end that should have caused it to fail like that.

I'm trying to remove some stripped screws from the right-side crankcase cover, going to find a vice-grip to pitch into the effort. I should be more in the neighborhood of the mechanical failure then. I will post pictures.

Peace.

[HondanutRider]

You might want to lightly hone the end of the connecting rod with some very fine wet emery paper, where the wrist pin goes though.  That should clean it up sufficiently, I would doubt it is damaged beyond needing athis sort of clean-up.

Regarding your valve mechanism, there isn't much to go wrong there, unless they look obviously broken or the cam surfaces excessively worn.  Once its assembled, you need to adjust them properly as the manual specifies.  Part of the valve train is the overhead cam mechanism, and you need to ensure you get that set-up and adjusted properly on re-assembly (i.e. follow the Shop Manual).  Pay particular attention to the cam chain tensioner mechanism, and examine the slipper guide and tensioner bar for excessive wear, replacing them if necessary. (Unless really badly adjusted before, these last two parts shouldn't have worn enough to need replacing - they really are otherwise quite robust.)

I don't think a failure or breakage in the transmission would cause a loss of power as you describe.  One of the teeth on the gears in mine had broken off and all it caused was one gear to be missing or difficult to work.  There isn't much inside the transmission to fail and cause a stoppage that you can't determine is wrong before tearing into it.  (e.g. Turnover by hand and select the gears, operate the kick by hand to see/hear movement to determine if anything might be broken inside.)  If you split the cases and open up the transmission - you maybe into a whole other world of re-assembly.  BTW using a vice grip on those screws is pretty hopeless...what is better to do is chisel it unscrewed (e.g. tap the head in a counterclockwise direction with a flat screwdriver driven at an angle onto the head so as to unscrew it) and then replace the screw with a new one.

[Kevin D]

Were the valve adjusters set properly?

I used to buy performance parts for my (long gone) SL100 from Powroll but their website seems to be out of order these days.
 

[foutuframboise]

Kevin, yes the valves were working fairly well prior . . I was just curious to know if there may be an alternative way of tuning them dead on , without guessing your way around the valve adjustment range ..

. .
Hondanut, thank you for this wealth of information. I will certainly apply the advice 

-----------
the jig is that my friends were coming through Colorado, and so I'm loading up my disassembled scrambler and taking it east to Hot Springs, Arkansas. takin' her home to the shop . .

 

so , we're all just going to have to somehow maintain a state of patience . .   

My plan is to lightly hone and freshen up my engine as is . . replace the rougher parts if absolutely necessary, re-surface wherever possible . . new rings & gaskets . .

and when I get everything cleaned up, I want to intelligently place a powerful magnet somewhere on the crankcase . . and I have heard that a mix of 20% diesel into the moto oil . . and ride about 10 - 20 miles very, very gently . . chilllll. don't over work the motor. get home, drain it all out . . clean out the magnet catch system . .

and Modify the oil pump region of the crankcase to direct oil flow to some sort of oil cooling setup, and back . .

.. and later down the road, I will be wanting to bore it out . . or do some sort of an engine swap . . I want to freshen up first, so that I can learn how much is to be gained, and what the real potential of 100cc engine really is. I want to learn how to modify these bikes with oil coolers, to do my best to maintain the health of the engine for as long as possible with as little maintenance as possible. I want it to be super fun, and a little less stressful to ride long distances. . I'm just day-dreaming . .

Guess it will all have to wait until the next couple of weeks

PEACE

[foutuframboise]

My disassembled bike fit perfectly into the back of my friend's prius . it was picturesque . . we're glad to be back, and back to work

Does anyone have any advice for removing a pin semi-seized in the piston? wrist pin clips are removed. I'm going to take hondanutrider's advice and clean the pin and inner piston with "emery paper". Is that the same thing as 2000-grit automotive sandpaper? . . also is there a particular direction that the pin is supposed to be removed from the piston? How do you get that thing out!?  )

[tomkimberly]

Purchase one of these:  http://www.motionpro.com/motorcycle/partno/08-0472/


Tom

[HondanutRider]

The pin should just be a tight slide fit in both the piston and the connecting rod.  If you can't remove it easily, then there might be some distortion jamming it up.  I'd try to gently tap it out using a piece of wood, for instance on the end of the pin, while ensuring the connecting rod (which is probably still connected on its big end to the crank) doesn't get too twisted or pushed sideways on its lower bearing.  To do this, you probably would have to support the rod on its flat side while trying to tap/remove the pin.