Implications of a broken kickstarter? '73 CB350 Twin

I

iContango

Been Around the Block
I recently swapped engines on my bike, hooked everything up, and noticed the kickstarter would barely catch - maybe one out of 10 attempts. It recoils fine, but the gear just did not catch. In the usual fashion, I kept kicking and kicking until I heard a snap. Now it doesn't catch AT ALL.

I finally got the bike running reliably (in Neutral), and went to take it for a spin last night. I start the bike in Neutral, hop on, pull the clutch, put it in first, and attempt to take off. ALl seems well, but when I let the clutch all the way out in 1st (attempting to fully engage), the bike shudders and lurches forward, then dies unless I pull the clutch in again.

My first thought is that the clutch is not adjusted properly - valid assumption right? So I locate the CB350 clutch adjustment procedure found on Honda Twins (<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.hondatwins.net%2Fforum%2Fviewtopic.php%3Ff%3D49%26t%3D8963&ei=jkZHUKirCIWMyQGmiYCwAQ&usg=AFQjCNE2e0s71REd-Pmrvt6SFO5s_td54w&sig2=ptAB4fXP1BsTopM15bWJUg">HERE</a>) and went to town for 4 hours attempting to get it adjusted properly. No matter how many different minor adjustments I tried utilizing all variables, the same thing happens - I cannot get going in first gear. Blood pressure rising.

One other thing I want to mention, is that the "neutral cam" within the clutch side plate (that controls the neutral light) appears to be 180 degrees off even though it is placed properly. Not sure why... but maybe this is an indications something is jacked up inside..

After talking to a friend, we were throwing around the idea that the broken kickstarter is causing issues as to where the clutch can't fully engage when taking off - maybe a gear is out of whack or broken inside, so SOMETHING... I have no clue. So I ask everyone here - what are your thoughts on the above? Could a boken kickstarter possibly cause the issues I am experiencing? If so, any suggestions? I realize the next step is probably removing the engine and splitting the cases :(

Thoughts?
 
Anyone? Trying to see if there is an alternative before I pull the engine and retire the bike for the winter...
 
In case anyone was wondering what happened... I split the cases and sure enough, the C-Clip holding the kickstarter gears/springs on the shaft had popped off, causing the gears to be strewn about the crankcase. This obviously caused issues when attempting to fully engage in first gear. Luckily I dont see any damage to any of the gears, so I am going to reassemble using a new C-Clip and probably never use the kickstarter for fear of that happening again!

While I'm in there I am going to do a full rebuild just for fun :)
 
Since I'm talking to myself, the moral of the story is this: Those who have a kickstart that does not "catch" should split their cases to ensure the c-clip hasn't popped off the shaft, causing the kickstart gears to spill all over and bind the transmission.

I can't be the only one, so hopefully this post helps someone in a time of uncertainty.
 
I bet you aren't actually talking to yourself, as I was reading, but only felt the need to comment when you said you were talking to yourself.

So I guess I was listening, something my wife says I don't do very often... 8)
 
Only the spring is behind the right cover. The rest of the mechanism, gears and such, are inside the crankcase/transmission area. The crankcase (what the side covers attached to is split horizontally. You have to disassemble the engine crankcase and remove the bottom half to access the kickstart mechanism. Since the crankcase is in 2 pieces, opening up is called "splitting the crankcase".

If you can find the problem without all that work, we figure you can save the heavy work for another time.

So check the clutch and so on before you tear the motor down.
 
I had the same thing happen to me after rebuilding the my motor, so when I split the cases again I decide to throw in the lumpier cam and performance valve spring kit I had been thinking about putting in a different "race" motor. Double check the little spring clip (wire looking thing) that holds tension on the kick start spindle gear as well. If the wire clip is stretched/worn, it'll pop off under pressure and you'll be back to splitting the cases and wonder wtf happened all over again ;)
 
Is there any solution for this problem? I had the exact same thing happen to me. I've split the case and have a new C-clip of the right size (12mm), but it pops off easily too; I can pop it off with my fingers without much effort. The groove it sits in is not very deep, so I'm thinking I may have to deepen it somehow and get a smaller clip?
 
I just found that a 10mm E-Clip instead of the stock 12mm C-Clip works very well. A new 12mm C-Clip I can pop off with my fingers; the 10mm E-Clip needed pliers to get off.


$0.63 cents at Ace Hardware.
 
So, from the op's first description of the problem it seemed fairly obvious that something broke off inside the motor. Maybe i'm paranoid, but i'm not even going to try to start a motor with a chunk of loose metal kicking around in there; as soon as i heard the snap it's time to split the cases to find out what broke.

As to using a 10mm e clip instead of a 12mm c clip, that's not a very good idea either. That's almost a 17% reduction in diameter from spec; the clip isn't going to sit properly and keeping the clip stressed out like that will eventually subject it to metal fatigue and it'll break. If the propper sized clip pops off like that it's either from the clip not sitting in the groove properly (like if there's something else stuck in the groove) or from wear on the sides of the groove (either the shoulder isn't high enough anymore or it's become sloped and spreads the clip open) If it was me, i'd put that thing on a lathe and cut the groove deeper so the 10mm clip seats properly, this isn't a big job and shouldn't cost much if you get the shaft out yourself.
 
johnson_steve said:
As to using a 10mm e clip instead of a 12mm c clip, that's not a very good idea either. That's almost a 17% reduction in diameter from spec; the clip isn't going to sit properly and keeping the clip stressed out like that will eventually subject it to metal fatigue and it'll break. If the propper sized clip pops off like that it's either from the clip not sitting in the groove properly (like if there's something else stuck in the groove) or from wear on the sides of the groove (either the shoulder isn't high enough anymore or it's become sloped and spreads the clip open) If it was me, i'd put that thing on a lathe and cut the groove deeper so the 10mm clip seats properly, this isn't a big job and shouldn't cost much if you get the shaft out yourself.
Click to expand...

Very valid points based purely on numbers. However, in my single personal experience just now, the 10mm flexes on as much as it should to seat and does not appear deformed when removed and compared to an unused 10mm clip.

A bit of machining on a lathe or similar solution is a great idea.
 
loudboy said:
...does not appear deformed when removed and compared to an unused 10mm clip.
Click to expand...

All that means is the stress applied to the part didn't exceed it's modulus elasticity. Metal fatigue is what happens when forces lower then a parts modulus elasticity are applied over an extended period of time; this is why elevators are actually built and tested to a minimum of 5 times the rated capacity. It is impossible to see how the clip seats in the groove unless you were born on krypton, ideally the clip is only stressed when you put it on or take it off, a properly sized clip should be able to relax back to it's original shape when it is installed in the groove, not be streched and under constant stress.

I'm not trying to be a smart ass here; it's entirely possible your repair will last a very long time, but it won't last forever, and when it fails: best case you have to split the cases, worst case it totally destroys the motor.
 
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