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Discussion Starter · #1 ·
So I bought this 1980 CM400T last fall with 23K miles on it. It had been garaged for a while but has been running good. I've had some carburetor issues but I've been able to sort them out mostly. I'm riding it daily and it does good. Today on my way home from a ride it jumped out of gear and now I can only get it into 1st. Luckily I was only a few miles from home and I know the back way. You don't realize how low 1st is until that's all you've got. The Clutch will take it in and out of gear and it feels like the shift lever moves it through the gears but it will only move in 1st. I got it into 2nd once but not for long.
Where should I start and what is the most likely cause? Seems deeper than the clutch, am I going to be pulling the engine and splitting the case?Thx
 

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Make sure the shift lever is clear of the case. If it took a tip or something it can happen. You Never know if someone knocked it over.

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Discussion Starter · #3 ·
I'll take a look. It did fall on that side when it was sitting for sale. I've had to straighten a few things out but it just started today after a few weeks of riding,
 

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Discussion Starter · #4 ·
I'm leaning toward a worn out clutch. I put the bike on the center stand and the wheel spins in the first 3 gears. The clutch is currently adjusted all the way out. I'm going to open it up and check the plates and springs.
Looking at clutches online I've seen a wide range of prices. I don't feel like I need anything high end for average use. I've also seen some used clutches for sale too. Any opinions on whats good for a commuter bike? I was hoping to make it till winter before really digging in on any kind of engine rebuild. I'm definitively capable enough for this repair but the last one I did was in '89. Any advice?
 

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Discussion Starter · #6 ·
Thanks for the reply and the recommendation . I'll probably get it out this weekend and check it all out then order what I need.

Any thoughts on oil? Does a wet clutch really need special oil?
 

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Short Answer: Yes, Yes it does but you can use JASO MA certified Rotella T meant for diesel trucks

Long answer: In the quest for efficiency car oil now uses chemicals called friction modifiers to decrease friction in an engine (less resistance means less power needed -> less gas -> more efficient). These friction modifiers will also decrease the amount of friction that a wet clutch can generate (friction is needed, youtube videos if you want to understand why). This will cause the clutch to slip. If you're using regular old castrol you might have found the reason your clutch is not working anymore. I think you'll need new clutch plates anyway.

As for oil, a lot of people seem to use Shell Rotella T since it is JASO MA certified (certification our bikes call for). The conventional kind is supposed to be really good for a traditional oil but the fully synthetic is even better (but more expensive and might cause oil leaks switching from conventional). It's also important to run motorcycle oil or Rotella T because an air cooled engine hits much higher temperatures than a water cooled car. Car oils aren't meant for this abuse and the oil will break down way faster than you will expect and possibly cause lubrication issues. Rotella T is designed not to do this, and probably other heavy diesel oils
 

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Castrol makes a motorcycle oil that is JASO MA certified. It comes in 10w40 and 20w50 . It costs us about 6.50 CDN (about 4.95 USD) per litre.
 
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