is my CB450K6 a gonner ?

I have a K6, for better or worse, here are the symptoms of the engine that I am aware of
first gear jumps out under load, ( I understand the dreaded detent roller is normally associated with 2nd gear, and its a k6 did they have that issue fixed by the K6's )
I dont have the same exhaust pressure on each side, stronger on right side from the rear of the bike. I have not done a compression test. Was told the engine has 9500 miles on it when I bought it, I have put 600 on it since then.
I have a stripped valve cover bolt, not really a big deal I know, but combine all these things is this engine worth saving or should I shop around for a k7 and hope to get lucky.

Brave or stupid this is my first bike, I dont have a shop so working on it myself would be a huge stretch.....
Survey says..... vote now....

Do you seriously expect us to diagnose your engine without even doing a compression test?

I think you need to take it to a qualified independent bike shop that doesn't mind working on vintage Jap bikes. A lot of bike shops won't have anything to do with the old bikes, but some shops, (like mine,) love the old bikes.

WE can't tell you what your options are and what they will cost over the Internet. You need a mechanic.

Have to agree with Alpha (I hate when that happens ). If you're not comfortable diving into the motor yourself, you need to take it toa competent mechanic who can determine the severity of the issues.

That said, to me it sounds like the bike is in need of a proper servicing. Basic wear and tear/useage is beginning to take its toll on the forty year old motor. Bound to happen at sometime. Take it to a good shop and have it thoroughly checked over.

Where are you located? We may be able to help you find a trustworthy place to take it.

that engine is real fussy for valve adjustments as it has torsion bar springs and the clearances are real tight and hard to set

right so basic tune up and adjustment is critical get that done and then a leakdown test and it will tell you all about your engine

I doubt the detent plunger is causing the gear to slip out, more likely the dogs are rounded over, you'll need to replace them, a parts engine is your best bet for replacement gears... As far as the unequal pressure, a proper tuneup is where you start, eliminate all the variables with it and see what's left, that's where your actual mechanical problems lie

Shifting issue is the same for all the 450s, they all wear out eventually. Even the occasional 500t had problems. Both my engines had worn detent rollers and both shifted like that until I fixed the rollers and the stars on then ends of the shift drum. Could also be a snap ring that is located under the sprocket cover that is supposed to hold the shift shaft in place. They pop loose and cause funny shifting.

Engine has two carbs with separate throttle linkages, its not hard for them to get out of adjustment and lead to uneven pressures in exhaust. That also means that its easy to set the idles screws off enough to cause the same issue.

Valve clearances can be set out as much as .002" before they are TOO loose normal use, many racing teams set them even further. The SMALL setting now is mainly for noise reduction, all the old mechanics say to set them looser than the manual suggests for longevity, allows more room for OIL. They beat themselves to pieces eventually anyway.

Honestly, now having worked on them for a couple years I can say this. I have have a background in mechanics and have the space to work on them. I have learned quite a bit about engines from this bike. Not so much from my 360, its pretty simple. 450's are not starter bikes when it comes to up keep, they need a lot of periodical maintenance to keep them happy. WHOLE lot of stuff spinning around inside them to get messed up, break, wear out, etc. Just setting the valve clearance requires an hour of prep work just to remove enough stuff to GET to the valve inspection covers.

Might be a better idea to get it tuned up and sold and then buy something that requires less work to keep running until you are comfortable with the upkeep.

dont run away from this bike they are wonderful once you get them running i have quite a few of them and they just sing

when they are running right

frogman said:

Might be a better idea to get it tuned up and sold and then buy something that requires less work to keep running until you are comfortable with the upkeep.

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I gotta second this one - I love my 450, and my wife will be learning to ride on it this year; but it was my first project bike, and in retrospect I would have been well served to pick something else. The rocker cams are an interesting but ultimately poor design, in that they have a tendency to eat themselves if they fall outside proper clearance, and they are quite dear to replace or resurface.

I set my valve clearances - per the Honda gurus - at .004" on the intake and .005" on the exhaust side. If you go to the 450 section of the hondatwins.net site I put together a sticky outlining the procedure.

That said, I will hold on to my 450 for a good long time. It's a hell of a lot of fun.

Where are you at? Some here may help if they know you are close by...