I still need to do the valves on my 83 750, so I was looking into how it's done recently, also I know a friend of my dads has a CB750 with the same engine who's done the valves on his.
The valves on Honda's have little shims of varying thickness which make the valves open and close to their proper specification, of course over time, they wear and thin out or otherwise distort. From what I've been looking at, on a 750 the shims are placed under the cam lobes, so what you do is use the tool recommended for compressing the valve spring, then pop out the shim and insert a new one. Of course, you don't touch them until you've measured them all and have figured out which thicknesses have to go in to bring the valves back into spec. As far as I know, the engine of an 82 Nighthawk is exactly the same mechanically as an 83's, so they both use this little shim scheme. Your BMW friend may be correct about set screw adjustments for BMW's (I don't know personally I've never seen internals of BMW engines), but that is not the case with these Honda engines. If doing valve adjustment for the first time, I would suggest setting up a larger allotment of time to do it in, but on the whole it shouldn't take very long at all, less than a day if you have everything you need to do it (you'll get quicker as you get more comfortable with doing it). I myself haven't done this procedure yet either, but like I say, my dads friend has and he tackles the valves on his other bikes too. For him, it only takes somewhere around an hour to do, of course, he keeps a pile of extra shims of varying thickness around, so he can pick and choose from without waiting around or driving somewhere to pick some up. You mentioned that you have a shop manual for the bike, so I haven't gone into too much detail about the procedure, I have a Clymer Manual which describes the adjustment pretty well, if you'd like to know how mine details the procedure I can do a little write up. Hopefully someone will reply who's actually done the valves though, bring insight to the nuances (if any) of doing it in reality. I think you can make a tool to compress the valves too, but I would probably just say it's less hassle to buy a valve compression tool so you can get them loose enough to pop shims in and out. -timhortons On Apr 23, 1:21 pm, Sharpey1 <[email protected]> wrote: > Hello everyone....Ok, new tires, front brakes, brake fluid, oil/air > filter, spark plugs and getting all visible chrome up to acceptable > levels of shine has been completed! Tires need to go on, but I'm also > constructing a poor-man's laser chain/rear wheel alignment tool, but > more on that later.... > > The bike has always had this, but I want to address it since I can > hear it when I start it up....there's what seems to be a sporatic > knocking sound from the valve cover area, left side of bike. Seems to > go away, or at least lessen when she warms up.....work with previous > owner and talked to him....said "Ya, probably need to get the valves > adjusted." > > The bike came with a Honda Shop Manual so I assumed he did all this > stuff to and could hand over the wealth of infomration stored between > his ears.....started describing the process of pulling shims, > measuring them, using a special tool, how to go about it, etc.....he > blankly stared at me and said "That's why I paid someone to do it." > > Great....so can my fellow Nighhawkian's lend a noob a hand? Does this > indeed sound like valve misalignment? Does it sound accurate on the > procedure? The manual I have is actually for another 82' model, a V I > think instead of an SC but I guess the motor is the same? > > Special tools? Shims? All this sound right? Something that can be > tackled fairly easilly or am I looking at a weekend's worth here? I > also saw the post on Sea Foam and carbon build up issues worth a try? > > I have a buddy who runs a newer BMW and indicated valve adjustments > are simply set screw adjustments and no big deal....want to make sure > I'm looking at the right thing in the manual as well, figure BMW'ers > would never think about seeing the inside of their engine anyway so I > take that with a grain of salt....thanks in advance everone! > > -Dan- > > -- > You received this message because you are subscribed to the Google Groups > "Nighthawk Motorcycle Lovers!" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group > athttp://groups.google.com/group/nighthawk_lovers?hl=en. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
