A little bit of newbie tech help...

[niteman]

Hey all,

I was doing some wrenching on the '86 cb450sc I bought yesterday, you know all the new purchase items like oil change, spark plugs, air filter, chain lube, etc... and I ran across a couple of things I could use some insight on. I am looking for a shop manual currently.

So here it goes:

The tach was inoperable when I bought it, the seller said that it was the tach itself. so, while I was wrenching I removed it. Once the tach was off, I took a small screw driver and tried the tach that way, it seems to operate fine. So back at the bike I inspect the cable...it came right out of the cable housing  It was broken half way down into the housing. So, how the heck do I change the thing out? I found a couple of links when searching through the forum for OEM parts, so I'll look on there for the cable.

Another thing, this might be a stupid noob question, but I have no shame. The forks are really soft...they are air adjustable and I can figure that much out, but what about fork oil? Does this model not use such a thing?

Thanks ahead of time for any help or direction,

Shaun

[happycommuter]

I've swapped a speedo cable, and it was ridiculously easy, I suspect tach is similar.   When you get the new cable assembly it should be pretty self-explanatory - screw one end in, tighten the nut on the other (after lubricating the cable I suspect).
Air pressure (very low) is in addition to the fork oil.  As I always say, fork oil is very commonly neglected by previous owners.  It deteriorates (viscosity breakdown) and replacement can improve things greatly, plus you get to choose a thicker oil depending on rider weight/ preference.

[ROJ]

Unfortunately I don't believe the tach cable is a simple screw-in and tighten. I had to change one on a '78 CB400TII Hawk (which is the same engine as the CB450SC I believe). In order to change the tach cable the left side engine case needs to come off which necessitates the oil to be drained. Yours might be slightly different, I'm not sure. It might just pop out, but I wouldn't pull too hard on it just in case it is attached inside, you don't want to damage that part. I;ll need to talk to a buddy of mine who has a 450 to be sure though.

[niteman]

Thnaks ROJ. I have one ordered through bikebandit.com...and thanks to that awesome link from OhioTim, I have a service manual now and can hopefully figure out how to change it out.

Thanks again guys...this forum has been awesome so far.

[ROJ]

I just realized that I said the tach cable was on the left side engine case. It is actually on the right, I got turned around without the actual bike in front of me. That manual you got is the same one I use to help out my friends (78 400TII hawk and 85 CB450). Its really helpful. Just another tidbit though, when the cable is removed from the tach, check the mounting point that goes into the back of the unit to make sure there are no hairline (or worse) cracks around it, if it breaks loose it will reak havoc on the tach internals.

[niteman]

OK, just got the Clymer Repair Manual today and the tach cable is not covered (at least I couldn't find it) 
Sooo, does anyone have any ideas? ROJ, you said that I might have to take the right side engine cover off? Did you get a chance to check with your friend?
Thanks again,

[ExTex]

If you look at the exploded drawings like this one: http://www.hondaparts-direct.com/fiche_section_detail.asp
you may be able to figure it out.

PS, this is a good site to order parts.  They have the best prices I have found.

Ride Safely,
 

[ROJ]

Shaun, sorry I haven't checked it out yet, but the engine will be coming out of the CB400TII (same engine just smalled displacement) this week (the rings need replaced). I will definately check then, and I'll have a few pictures of all the internals when I change the rings, just to help out all you 400/450 twin guys. If you need to know sooner let me know and I'll get the info for you ASAP.

[niteman]

Thanks ROJ. No hurry, but looking forward to some of the pics of the ring replacement, that would be good info.

I actually figured out the tach cable and feel pretty silly thinking that it was all that difficult... one of the 8mm bolts on the right side cover is there as a retaining bolt to hold the tach cable 'boot'. It was so much easier than I was making it. Turns out the tach is busted to heck though, so the cable is new but still no tachometer. I'm currently looking for one of those now.

Thanks again.