1985 Honda 250SX - All Road Lead to Ignition?

[bigtrout3]

I've got a 1985 Honda 250SX that has some issues that I think are all related, but I can't be sure.

Problems:
1. Reverse / Neutral lights don't come on
2. Ignition switch "off" when running will not turn the bike off (but the kill switch on the left handle will)
3. Headline doesn't turn on
4. When shifting into reverse, the engine dies
5. No fuse - someone deleted the 15A fuse so I reinstalled one.
6. Engine is kind of noisy - almost like chain slap, but I can't be sure. (edited to add this)

Looking at the wiring diagram it looks like problems 1 to 3 are probably related to the ignition switch, but I show resistance when testing the red and black wires on my multi-meter which would seem to indicate the switch is ok.

Problem 4 I can't figure out. At first I thought it was the reverse switch, but after reading around it seems all that does is tell the light to come on?

Other than that the bike is solid. No issues in forward gears and starts up easy with the electric start. Maybe I have a spooky ghost living in the wiring harness.

Anyway, any help on these issues would be a big help.

[bigtrout3]

I was able to solve item 4 - engine dies when shifting into reverse. A simple clutch adjustment was all that was needed.

Now on to the electrical. I suppose my and my multimeter are going to get well acquainted...

[bigtrout3]

Further updates:

I traced the issue with the key off in the ignition not stopping the engine back to someone who had been in there before putting the wrong wires in the wrong sockets. The b/w wire was going into the black wire to somewhere else so when I traced everything back none of it made sense until I remembered my colors from pre-school.

In the meantime I had spliced in an extra 250ES ignition switch, which I suppose was going to happen sooner or later, so why not now?

So that leaves the noisy engine and the lights issue. I think the headlight and taillight are going to be solved by a new light switch as the current one had a bunch of chewed up wires and is not giving me any readings when I test the on/off switch. We'll see. The noisy engine I'm hoping will be a matter of valve adjustment.

Anyway, not a lot of action in this thread other than to document it for any future 250SX owner.

[shortline10]

You can try the valve adjustment but the most common problem on that model is a loose timing chain .
Their are a few threads on this site on easy fixes .

[bigtrout3]

You can try the valve adjustment but the most common problem on that model is a loose timing chain .
Their are a few threads on this site on easy fixes .

Right on. I figured it was valves or timing chain. I suppose I'll do the chain replacement on this one. I've got a 250ES that also needs a chain rebuild, but it's not nearly as bad as this one and the 250SX will be good practice for Big Red.

Is there any preferred vendor for the rebuild parts or any old thing on E-bay will do? Reading the other thread I found on 3WW, it doesn't seem too involved and even the service manuals don't make it out to be a big job.

[whiteman350x]

If you are doing the timing chain, I would say that you go ahead and replace the one way bearing in the clutch while you are in there. You have to remove it so i would put a new in in its place.. Might keep you from going right back in there.

[bigtrout3]

Success! The new light switch works. Headlights and neutral light work, but reverse still eludes me. I think the bulb is too small for the socket because even the neutral I have to wiggle around to get it to light up.
So, I'll adjust the valves, but plan for a timing chain job and this thing should be ready to get back out on trails.

[whiteman350x]

The parts store replacement bulb for the reverse and neutral lights is a sylvania #37. They fit good and are so close to the same amperage I can't tell any difference from original.

[bigtrout3]

Those sylvania #37s worked a treat, thanks whiteman.

The exhaust valve had quite a bit of lash, but the intake was ok. Even after setting them, I've got a bad tick, so chain and clutch parts are on the way.
But, all the lights work, it goes into reverse, and rides like a dream.

Only issue is it wants to pull to the right. It's like the forks and the handlebar aren't lined up almost, but maybe it's the tire?

[Shep1970]

Just put more air in the side it pulls to. Or less in the other. If u have older tires having the same air pressure wont matter/may have been over inflated at one time, who knows....just inflate/deflate till it goes strait.

shep

[bigtrout3]

I went through and changed the timing chain. While I was in there I replaced the clutch pack and the one way bearing. The thing shifts real smooth now.

But, the engine is still noisy. The old chain was definitely no good, the tensioner was all the way out and the chain was still really sloppy - I could move it quite a bit with a screwdriver through the valve adjustment cover.
I used a DID chain so it should be high quality, made sure I was doing it on TDC of compression stroke, both lobes down, index marks all lined up (two dots on top of camshaft, one dot on the timing gear). When it starts I need to give it some throttle, but the racket is pretty bad. It feels like it has plenty of power, but I didn't want to run it too much in case it was something with the valves.

I checked the valves and reset them to .003" per the specs on the compression stroke of TDC. They weren't out of alignment.

Here's a video. In short, what is this noise?

https://youtube.com/shorts/FQ3KZjGhOIA?feature=share

[shortline10]

Hard to tell from the video but theirs 2 Possibilities , either your timing chain tensioner is worn out and can’t hold the tension or piston slop .
Valves will make a ticking sound and a loose piston is more of a deeper rattle/ knocking sound .
Years of running a loose timing chain tend to chip the teeth off the tensioner causing it to fail .

[bigtrout3]

I've seen through the eye of the needle.

The camshaft was 180 degrees out of phase. I popped the valve cover off again on TDC of compression and there it was, plain as day.

I think I got so absorbed in following the manual, that I forgot to think about what I was doing. I was using the Clymer manual and it only briefly mentions "bring to TDC." I must have missed it.

In any event, it runs like a sewing machine now. All is well. Thanks to everyone for their help.

[patriot1]

Great job! Thanks for keeping us posted.