July 2011 6

Hello,
I was browsing around the net looking for suggestions / info on my tapping issue.

My cm 450A is tapping and have been told it’s the lifters and they need adjusted, what tools and what do I need to do to resolve this issue? I have been to several bike shops around me locally and have been told they can’t work on anything that old due to this issue or that.

The bike runs like a champ, no over heating issues, cold starts without a hitch, hasn’t died on me while driving upwards of 2 hours straight knock on wood. It’s just loud, sounds like it’s chopping rice like a moped…

So it looks like I’m stucking doing this on my own. Any advice would be greatly appreciated.

P.S. I am somewhat mechanically proficient when it comes to vehicles, however all the work I’ve done on this bike (New handle bars, new headlight assembly, paint work, new seat cushioning and cover, new battery, oil change, new plugs and wires) I’ve done myself without a manual. But when it comes to opening up the engine, I’m clueless.

Hi Onnie,

Tapping from the top end is commonly due to valve clearances that are out of adjustment. If valves aren’t kept in spec for long periods of time, damage can be done to the valve train. A rattle sound is often caused by a stretching cam chain.

You’ll be surprised to learn how simple it is to adjust the valves on your bike. It should be done every few thousand miles. I generally check my valves whenever I change the oil – it’s easy enough.

For tools you won’t need much. You’ll need a basic set of metric sockets, a flat head screw driver, a 10mm (or is it 12mm) wrench,and a set of feeler gauges

Feeler gauges can be bought at most auto parts stores, or Sears always has them as well. Just make sure to get a set that has the sizes you need. For your bike the intake clearances are 0.08-0.12mm and the exhaust clearances are 0.12-0.16mm . So just make sure your set has sizes in that range and a couple up and down in each direction.

You can download the repair manual for your bike from my site: Honda CM450 Service and Repair Manual. Valve adjustment procedure starts on page 68.

Let me know how it goes.

Cheers,
Evan

Ok so I adjusted the lifters to spec accoring to the manual exactly like the manual said. The bike now seems to have a more rumble to it, the lifters are still tapping but sounds like a lower pitch as if they may be now too loose…

Before they sounded like a air compresser tapping, now sounds like a box fan tapping if that makes sense. I watched a couple videos on youtube of others adjusting their valves and one guy said you cant hurt anything going a little loose but you can hurt the engine if going too tight.

So in this case should I leave it as is (seems to be running fine, just as a lower pitch with a little more rumble) or should I tighten them back up to where there is no play in the lifters just like when I started?

Great Onnie! Yes, you’re right, it’s better to have them too loose than too tight. You won’t physically damage anything by having the clearances set too loose, but the bike may not run properly. Sounds like you’re probably OK. Keep in mind that every tappet valve train is going to make noise. Even with the valves in perfect spec there will still be some tapping – it should sound like a sewing machine.

Just let them be, and next time you change your oil check them again.

Cheers.

i did exactly that but now i cant keep the bike running for crap

Well – having the valves set isn’t your issue then!

If the valves are now in spec than that’s one thing to check off your list. Getting an old bike to run sweetly takes some effort and can be frustrating at times. What’s the symptom? Carb related?

Alright, am a new rider, just got my 82 nighthawk450 2 weeks ago and have been doing alot of online reading/shopping, do you know you can HARDLY find anything for these? LOL..well my delema at the moment is height on this baby! Im a 5’5 girl rider and im tip toeing while sitting, I have adjusted the rear shocks to the lowest point which help about an inch and am looking to go to the m/c salvage yard tomorrow to find me some matching, shorter shocks, But I have heard there is a shock lowering kit/bar to readjust the shocks to a ‘further back” position…can I find them? NO..LOL if anyone has and info or possibly pictures of these ( my dad can use his “master metal and welding skills” to help with this) any input or advice there is to give this “new rider” would be greatly appreciated!!

Hey Trusten – The Nighthawk 450’s are excellent little scoots. They aren’t particularly tall, but I can see how it might be a little above your comfort level.

One thing you want to be careful with when lowering a bike is upsetting the geometry of the bike to a point where it doesn’t handle as it should. If you reduce the height too much you may find the bike will steer very awkwardly, because it isn’t balanced properly front to back.

If you haven’t done so, you should try dropping the front suspension in the clamps about an inch. That will also drop the seat height a little more, and is free and quick.

I doubt replacing the shocks is actually worth the effort or cost. With the shocks set to their lowest and the forks lowered a bit the bike should be sitting pretty low. As a new rider having a lower bike is certainly reassuring, but as your proficiency in the saddle progresses you’ll realize that having a strong sturdy flat foot on the ground isn’t as necessary as you might think. Lots of short riders ride tall bikes comfortably. Take for the example a guy like Gaston Rahier (seen in the middle below). He’s one of the most accomplished motorcycle racers of all time and was a very short guy riding very tall bikes!

If your father is a welder you could probably just cut off the shock mounts on the swingarm and move them back a little. A fun afternoon project!

Best of luck with your new ride! Cheers.

My bike is currently just running the cdi box an the coil for the spark plugs. the rest of the wiring is completely gone, i have a battery for the tail light and the head light but  need to find a way to charge it or have a wiring diagram to run with out a battery. o an i also have no ignition, any advice or info would help.

You can buy a regulator/rectifier combination unit to run the lights for about $20 from a handful of sources. Rocky Moutain ATV, Old Bike Barn, etc.

I recently bought a 79 KZ650 off my roomate, bike had been sitting for a few years and of course did not run when i purchased it. I took it to someone who threw some spark plugs in it and gave it a small tune up i would assume to get it running(in my excitement i do not remember what all they said they did to get it running, i didnt care because the bike was running) after a few hours of riding i started to have some issues.

a. the bike would run fine while at speed, but when i would be stopped and at idle, it would tick(tick explained further down)  and eventually die if i didnt stay at the throttle, also a few friends i was riding with informed me that all they could smell was gasoline when they were behind me and informed me i was running too rich, then after about 300 miles the bike finally wont start up

SO i guess what im saying is, i have no clue what to do, and would love to troubleshoot this myself, i would much rather learn to work on this bike myself, i pulled the brand new spark plugs out and they were all gunked up, do i need to re-jet? if so what all does that involve, im going to pull the carbs off today and check them out and try cleaning them via a giant pot of boiling lemon juice

also, ive located the ticking noise to the automatic petcock? i have the same bike and set up as pictured in this video(http://www.youtube.com/watch?v=6mwa1jz04fQ), and this guy is saying i need to cap the petcock and when i did that is when the bike decided it didnt want to run anymore, it started up fine before i did that and when i removed the cap it really wont start.

with re jetting, do i need to re jet everything? or just a certain jet since it is running too rich.
any help is greatly appreciated, as i have no clue what the hell to do

Hey –

You don’t necessarily need to rejet your bike. Is the bike modified in any way? Aftermarket exhaust or intake?

It sounds like you just have some carbs that are still a little gummed up. It can sometimes take a couple cleanings to get all the dirt out of everywhere it shouldn’t be.

‘Ticking’ I would associate with the valve train, but I imagine you are likely referring to more of a ‘hiccup’ type problem caused by the carbs and fuel flow. Definitely pull those carbs and verify they are spotless. Make sure all the passages are clear and the jets are void of any dirt. Then make sure your float needles are in good condition and seating properly.

In the video the guy has replaced his vacuum petcock with a gravity fed petcock. Because of this he has plugged up the port on the carbs used for the vacuum line because he no longer needs it. If your carb still has the standard vacuum fed petcock then you absolutely do not want to plug up that port, otherwise you won’t get any fuel into the carbs. That port should be connected to your petcock by a hose.

I have an 1988 Yamaha Venture XVZ1300. After a short 150 mile road trip I noticed that my head lamp and illuminated gauge display panel lights were not working. My first thought was to check the fuses of which all checked out okay. Next I removed the headlamp and checked the bulb, it tested okay as well.
I used my multimeter to check  voltage from the connector  going to the headlights. The voltage was very low which leads me to believe that I may have a short somewhere. Does anyone have any tips or experienced a similar problem that might help me crack this one? After taking a look at the electrical schematic I am not relishing the idea of tracing down a short.

There are a LOT of wires on that bike, and it does indeed sounds like you have a short or a bad ground.

I always start chasing wiring problems right at the battery.

I once had a hell of a hard time tracking down an electrical issue on a Venture 1300 (a 1983 model). I checked all the wiring over and over and sanded clean all the grounds. The issue ended up being the main battery ground cable itself. The connectors were solid and looked new, but the wire was shot. I eventually cut it open and found the wire to be completely corroded on the inside. Replaced it with new and everything ran perfectly.

I would imagine your issue is closer to the fuse block than the bettery, but you never know until you just tear into it and spend a couple hours scratching your head.

Hello everyone.  This is my first post, I am new to the sight.  I bought a bike a few months back and have done a lot of work to it.  I am turning it into a little cafe racer.  New tires, brake and clutch cables, levers, handlebars, grips, air filters, fuel lines, brake light, petcock, cleaned and rebuilt the carbs, gas cap, cleaned the tank out, and a number of small items here or there.  Wish I could upload a photo but for some reason i am unable to.  this task has had me on the internet a lot since this bike is so old and parts are really hard to find.  What actually brought me to this sight is some electrical problems that I have been having.  charge battery drive for a while and what do you know.  No more battery.  It’s pretty frustrating to say the least.  it’s got to be one of four things.

1.  Bad Stator

2.  Short in the wiring somewhere

3.  Bad Regulator

4.  Bad Rectifier

One of the problems that I am having is finding these parts new.  Ebay is a wonderful way of finding all of these parts but you never know if they are going to work properly.  I would also like to rewire the bike to make it as simple as possible.  I dont care about the turn signals or gauges.  They are just not important to me.  Evan gave a few diagrams for this but I am kind of afraid to start tearing everything apart and screwing the bike up.   Although I would like to have brand new wiring to go with everthing else.  If anyone can give me advice that would be great.  It has been a lot of fun..  Thinking about getting another vintage honda soon.

How’s your CB175 doing? Those are great little bikes – a hoot to ride!

You are right that ebay is going to be one of your best sources for parts. Finding a new wiring harness I fear will be a challenge, but I’m sure there are still a few floating around out there. If you’re worried about your wiring you can always just replace each wire manually yourself. It’s a tiresome job but ensures a quality product.

I would look for shorts and bad grounds first. Always. What sort of voltage readings are you seeing across the battery?