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Discussion Starter #1
So I asked this in my thread about the project bike I currently have but I figured this would be the better audience as I'm trying to get some words of wisdom or advice.

Basically my wife got me a 1981 CM400T last November, because a friend was looking to sell it and she thought it would be a good project bike for me to work on before I took the BRC and started riding. For the past bunch of months (9 I think) I've been tinkering with it and buying things for it, trying to get it in riding condition. Unfortunately for me it's always had problems starting, it would crank and crank and crank and eventually catch. I'd let it run for awhile while I worked on other things (to let the fuel run through and the carb cleaner do its magic).

So I took the BRC last weekend, and had an absolute blast. It was a huge amount of fun and I learned more than I ever thought I would. I was really excited to get out on my bike, so I came home and started working on it a bit more: basically I wanted to do some tuning to it before I tried to ride it in a parking lot (make sure brakes work, etc.).

When I got on and tried to start it up in neutral... it would crank and crank and crank without anything happening. Kind of disappointing. Also, the front disc brake has seized up.

My question now is: I'm wondering if I should keep working on this bike and make it my primary or should I keep it (it's really costing me nothing to have it sit in my driveway) as a project bike and start shopping for something with a few less miles that will be more reliable. I don't have a huge amount of time to spend with the bike (basically all I've got are weekends) and I would rather spend the time doing smaller amounts of tuning and maintenance (and riding!) than, say, rebuilding the carburetors.
 

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ZAMM Fanatic
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Befriend a motorcycle mechanic. Take beer to the local MC dealershop at quitting time (or donuts at 9 am) and ask if you can ask a few questions.

Crank, crank, crank is fixable. It's either a fuel problem or an ignition problem. Figuring out which is easy.

Hit it with some starting fluid. If it imeediately starts up you know youv'e got a lack of fuel problem. Otherwise it's ignition, compression, something else.

Fuel problem could be a drippy fuel bowl so it's empty when you go to crank, choke not working, etc.

Ignition, you simply stick a screwdriver in the spark plug boot and look for spark as you crank. If you've got spark, it ain't an igntion problem --- although it COULD be too advanced timing.

Completely worn out rings, well, is your bike smoking blue? I've seen an engine that didn't have enough compression to start --- unless you pulled the plug and gave it a squirt o f oil to seal the rings. No compression, fuel pump doesn't work cause hyouv'e got no vacuum, etc.

Whether you sell it or keep it fixing these problems is worthwhile, either $$ wise if you go to sell it, or losing the aggravation if hyou keep it. And they shouldn't be major.

Having been both a small engine (lawnmower) mechanic and & auto mechanic I could diagnose most no-starts or hard-start in under 2 minutes. But motorcycles.....slightly different. I claim no e xpertise other than "air, fuel, correctly timed spark, compression" HOpe this advice gets you one step closer.

ps you'll always regret and miss a bike that you enjoyed that you SOLD simply because of some aggravating problems. My Ninja ate alternator belts. Gawd I miss her. Pieceof @#$ bike that was incredibly fun to ride --- when she wasn't stranding me.
 

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Discussion Starter #4
REALLY good advice there, I'm definitely going to spend some more time troubleshooting the thing tonight. I knew the screwdriver trick (and a couple months ago when I was troubleshooting these problems I tried that, the sparks looked good). I'll swing by an Autozone on the way home and pick up some starter fluid, but here's a question: Where exactly should I put it? Gas tank?

I'll also be picking up some more gas, so that if the gas tank is just low I can refill it (and put more carb cleaner in).

One thing to note is that I really haven't gotten too attached to the bike yet, I've only sat on it while it was running and dreamed. Still, I'd hate to have put all this time and money into it if I could easily fix the current problem and be riding soon.
 

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I had the same problem you do. I brought a 96 Savage and had alot of issues with it. I'm actually still waiting to pick up the carb at shop tomorrow. Spent more time "looking" at the bike rather than riding it. So,,,I went out and brought a new bike. Now I'm riding the new bike, and when I get the old one fixed I'll give it to hubby.
 

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Into the throat of the carburetor.

but here's a question: Where exactly should I put it? Gas tank?
An internal combustion engine (ICE) doesn't actually burn liquid fuel and air. What it burns is fuel VAPOR mixed with air at a 1:12 ratio, or thereabouts. Fuel droplets are atomized by the carbureator and evaporate because of heat in the intake manifold, etc.

The result is a highly flammable fuel/air vapor.

Straight gasolilne, if you put enough in to get the plug wet, will actgually PREVENT a spark from igniting the mix. That's called " flooding" an engine. If your carb sits there and fills the intake with gas, by dripping, it can make it as hard to start as no gas at all.

Pull the plug, if it's wet, you've got a fuel leak into the engine. Often the oil level will go up as gas runs past the rings and into the crankcase, mixing with the oil and making it very, very thin, and useless for lubrication.

Starting fluid is Ether, or something similar, except it evaporates even faster than gasoline, and especially, at much lower temperatures. So you take your air filter off and spray it into the throat of the carburetor, or have a friend do so while you're cranking the engine.

I normally give a 2 second blast BEFORE cranking to "wet" the intake manifold so there's lots of ether when that piston takes it's first big suck of ...well, not air, but "charge."

After that you can usually give a two second blast every five seconds and keep an engine running even if it's getting no gasoline at all.

Careful with this stuff, VERY flammable, and don't leave a can in a hot car on a summer day.

I'm a nervous nelly but I ALWAYS keep a fire estinguisher nearby when working on fuel lines, playing with gas, ether, etc.

The problem May be complex to fix, like a carburetor rebuild, but DIAGNOSING the cause of a no-start isn't all that hard.
 

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I think that ultimately, the decision to keep or sell the 400 should be made after you've gotten it sorted out and actually had a chance to ride it. Otherwise, you won't know how it feels, and if you get another bike, it's unlikely you'll be motivated to fix the 400.
I know where there's an '80 400T that I can get for a sing, but there's no title. I'm still pondering getting it, so I'll have a backup for when I have to take my 450 off the road.

The 400 uses a lot of the same components.
The leak that was mentioned would show up as fuel dripping out of the small hose that's attached at the bottom of each carb. You may have bad gas in the tank, which is very common with the ethanol that they put into today's fuel.

I would remove the rubber boots from the carbs (towards the rear) and check the choke operation, as well as seeing that the slides are moving easily. If the chokes are functioning, but the slides are sticky, you can remove the upper covers from the carbs and remove the slides and clean everything.
The slides themselves, or the bores they ride in could be corroded or gummed up. The needles they operate could be bent or otherwise sticking in the jets.

By all means, buy a workshop manual and read through the various sections on dealing with the carbs.

Any idea how old the fuel is?

Oh, I wouldn't buy a can of starting fluid, as it only serves a single purpose. Get a can of spray carb/choke cleaner- 2+2 or Wal-Mart's Super Tech brand, which is just as good, but cheaper. That way, you'll have something that's also useful for cleaning parts. You can spray that directly into the carb opening with the boots off and work the slides up and down with your finger. They should slide up and drop back down by their own weight.
 

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Discussion Starter #8 (Edited)
I think that ultimately, the decision to keep or sell the 400 should be made after you've gotten it sorted out and actually had a chance to ride it. Otherwise, you won't know how it feels, and if you get another bike, it's unlikely you'll be motivated to fix the 400.
I know where there's an '80 400T that I can get for a sing, but there's no title. I'm still pondering getting it, so I'll have a backup for when I have to take my 450 off the road.

The 400 uses a lot of the same components.
The leak that was mentioned would show up as fuel dripping out of the small hose that's attached at the bottom of each carb. You may have bad gas in the tank, which is very common with the ethanol that they put into today's fuel.

I would remove the rubber boots from the carbs (towards the rear) and check the choke operation, as well as seeing that the slides are moving easily. If the chokes are functioning, but the slides are sticky, you can remove the upper covers from the carbs and remove the slides and clean everything.
The slides themselves, or the bores they ride in could be corroded or gummed up. The needles they operate could be bent or otherwise sticking in the jets.

By all means, buy a workshop manual and read through the various sections on dealing with the carbs.

Any idea how old the fuel is?

Oh, I wouldn't buy a can of starting fluid, as it only serves a single purpose. Get a can of spray carb/choke cleaner- 2+2 or Wal-Mart's Super Tech brand, which is just as good, but cheaper. That way, you'll have something that's also useful for cleaning parts. You can spray that directly into the carb opening with the boots off and work the slides up and down with your finger. They should slide up and drop back down by their own weight.
I've actually had the bike running before (as I said I had it for around 8 months, doing various maintenance tasks). It's been about 2 weeks since it was last cranked and allowed to run for any amount of time, and then it ran for about 20 minutes without any problem, just idling while I did other things.

I'm actually messing with it right now, trying to get it to turn over. I've done a bit more troubleshooting: I can get a spark to jump from the cables to the engine block if I use a screwdriver (and it sounds like it's trying to start then). If I keep at it, it will backfire but not start. So that sounds like it's actually getting fuel into the carb and vaporizing it alright, just not igniting it and it goes through to the muffler. I think. I could be completely wrong.

I pulled the spark plugs, and the end was black. Not wet, just black. So if I'm understanding the mechanism right, it sounds like I'm running too rich. I'm going to try cleaning off the spark plug tips and I'll try again.

The gas is actually pretty recent vintage, maybe a month old.
 

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Discussion Starter #9
AH HA! Sorry for the double post, but I'm excited. After taking it step by step and cleaning up the spark plugs it works. Now at least I can ride it before I make the ultimate decision... even if it does strand me.
 

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Could need fresh gas, the petcock could either be shut, plugged, or the fuel level is too low. The points could be shot or out of adjustment. The spark plugs could be bad, check for spark with them plugged in and touching them to the engine block. The choke could be stuck shut or the air cleaners could be plugged up.Thirty plus years can really turn little bad things into large bad things.
 

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Discussion Starter #11
So I did a few test rides on it and it died each time, and I fixed a few more small things I could find... but I think it's about time I threw in the towel. I really hate doing it, but I want to actually ride rather than talk about riding and wrenching on this bike. I've spent a lot of hours on it, and I foresee a lot more hours.

I'll probably keep it around, as it costs me a pittance to keep it around and I could continue to work on it as I get time.

On the plus side, this does mean that I get to shop for something else that I can actually ride.
 

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So you're wondering if you should buy a bike to ride while still keeping the old clunker to work on for fun?

Dude, that's not even a question.

:biggrin:
 

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I want another project bike. But I gotta fix my Ninja first, or get it fixed. There is a 78 KZ1000 P I know of that has been bobbed and lowered that I wanna pick up. Last time I talked to the guy he wanted around $500 for it. Don't know the last time it ran and the wiring looks like a 4 year old did it. So I am not sure on it.
 
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