Author Topic: Taking her for a walk...  (Read 12810 times)

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PeggySue

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Taking her for a walk...
« on: July 15, 2012, 09:49:09 PM »
So, after deciding that going to O'Keefe wasn't on her 'to do' list, my little Honda (CM400T) got her a** in gear when we arrived back in Terrace.
Running rough, but running, so I decided that maybe an easy, longish drive in the country might blow off some dust.
Beautiful sunny day to spend pushing the Honda, miles from cel service.
Looking like there was negative pressure keeping gas from filling up the inline filter, for some reason?

Still, kindness of strangers and all that, I got some funny looks from the kids who gave me a lift. Hey, they asked (what I thought was wrong with the bike)!
Was only about 5 km from QBall's place when she pooped out, for the third and final time. She's chewing thru gas like it's free.
Got her on the truck to his place and gassed up, re & re the carbs (again) for a look. Still ran rough... but made it home okay (45 min drive on a good day took me an hour).

Today, cleaned and blew out the inline filter, and petcock with compressed air hoping it was something blocking the valve. Cleaned the air filter too.
A small amount of cr4p, but nothing to account for her current malady.
Took her for a ride, and she sounds better, not losing power and 'surging' like she was, but still needs something...

May have to screw with the carbs some more, I guess.
All new seals in the twins, and everything 'looks' good, moves well, and should be fine.
Bleh.

One more time, from the top,
P.

Rusty Bucket

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Re: Taking her for a walk...
« Reply #1 on: July 16, 2012, 11:13:45 AM »
Since the motor ran - and then stopped - and then ran again, I'd most likely be thinking of things that would prevent fuel from making the short journey under gravity's invitation from the tank to the carbs.  The three suspects here would seem to be vacuum petcock (is there a 'prime' position?), the fuel filter itself (which might want to be replaced for the sake of eliminating a potential culprit) and the tank venting system (which might vacuum lock the fuel in the tank - easily trouble-shot by opening the filler cap and listening for an inlet 'whoosh')  The tank vent fits the symptoms the best, but it tends to be a problem in newer motorcycles, rather than older ones.  When the motor stops, I'd want to see fuel flow from the feed line to the carbs if it was removed, and of course, without the engine running, this is just what wouldn't happen with the vacuum-operated petcock.  An inspection of the vacuum line that operates the petcock would be in order, if the bike is so equipped.  Also, you can operate a vacuum petcock with your own vacuum as a test, either with your mouth or a small vacuum pump.  If the bike quits, and it seems to be a fuel dlivery problem, and the tank isn't vacuum locked, then applying a vacuum to the vacuum tube operating the petcock diaphragm should make the fuel flow.  If NOTHING can make the fuel flow from the tank to the carbs, (and the alternative is being stranded with a non-running engine) I might carry a length of fuel hose and a coupler to bypass the petcocks inlet filter, the petcock, it's vacuum system and all with a straight syphon from the tank to the carbs...  none of this accounts for high fuel usage, though.  That (and the external filter with detritis in it) sounds more like needle/seat problems.  Surging is usually a lean problem (and common in the bikes of the era, though less-so in Honda's than, say, in Suzuki's), and marginal fuel supply would explain that nicely, but if at the same time the bike is giving problems it is also gulping vast mounts of fuel then the supply side - tank, lines, petcock - could hardly be faulted in that case.  The dichotomy between apparently too much fuel and too little will need further investigation.  Interesting presentation of symptoms.  Persevere;  nobody knows the troubles you've seen (as you do)

PeggySue

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Re: Taking her for a walk...
« Reply #2 on: July 16, 2012, 06:16:44 PM »
Yowza,
Thanks for all the great advice/ideas! You've got me thinking...

I'll start at the source, tank: has no venting system, other than what might leak in at the gascap (assuming this is the way she works.
Would my cheap nylon tank-bag mess with the air flow there?), only two holes in the tank, one for the cap, one for the petcock.

The petcock has no prime position, it is a real basic model, on/off/reserve with a short rotating handle, one route in, one route out. Now 'very' clean.

Will pick up a new inline filter tonight...

Which leaves the carbs.
Le sigh.
I can only assume that the bike's tank is smaller than I remember (haven't been out on a really long ride in a couple of years, mostly to work and home since then),
and pull the carbs, blow out all the nooks and crannies and order anything else which looks worn (there was a slightly dodgy-looking diaphram in there)...
It's a simple carb setup, no fancy electronics to give me grief, so I should be able to sort this out. Right?

Right.
Going with the assumption that it's a fuel delivery issue, set up for a richer mix and will worry about the fuel economy once she's running a little smoother.

Fingers crossed, everybody...

Rusty Bucket

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Re: Taking her for a walk...
« Reply #3 on: July 16, 2012, 07:16:52 PM »
The minimum fuss/no money first check would be fuel flow from the tank - and yes, there would be some small chance your tank bag might affect this.  The very simplest tank vent is a hole drilled in the gas cap - have a look and see that there is one in the bottom of the cap;  they are small, but vital.  If the rubber seal on the cap is in good shape, a blocked vent can - after a short time - prevent fuel flowing out of the tank by creating a vacuum lock.  Easy to check:  disconnect the fuel line and the vacuum line (still not sure whether this is a vacuum operated petcock? if so, you'll need to apply a vacuum to the vacuum line to make the fuel flow) and have the tank fill a gascan with a couple litres of fuel which should flow with a good strong unbroken stream - if it does this with the filler cap closed and the tank bag (with whatever you were carrying) on the tank, then the makeup vent in the tank is working fine.  If the fuel falters after a bit  the vent would be the likely problem.  If the fuel refuses to flow from the get-go, then the petcock's screen might be clogged, or the petcock's diaphragm (if vacuum actuated) might be too shaky to allow a good flow of fuel.  So, having passed that test satisfactorily the tank's venting is not the problem, and the petcock is able to do it's job.  Good.
  Next up would be the vacuum line itself (again, if the petcock is vacuum actuated), twist and examine under direct light looking for cracks and dry-rotting.  Look at the fittings it attaches to.  Seems ok?   Apply a vacuum and see the hose is still good - put both ends in your mouth, apply a vacuum, and seal the tube with your tongue - the vacuum should seal it to your tongue for a considerable time.  Having passed that, the vacuum line is ok.   A  really screwed-up vacuum petcock can allow fuel to flow through a damaged diaphragm into the engine - this shouldn't ever happen - but it does.  Check the dipstick and smell the engine oil if a lot of fuel suddenly disappears - it occasionally shows up again in the crankcase.  Much better that it should overflow out of the carb's floatbowls, which is what will happen when needles and seats are less than perfect, and would be the only result with a standard manual petcock which has no other port into the engine. 
  Now you can undertake the poking and probing of the carbs themselves, because the fuel is pretty definitely showing up at their door, and they are mismanaging it somehow.  Remember little pieces of fuel line itself are very commonly found in float needles;  especially common when there have been recent problems and the lines have been removed many times.  Again, I'm just not sure whether the problem is too much fuel, or too little -  if it flows from the tank with good volume, and doesn't end up on the ground or in the crankcase, then the problem might be entirely elsewhere.

PeggySue

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Re: Taking her for a walk...
« Reply #4 on: July 17, 2012, 07:28:28 PM »
Well, had a look at the tank cap, the seal is in good condition, and yes, the vent hole seems clear.
The petcock isn't vacuum operated, just a simple valve. It appears that the carb itself pulls gas thru the (new) inline filter when it first starts up.

So far so good.
Skipped the vacuum hose test, tho the thought of sticking a gas line to my tongue was mighty tempting...

The dipstick was plain old oily, but not nearly as it should be... she's sucking up the oil too, it seems.
So, checking the plugs... fouled on both and wet on one side, but at least clean now. Checked the gaps against the manual.
Ran a little better just after the plugs were cleaned, for what it's worth.
She's due for new rings this winter anyway, so maybe some hotter plugs for the duration of the summer (in Terrace that's about 2 more weeks of dry riding)?

No overflow from the carbs, or staining below them indicating such.

I ordered new diaphragms to stick in the carbs, so will tough it out until they arrive next week, and hope for the best.
Will be sure to use brand new fuel line when putting the carbs back on, too. The old stuff is in pretty good shape, but why chance it for $.50 worth of hose?

Betting on mismanagement of the fuel, and oil at this point.

In for a dime, in for a dollar,
P.

fast1

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Re: Taking her for a walk...
« Reply #5 on: July 26, 2012, 11:33:20 PM »
  Do you still have the stock airbox? Had a customer once put a rag under the seat effectively blocking the intake for the airbox. have also seen mouse nests in the airbox, same problem. You are either getting too much fuel or not enough air. Possible C.D.I. but doubtful. Just cause you put in new needles doesn't mean there sealed. If the diaphragms don't do it stick them in a box and send them to me. Cheers.

fast1

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Re: Taking her for a walk...
« Reply #6 on: July 27, 2012, 11:59:50 PM »
  If the diaphragms are the little ones on the side of the carbs delete the spring when installing the new ones. These are air cut valves designed to reduce popping of the exhaust on deceleration. Simply removing the spring will bypass the system. The diaphragm and square o-ring must be in good condition. While your exhaust may pop mileage and throttle response should improve. This was a Honda only thing and only lasted a few years but many were cursed with these evil devices. Anyone owning a late 70s to mid 80s bike should can these. Cheers.

PeggySue

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Re: Taking her for a walk...
« Reply #7 on: August 07, 2012, 12:54:55 AM »
On and on.... the saga continues!

The airbox is stock, and I've given the filter a good cleaning with compressed air (as per the manual). There's really not much to it, I can see why some are stripped out.

Got the diaphragms in today, and it started up beautifully, idled nice.... didn't seem to have any effect when I put the choke on (out of habit, more than anything), but it got my hopes up.
And then... nothing. Turning the throttle seemed to have NO effect.

Checked the linkage, and it was fine, but still not enough gas in, and it seemed to use up it's supply, as it stalled and then took quite a while starting again? Finally got it going, but the fuel still seemed to be getting lost this side of the cylinders. No overflow out of the carbs. But still 'surging' when she decides to go, which from first gear was a struggle... tho in second/third, seemed to improve. My in-line fuel filter (which is now sitting horizontally due to some creative shoe-horning with the new fuel hose) seemed to have air bubbles in it, so I cut the hose a little shorter trying to at least have it sit diagonally... Meh? Dunno, it was worth a try.
Another turn around the block, and I had to come home, and walk away for a bit.
Maybe once I've it's cooled down...

I'll pull out the springs and chuck them the 'next time I pull the carbs', which should be soon, no doubt. At least it wasn't a waste putting in the new parts, as I could see light thru the old diaphragms! Maybe put my old mufflers back on, in case it's something to do with back-pressure....?

Well, I can't make it any worse....

P.

MaximX

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Re: Taking her for a walk...
« Reply #8 on: August 07, 2012, 04:28:26 PM »
Wouldn't hurt to have someone else look at it perhaps, has anyone from the club done that?  I am no expert but from experience know it is good for me when I am at the end of myself to have someone else to bounce things off and actually look at it.  No fun to have a bike that is not responding to some TLC.  It also is hard to imagine where all that gas is going....is your crank case filling up with it?  I am sure you would notice that.
My bike runs fine even with the mufflers off, different mufflers (than stock) should not have an extreme effect on a motor that is not a 2 stroke.  Sorry to hear of such frustration in having a persnickity bike.....The basics are: Compression, Ignition, and fuel...sounds so simple hey?  But somewhere things go wrong.  Then it teases with a bit of running, gotta be carbs one would think, and where is all that fuel going?  Scratches head.....I will look at it if you like, got the time to do it....Mike  562-4174

PeggySue

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Re: Taking her for a walk...
« Reply #9 on: August 10, 2012, 11:19:01 PM »
Thanks for the offer Mike, appreciate the moral support.
It gets a little tough pulling wrenches out in the sticks, when it seems like every part you need takes at least a week to get here.
And then may not even do the trick...
Anyway, had her out (on the truck) to QBall's place yesterday, as his dad (who's a clever sort of fellow) is visiting, and didn't mind a puzzle to ponder.
We pulled the carbs, again (getting REALLY good at that), checked and balanced them once they were back on.
Then checked the plugs once it had been running a bit.... one side cold, one side hot.
Pulled the coil and put the tester on it, even tho we had seen sparks from both plugs when we pulled and checked them, earlier.

Then came the 'ah-HA' moment.
It's partially pooched.
The general consensus being that a new one would help keep my plug from drowning in gas, misfiring, smoking, and generally running very poorly.
Luckily I was able to find an aftermarket with the right specs for a good price, so now I get to hurry up and wait.
With any luck this will sort her out, and we'll get in a bit of riding before the weather turns.

Keep your fingers crossed!

Hope to see you all in September,
Peg

Fritz

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Re: Taking her for a walk...
« Reply #10 on: August 11, 2012, 12:45:05 AM »
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Kaw-meister

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Re: Taking her for a walk...
« Reply #11 on: August 12, 2012, 12:21:01 AM »
if all things look great with the fueling system, and it does not want to flow. some petcocks can be assembled with the internals backwards? I am not familiar with the honda system, just a thought.  ::)

PeggySue

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Re: Taking her for a walk...
« Reply #12 on: August 12, 2012, 06:56:45 PM »
Thanks Fritz, hopefully that's what I'm missing... a little luck!

Kaw, the petcock is so incredibly simple that when I pulled it to check if it had a dirty filter, I had a "that's it??" moment... it's basically a short tube out of an 'on-off-reserve' valve, with the reserve setting allowing gas to enter the petcock thru a hole in the body, at the base of the tube. Nothing fancy to go wrong there, but now it's even cleaner! Thanks for the suggestion tho, it's good to have suggestions to work with...

Waiting impatiently,
Peg

PeggySue

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Re: Taking her for a walk...
« Reply #13 on: September 20, 2012, 06:52:44 PM »
Keep calm & carry on, right?

Well, after a month and a half of waiting for postal deliveries on two separate coils, we have a winner.

(Note to self, 'Universal' fit doesn't always mean that it fits your bike...)

Had to fabricate a little bracket to mount it up, and sort out some wire connectors, but it's in.
Rode home from QBall's place on Tuesday, and at top speed she hardly complained at all. Some low end surging and still some fuel supply problems, I think, but running.

However, stopping for gas just on the far side of town was a MISTAKE. Wouldn't start after the fill up.
Had to call her a ride, and get a buddy to truck her home.

LUCKILY, the breakdown was right next to a (closed) bike shop, and I was able to use their ramp to load up!
(small miracles... I'll take em where I can get em)

So, today, back to the drawing board.

Looking again at the carbs, and may pull them one more time and take them in for ultrasonic cleaning. Besides, I'm GOOD at pulling the carbs! The inline filter was a little dirty, but nothing that should be a problem. Replace filter, too. Check.
Will have to pull the plugs and have a looksee at their condition too, checking if the new coil actually made a difference. When we tested the old one, the numbers were a little weak, so... new coil.

Fella at one of the bike shops (not the Honda shop, which incidentally won't touch my bike because it's "too old"... I was tempted to ask the guy how old his wife was. Grr.) said it really sounds like a primary jet problem, and that even a very small amount of varnish will mess with it, even if the jet looks clear. True, and worth another look, I guess.
He seemed to think the petcock and inline filter looked okay, but still offered to order me a new one if I wanted to drop another $100. Thanks, but no thanks.

On the bright side, all that nice weather spent waiting for the coil/s had me painting my freshly-sandblasted Enfield frame and bits... 8 coats later, she's got a really nice satin finish in black, and is at that point where you start putting things back together! Oh, the joy... it's almost as good as being able to go riding. I'll take it.

Peg




MaximX

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Re: Taking her for a walk...
« Reply #14 on: September 20, 2012, 08:21:19 PM »
With the great weather I was hoping for a triumphant ride story from you.  Would not start...should to be a no gas problem (but as any of us who have been around for a while knows, sometimes it is not all that simple) for some reason, I also suspect possible petcock problems if it is vaccume operated...it was running well, then no giddyup.  Man that would drive me around the bend.
Others have been helping you and I have not even seen the bike, so perhaps comments from me are not all that insiteful or helpful.  What I will say is I find your reports witty and interesting to read.  Got to hand it to you for all the effort you are putting into that bike and may it finally reward you.

Mike