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Runs (almost) fine in neutral, no power in gear

Started by karmisol, April 12, 2022, 12:11:42 AM

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karmisol

Hey all! & thanks for a great forum!

Last year I got it running to the point that it passed the government inspection and became classed as a veteran bike (i.e no government inspections required anymore).
Part of the inspection is that the inspector rides the machine in order to verify that the brakes work. I.e it ran fine

Two weeks ago was my first test of the season. I don't have  a drivers license for it so I spent the ride on a parking lot training slow driving in first gear (part of the drivers-license test here).
Here I had only one issue with the machine once it got hot, every now and then when I held the clutch the engine started racing up to 4k but would come down to normal 1.5-2k as soon as I released the clutch.

Yesterday I tried the bike again, and it had almost no power at all. I couldn't get away from our 30 degree uphill parking lot without the engine dying - even when trying to keep the engine on a high RPM while releasing the clutch. It got slightly more power when playing with the choker but only enough to get a 1-2 meters up the parking-lot hill.

What I have done:
I replaced the fuel from last year and I checked the air filter which looks to be brand new (hadn't checked it since buying the bike last year). When checking the air filter I also looked down into the carburetor and it looked clean (but I have no idea if that says anything about anything)

As you might have figured out - this is my first bike and also my first project involving an engine of any kind.

fret not

Welcome to the world of motors and mechanical things.  I think one must have the desire to ride in order to overcome the obstacles of "making it work".  I am not a mechanic but I have had some sort of 'motor thing' since I was a teenager, so I have some mechanical experience.  The desire to ride helps overcome some of the obstacles one finds.  Basically, if you want to ride you have to 'fix' the bike.  This is not rocket science but may as well be for some.  It helps to have some aptitude for mechanical things, and this can be learned.  You will find most of the information you need in the discussions on this site, so I suggest you become familiar with the site and the typical issues of this model of Yamaha.  There are plenty of discussion threads regarding the carburetor and the importance of keeping it clean (internally).  The XZ550 has some quirks, but mostly it is a very nice motorcycle.  If you are going to ride and enjoy this bike you are going to get an education because it will require your attention and effort.   
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

fret not

This is where we begin asking questions: Does the motor run smoothly?, Does it rev up?  Are the wheels free to turn? (wheel bearings, dragging brakes, etc.)
Is the ignition timing correct?  Valve clearances? 

Have you checked or changed the motor oil?  Is the cooling system filled?

Start filling in the blanks and we will go from there.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

karmisol

Thanks for your engaging message! I do look forward to learning all of this.

Does the motor run smoothly?
-Yes, to me it sounds like it runs fine, however I think I heard it backfire once while starting up

Does it rev up?
- Adding gas I have no problem going up to 6K RPM. Didnt try higher. Seems responsive and happy

Are the wheels free to turn?
- Yes, I can roll it myself when it is in neutral or the clutch is held

State of motor oil?
- Changed last year september. Not used a lot since then

State of cooling system?
Changed last year september. Not used a lot since then.
(This I will change as I have a bunch)

Is the ignition timing correct? Valve Clearance?
No idea, I will research these topics!

Thanks for your pointers. I'll come back once I have looked at the ignition timing and valve clearances.

jefferson

Your running problems sound carb induced and this bike is know for this. It also might have a vacuum leak that caused it to rev up on it's own, or did you have the wheel turned sharply as the throttle cable can be routed wrong and cause an increase in rpm when you turn the handlebars.

First thing is to replace the gas which you mentioned and I would look for some no ethanol fuel and only run that if you can. The second thing I would do is run a tank mixed with Chevron techron fuel system cleaner. It will clean up any fuel residue that may be causing issues, but won't touch dirt. Since you lost power from one day to the next it points towards some dirt getting lodged in a jet which means a teardown and cleaning.
Good luck with your project and learning.

fret not

As mentioned, check the routing of both clutch and throttle cables to make sure they are not interfering with anything, and functioning correctly.  If the cables are not a problem then next to check is for air leaks: cracked carb boot, gasket, throttle shaft seals, diaphragm in the fuel pump, .  .  .  .   :police:

Issues like this are not uncommon, especially for bikes that have had hit and miss upkeep by untrained hands.  This is a learning process.  My lazy approach has been to check the easy things first, then the most probable ones.  This is not rocket science, but it can be complicated.  As previously mentioned, the carburetors may need to be thoroughly cleaned.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

karmisol

A small update for you people!

I am amazing at dropping my bike...

I have now cleaned the carbs (which looked nice, nothing obviously wrong there). However after starting it had power enough for me to get confused and drop it....
After dropping it didn't start for the rest of the day.

Yesterday (week after) it started nicely but as I hurriedly tried to move it outside I dropped it again after which it didn't start for the rest of the day.
Looked at the spark plugs & verified that they still get power and changed the oil.

The bike is still a bit hard to start (even when it starts) so I think my next checkup is valve adjustment - but for that I need some tools so next update will be in a while.

Btw. I have not checked the throttle cable but I am quite sure it is incorrectly routed as I have noticed exactly that issue.

fret not

One very important point is that the battery must be well charged if you want the ignition system to work.  Hopefully you have a VOM (volt ohm meter) to check the battery and the charging system.  Also, tell us that you do have a repair manual (indispensable).  Check the links on Prophet Of Doom's postings, as he has made available various manuals etc. to download.  One step at a time, usually.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

SonnyT

Probably most important is a FULLY charged battery and the Chevron or Berrymans B12, much stronger than instructions on can.

karmisol

#9
Thanks! I have not checked the battery voltage but I have been trying to start until the battery runs out so...

Is there any way to make the machine less battery reliant (upgrade some power-hungry part, add a boost converter?) or should I just buy a stronger battery?'

ps. I did not understand the 'Chevron or Berrymans B12', maybe something well known in US?

Walt_M.

The TCI needs 10.6 volts to fire the spark plugs while the starter will spin the engine well below 10 volts. Keeping the battery on a trickle charger is probably the simplest solution. I have considered a couple of other things, one would be a different ignition such as an Ignitech. I haven't tried one and haven't contacted them as to the firing voltage of their unit. The other would be to run 2 batteries with an isolator, one for ignition and the other for the starter.
Whale oil beef hooked!

jefferson

The condition of the starter has alot to do with how much it drags down the voltage when energized. The seal in the nose of the starter leaks oil into the case and gums things up. If you haven't had the starter apart and cleaned things up along with replacing the seal it would be worth your while. The commutator and brushes need a nice shiny surface to work well.

SonnyT

Chevron Techron and Berrymans B12 are fuel injector/carb cleaners.

karmisol

Hello again! I found one probable reason why it is not starting anymore.

In the attachment is a picture of the wire coming from the gas handle. When it is not being held - it is still on and does not touch the "idle adjustment screw".

I'm not sure how this happened as it has been touching before. Maybe it is after my carb-cleaning.
What confuses me is that I can't figure what the reason could be for the wire to be too tight now.

jefferson

Do the throttle shafts move freely and completely with the cable taken off? You need to find out if it is a carb problem or throttle cable problem.

briandneville

is the cable hung up or not seated properly at the throttle (grip) end?  Sounds like something has 'shortened' the cable length.

How did it come to this?

karmisol

Hello all! Thanks for all your help and suggestions, they help me a lot and without you people I wouldn't have had any chance at getting this far!

Again work has been done and things are looking up. Continuing here so people can get a feel for my level of experience  ::)

To review:
  Started with working machine without power, changed oil and cleaned carbs
  - Resulted in badly connected gas wire
  Adjusted some gas wire screw at handle and fixed incorrectly connected wire to carb
  - Resulted in working machine, I let the machine run hot and then adjusted the idle-adjustment screw to so that it idles around 1700rpm

Today I started it, and it works fine but revs up to 4000rpm. I can make it behave a bit with the choker (video (warning high volume): https://imgur.com/a/pKAubRB )

Questions:
- Could revving up to 4000rpm be a timing issue?
- Does it look like my choker is too sensitive?
- Any suggestions on steps should I take to get a nice, consistent idle speed?

jefferson

With the choke on it is going to rev high. Try to modulate the choke to get an idle around 2000 rpm to warm up some. As the engine warms up the revs will start to come down so it is something you need to be adjusting on until fully warmed up. I usually don't spend much time warming up and take off and shut the choke off once moving.

briandneville

Moving the choke lever away from the forks enriches the fuel mix, which will not allow you to properly adjust anything else.  Use the idle adjust to keep it from dying once warmed up, not the choke.

In your video the engine appears to be fully warmed up, so you should not be using the choke at all (pushed all the way towards the forks, where the engine dies in your video).  Keeping it from dying at idle requires proper adjustment of the idle mix screws and the idle control.  Increase the idle using the idle control to the point where the engine won't stall, then adjust the idle mix screws (one at a time, turn counterclockwise until the rpms stop going up, then close 1/8 turn), then reduce the idle using the adjust control to about 1300, re-adjust the mix screws, then the idle speed...You want to get to the point where it is idling at 1300 or less when fully warmed up.

Your other issue may be a need to synch the carbs, which adjusts the butterfly valve in the front carb to match the vacuum level (suction) with the rear.  You can search this topic on this forum to find out how to do this using a simple home made device (or you can purchase a set of gauges to do this).  The adjustment is done using the threaded rod that joins the front and rear carb butterfly valves (this is what the throttle cable is attached to).

How did it come to this?

karmisol

Hey! Sorry for the late replies here, had to put the vision on hold for a while.

Updates: I bought new intake manifolds and it seems to have fixed the issue. I can't promise it is fixed as my alternator broke while in the garage - but at least I can start it and it runs fine until the battery runs out.

A new stator is being installed this weekend, I may add an extra coat of epoxy to the windings as it seems quite "bare" - hope it fits too (Arrowhead AYA4000)