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-   -   1VJ persistent stalling problem (https://www.horizonsunlimited.com/hubb/yamaha-tech/1vj-persistent-stalling-problem-6169)

lee5500 30 May 2004 18:27

1VJ persistent stalling problem
 
From help received on a previous post I have established the following...

The bike stalls when decelerated. If I stand to the side of the bike, push it forward just a foot and pull on the handlebars to jolt it to a stop it will stall every time. It is not related to the brake light and when in gear the engine can be kept running with lots of tweeks on the throttle.

HELP!

lee5500 30 May 2004 19:21

This bike is starting to get me all emotional.

I've just been around it waggling wires and suddenly it wont even tick over but still starts and runs with a bit of throttle. I suspect that it is an electrical problem and may be a wire shorting out somewhere, but if so how come it will still start and run with some throttle?

Matt595 3 Jun 2004 07:35

hi,

Do the valve play (cold engine)

Clean carbs and blow with air in deceleration membrane part and all others, check fuel intake valve in carb, it might be the cause as unleaded fuel may destroy the rubber on it.
Buy new one.

Spark plug change

Check spark coil

Check fuel level in carb 25-27mm if you hold it up down.

Check ignition sensor on left part engine side it may be broken and it wont work properly when engine gets warm.

Take compression of the engine, if needed.

Bye

Teneres dont often have serious problems, Im sure its a little one.

Matt

Matt595 11 Jul 2004 08:41

When thinking further,

I think you might have dirt in your fuel pump, clean it if you can.

Clean carb.

Clean also air filter

And oil the starter in carb and its cable.

Cheers,

Matt
3AJ

FredXTZ 11 Jul 2004 15:58

Have you tried to adjust the idle mixture screw [read : turn out a bit]?
FYI the French word 'starter' means choke.

------------------
Fred, XTZ660, Holland.

Matt595 12 Jul 2004 00:06

OOps,

Yeah it means choke...I didn't speak of starter! sorry and thanks Fred !
Me I think you have a fuel problem, either lot of rust from tank in fuel pump or to much deposits of something in carb that will make the floater "glue" itself in upper position and cut off intake.
Have you changed from leaded to unleaded fuel recently?

Matt



[This message has been edited by Matt595 (edited 11 July 2004).]

lee5500 27 Jul 2004 15:19

Thanks for all the advice. So far I have replaced the carb inlet rubbers, changed the spark plug and checked the compression (110 which was low as expected) as well as the usual obvious stuff (idle screws etc) and had the carb serviced. Still no joy. I'm loathed to get a re-bore done which will cost a load when no-one (including motobike mechanics) can tell me what the problem may be. I'll try some more of the suggestions above in the mean time and any further advice is much appreciated.

Matt595 27 Jul 2004 23:01

Hi again,

You must have a strange problem,
I still think its a fuel problem /
Or a combination of small problems.

For example the engine could be to rich on fuel at low throttle due to the "switch"/"switch chamber"(im not sure this is the name in english to say it) in bad condition in carb as these go up and down each throttle turn, then will enlarge and let to much fuel go into cylinder; check appearence.
Or/
You have dirt in the small interiour idle passage of carb; take carb off, disassemble, and blow with compressed air.
Or/
Dirt in the little breather pipe to fuel pump, it will only work with much vacum; take off and blow with air in the pipe.
Or/
Why not dirt in fuel swithes at fuel tank, then fuel will only arrive when engine runs fast, I doubt; screw off clean and oil.
Or/
Rust from tank in fuel pump membrane, I had that on mine; open pump clean with fuel.

In my mind it must be either carb or pump.
Though it could be compression of cylinder, if low it could be thhe cylinder that need a rebore or just valves who needs tto be remade; less expensive.
If you want to have an idea if the valves have the right play, take a big screwdriver with plastic hold part, run engine, put screwdriver in contact near the rocker arm, put your ear to the plastic part of screw driver, do this for all the four axles, especially exhaust ones, if you don't hear a click click click sound, your valves don't have enough play and they will leak compression out and burn.
Combined with a bad carb setting or dirty air filter and all the above..it could do the problem.
My cylinder at 70 000 didn't even need rebore.

Or electric..
one + cable somewhere is torn by vibratiion/heat and makes contact to the chassi, will create parasites to ignition and it won't work normally on low charge, maybe.

CDI box.. I don't think so...but to be sure you could ask someone to try with theirs and see if it do the same.

Just some cable not giving enough contact due to oxidation; clean all with contact cleaner.

Short cut the security switch on side stand; put together the cables.

Good luck,
Let me know if you find it, would be knowledgeble,

Matt




lee5500 29 Jul 2004 00:38

Thanks for the help. The fuel pump will get priority attention as it has been accross west africa and had some dodgy fuel in it as well as the tank being very old.
To clarify - it the bike is stationary and ticking over it just requires a sharp jolt of the bike in any direction to stall it (not an instant cut out but quick loss of revs).

Melancholy67 6 Aug 2004 22:40

I had all sorts of fun with my XT which had also been down through Africa. My problem manifested itself as an intermittent cut out when the vibrations from the engine changed either decelerating or with strong acceleration. It turned out I had an intermittent connection on 2 of the wires going into the CDI connector block. These were fractured inside the sheathing and took me 2 solid days to track down. In the end I found them by luck.

But it sounds like more of a fuel problem if you dont have a sudden cut out but a slow run down of revs.

Either that or a bad short which is only activated by jolt and bleeds too much current from the ignition system to maintain a reliable spark. I once had this with an old Triumph Herald.

Having said that I am not a vastly experienced mechanic and the other suggestions seem more plausible

Good luck

George


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