2010 Yamaha Fino problems - techie help please?

[cliveshep]

I have a Yamaha Fino, older type with the tear-drop speedo and fuel gauge. I've had it just over 15 months now, and done 15,000 km on it bringing it's life total to 30,000km.

It runs like a dream, we have it serviced regularly, and have changed out brakes, tyres, air filter, had the carb cleaned, changed belt and clutches and generally try and keep it in tip-top condition. In return the bitch has been getting increasingly hard to start, and now won't start at all on manual choke. It now needs full throttle, no choke, a battery booster connected (I've got a mains booster/charger for starting cars with flat batteries) and sit and hold the starter button for maybe 2 or 3 minutes before it starts to fire. Even then I have to keep the starter going until after maybe a further 10 seconds the revs pick up enough to let it run.

 

I figure if I can't get this problem sorted pdq I'll fry the starter coils at the very least. 

 

Perversely, once it does start, it ticks over perfectly, runs smoothly, and is as nippy as ever.  Not THAT nippy of course as it is only 115cc but pretty good.

 

I personally took the carburettor off today and stripped it as it would not slow down, running fast enough to "creep", this was after the shop did a service and took the carb off at my insistence and stripped and cleaned it. This was to clear a flat spot fault that had developed from a standing start pull away.After that oil-change and carb clean service it began to refuse to start. The shop man is good for punctures, building wheels and servicing, carbs are just about in his capabilities, but he freely admits that anything else is beyond him He probably realises I know more than he does on the techie side and "that ain't an awful lot"!

 

What I found was (a) the shop don't know what they are doing, when I asked if it had a fuel pump they said "no, gravity fed" but taking it all apart myself it does have a vacuum operated fuel pump connected to the inlet manifold and (b) the plastic nut retaining the "dash-pot" needle fell out in may hand, the needle was free to operate independently of the slide. Guess he didn't screw it back properly. I call it a "dash-pot" as it is similar in principle to the old Stromberg or SU carburettors on old English cars like Austin and Wolesley and MG and Triumph (showing my age here) except that this one has a soft diaphragm instead of the "bell and oil damper" on top like SU's.

 

It has a manual choke, and there is what looks like a solenoid valve on one side that I assume is to shut-off fuel flow to prevent "dieseling on" as we used to call it when the ignition was turned off but perhaps someone can confirm that point?

 

It still won't bloody start easily, but when using full throttle it does eventually deign to start and it then it now ticks over smoothly with no choke and runs perfectly.

 

I'm minded to fit a fuel pump kit, or complete pump, IF I can find someone who sells Yamaha parts near me, on the basis that it has now done 30000km over 7 years and the diaphragm is probably knackered anyway or about to be. 

 

But apart from that I am stumped. It has a perfect spark, nice and viciously blue and crackly, just as a spark should be, new spark plug so I can discount electrics I think, the carb has been cleaned to within an inch of it's life twice now, and all the little piercings and jets are clear. The only thing I did not remove was the little electric solenoid thingummyjig on the side.

 

So please oh Enlightened Ones, give of your measured advice here. What can be stopping it starting until a good 90 seconds plus of cranking have elapsed, and given I am in Khlong Sam Wa midway between Minburi and Lamlukka and not that far from Rangsit where can I source Yamaha bits? The main Dealer reputed to be in Minburi Market has vanished, no one knows to where, and even the motorcycle taxi drivers have no idea where to buy Yamaha bike bits.

 

Thanks in anticipation and Happy New Year to all of you - and to me if I can get this bugger sorted!

[ktm jeff]

It does indeed sound like a fuel issue. Can you " introduce " a second fuel supply while cranking the engine over.  Some easystart or petrol in a spray bottle into the airbox would bypass the carb. If it starts its a fuel problem. Maybe the diaphram you mentioned, or the fuel tap, vaccum pump. 

[papa al]

"once it does start, it ticks over perfectly, runs smoothly, and is as nippy as ever."

It is a starting problem, not a running prob.

so fuel supply fault seems unlikely.

How much costs a new carb.?

Not much.

[cliveshep]

I'm pretty sure it is a fuel problem, it has a spark all the time, problem is there is nothing for the spark to ignite. Proven as once it goes no problem.

 

My feeling is at slow starting revs it isn't pumping fuel in, but once the fuel starts to go in and the thing starts hit 'n'miss firing revs increase along with manifold vacuum driving the pump and more fuel is pumped allowing it to run.

 

The more I dwell on it the more likely that seems to be the case.

[cliveshep]

"The more I dwell on it the more likely that seems to be the case" or not. Took the outlet side pipe off the pump this morning - petrol flows straight through and as it is above the carburettor it would reach the float chamber no problem. I know the float and needle valve work properly, so what is left?

 

Only that electrical gizmo on the side and I don't know what that does.

 

Any ideas anyone?

 

[papa al]

11 hours ago, papa al said:

"once it does start, it ticks over perfectly, runs smoothly, and is as nippy as ever."

It is a starting problem, not a running prob.

so fuel supply fault seems unlikely.

How much costs a new carb.?

Not much.

clarification:

not a fuel supply fault to the carb.

not a spark prob.

so what does that leave?

carb, so...rebuild kit or new

BWTFDpK

 

[VocalNeal]

14 hours ago, cliveshep said:

but taking it all apart myself it does have a vacuum operated fuel pump connected to the inlet manifold and (b) the plastic nut retaining the "dash-pot" needle fell out in may hand, the needle was free to operate independently of the slide.

 

The first rule of troubleshooting.  What has changed? In this case Somboon has taken the carburetor apart.

 

Take it to a proper Yamaha dealer and tell them you are happy to buy a new carburetor. Probably less than 1000 Baht.

 

If you must...

 

Parts list with exploded diagram

https://drive.google.com/file/d/0B0fPe4feWkfeNFlpOFJRNVhRYnF0dXRfWm00LVJvQQ/view

 

This has nothing to do with what has changed.

 

Does it have an actual fuel pump or simply a vacuum operated fuel cock on the bottom of the fuel tank.

Check by removing the fuel hose from the carb and the vacuum pipe from the manifold and sucking on the vacuum line.  Check or replace the rubber/plastic vacuum hose. 

 

When it is running at idle adjust the idle mixture using the usual procedure of raising idle speed with throttle adjusting screw and then adjust the idle mixture (pilot jet screw) to get the best idle, then return idle to correct speed with the throttle screw. 

[cliveshep]

Thanks for the Yamaha parts list - in English too. I am coming to the conclusion having spent 5 minutes with a

"Startall" boosting it's poor little battery grinding away on the starter this morning that is has to be the carb somehow, and that a new one is probably in order, and that I should throw up my hands, give in, and take it to Yamaha.

 

We did find a Yamaha main dealer service centre this morning - it was closed until Tuesday. Don't know why they bother, next year will be the same as this one and last one no doubt, as they say, new date but same shit. Anyway, we'll take it in and let them sort it on Tuesday.

 

So thank you every one for your suggestions, not your fault the bugger has beaten me.

[cliveshep]

Update - overnight it pissed petrol all over the floor showing (a) the float valve is stuck and (b) the vacuum operated fuel cock is naff and does not shut off the fuel.

 

So 'Ol Grumpy once again took it all apart, sorted the carburetter float needle issue, put it all back together in the process breaking the gasket.spacer on the inlet manifold.

 

Tuesday - tried to start it to take it to Yamaha. Inevitably the battery started to run down, connected booster, bike finally started but now would NOT continue to run. Stopped of it's own accord. 

 

Tried to start it again - burnt out the starter motor.

 

Wednesday - Yamaha Main Dealer sent a tail-lift truck to collect it and take it to the Yamaha workshop. Fight with wife over asking her to translate things - refused because menstrual bad temper. Came home with wife and left them all to it.

 

Mid afternoon they phoned up - wife could not translate the technical details of what they needed to replace, two expensive bits she said, they would have to order one in, bike would not be done until next week, please come to shop and pay half the anticipated bill under 5000 baht total. 

 

So went to shop - half turned out to be 3000 baht in case we legged it and left the bike with them plus 400 baht for the transporter and driver.

 

Chatted with the boys - they will fit a new carburettor - 2000 baht they said, wife said 2500, a new starter motor, a new vacuum valve, a new manifold gasket and spacer and two speedometer bulbs for good measure. Lots of laughter and smiles asking me how I undid the various bolts and did them up again. Got mildly bollocked when I admitted destroying the inlet manifold spacer by ramming the bolt through with a screw gun - use a "T"-spanner they insisted, more gentle and a Startall mains battery booster it far to powerful for a bike battery! So - chastened I left them with it thinking £114 max is fair enough for the work and list of bits if they keep to the price!

 

Did say to them I'd be after blood if after all this it did not start easily - they insisted it would!

 

[ktm jeff]

Sounds like they understood the problem and identified required parts. Vaccum valve is a susspect. Good price and good to hear what seems to be very good service. 

[papa al]

Endever to persevere.