Older Yamaha Mio dies when you let off throttle

[ClareQuilty]

A reasonably nice older Mio I picked up recently for 5,000 baht has a problem - it stalls out when the throttle is backed off. When I bought it, I noticed the idle was set quite high, and since then I had it set lower to a more normal idle. Alas, after that, this problem manifested.

I'm wondering of the best solution is just to set the idle very high as before (which is to me slightly annoying), or if this could be just a case of the carburetor needing cleaning, or perhaps something more involved such as "floats" (maybe I'm paranoid, but I'm always expecting gasohol damage).

Edited November 6, 2015 by ClareQuilty

[papa al]

.

Don't clean the carb.

Leave the idle high.

If the "bike" has been "using"

"Gasohol" then "float" is "ruined" for sure.

You can "quote" me on that.

Edited November 6, 2015 by papa al

[seedy]

Carb rebuild required. Replace all gaskets, rubber hoses,and the float too.

Check intake manifold for air leaks at the same time. I do not know if Mio uses a rubber manifold between the carb and the cylinder head, but this may be cracked and sucking in air also. Cheap and quick to replace when carb is off.

[kiniyow]

New Carbs are Preset and not expensive..Problem fixed

[cnx355]

I had the idle problem before and after many visit to Yamaha , they replaced the air intake gasket ( not expensive ). That cured the many idle problems.

Then after a few months I had to replace the carburetor as the float assembly had problem too and fuel leaked after stopping the bike.

Mine is a Yamaha Nouvo almost 10 year old. Yamaha do not sell carburetor kit here to rebuild. The new carburetor cost about 3,200 Bahts, installed.

The electric choke in also included ( a 1000 Bahts value) with the carburetor. Now I have a spare electric choke. Ha ha.

Now, it run like a new bike. I hope the new carburetor has the proper part for use with gasohol.

[ClareQuilty]

Thanks guys. When we say "not expensive" we may mean different things. I would say rebuilding the carb would sound cheap at under 1,000. Is that ballpark or am I barking up the wrong tree?

[JAS21]

That's a ballpark figure ... depends how big the ballpark is of course.

Are you moving your interests away from the motoring section for good ... just asking

Edited November 8, 2015 by JAS21

[ClareQuilty]

New Carbs are Preset and not expensive..Problem fixed

I just got the news from the shop - they said it needed a new carburetor and quoted (vaguely) 2,000 baht. This doesn't seem cheap at all to me - the vehicle's only worth 5,000 baht all in, and I've had four stroke engines rebuilt for 2,000 before. I find it hard to believe there isn't some way of rebuilding or jury-rigging the carb for a few hundred baht - I think this mechanic may be a cheat.

[macknife]

New Carbs are Preset and not expensive..Problem fixed

I just got the news from the shop - they said it needed a new carburetor and quoted (vaguely) 2,000 baht. This doesn't seem cheap at all to me - the vehicle's only worth 5,000 baht all in, and I've had four stroke engines rebuilt for 2,000 before. I find it hard to believe there isn't some way of rebuilding or jury-rigging the carb for a few hundred baht - I think this mechanic may be a cheat.

Ha ha!

[papa al]

Try another mechanic?

[ClareQuilty]

I've taken it to the mechanic down the street, he says he'll finish Monday afternoon. You know, this is the first time in a decade of living in Thailand that I've been blatantly cheated.

[papa al]

This is sad.

How much money were you cheated out of exactly?

[Madgee]

New carb for an old Mio is about 915baht off the shelf and is pre-set.

Jeez, I really cannot believe the OP thinks he is being ripped off.

[ClareQuilty]

This is sad.

How much money were you cheated out of exactly?

I paid 500 baht. The shop only took the bike apart, looked at (and supposedly cleaned) the carburetor, and then quoted the ridiculous 2,000 baht price for a new carb. After I declined to agree to this, they put the bike back together, and it runs no better than it did when I dropped it off. So, I figure the reasonable charge for that might've been 100-200 baht - the 500 was clearly a rip-off.

[ClareQuilty]

New carb for an old Mio is about 915baht off the shelf and is pre-set.

Jeez, I really cannot believe the OP thinks he is being ripped off.

Well, they quoted 2,000, which is terribly high if the part is only 915 wholesale.

[papa al]

Just set the idle higher.

Pics?

Edited November 16, 2015 by papa al

[macknife]

Did you even take it to Yamaha? main dealers are very cheap here and at least they won't try and rip you off. (In my experience anyway)

I had minor carb problems similar to yours on my Honda, and my bill was about 800B with a belt change and new plug.

[ClareQuilty]

Just set the idle higher.

Pics?

Yeah, the idle was very high when I got the bike.. I'll try that if this latest shop doesn't fix it. I don't have any pics, alas, the bikes 45 minutes away with a renter.

Did you even take it to Yamaha? main dealers are very cheap here and at least they won't try and rip you off. (In my experience anyway)

I had minor carb problems similar to yours on my Honda, and my bill was about 800B with a belt change and new plug.

I didn't try Yamaha, but that might've been a reasonable idea. I usually have bikes so old (two-strokes), that the non-dealer mechanics seem more familiar with them, so I've totally gotten out of the habit of even thinking of the dealer as an option.

[ClareQuilty]

Holy cow, now the bike won't run at all. My renter got it back from the repair shop and drove it a few days, but now it won't even start. Renter gave up on it in frustration and I lost a customer. :'(

Turns over, but won't start, so my guess is no fuel getting through the carburetor. Plenty of gas in the tank.

Its been sitting a few days now as its quite far from a repair shop, I'll probably have to either hire someone to go get it on a truck, or get a friend to push me from behind by foot while driving his bike.

Edited November 24, 2015 by ClareQuilty

[papa al]

I've seen the biker pushing another thing.

Very cool.

Do that.

[ClareQuilty]

I've seen the biker pushing another thing.

Very cool.

Do that.

I did, but the pusher was the mechanic from the nearest shop, one I didn't know well. I was the pushee.

It all went well, but when we got back to the shop he told me it was the battery, and wanted to install a 600 baht replacement - to my mind this was patently ridiculous, as the bike was turning over strongly even after 20 minutes of various people trying to start it on three previous occasions, the horn blew strongly, etc.

So, I said 'no thanks', gave him the 50 baht he asked for the push-push, and rolled the bike away to a secure location, and will get a trusted mechanic to come get it by pickup truck sometime soon. I'd rather pay him something to pick it up than pay a dishonest one.

[papa al]

Claire,
On post 11 you reported the first time ever being blatantly cheated (300baht).
Now this other mech is trying to cheat you?
Very bad run of luck.
Could karmic considerations be a factor?

[ClareQuilty]

Happy to report the Mio is running reliably now after my local shop had a look at it. I wouldn't say its running wonderfully well (its not very smooth), but it never dies, and starts readily. And the total cost? - 30 baht. Who knows?