New member from France with a 1986 Aero 50

[GSX1400]

Yes, we sure know how to invent so many taxes here...

Thanks for the Aero!

[GSX1400]

4200 kms today.
It's been a couple of days that I'm having a problem with my scoot.
The idle has been too high. I thought I had an air leak. I know one of the threads on the carb was tired.
Had a Helicoil put in, changed the 2 o-rings on the flange.
Still had problems, idle and richness adjusted.
Started bogging out sometimes.
Screwed the richness screw in and it still idled. *?

Took everything apart tonight : there is some sort of sand in the floater bowl.
Just like the first time when I bought TT.
AND I have an in-line fuel filter.

So, ultra-sonic cleaning for the carb and close inspection of the fuel filter.
The filter is dirty.

Tomorrow, I'll go out and buy another filter. Didn't want to start it again without changing the filter before...

My tank is not rusted, I suppose I must have picked up some bad gas at the station...

I'll post some pics and open up the filter to show you.

[GSX1400]

Still having problems with the idle.

Concerning the carb I'm wondering if someone know if there should be an Oring on the air screw and on the idle screw.

I looked at the shop manual but didn't see this information.

[mousewheels]

Honda phased in O-rings in the late 80's. I looked at 86, and 87 Aero 50, 87 Spree and 87 Se50, none have O-rings on those screws. 1988 Elite SA50 had one o-ring on the air screw.

[GSX1400]

Should I put an oring on?
I was wondering how air could avoid entering by the threads of the air screw and falsing my settings...
And where should I put it :
* between the head of the air screw and the spring
OR
* between the spring and the carb body

[mousewheels]

Should I put an oring on?
I was wondering how air could avoid entering by the threads of the air screw and falsing my settings...

-- Air leak at air screw threads causes no change in mixture --
The needle/seat sets the flow rate. High vacuum side is on the side which flows into the carb.

Air screw threads are on the weak side of the vacuum. It is near atmospheric pressure at the shaft and threads. So not much air flows there, and what does will not impact the needle setting.

between the spring and the carb body

That is where the later models placed the o-ring

Airscrew_Leakage.jpg (111.62 KiB) Viewed 5613 times

[GSX1400]

I think you'll need some good welding skills to repair your carb now that you've cut it open to show me!

Thanks for your feedback.
So, no point in getting a headache with the supposed air leaks on the air screw threads.
My problem seems to be elsewhere.

I have stripped the carb down again and gone for another ultra-sonic cleaning.
But it is really clean and all the passages look nice (I did the "trick" with the light to see through the holes).

Sorry, my explanations aren't very easy due to my lack of vocabulary (still learning...).

[Wheelman-111]

Greetings:

Yes, Monsieur Mouse is a wizard when it comes to explaining things.

Just a hunch, but maybe check your reeds (les clapets) for a gap. Trouble here affects idle - a LOT! If you haven't already done so, replace la bougie. Sometimes that's all it is...

[GSX1400]

The reeds are the original ones and have 4200 kilometers on the clock.
Would it be possible for them to be out of order already?
The plug is 3500 kilometers old.
I checked it and it is like new, clean, color is chocolate. Gap is ok.

I'm going to check for air leaks because the engine is behaving as if it were too lean.
When you accelerate, the rpm's drop slowly.
I tried putting a bit of gas around the carb flange to see if an air leak was there, but nothing changed on the idle.

It's 9:30PM here, so I'm not going to work on it any more for today. See you tomorrow and manys thanks for participating!

[Wheelman-111]

Salut:

Reeds are unpredictable. Either the metal loses its "spunk" or the plastic becomes undermined from contact - oh, just about 100 times per second on average... Sometimes a spark plug looks great, but doesn't run. Isn't it worth the 15 francs for a new one to see?

[GSX1400]

I'll check the reeds then.
I have an extra plug, I'll put it in too.

I hope reeds are still available if they have failed...

[GSX1400]

I did a compression test to see if everything was ok.

Today (4200 kms) :



When I got TT (950 kms) :



Carbon building up I presume...the shop manual says it's ok until 12 kPa so I'm not opening it up yet.
It is running on full synthetic 2 stroke oil.

[Wheelman-111]

Greetings:

Carbon deposits tend to increase, not Decrease compression. Bad reeds will result in lower readings. So will worn-out rings, leaky seals, holes in the piston... I've seen 'em all. Carb must be held wide open to check compression, or better still removed from the intake altogether.

[GSX1400]

Hi,
I did the compression test without the carb in place.
Took the reeds out and they look like new, well closed not deformed.
So, if I beleive my compression test and dismanteling, we can say the reeds are ok are carbon is building up (in still acceptable proportions).
Had to make my own reed/inlet pipe gaskets. The original ones were so hardened I had to cut them to take everything, stuck together like glued, apart.
Made them with some gasket paper I had (1 millimiter thick).

I'll post some pics later.

[GSX1400]

So...did a couple of tests.
First I changed the orings on the carb flange (they were all softy and deformed???), put some silicon one in place and also changed the oring on the auto bystarter to be sure there are no air leaks.

It looks like the auto bystarter is the culprit...

I unplugged it, adjusted the carb (engine was already hot) and the thing went on idling for ever. Went to drive it and everything was ok.
Plugged the auto bystarter back on and did a little ride in the street trying to speed it up.
Back in the yard and the thing started idling badly, almost stalling. Quickly unplugged the auto bystarter and the idle slowly went back to normal.

Looks like it's this bystarter that's fecked up? How does that happen?
I never messed around with it.
It looks ok (the needle isn't scratched or else, the "piston" moves up and down by hand, nothing looks stuck)...

IF it is this bystarter thats out of service, does Honda still sell it? Otherwise, what to do?