carburettor/dell orto max tilt angle

[StubkierDK]

Hey

In the search for the source of a miss colored right spark plug (black/wet):

I am currently checking the coils and  the wires.

However i also notices that the carbs are tilted very different. For the left one the slider moves veritical up and down, but for the rigth one the slider moves at and angle of 20� to 30� inwards the engine block.



So my question is how far of from center can a carb tilt and still function ?



I can se that in the other direction - inlet to outlet the max angle is 40°. But I can't find any information on the other angle?

Have a nice Sunday

BR Simon

[jvb]

Do not know about the angles  - but check that the seal at the base of the of the choke/enricher has not hardened enough to not seal  and  allow fuel to leak/poor through and flood the cylinder.

[jacksonracingcomau]

Not your issue, concentric carbs can lean to corner
Choke circuit check, as above, my 2c says plunger stuck in body

[StubkierDK]

Not your issue, concentric carbs can lean to corner
Choke circuit check, as above, my 2c says plunger stuck in body

Just inspected  both the carbs. The choke action is fine :) And a the problem is only there a constant speed! I do'es not feel like a stuck chock.

Thanks for the feedback - will look into it :)

[Kiwi_Roy]

Why don't you just straighten the RH carb, it would look better if nothing else.

BTW those cables take quite a bend around the frame and the choke looks to have a kink in it.

[Charles in Lake Charles]

Check the floats to determine if they have gas in them. Also change the float needle and adjust the float height.

[StubkierDK]

Check the floats to determine if they have gas in them. Also change the float needle and adjust the float height.

There is plenty of gas - the problem is a new "feature" and normally it runs fine. So i don't see a need to change the carb setting unless I am missing something ?

Why don't you just straighten the RH carb, it would look better if nothing else.

BTW those cables take quite a bend around the frame and the choke looks to have a kink in it.

straighten it up - and yes it looks much better and there is no more kinks in the cables. However it did not solve the problem. The misfire/lack of power at constant speed is still the same.

Checked the coil both left and right provide around 5.3 to 5.2 ohms of resistance.

[Charles in Lake Charles]

Check the float to determine if it has a leak. If so, it will get gas inside the float and make the cylinder run rich.

[NCAmother]

I know this won't fix the problem, but I would index or make sure the plug straps are pointing in the same position.   Off the top of my head, the plug strap should be pointing in the direction of the exhaust valve.  Also, take a double look at the spark plug gaps.  It might help or not

[StubkierDK]

Check the float to determine if it has a leak. If so, it will get gas inside the float and make the cylinder run rich.

Arhh yes completly forgot about the floter which could loose its buoyancy - will look into that. That migth explain the sudden change.

There have always been a small lack of power at 4500 to 5000rpm but this mixfire thing is new.

[StubkierDK]

Arhh yes completly forgot about the floter which could loose its buoyancy - will look into that. That migth explain the sudden change.

There have always been a small lack of power at 4500 to 5000rpm but this mixfire thing is new.

Did a quick check before heading to work:


They are the black type and not the white ones. When I come home I will try to submerge them in gasoline to look for any bubbles just be 100% sure. A faulty float could explain why is works fine when i rev/accelerate and give it some gas. At constant speed the carb will overfill. 

[jacksonracingcomau]

Did a quick check before heading to work:


They are the black type and not the white ones. When I come home I will try to submerge them in gasoline to look for any bubbles just be 100% sure. A faulty float could explain why is works fine when i rev/accelerate and give it some gas. At constant speed the carb will overfill.

Something to watch, when float sticks on VHB, they don't overflow to floor but fill manifold, if it has been left standing with tap on, very good chance the oil is diluted with petrol.
But as far as running goes, sunk float isn't much different to choke on, the most noticeable is at idle, basically it won't.
Have you proven choke circuit by pulling RH choke cable when idling ?
I don't like that choke cable running over frame rail, will be even tighter with straight carb.
Individual flip up choke levers are much more reliable, ready available

[centauro]

Assuming you find nothing wrong with everything you have checked, there is one more thing to look at. Remove the accelerator pump fitting and see if the plunger spring and ball check valve is not sticking open; cleaning all the bits and re-assembling in the proper order might fix your rich condition. All VHB carbs equipped with these pumper valves sooner or later tend to suffer from this; a complete carb rebuild with new seals and gaskets always helps while you have the carbs apart,of course.

[yackee]

When my t3 started misfiring/stumbling this summer suddenly on one cylinder it turned out that one of the ignition points had opened up. I re-adjusted and it solved the problem (after having torn down the carbs looking for a fueling problem).

When my floats failed (another episode, and with the white ones), the symptom wasn't mis-firing at speed, it was just impossible to get the bike started.

Given how easy it is to check the points, I would recommend opening up the distributor and taking a look.

The other thing non-fuel-related, of course, is the ignition coils, which I know from experience can cause mis-firing as they slowly fail.

[StubkierDK]

Assuming you find nothing wrong with everything you have checked, there is one more thing to look at. Remove the accelerator pump fitting and see if the plunger spring and ball check valve is not sticking open; cleaning all the bits and re-assembling in the proper order might fix your rich condition. All VHB carbs equipped with these pumper valves sooner or later tend to suffer from this; a complete carb rebuild with new seals and gaskets always helps while you have the carbs apart,of course.

the carbs got a gasket service last winter. The accelerator pump looks like this:


it allows flow one way but not other.

When my t3 started misfiring/stumbling this summer suddenly on one cylinder it turned out that one of the ignition points had opened up. I re-adjusted and it solved the problem (after having torn down the carbs looking for a fueling problem).

When my floats failed (another episode, and with the white ones), the symptom wasn't mis-firing at speed, it was just impossible to get the bike started.

Given how easy it is to check the points, I would recommend opening up the distributor and taking a look.

The other thing non-fuel-related, of course, is the ignition coils, which I know from experience can cause mis-firing as they slowly fail.

Both coil have similar resistance (5+ ohms) however they are old (looks original). and there is electric ignition. but i guess electronics also can fail.

thanks for all tips and tricks

[StubkierDK]

The float have now been soaked in gasoline over night in there is no leaks.

However did some more googling and found another danish guy with a problem which sounded similar:
http://www.thisoldtractor.com/guzzitech.dk/gb_en_mikaels_story_3.htm

I pulled of the cylinder heads and first poured some gasoline into the intake port - no leak. However when I did the same on the exhaust side a wet ring slowly expanded from the valve. So i guess i have a improper seal. 

Br

[yackee]

Also, as to carb tilt, I have a dell'orto sidedraft carb (PHB, not too different from the carb you have on the T) on my Vespa, and they can indeed tilt quite a bit and still function. For the Vespa you have to mount the carb perhaps 30 degrees from vertical to get it to fit in the available space under the engine side cowl. So you could tilt yours much more than the photo shows and it would still work fine.