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[Simplo]

Hi Adrian,
I'm almost convinced it is a carb problem, as you can read in my last post, with the "small jet carb" the engine runs well and it runs well every time I put the choke on with my old carb.
I'm start to think that my carb setting is not a standard one.
Mine is an officially imported 2006 350 STD.
It has PAV and it arrived with the "big" air filter in the side box and the empty original air filter.
After a few months I changed the filter with the original one, tha small one just in the "coffee box".
It always worked.
May the bike discovered it doesn't have the original filter after 9 years and 1 half?

[Adrian]

If it took your bike that long to spot the filter change, I don't think it's the reason for the problem either! As I said earlier, new carburettors for the 350 can be found cheaply enough for you to experiment and confirm one way or the other whether the existing carburettor is faulty. If you like the bike enough it could be a small price to pay.



Forgive me if you have already seen it, but our hosts offer a jetting guide for the standard Mikarbs fitted to the 350 and the 500 allowing for different exhausts and air filter, as well as showing the factory settings.



http://www.hitchcocksmotorcycles.com/pi ... _guide.jpg



Hope this helps, we still want to see you defeat this problem.



A.

[Simplo]

Hi Adrian, thank you for your reply.
I already purchased from Hitchcock a spare needle, just because I blended mine during carburator cleaning.
I asked for a standard one and, using a caliper, it seems just like the old one, so I'm pretty sure I'm using the original needle.
As I wrote some post before, I tried two other carbs: both are signed VM-24, but the firs one is branded something like "mikuni license" the other "Royal Enfield".
The first one has choke leverage instead the black cap and it seems a smaller needle (no idea about the pilot jet) and float setted ad 24mm.
The second one ha same needle as mine and jet setted ad 22mm.
The first one works perfectly.
The second one starts the engine with choke, but doesn't idle and does not respond to throttle, even trying other air screw and needle settings...
How can I misure what main jet/needle and pilot the first carburator mounts?
Thank you

[Adrian]

Aren't the jets and the needle on the first (good) carburettor engraved with some numbers or other markings, however small? You may need a magnifying glass, though. I will have to re-read your earlier posts.



I would be quite tempted by this from our hosts' stock of used parts now, though I do wonder why it was removed from the bike.



http://www.royalenfieldspares.com/Used- ... s/USED2454



There seems to be more than one Indian manufacturer making carburettors for the 350, Mikarb (the licenced Mikuni copy most commonly used) and another company called Spaco, possibly to a slightly different specification. I think I have seen these for sale, although their web site does not list a VM24.



A.

[Creaky45]

Simone, Going back to your very first post it seems the bike was running well and then, when you went to start it it would not start. That can have nothing to do with needles or jets as they can't change themselves. OK you may have bent the needle but that was after you had the problem. You have checked everything possible it seems and all us experts can't solve the problem. If it were me I would try a complete new carby or pull the head off and look for problems there. My friend had a similar problem and after removing the head and finding nothing wrong there that we could see we had an engineering shop reseat the valves making the head as new and sure enough the bike ran perfect after that and we still don't know what the real cause was. Maybe bad seat or sticking valve but, as I say we could see nothing wrong. Just a thought. Another Enfield mystery. Welcome to the club.

[Leon Novello]

Another cause of these symptoms could be a loose Earth wire, particularly from the battery to the frame; my nightmare was caused by the Earth wire connection to the back of the left-hand toolbox being loose.

[Simplo]

Hi all,
sorry I'm "spamming" the forum, but I hope this thread will be useful to someone else facing my same problems.
Yesterday I made some new test and I can say the problem is DEFINITELY on the carb.
Let me recap:
Now I have 3 carburettors
Carb1 - the original one MIKARB
Carb2 - a spare used carb MIKARB
Carb3 - a brend new carb from India branded "Royal Enfield" (no idea if it is a fake or original one).
This are settings:
Carb1:
needle: Y373 (now replaced with Hitchcock one labeled A(or DELTA) 4H7
needle clip: 3
throttle valve: 2.5
air screw: 2 turns
float: 24.5mm
Carb2:
needle: A(or DELTA) 40H7
needle clip: 3
throttle valve: 2.0
air screw: 2 turns
float: 24.5mm
Carb3:
needle: A(or DELTA) 40H7
needle clip: 3
throttle valve: 2.5
air screw: 2 turns
float: 24.5mm

This are the behaviours of the engine

Carb1:
starts with choke
idles without choke
coughs and turn off when using the throttle without choke
it runs with choke on
Carb2:
all works fine!!
Carb3:
starts with choke
doesn't idle without choke
fires from exhaust when using the throttle

Ok, the main difference seems to be the throttle valve!
So I tried to use the Carb2's valve on the other carbs.

Carb1:
all works fine!!
Carb3:
starts with choke
doesn't idle without choke
fires from exhaust when using the throttle

I can't find any logical explaination of all this!




Ah, if you ear about any "carb assemble/disassemble" championship, please lete me now! Now I can dissasemble, separate part by part, clean and reassemble Bullet's carb, in less than a minute, without tools, with an and tied and with a blindfold on!

[Simplo]

(sorry for the double post, I'm trying to repost it with the right formatting)

Hi all,

sorry I'm "spamming" the forum, but I hope this thread will be useful to someone else facing my same problems.
Yesterday I made some new test and I can say the problem is DEFINITELY on the carb.

Let me recap:

Now I have 3 carburettors

Carb1 - the original one MIKARB

Carb2 - a spare used carb MIKARB

Carb3 - a brend new carb from India branded "Royal Enfield" (no idea if it is a fake or original one).

This are settings:

Carb1:

needle: Y373 (now replaced with Hitchcock one labeled A(or DELTA) 4H7

needle clip: 3

throttle valve: 2.5

air screw: 2 turns

float: 24.5mm

Carb2:

needle: A(or DELTA) 40H7

needle clip: 3

throttle valve: 2.0

air screw: 2 turns

float: 24.5mm

Carb3:

needle: A(or DELTA) 40H7

needle clip: 3

throttle valve: 2.5

air screw: 2 turns

float: 24.5mm



This are the behaviours of the engine



Carb1:

starts with choke

idles without choke

coughs and turn off when using the throttle without choke

it runs with choke on

Carb2:

all works fine!!

Carb3:

starts with choke

doesn't idle without choke

fires from exhaust when using the throttle



Ok, the main difference seems to be the throttle valve!

So I tried to use the Carb2's valve on the other carbs.



Carb1:

all works fine!!

Carb3:

starts with choke

doesn't idle without choke

fires from exhaust when using the throttle



I can't find any logical explaination of all this!



Ah, if you ear about any "carb assemble/disassemble" championship, please lete me now! Now I can dissasemble, separate part by part, clean and reassemble Bullet's carb, in less than a minute, without tools, with an and tied and with a blindfold on!

[Simplo]

Sorry, the text doesn't respect my carriage returns!

It is very boring to read it in this way...

Thecnology is killing me this days!

Last try:

(sorry for the double post, I'm trying to repost it with the right formatting)
Hi all, sorry I'm "spamming" the forum, but I hope this thread will be useful to someone else facing my same problems.
Yesterday I made some new test and I can say the problem is DEFINITELY on the carb.

Let me recap: Now I have 3 carburettors
Carb1 - the original one MIKARB
Carb2 - a spare used carb MIKARB
Carb3 - a brend new carb from India branded "Royal Enfield" (no idea if it is a fake or original one).

This are settings:
Carb1:
needle: Y373 (now replaced with Hitchcock one labeled A(or DELTA) 4H7
needle clip: 3
throttle valve: 2.5
air screw: 2 turns
float: 24.5mm
Carb2:
needle: A(or DELTA) 40H7
needle clip: 3
throttle valve: 2.0
air screw: 2 turns
float: 24.5mm
Carb3:
needle: A(or DELTA) 40H7
needle clip: 3
throttle valve: 2.5
air screw: 2 turns
float: 24.5mm

This are the behaviours of the engine
Carb1:
starts with choke
idles without choke
coughs and turn off when using the throttle without choke
it runs with choke on
Carb2: all works fine!!
Carb3:
starts with choke
doesn't idle without choke
fires from exhaust when using the throttle

Ok, the main difference seems to be the throttle valve!
So I tried to use the Carb2's valve on the other carbs.

Carb1:
all works fine!!
Carb3:
starts with choke
doesn't idle without choke
fires from exhaust when using the throttle


I can't find any logical explaination of all this!

Ah, if you ear about any "carb assemble/disassemble" championship, please lete me now! Now I can dissasemble, separate part by part, clean and reassemble Bullet's carb, in less than a minute, without tools, with an and tied and with a blindfold on!

[papasmurf]

Simplo, some 30 years ago, I had to strip down, and reassemble a large number of Bren guns.
I did not get quite this fast though:-