VB leaking petrol

Singles, twins and fours.
Gui.dorey
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 218
Joined: Tue Sep 05, 2017 7:42 pm
Contact:

Re: VB leaking petrol

Postby Gui.dorey » Tue Jan 12, 2021 2:21 pm

I’m not sure how the carb is attached to the head on the VB, but if it has a downdraft (at a down angle to the head), then tickling the carb might be counter productive. The reason is the petrol will flow directly into the cylinder and wets the plug. So, either no tickle and just wait a bit after opening the tap to let the float fill up, or just the slightest tickle so there is no overflow.

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 4219
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: VB leaking petrol

Postby nevhunter » Wed Jan 13, 2021 12:25 am

A SV doesn't flow straight into the cylinder as an OHV does.. The SV Carb is attached to the cylinder and it has to go uphill at the port to get into the motor proper. Many OHV carbs are seriously angled down and have to have suitable bowls to keep THEM level. Most motors seem to need tickling to fire up even if still warm especially if the bike is leaning towards the carb bowl, which has a similar effect to lowering the float level. Nev

MarkOgden
Posts: 55
Joined: Mon Sep 05, 2016 9:12 pm
Contact:

Re: VB leaking petrol

Postby MarkOgden » Sun Jan 17, 2021 10:35 pm

Here is what I do to start from cold

Fuel tap on
Adv/ret lever set about half way
Full choke
Find TDC with kickstart
Press tickler for a second
Exhaust lifter lever pushed forward - valve lifted
Rotate kickstart another 90 degrees of so
Exhaust lifter lever pushed back - valve on cam
Kick - with no throttle ......

It invariably fails first kick
Second time as above
Third no tickle
after that vary the adv/ret slightly and bascially as above. Never really found an ideal even now.

Bit of pig really, but 5th or 6th kick usually gets it.....

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 4219
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: VB leaking petrol

Postby nevhunter » Mon Jan 18, 2021 12:34 am

I'm sure all that complexity is not achieving much. Forget the choke. Leave it open. Cold, tickle till some fuel comes out then bleed some compression away on the decompression lever then give it a decent kick with throttle about 1/4 open. If it doesn't start then check the spark. Magneto. Most starting issues get back to weak spark or a delicate "kicker". Nev

User avatar
Brian_Walker
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 121
Joined: Mon Mar 19, 2018 9:40 am
Location: Sydney, Australia
Contact:

Re: VB leaking petrol

Postby Brian_Walker » Mon Jan 18, 2021 5:40 am

Had to help someone not so long ago with flooding VB and starting issues, new needle fitted but still leaking, ended up lapping the needle with a little Ajax sink cleaning powder, this gave a nice seat but still flooding occasionally turned out to be the brass clip that keeps the needle against the float was bent and not applying enough pressure on the needle to hold it in place. As Nev says no substitute for a good healthy kick or try a few bump starts to clear it if it been flooding.
1951-52 VCH under restoration

MarkOgden
Posts: 55
Joined: Mon Sep 05, 2016 9:12 pm
Contact:

Re: VB leaking petrol

Postby MarkOgden » Mon Jan 18, 2021 9:01 am

Nev

It's basically as per the manual. For sure I'll give your method a try. Spark seems OK, Mag reconditioned about a year ago.

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 4219
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: VB leaking petrol

Postby nevhunter » Mon Jan 18, 2021 10:47 pm

Pressure the kicker with force like you would get a spade into the ground with. Don't stab at it. Do NOT straighten your leg fully in case it kicks back, and something will get damaged, like your hip, ankle or achille's tendon. Have the forward part of your foot on the pedal, not the ball. This way even if it kicks back viciously, you don't get injured. With very high comp. engines don't open the throttle much. If the cylinder doesn't fill, its easier to kick. Nev

MarkOgden
Posts: 55
Joined: Mon Sep 05, 2016 9:12 pm
Contact:

Re: VB leaking petrol

Postby MarkOgden » Wed Jan 20, 2021 11:00 am

Nev

I think my kicking technique is OK - I have other bikes which start fine on a kick, but guidance is appreciated.

It definitely needs choke when cold, and I do think opening the throttle when kicking floods it. I wonder if adv/ret is set correctly on start. I know all of that is a bit trial and error. Incidentally manual states full advance is with the lever pushed fully forward. I'm not convinced. I seem to recall it depends on which way it is connected with the points baseplate thing....

will_curry
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 349
Joined: Thu Oct 08, 2015 12:56 am
Contact:

Re: VB leaking petrol

Postby will_curry » Wed Jan 20, 2021 3:04 pm

Lever forward to advance - tight wire - seems to be standard for road-going Ariels.
Here the advance/retard cable goes into the back of the magdyno. It's quite possible
to fit slack-wire magdynos - one of mine has one fitted.

User avatar
Bob.Murphy
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 979
Joined: Thu Nov 29, 2012 10:32 pm
Location: Kirkliston, on the West side of Edinburgh.
Contact:

Re: VB leaking petrol

Postby Bob.Murphy » Wed Jan 20, 2021 3:23 pm

There are different end-cases for the MO1 Magneto - I also have the "Slack cable for advance" version fitted to my 'VH' as I used to have to ride my 'VB' with my thumb stuck between the bar and advance lever to stop the vibration retarding it :D .

If you look closely here you can see the advance cable exiting the mag just behind the cylinder.

DSCN8698.JPG


Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH


Return to “Four stroke”

Who is online

Users browsing this forum: No registered users and 23 guests