CVH Ignition Timing
john inman
slightley tuned eg lightend+balanced bottom end, ported and polished
ports(std valve size), kent cvh22 cam+pulley and kawasaki zx6r bike
carbs.Thing is it will not run ! Set timing at 8 deg btdc will not
start at all,at 12 deg btdc starts but rough and will not tick over
and gets very warm within 2 minuets temp guage reads nearly 1/2 on the
scale ! And the plugs look burnt (lack of fuel ?) Any help will be
very much appreciated.
Hamish Freeman
It certainly sounds as if you are not getting sufficient fuel through to run
the engine. There might be a number of reasons.
Without knowing your level of experience and without wishing to offend,
first let us assume that the engine is timed on the right stroke - not the
first time that might have happened. Should it be on the wrong stroke it
will possibly see only the residual fuel in the exhaust manifold.
Is fuel getting to the carbs?
Are you actually seeing fuel disappear from the float chamber if the supply
is cut off?
My only experience of twin Japanese carburettors was with Aisins, which were
fitted with anti-diesel solenoid valves which if not energised reduced fuel
throughput to less than idle requirements.
If fuel is in abundance and the timing is correct then what of the jets for
these carbs? Were they set for this size of engine?
Maybe not a lot of help but the above at least gives a starting point.
Good luck
Hamish
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bobbyc...@tiscali.co.uk
12 degrees on the timing and i have the carbs set to run quite rich.
It will sit at 800rpm and rev to the red line. You don't say if the
bike carbs, cam etc are a new addition or if you had this set up for a
while and it all ran ok before. I don't know of any other Qs running
bike carbs but they are a popular conversion in XR circles - Perhaps a
question on the XR2 forum may help.
Bob Craig
>----Original Message----
>From: john....@virgin.net
>Date: 30/08/2011 20:14
>To: "Quantum Owners Group"<quantu...@googlegroups.com>
>Subj: [Quantum Owners] CVH Ignition Timing
>
>very much appreciated.
>
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Jim Hearne
distributor.
Jim
--------------------------------------------------
From: <bobbyc...@tiscali.co.uk>
Sent: Wednesday, August 31, 2011 1:37 PM
To: <quantu...@googlegroups.com>
Subject: Re: [Quantum Owners] CVH Ignition Timing
> quantumowner...@googlegroups.com
jin
degrees with it and it runs a bit better / cooler but it has leaned
out the fuelling considerably checked with my AFR gauge, it used to
sit just at rich on idle but then with 8 degrees its gone way lean,
not too much of an issue on idle but it gives you an idea as to what
effect the timing can have on mixture, ive got some new jets but yet
to fit them ,
mind you though, i dont trust the vague timing pointers on the cvh at
all, ive about 2-3mm side to side play in my timing belt cover which
must be worth 2 or so degrees either way.
good luck
On Aug 31, 1:40 pm, "Jim Hearne" <j...@quantums.info> wrote:
> 12 degrees was what i always ran my CVH's at when i still had one with a
> distributor.
>
> Jim
>
> --------------------------------------------------
> To: <quantu...@googlegroups.com>
> Subject: Re: [Quantum Owners] CVH Ignition Timing
>
>
>
> > I have a similar state of tune but with twin weber dcnf carbs. I have
> > 12 degrees on the timing and i have the carbs set to run quite rich.
> > It will sit at 800rpm and rev to the red line. You don't say if the
> > bike carbs, cam etc are a new addition or if you had this set up for a
> > while and it all ran ok before. I don't know of any other Qs running
> > bike carbs but they are a popular conversion in XR circles - Perhaps a
> > question on the XR2 forum may help.
>
> > Bob Craig
>
> > >----Original Message----
>
>
> - Show quoted text -
john.inman e-mail
TonyV
If it's only connected to one inlet runner, you'll only get dizzy
advance when that particular runner is under vacuum.
That can cause a ticking noise - the vacuum advance unit returning to
its stop position due to lack of vacuum from the other 3 carbs.
And it'll cause running problems, because you'll only be getting
distributor advance for some of the cylinders.
Test this by disconnecting the vacuum pipe - does the ticking stop?
Places like Vulcan can supply distributors which have been modified to
give an increased static advance and run without vacuum.
Or you could just disconnect the vacuum entirely and advance the
distributor to compensate, although with some loss of driveability.
TonyV.
On Aug 31, 5:55 pm, "john.inman e-mail" <john.in...@virgin.net> wrote:
> Great advice thanks a lot,Got it running now ! Increased the fuel flow a
> bit.But changed the dizzy and wow runs as sweet as a nut ! . But just 1
> little problem,its a lucas dizzy(small black cap) as ive converted it from
> the bosh original.Theres a clicking noise and you can feel it thro the dizzy
> body,now am i missing a part that fits between the dizzy drive and the cam?
> as this is all i can see is wrong.Once again any help is much appreceated.
>
jon jackson
Utube "Sprint on bike carbs" it was the only one!).
Firstly they can be a bugger to start and they have to be at the angle of
the float chamber split (parallel to ground) they do have a choke however to
get em started.
I found that jets were available on Ebay and you generally need to open them
up slightly for car use.
You must regulate the fuel pressure at no more than 1.5 psi (much like SU's
as opposed to about 3.5 for Webers etc). There is a pipe that must vent to
atomosphere and is siamesed. Mine gave as good performance as the Dellorto
45's and about the same fuel thirst as in 28 mpg on Sprint and 23 mpg on
Pinto lump of iron, however owners used to boast better fuel consumption
than Webers but Webers are not as good as Dellorto for road use.
A quick call to the Blogg brothers who specialise in these conversions would
be a good idea.
Well that is all I know but I like the sound of what you have done.
Good luck its worth the trying.
Jon 2+2 RST
Mark
Fair enough I don't have a dizzy, but mine runs lovely.
The fuel compsumsion is anything between 30-45 mpg depending on
driving style. Can't remember what the carbs are from, but I am using
a bike fuel pump.
Since fitting them almost 4 years ago I've not had to 'reset' the
carbs, this was a big factor in getting them over webbers, along with
cost.
Mark
> IMPORTANT NOTE: All information presented herewith is provided on an "As Is"
> basis, without warranty or the implication thereof. Neither the Quantum
> Owners Club nor the individuals associated with the Quantum Owners Club or
> in the preparation of the above information shall have any liability to any
> person or entity with respect to liability, loss, or damage caused or
> alleged to be caused directly or indirectly by the instructions contained
> within this or related message(s).
>
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> IMPORTANT NOTE: All information presented herewith is provided on an "As Is"
> basis, without warranty or the implication thereof. Neither the Quantum
> Owners Club nor the individuals associated with the Quantum Owners Club or
> in the preparation of the above information shall have any liability to any
> person or entity with respect to liability, loss, or damage caused or
> alleged to be caused directly or indirectly by the instructions contained
Ian Harrison
This is the reason for my megajolt project.
Those of you who know how long my projects take to complete will be expecting a report sometime in the next two years...
Ian
Sent from my iPhone
john inman
connected to number 1 inlet pipe, will give vulcan a ring tomorrow and
blogg bros which is not far from me.Now does the megajolt system not
need a vacuum pipe ? Sorry if it sounds like a daft question but new
to the kitcar/car tuning world, many thanks for all of your help
Ian Harrison
This plenum method could bbe used to smooth out your pulsing.
My megajolt will use tps.
Ian
Sent from my iPhone
Mark
I'm running tps megajolt on my zetec. Dead easy to set up, espcially
if your carbs already have a tps.
If you want a look at what I've got I'm in York.
Mark
john.inman e-mail
Ian Harrison
Sent from my iPhone