jacko
|
| posted on 21/9/13 at 08:05 PM |
|
|
When its running are the slides moving up and down not sticking im thinking out allowed
|
|
|
|
|
RobBrown
|
| posted on 21/9/13 at 08:55 PM |
|
|
quote:
Originally posted by jacko
When its running are the slides moving up and down not sticking im thinking out allowed
Any ideas at this stage are welcome - but yes the sliders are moving when I blip the throttle, not otherwise.
Have taken everything off again re-sprayed everything in carb clean - jets in carb cleaner overnight, ready to try again tomorrow.
Removed all the spark plugs - mostly clean - white electrode, but one plug is blacker than the others with white electrode, not wet.
peered into chambers - nothing looks abnormal there, remarkably clean.
Took carbs off but left fuel pump connected just to see whether anything was seeping through the carb - but nothing.
Can now only be electrical - surely.
|
|
|
RichardK
|
| posted on 22/9/13 at 01:34 AM |
|
|
quote:
Originally posted by RobBrown
fuel level is higher than the join between the bowl and the carb. not measured float itself yet.
[Edited on 21/9/13 by RobBrown]
Doesn't sound right to me most carbs I've worked on has the level between 1 & 3 mm below the join?
Cheers
Rich
Gallery updated 11/01/2011
|
|
|
RichardK
|
| posted on 22/9/13 at 01:46 AM |
|
|
A quick google suggests 4.1mm below the joint? Obviously I don't know the age or model of your carbs but do you own research, not many posts
that do it the way I'd it with the tube the workshop manual does the upside thing and measure.
Hope you get it sorted.
Cheers
Rich
Gallery updated 11/01/2011
|
|
|
RobBrown
|
| posted on 22/9/13 at 02:48 PM |
|
|
quote:
Originally posted by RichardK
A quick google suggests 4.1mm below the joint? Obviously I don't know the age or model of your carbs but do you own research, not many posts
that do it the way I'd it with the tube the workshop manual does the upside thing and measure.
Hope you get it sorted.
Cheers
Rich
Isn't that when the carbs are on the bike? Should I be changing the float so that tbe fuel level when on the manifold is bleow the bowl join?
Any idea by how much preferably something ican measure before I put it all back together.
|
|
|
RobBrown
|
| posted on 22/9/13 at 05:41 PM |
|
|
Jets soaked in cleaner overnight.
Floats checked and are all perfectly aligned.
But still the same cut out issue after 10-20 seconds
Now you know when you remember a crucial piece of info...
The reason that I was originally at 120 main jets is because I had these carbs running consistently enough to be able to AFR them at WOT and get them
running. Now I didn't have the cutting out problem then.
The only thing I have changed since then is that I moved back to a stock cam (rather than a lumpy one) and moved across to MJ as I had real issues
with the Dizzy (and I had had it on the shelf for a couple of years meaning to fit) - and it never started when I lined-up all the arrows for TDC.
I'm slowly convincing myself, especially what I've seen over the weekend with changing needles and jets and screws not making a blind bit
of difference to the cut out issue, that it's an MJ problem somewhere, so tomorrow:
- New Coil
- New Ignition Module
Will try new plugs first though (cheaper!)
Any further comments appreciated. We will get this sorted one way or another.
[Edited on 22/9/13 by RobBrown]
|
|
|
mcerd1
|
| posted on 23/9/13 at 07:40 AM |
|
|
have you tried it with MJ disconnected so that its just the EDIS4 plugged in ?
this should run a fixed 10° advance as a 'limp home mode'
-
|
|
|
RobBrown
|
| posted on 23/9/13 at 10:48 AM |
|
|
quote:
Originally posted by mcerd1
have you tried it with MJ disconnected so that its just the EDIS4 plugged in ?
this should run a fixed 10° advance as a 'limp home mode'
Yes - still cuts out after a short while, so not the MJ unit itself that's at fault - My theory it's somewhere in the rest of the wiring
(possibly coil).
|
|
|
mcerd1
|
| posted on 23/9/13 at 11:27 AM |
|
|
how solid is your VR sensor mounting ?
a few folk have had issues with it moving/vibrating just enough to stop working (needs to say about 1mm from the trigger wheel from memory)
-
|
|
|
RobBrown
|
| posted on 23/9/13 at 02:10 PM |
|
|
quote:
Originally posted by mcerd1
how solid is your VR sensor mounting ?
a few folk have had issues with it moving/vibrating just enough to stop working (needs to say about 1mm from the trigger wheel from memory)
The mount is solid, but the sensor could be as much as 2mm away, from memory. I can double check when I get home tonight.
|
|
|
RichardK
|
| posted on 26/9/13 at 11:40 AM |
|
|
I still think float height is your problem, no venturi effect over the idle jets mixing not enough air with fuel so neat fuel is just been delivered
and flooding. This also explains why it runs better with smaller mains fitted too.
If this does turn out to be the problem dump your oil too as it could be contaminated if it's been flooding alot.
Hate to say this but I would whip the carbs off and set the floats to exactly to spec, I saw a video recently where a guy used a bar code off a cereal
packet at marked the height on the fine line and this cardboard was easier to get I between the carbies, neat trick I thought.
I have in the past also used an old needle valve and glued up the sprung pin and used this one to set the float height, when correct just swap it back
to the proper one. This way it doesn't matter what angle you hold the carbs while adjusting the float tang.
Really do you you get this sorted mate as I know how frustrating things like this can be.
Cheers
Rich
Gallery updated 11/01/2011
|
|
|
RobBrown
|
| posted on 26/9/13 at 12:20 PM |
|
|
Thanks Richard
I'm in the process of just making sure everything else is OK.
I'm also not sure what height to set the floats to. The 4.1-5.1mm figure is for when the angle is close to the original bike mounting angle. I
could just lower them all to a consistent height and see if that makes a difference. They are all currently at 4.1mm (using the upside down method)
I'll hopefully know tonight whether the other things have worked, which are:
New Spark Plugs
Repositioned VR sensor
New Coil Pack
New Fuel filter between tank and pump (awaitng delivery of this before being able to test the rest).
|
|
|
RichardK
|
| posted on 26/9/13 at 01:06 PM |
|
|
This was the geezer in the video linky
You'll have to get that specific info about heights from the correct service manual, can't guess it mate.
Cheers
Rich
[Edited on 26/9/13 by RichardK]
Gallery updated 11/01/2011
|
|
|
RobBrown
|
| posted on 26/9/13 at 01:53 PM |
|
|
quote:
Originally posted by RichardK
This was the geezer in the video linky
You'll have to get that specific info about heights from the correct service manual, can't guess it mate.
Cheers
Rich
[Edited on 26/9/13 by RichardK]
I've seen that vid in my travels (i liked the bar code approach too), what I'm not sure about is the height I should be setting,. This vid
is geared towards an upright setup of the carbs, whereas for a car these are more horizontal. My current float heights are set to spec in the original
position.
Any suggestions on what height to set to for a horizontal setup (angled slightly for level float bowl)?
|
|
|
RichardK
|
| posted on 26/9/13 at 02:01 PM |
|
|
Can you show a picture of them fitted mate, not sure I understand, usually you try and get them so the joint is parallel with the ground. Although
that said I have been known to wheelie bikes a fair distance so doesn't seem to make that much difference.
I'd get a standard manual and set it to that and leave it alone, it was just your comment about the level being above the joint that
doesn't seem right.
Cheers
Rich
Gallery updated 11/01/2011
|
|
|
RobBrown
|
| posted on 26/9/13 at 03:11 PM |
|
|
According to the manual the float heights should be 4.1-5.1mm. My carbs using the manual method are all set correctly at 4.1mm.
However the manual reflects them being fitted to a bike, which has the carbs in more of an upright position .
I have fitted the carbs to the car horizontally so that the float bowls are level, which is a different orientation to when they were on the bike.
Using the clear tube in the bottom of the bowl method the level of the fuel is above the join of the float bowl.
If the level is meant to be below the join then it could mean raising the float level by about 10-15mm to achieve this - I've not read anywhere
that this needs to be done when fitting bike carbs to cars is my only worry.
To be honest changing the float level will be my last resort tonight, once I've been able to assess whether the other things have made a
difference - and I don't remember having the same cutting out issue when I first installed the carbs with theh Dizzy fitted.
Will let you know later...
|
|
|
jacko
|
| posted on 26/9/13 at 05:10 PM |
|
|
http://www.boggbros.co.uk/gallery5.html
I wonder what they do to get these working 
|
|
|
RobBrown
|
| posted on 26/9/13 at 09:21 PM |
|
|
I think I have the answer...
One of the things I was waiting for in the post today arrived... A compression tester. The result may explain the low rpm cut out issue...
Cylinder 1 = 50 PSI
Cylinder 2 = 0 PSI
Cylinder 3 = 150PSI
Cylinder 4 = 100PSI
I think I have a problem in the front two.
I won't know whether it is valve related or piston related until I get the head off will I - unless you guys know of a smart way of checking?
I've not tried the new coil or plugs yet. Awaiting your recommendations.
I've got another head I can swap in if it's the valves, but rings is a messy job having to unbolt all the bottom end
|
|
|
RichardK
|
| posted on 26/9/13 at 11:55 PM |
|
|
Sh1t, sorry to see those figures, at least progress is being made.
Cheers
R
[Edited on 27/9/13 by RichardK]
Gallery updated 11/01/2011
|
|
|
snapper
|
| posted on 27/9/13 at 05:55 AM |
|
|
Spoon of oil down each plug hole, if compression increases its the rings
If not head off check gasket ( you'll change this anyway) then upend head and fill chamber with fluid to see if valves are seating
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
|
|
|
BaileyPerformance
|
| posted on 27/9/13 at 08:04 AM |
|
|
Did you check the compression with the throttle open? I'm thinking you did it with the throttle closed, and the throttles on cylinders 1 and 2
are so far out of balance with cylinders 3 and 4 that no aid is getting on hence no compression. This would also not help it starting.
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
RobBrown
|
| posted on 27/9/13 at 10:32 AM |
|
|
The compression check was done with all spark plugs out and the fuel line disconnected. Admittedly the throttle position was closed. Are you saying
that teh balance would impact the compression readings to this extent.
|
|
|
BaileyPerformance
|
| posted on 27/9/13 at 11:24 AM |
|
|
quote:
Originally posted by RobBrown
The compression check was done with all spark plugs out and the fuel line disconnected. Admittedly the throttle position was closed. Are you saying
that teh balance would impact the compression readings to this extent.
yes, it will, you MUST do a compression test with half or more throttle.
i think most of you problems come from the fact you throttles are wildly out of balance, with engine off look down the throttle to see if all 4 are
open by the same amount (closed throttle)
The engine wont start / struggle to start if 2 of the throttles are fully closed, this may explain why it will run at higher RPM but not idle.
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
RichardK
|
| posted on 27/9/13 at 12:17 PM |
|
|
Personally I wouldn't have thought having the throttle shut would cause 1 to be zero, but I'll bow to Baileys experience as he's far
more knowledgeable than I, another tip to get the butterflies close is to open up the idle screw a little and then use a small strip of copier paper
in the bottom of the mouth and adjust each butterfly until you can just pull the paper out with the same kind of resistance on each carb and then use
the idle adjustment screw to close all of them a little back to being very nearly shut.
If there are tiny holes in the mouth directly where the edge of the butterfly closes over it make sure they are clear whilst you're playing and
all of these holes should be covered uncovered equally on each carb but the paper trick should get you close.
Wish I was closer mate or I'd give you a hand.
Cheers
R
[Edited on 27/9/13 by RichardK]
[Edited on 27/9/13 by RichardK]
Gallery updated 11/01/2011
|
|
|
RobBrown
|
| posted on 27/9/13 at 12:19 PM |
|
|
quote:
Originally posted by BaileyPerformance
yes, it will, you MUST do a compression test with half or more throttle.
.
OK - I will try this tonight to see if it makes any significant difference to the compression readings
I've got a new head gasket ready...
Thanks
|
|
|
