| Author |
 Topic  |
|
| |
Current Topic Rating:  | Join the Forum to Rate this Topic at: Classic Motorcycling Australia Forums
|
|
|
peen0_0
Level 3 Member
Victoria
224 Posts |
 Posted - 30 Jun 2011 : 10:18:18 AM
|
|
Have a new set of CR's on the beast, fed by a new carter fuel pump. Problem is that the carb's are pouring fuel out of nearly every orifice (much like me after a good curry!)Guessing that the constant flow, low pressure fuel pump is to blame, but would have thought that the needle and seat would stop the flow?? Any thoughts gratefully received. Cheers, Tony.
|
|
|
john
Forum Moderator
Victoria
3130 Posts |
Posted - 30 Jun 2011 : 12:13:16 PM
|
| What pressure have ytpu got. I always found it best to have a small tank above the carbies, with a return feed back to the tank. That way I had gravity feed but no fula starvation. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
 |
|
|
peen0_0
Level 3 Member
Victoria
224 Posts |
Posted - 30 Jun 2011 : 12:53:58 PM
|
Haven't measured the pressure yet John, but as I said, I suspect that it is the problem?
I like the header tank idea. We had that on one of the earlier outfits. Doing the full pull down, float levelling, pressure testing, ballancing this tomorrow, so we'll see? Any other thoughts in the interim gratefully received. Cheers, Tony. |
|
|
|
Buck
Level 2 Member
Victoria
26 Posts |
Posted - 30 Jun 2011 : 7:19:46 PM
|
Just a bit further if anyone has had the same problem. The Carter is a low pressure high volume. Pinching off the fuel line the pump continues to run without varience in it's activity, but the fuel stops due to pinching off. Intiatlilly the fuel came in a stream from what appears to be overflow vents high up near the throttle body on the right as you look at the carb. I gave each a clip in the ear and it reduced this issue, I then worked the throttle and it spat from each carb from that vent each time I activated the throttle, (Bike not running) I then noticed that I got fuel from the back of the carbs and had a hormonal moment and ran inside where I received no love.......at least I was away from the hammer, I appreciate the header tank we ran one on our first unit, evryone tells me it must be the carbs not the pump.
Anyway guys just thought I would expand hoping for some advice.
Buck, the passenger
|
There is a bear in there and a bundy as well.... |
|
|
|
Cookey
Level 1 Member
New South Wales
6 Posts |
Posted - 30 Jun 2011 : 11:51:25 PM
|
| Yep...Had the same problem on my P4 836cc when I went to CR's. The needle & seats aren't really up for positively pumped fuel loading. As with JD, I ran a small header tank with a top outlet returning surplus to the tank, but.... put a ball valve tap in the return line. The ability to regulate the endflow provides optimum control on fuelling the carbs, allowance for different pump swaps (pressure)and gave better pump existance since without some measure of back pressure the pump revs its heart out!! I run the same system on the F2 which had a low rev range flooding problem on the FCR flatslides. Fixed. I'd view the Carter critically. You don't need the high volume passage. I always ran avgas with a Facet pump without any glitches. The honda's CR's were 31mm running #128 mains with YY8 needles leaned off x2 notches. A simple tuning/balancing trick - X4 pieces of wire under the slides and pointing level out of each carb bellmouth. Very slowly, just crack the twist grip while watching across each wire from side on. All 4 wires should dip together/similtaneously. Adjust any lagging or early slide to accord with the others and you're done. Hope this helps a bit. |
"Ignorance is curable. Stupidity is forever." |
|
|
|
conker
Really - acotrel - Now banned
Victoria
361 Posts |
Posted - 01 Jul 2011 : 09:05:10 AM
|
| Doesn't the Motec engine management system control fuel flow? |
|
|
|
john
Forum Moderator
Victoria
3130 Posts |
Posted - 01 Jul 2011 : 09:27:08 AM
|
| Alan we are running steam powered bikes not electricl bikes. Motecs dont work on P4 machines. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
|
|
|
conker
Really - acotrel - Now banned
Victoria
361 Posts |
Posted - 01 Jul 2011 : 8:15:00 PM
|
| What Motecs don't work on P4 bikes - even if you paint them black? |
|
|
|
john
Forum Moderator
Victoria
3130 Posts |
Posted - 01 Jul 2011 : 8:54:54 PM
|
| lets stick to the topic rather than stick the topic Al. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
|
|
|
Allan
Site Moderator
National
599 Posts |
Posted - 02 Jul 2011 : 06:55:09 AM
|
| in days gone by we rode our "push bikes" to the local car place es got SU carby float bowls to feed our Amals with pressure pumps |
Allan Greening |
|
|
|
conker
Really - acotrel - Now banned
Victoria
361 Posts |
Posted - 03 Jul 2011 : 08:58:16 AM
|
| Aren't we talking about modern historic bikes? |
|
|
|
peen0_0
Level 3 Member
Victoria
224 Posts |
Posted - 03 Jul 2011 : 10:32:59 AM
|
| Problem solved, the header tank has done the trick. The supposed "low pressure" pump is a little more high pressure than we suspected. Conker, are you suggesting that Buck and I cheat? We don't use any out of period parts on our bikes! Perhaps you might like to talk to us face to face about our love of racing? Cheers, Tony. |
|
|
|
Buck
Level 2 Member
Victoria
26 Posts |
Posted - 03 Jul 2011 : 11:01:45 AM
|
Hey Conker, perhaps when you get on the site you consider the question, Peen and I were after advice and as you can see Cooky was good enough to provide some, not negative self serving comments like yours, Look forward to meeting you.
Buck |
There is a bear in there and a bundy as well.... |
|
|
|
Geoffpgrant
Level 3 Member
South Australia
204 Posts |
Posted - 09 Dec 2011 : 5:10:12 PM
|
I am a bit late getting onto this topic but just in case somone is still watching it I offer the following. Not sure about these specialist fuel pumps! I had a couple on my beast when I bought it but after a couple years of grief have now got two early model Commodore fuel pumps (on separate switches so I can control them independantly) running to a header tank as described above. It works perfectly - and I suck a lot more fuel than your average Honda.
Geoff
Sidecar #30 |
|
|
| |
Topic |
|
Carb problems
