Vogon SuperTrooper Posted January 21, 2001 Share Posted January 21, 2001 Have had new battery put in, which lives right below the carbs of my 91 xflo. Not a simple operation as chassis has extra tube where it oughtn't. So car now starts but rapidly develops a sort of two-beat note. po-po-po-po-po. Blipping the accelerator just speeds this clear two beat note until it's clearly turning so fast as to be indistinguishable. I'm nervous because it simply doesn't feel right. Has anyone any ideas? Chalres Link to comment Share on other sites More sharing options...
AMMO Posted January 21, 2001 Share Posted January 21, 2001 Charles How about a leaking exhaust gasket on the head. Without burning yourself try to put your hand near the head / header pipe join and while you or someone else blips the throttle try to feel if there is any gas escaping. Please be careful and dont burn yourself. AMMO Link to comment Share on other sites More sharing options...
old captain slow Posted January 21, 2001 Share Posted January 21, 2001 A rythmic beat can be the engine flooding. Have you disturbed anything around the carbs? Link to comment Share on other sites More sharing options...
millsn Posted January 21, 2001 Share Posted January 21, 2001 Obvious but have you checked that the battery connections are done up tight. If they lose continuty the engine wil stutter. Nigel Mills - xflow Link to comment Share on other sites More sharing options...
Rory McLeod Posted January 21, 2001 Share Posted January 21, 2001 Hmm Charels: An engine going po-po-po-po-po is not good. If it goes po-po-pi-po-po may I suggest an engine tuner, and if (heaven forbid) it goes po-do-diddle-eye-do I reckomend you copyright it for the spice girls next single... smile.gif smile.gif Yours in Ineffable foolishness Link to comment Share on other sites More sharing options...
Rory McLeod Posted January 21, 2001 Share Posted January 21, 2001 And in Germanic spelling mode...wink.gif Link to comment Share on other sites More sharing options...
EFA Posted January 21, 2001 Share Posted January 21, 2001 Charles, I seem to remember from crawling under your car at Mulsanne Corner that is an Xflow 1700 SS??? If so..... Check the distributor cap is fixed sound, and that you did not damage or dislodge the HT leads where they plug into the disti cap. Above all DONT DRIVE IT FAR. You may do some significant internal damage if the ignition is not working properly. Arnie Webb Organiser- L7C Le Mans Trip To book for this years Le Mans Trip see The Le Mans Trip Website Its nearly full!!! Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted January 21, 2001 Share Posted January 21, 2001 At what speed did you run over Arnie then Charles ? Can't have been too fast if he still remembers it's a X/Flow 1700!!!!!!! Link to comment Share on other sites More sharing options...
EFA Posted January 21, 2001 Share Posted January 21, 2001 It was an early attempt at dieting......... Arnie Webb Organiser- L7C Le Mans Trip To book for this years Le Mans Trip see The Le Mans Trip Website Its nearly full!!! Link to comment Share on other sites More sharing options...
Vogon SuperTrooper Posted January 22, 2001 Author Share Posted January 22, 2001 Thanks all. I'll report back once returned from the burns unit with a stomach pump, a rubber cat suit and a recording contract from Stock Aitken and Waterman [who they?] Chalres Link to comment Share on other sites More sharing options...
Roger King Posted January 22, 2001 Share Posted January 22, 2001 Charles, Check that you haven't knocked the carbs way out of balance. It is possible that you have an engine running on only two cylinders at tickover. As you increase the revs, the effect becomes less. Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted January 22, 2001 Share Posted January 22, 2001 Roger, Is it true that balancing carbs (or TB's) only really has an effect at small throttle openings? I was wondering because if this is true, I could probably stop worrying about it when I'd rather be concentrating on driving (like on the start line of a sprint or in the pits on a track day) Mine do drift out fairly regularly. Alex Link to comment Share on other sites More sharing options...
Roger King Posted January 23, 2001 Share Posted January 23, 2001 Alex, Sorry, that isn't what I meant to imply. It's just that if one carb is open, say, 3 degrees more than the other, this will have a large effect at tickover. Instead of both carbs being open, say, 2 degrees, you may have one completely shut and the other open 3 degrees. This is a major imbalance in the amount of air that can flow through each carb and will lead to rough part throttle running. On full throttle, say 85 degrees open, a difference of 3 degrees is not that significant in terms of the amount of air that each carb can flow and will therefore have a much smaller effect. It is still important to get the balance correct on the track, because it can affect the way the engine picks up from low revs. That said, if I were driving on track and suddenly realised that the carbs had gone out of balance by 3 degrees (decide for yourself if I really am that good), I don't think I'd bother to stop until the end of the session. Of course, as soon as you trickle back to the paddock you'll notice. Link to comment Share on other sites More sharing options...
Dave H Posted January 25, 2001 Share Posted January 25, 2001 Charles, the list of things to check in the "under carb/battery" area are - HT leads, throttle cable - make sure its fed into the holder on the carbs OK. The adjuster between to 2 sets of carbs is easy to knock out of adjustment. If the carbs were removed to fit the battery then check the carb/manifold unit is not leaking at either the carb or inlet end. Failing that, remove the filters and try covering each inlet up and seeing what happens - if it is running on only 3 (or 2) cylinders at idle then you should hear a distinct difference when you stop a working one from breathing. Dave H Link to comment Share on other sites More sharing options...
Vogon SuperTrooper Posted January 25, 2001 Author Share Posted January 25, 2001 Thanks Dave H and co. On turning over for the first time this morning there was a puff of something that escaped between the rear carb manifold. So tightened that a bit. But two stroke sound (as it were) still very pronounced and I can't, to be truthful, sense which cylinders are making this embarrassing noise although I think it's the front ones. Will I have enough space by removing the carb filters to get at the doings below?. I'm going to go and have a fiddle now. Will log on this evening so your continued patience, wisdom and help very much appreciated. Incidentally, is this a job a total walnut-fisted novice should even be attempting? regards Chalres Link to comment Share on other sites More sharing options...
Violet Elizabeth Posted January 26, 2001 Share Posted January 26, 2001 Had similar probs with my X-flow last weekend, sounded like a tractor. After a chat with James Whiting on Monday he suggested all sorts of things to unscrew/fettle on the carbs (love the way he treats me like I know something!). Subsequent call to the father-in-law (rally engineer for decades), who is well aware of my ineptitude, brought my screwdriver wielding to an abrupt halt. Limped round to JW's instead, discretion being the better part of valour. Link to comment Share on other sites More sharing options...
I.Mupferit Posted January 26, 2001 Share Posted January 26, 2001 Charles If carb. balance is the problem, Halfords sell a reasonably priced multi-carb balancing device which whilst not super accurate isn't too bad either. Can't remember the manufacturer but it does come with full instructions and is quite easy to use. Brent PS Just remembered the name - Gunson. They make all kinds of diagnostic equipment. smile.gif Link to comment Share on other sites More sharing options...
Vogon SuperTrooper Posted January 26, 2001 Author Share Posted January 26, 2001 Point taken. Will take car and assembled parts to man at garage, pronto. Thanks c Link to comment Share on other sites More sharing options...
Peter Carmichael Posted January 27, 2001 Share Posted January 27, 2001 This advice is offered because I have already pictured Charles following it, resulting in mild amusement. The Dave Andrews approved way of testing carb balance is to stick a piece of rubber tube in your ear and then use it to listen to each trumpet in turn. The difference in balance is most apparent at idle, where you are aiming for a steady hiss and an overlaid "wop-wop-wop-wop" noise. Link to comment Share on other sites More sharing options...
Vogon SuperTrooper Posted January 27, 2001 Author Share Posted January 27, 2001 Thanks Peter - oddly enough I watched someone employing this sophisticated technique shortly before I left his garage last Tuesday and about half an hour later my car started sounding like Old MacDonald's tractor. So it doesn't seem that balanced carbs has become the issue. Cahlres Link to comment Share on other sites More sharing options...
Peter Carmichael Posted January 27, 2001 Share Posted January 27, 2001 Ah, well that means that pretty much everybody has been barking up the wrong tree with this thread. Perhaps we didn't pay enough attention when you were explaining how traumatic the noise is or how the the puff of something appeared. FWIW, a puff of something white (fuel vapour) is frequently a lean misfire. Sounds like a carb sneezing. I will add my worth to the opinion which suggests expert remedial attention. The usual technique in diagnosing mechanical gremlins is to examine what it was that you last changed. Whenever you hand over your car to others things get changed beyond your knowledge (and frequently beyond their knowledge) allowing the nurture of the undiagnosable gremlin. Best of luck. Link to comment Share on other sites More sharing options...
millsn Posted January 27, 2001 Share Posted January 27, 2001 When I had problems of the carbs going out of balance regularly, I found that the rubber washer that should sit behind the balance adjuster screw, was missing. Replacing it allowed me to keep the carbs in balance. Link to comment Share on other sites More sharing options...
Vogon SuperTrooper Posted January 31, 2001 Author Share Posted January 31, 2001 Doctor's report: apparently the forward carb did fall out of kilter (hosepipe test)but still there's a question mark over compression ratios which are different for each cylinder and, in two cases, low. Rolling road next stop? So she sounds gorgeous now, which matters. thanks all for your contributions and suggestions. Charles Link to comment Share on other sites More sharing options...
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