claggy001 Posted April 25, 2004 Report Share Posted April 25, 2004 Can anyone suggest some possible causes for my TR7's problem? I had a new unleaded head fitted last August. When I collected it from the garage (not a specialist) it was running slightly rough. They had the engine krypton tuned by a tuning specialist (non-Triumph again) and attributed the rough running to worn carbs. Before the HGF which led to the head replacement it ran smoothly with a steady tickover. After about 30 miles it started to run very lumpily at idle with the occasional backfire thrown in. At idle the rev counter now jumps all over the place. I took it back to the garage concerned who suggested the problem may be sticking valves in the new head so since then I have added Redex to the fuel, with no improvement. It starts fine and when cold seems smoother. In the winter it appeared to run smoothly even once warmed up. As this problem is clearly beyond the original garage to sort I need helpful suggestions. My own thoughts are (in no particular order) carb flexible linkage fuel supply (float chambers) timing/tuning/carb balance overhaul carbs. Any suggestions on where to start gratefully received. Mark Quote Link to post Share on other sites
rayjones Posted April 25, 2004 Report Share Posted April 25, 2004 Mark, Two thoughts come to mind. First one being that you have an air leak in the induction tract somewhere, manifold or carbs. As the leakage would be small, it would probably be relatively little at higher throttle openings. Does it tickover better with the choke slightly on? Check that the breather pipes from the rocker cover to the carbs is OK. The other possibility is that the valve clearances are too tight, easy to check once you have the rocker cover is off, they should be 008" on the inlets and 018" on the exhaust. Did the head come from a Triumph specialist? In warmer weather maybe the clearances get too close! Ray Quote Link to post Share on other sites
claggy001 Posted April 25, 2004 Author Report Share Posted April 25, 2004 Ray, thanks for your reply. The head came from a reputable Lincoln based Triumph specialist (I'm waffling to avoid advertising) and was supplied fully assembled & shimmed up. As you suspect the car does run better with a small amount of choke. I got new breather pipes last year (found them in the shed today!) so I'll try fitting those. Also the flexible mountings look perished. Could they have something to do with it? Mark Quote Link to post Share on other sites
rayjones Posted April 25, 2004 Report Share Posted April 25, 2004 Mark, Its possible that the flexible mountings are perished enough to let air in. Mine looked bad too, so I changed them a year or so ago, but they looked OK on the inside. If you do change them, get the original Triumph ones, (more expensive, S&S had them) as I've been told that the pattern ones only last a matter of months. My tickover problems at the time just turned out to be carbs too lean and out of balance. Maybe the Krypton tuner screwed them up, due to lack of experience on SU's if they were OK previously. Ray Quote Link to post Share on other sites
Guest stagmann Posted April 28, 2004 Report Share Posted April 28, 2004 I will second what Ray said about the cheap and cheerful carb mounts. They are shirt with the r removed. Go for the originals. they cost more but will last about ten times as long. Quote Link to post Share on other sites
Guest Karlbristol Posted May 13, 2004 Report Share Posted May 13, 2004 Had pretty much the same problem with mine. Uphill no power, backfiring and stalling. If it has an electronic ignition, make sure it's not damaged inside. I changed mine from a pirahna to a magnatronic which improved reliability straight away. Changed the 4 plugs to NGK's and no longer having the initial problems ... Hope you get it sorted... Karl www.thamesmarketing.com/tr7 Quote Link to post Share on other sites
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