Michel Higuet Posted October 31, 2023 Report Share Posted October 31, 2023 (edited) The TR is running fine except the idle is too high 1300 rpm, must not be the first one here... idle screws are unscrew, motor start at 1000 rpm and slowly climb to 1300 rpm, no air leaks ( from outside ) Carburation seems ok Pistons closed, motor stopped first mark on the pencil - running at 1300 second mark on the pencil. Conclusion butterfly valves are close but let the vacuum pass but need to be adjusted. A TR is not the kind of car where you get bored... Edited October 31, 2023 by Michel Higuet Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 31, 2023 Report Share Posted October 31, 2023 Have you read this about synchronising the SU carbs? http://tr4a.weebly.com/uploads/2/1/9/8/21980360/type_hs_tuning__tervicing.pdf The bit you need is item 24 onwards. Multiple Carbs. Quote Link to post Share on other sites
MadMarx Posted October 31, 2023 Report Share Posted October 31, 2023 On many SU carbs the throttle blades wear out on the sides. Then too much air leaks to them, leading to high idle speeds. Also to mention worn out throttle shafts and bearings. Quote Link to post Share on other sites
Michel Higuet Posted October 31, 2023 Author Report Share Posted October 31, 2023 My problem are butterfly valves, if they closed completely the motor will never even start. I have already to adjust it on one carb one weeks ago but didn't succeed. There is the " how easy unscrew refit and no light " and other " I try I try but can't achieve ". Better looking at this... https://www.sw-em.com/SU_Carb_Throttle_Plate_Early_vs_Late.htm Quote Link to post Share on other sites
Michel Higuet Posted November 2, 2023 Author Report Share Posted November 2, 2023 OK done, butterfly valve adjusted idle rpm 1000 I was lucky slightly touching one screw who untighten the butterfly valve and the head of the screw felled off, broken... Next step is checking ignition stability with a vacuum valve... Quote Link to post Share on other sites
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