swood1 Posted May 13, 2015 Report Share Posted May 13, 2015 Hi all, This maybe a simple question for many here but I still have lots to learn. On from some advice of the forum I have decided to clean my carbs as I have issues with them sticking (I have read the other comments/proposals on the forum), if I am going to clean them I may as well replace the gaskets but I have no idea of whether I have H4 or H6 etc. Can anyone advise how I determine the model of SU carbs I currently have? The car is a 1966 TR4a, the carbs are the SU carbs Regards Steven Quote Link to post Share on other sites
Fireman049 Posted May 13, 2015 Report Share Posted May 13, 2015 Hi Steven ~ Being a 1966 TR4A your carbs. will be HS6 (1.75") with short choke tubes. Tom. Quote Link to post Share on other sites
MRG1965 Posted May 13, 2015 Report Share Posted May 13, 2015 HI Steve a picture paints a 1000 words, if you post photo you'll get a definite answer, but Toms right they should be HS6, but my TR4 should have H6's but somebody has replaced them with a pair of HS6's at some point. If they have a tag on the float chamber you'll be able to id them exactly and even which car they are supposed to be on, if they are still attached. Mine also has a sticker on the float chamber instead of a metal tag. Mark Quote Link to post Share on other sites
Trevor S Posted May 14, 2015 Report Share Posted May 14, 2015 Hi Steven, Enclosed is a photo of SU H6 carbs and SU HS6 carbs. Hope this helps. Quote Link to post Share on other sites
swood1 Posted May 18, 2015 Author Report Share Posted May 18, 2015 (edited) Hi all, I eventually managed to get some photos of my carbs. How do I tell the difference between SU H6 and HS6 carbs? http://i995.photobucket.com/albums/af75/sw-horology/carbs31_zpsq8ggqi1q.jpg http://i995.photobucket.com/albums/af75/sw-horology/carbs11_zpsgtssmkdk.jpg Edited May 18, 2015 by swood1 Quote Link to post Share on other sites
swood1 Posted May 18, 2015 Author Report Share Posted May 18, 2015 I think I have answered my own question, mine look like HS6 carbs. Quote Link to post Share on other sites
peejay4A Posted May 18, 2015 Report Share Posted May 18, 2015 That they are. Quote Link to post Share on other sites
Peter Cobbold Posted May 18, 2015 Report Share Posted May 18, 2015 (edited) When cleaning dont muddle the piston and dome between carbs. And dont use emory paper etc to clean the inside of the dome and the rim of the piston. Use carb cleaner on rag. If the gap is widened the piston lift will decrease. With the filter off the piston should be easy to lift with finger. Possible causes for a stiff piston is bent damper rod, seized damper, air in damper not vented at top, corrosion, high spot inside dome due to a ding from outside, or distorted dome due to over-heating during polishing. However if both pistons are equally stiff, suspect wrong spring fitted or has been cut down -measure on kitchen scales Peter Edited May 18, 2015 by Peter Cobbold Quote Link to post Share on other sites
swood1 Posted May 19, 2015 Author Report Share Posted May 19, 2015 Thanks Peter, I shall buy myself some carb cleaner, I have a step by step plan for how to strip down the carbs for checking over. Steve Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 19, 2015 Report Share Posted May 19, 2015 Thanks Peter, I shall buy myself some carb cleaner, I have a step by step plan for how to strip down the carbs for checking over. Steve Work with safety glasses when you use the carb cleaner. I spent ages having my eyes washed out in hospital after accidental spraying. Peter W Quote Link to post Share on other sites
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