EliTR6 Posted May 24, 2020 Author Report Share Posted May 24, 2020 Even my hangover couldn't keep me from tinkering this morning The 4 amigos are ready for action! Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 24, 2020 Report Share Posted May 24, 2020 17 hours ago, Lebro said: Interesting that your choke cable goes to the front carb. Bob More luck that it was long enough to reach there. I had to re-route and change to a different choke cable when I fitted the HS 6 carbs. in place of the H type with the underslung choke mechanism. Mine too goes to the rear carb. Peter W Quote Link to post Share on other sites
EliTR6 Posted May 24, 2020 Author Report Share Posted May 24, 2020 I just spent an hour trying and failing to get a decent idle. The car would rev straight to 4.5k rpm or almost stall at 500rpm. I suspect an air leak. And I think I know where it's coming from Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 Looks like I'm going to have to try my hand at centering the jet (without the proper tools) this afternoon! I was screamed at by a neighbour whilst trying to get the car running properly yesterday evening. He wasn't happy with the constant 4000rpm exhaust bellow while I was trying to figure out what was wrong Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 No proper tools needed to center the jet. just a spanner to fit the jet holder. Remove top cover, remove spring, remove piston with needle (carefully) wind the mixture adjuster (jet) up as far as it will go slacken off the larger nut underneath (this clamps the jet holder in place, ½ turn will do it) eyeball down to see if jet is more or less central. Replace the piston with needle, guiding the needle down into the jet replace top cover without the spring (& leave the dashpot plunger out) now lift the piston a small amount & let it drop, it should hit the bridge inside the carb body with a clunk, wiggle the jet assy until it does. tighten up the locking nut underneath, & re- check for clunk. if OK wind the jet back down to starting position, & replace the spring & dashpot piston put oil in dashpot, Job done. Bob. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 26, 2020 Report Share Posted May 26, 2020 I have as 'add-on' exhaust silencer to insert in the tail of the exhaust if I am going to be running the engine for any period at home. It as good as stops comments or complaints as the exhaust is very quiet. Shuts it up a treat. Take care when removing it gets hot. The loud motorbike world sell this as a paddock silencer and it has a handle to protect hands when removing. Peter W Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 26, 2020 Report Share Posted May 26, 2020 Hold on.....why should a rebuilt pair of carbs need the jets centring? That process is part of the rebuild service surely. Worth checking though. Peter W Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 Quite right, & of course they are easy to check: wind jet fully up, ideally remove spring from under cover, lift & drop the piston - does it go "clunk" if so all is well. replace spring, & lower jet. Bob. Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 Is this normal? The jet holder assembly is off-centre Here's a video of me screwing it all the way in by hand Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 (edited) It looks to me that the larger nut under the carb body (above the jet adjusting nut) is already loose, you should only slacken it after you have raised the jet. once the large nut is tight, the outer ring you can see moving will be fixed in position. Bob. Edited May 26, 2020 by Lebro Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 1 minute ago, Lebro said: It looks to me that the larger nut under the carb body (above the jet adjusting nut) is already loose, you should only slacken it after you have raised the jet. once the large nut is tight, the outer ring you can see moving will be fixed in position. Bob. It's the larger nut I'm tightening in the video Shouldn't it wind in fairly close to the centre? Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 (edited) No not necessarily, it is free to move around once the big nut is loose. you should be able to move it sideways to get it more or less central, then you use the piston & needle to get it spot on. Then you tighten up the top nut to lock it there. But, make sure the jet is all the way up (lower, smaller nut under carb body) before slackening the big nut. Bob. Edited May 26, 2020 by Lebro Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 3 minutes ago, Lebro said: No not necessarily, it is free to move around once the big nut is loose. you should be able to move it sideways to get it more or less central, then you use the piston & needle to get it spot on. Then you tighten up the top nut to lock it there. But, make sure the jet is all the way up (lower, smaller nut under carb body) before slackening the big nut. Bob. Thanks. Jet is fully wound in, only the big nut is loose and it pulls the whole assembly askew when it is tightened. My brain hurts Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 Leave it loose, drop the piston & needle right down, the needle will hold the jet central while you tighten up the big nut. It may take a few goes to get it right, but that is the method to use. Bob Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 That's the method I've been trying for hours. Works fine whenever everything is loose but as soon as I tighten the big nut the needle sticks I'll continue fiddling for a bit, hopefully something will click Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 I'm tempted to order a new bearing assembly to try Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 26, 2020 Report Share Posted May 26, 2020 Yes I have had this experience too. When it is stuck and the big nut is locked tight, unwind the mixture nut (small nut) down 1/2 turn. Does the piston now drop OK with a reassuring clunk? If so you are ready to go. Peter W Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 26, 2020 Report Share Posted May 26, 2020 (edited) 2 minutes ago, EliTR6 said: I'm tempted to order a new bearing assembly to try Do you still have your old HS carbs? Borrow the jet bearing from your old carbs and try one of them in your rebuilt items. Peter W PS Check the jet size compared to the needle. Take the needle out of your rebuilt carb and drop it into the jet of the rebuilt carb. Does it go all the way down to its shoulder? It should. There are 3 sizes of jet. 0.090", 0.100" , & 0.125" You need 0.100" jets to work with SM or TW needles. All 3 jet sizes look similar, 'til you try a needle in them Edited May 26, 2020 by BlueTR3A-5EKT Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 (edited) 1 hour ago, BlueTR3A-5EKT said: Do you still have your old HS carbs? Borrow the jet bearing from your old carbs and try one of them in your rebuilt items. Peter W PS Check the jet size compared to the needle. Take the needle out of your rebuilt carb and drop it into the jet of the rebuilt carb. Does it go all the way down to its shoulder? It should. There are 3 sizes of jet. 0.090", 0.100" , & 0.125" You need 0.100" jets to work with SM or TW needles. All 3 jet sizes look similar, 'til you try a needle in them The old ones have gone, I bought the new ones on an exchange basis. The jet is now as centred as it will ever be. However the piston is sticking slightly in the dashpot. It slides down perfectly if I tilt the dashpot towards me a fraction of a mm and also if I rotate it 120 degrees. Arggggghhhhhghhgghhhhhhrrrhhhhhhh I'll give it a go with an old needle after work Edited May 26, 2020 by EliTR6 Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 26, 2020 Report Share Posted May 26, 2020 Remember the dash-pot and piston are matched to each other. Clean the pistons and dash-pots with carb cleaner and wipe out. Check the metal piston tube that runs up in the dash-pot has no nicks or burrs on it. You can test their 'match' this way. See this from University Motors. https://www.youtube.com/watch?v=IfU47Oqq9wA Here is someone setting HS6 on a TR4 https://www.youtube.com/watch?v=Eukw8YZsFHA Cheers Peter W Quote Link to post Share on other sites
DavidBee Posted May 26, 2020 Report Share Posted May 26, 2020 (edited) 31 minutes ago, EliTR6 said: Arggggghhhhhghhgghhhhhhrrrhhhhhhh How very frustrating, Eli! Be kind to yourself. You've done so much in such a short time. The electrics, the screen, underbody waxoyling, oh, and seats; even the upholstery! That's quite some achievement. I can think of only one thing which would possibly be more frustrating still. Edited May 26, 2020 by DavidBee Tweaking Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 (edited) 1 hour ago, DavidBee said: How very frustrating, Eli! Be kind to yourself. You've done so much in such a short time. The electrics, the screen, underbody waxoyling, oh, and seats; even the upholstery! That's quite some achievement. I can think of only one thing which would possibly be more frustrating still. Thanks David and thanks everyone for the kind advice I should have stuck with the old carbs. Better the devil you know! I really thought the new onea would be plug and play I just started the car again and the problem (rear) carb is sucking a lot of air and the front one hardly anything. I'm going to give it a rest for now. Cheers everyone Edited May 26, 2020 by EliTR6 Quote Link to post Share on other sites
EliTR6 Posted May 26, 2020 Author Report Share Posted May 26, 2020 (edited) Went surfing with mates to clear my head. Much better! I did the drop test on the difficult carb. 8-10sec. I've got the old sm needles and new spare jets. I could always remove the spring seat if I need to test other needles. I was told the carbs had BDM needles and yellow springs fitted. In fact, they are TW needles, a very different profile (and fixed, not biased like BDM) and the springs don't have any markings on them. The specialist who sold me set hasn't replied to my polite email from over a week ago so I'm on my own (thank heavens for you chaps) on this one. I'm going to order the SU adjustment kit. Hopefully I'll get it by the end of the week and I'll clean everything with clinical care and do the drop test with both pistons. Should the linkage rods between throttle bodies and choke be able to swivel within the nuts when disconnected ? They're very tight even and needed a bit of a rub with emery paper to fit. Throttle stop is all the way out, linkage is disconnected and the spring is pulling the spindle closed. Without taking the carbs off to shine a light through the other side, it does look like it's not sealing perfectly on the bottom. Am I being paranoid? Edited May 26, 2020 by EliTR6 Quote Link to post Share on other sites
Lebro Posted May 26, 2020 Report Share Posted May 26, 2020 I see what you mean, maybe the butterfly needs to be centered. This is done by slackening the two screws holding the shaft to the butterflys (just a little - you won't be able to unscrew them as the they are peened over), just enough that the butterfly is not tightly clamped. Then by wiggling the butterfly in the shaft while trying to close it it should self centralise. I'm surprised you have to do this though. Bob. Quote Link to post Share on other sites
EliTR6 Posted May 28, 2020 Author Report Share Posted May 28, 2020 On 5/26/2020 at 11:29 PM, Lebro said: I see what you mean, maybe the butterfly needs to be centered. This is done by slackening the two screws holding the shaft to the butterflys (just a little - you won't be able to unscrew them as the they are peened over), just enough that the butterfly is not tightly clamped. Then by wiggling the butterfly in the shaft while trying to close it it should self centralise. I'm surprised you have to do this though. Bob. Thanks Bob. You and me both The piston clunks perfectly with a 0.25mm (0.01") spacer slid under one side of the dashpot so I know it can line up Quote Link to post Share on other sites
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