TR4/4A Install after jet gland replacement SU H6 in TR4

[Chasman3]

I have removed the carburetors from my new TR4. They were dirty and weepy on the bottom of the jet assemblies. I have completed the task of R & R but now am not sure where to preliminarily set the jet adjusting bolt on the bottom before I tune? There is a mark on the head so I set 2 1/2 turns from the bottom. Both carbs have be separated from the connecting rod which also got thoroughly cleaned. Between solvent and fine brass wheel, thing look pretty good. Carb 1 (closest to the firewall) was missing the washer between the carb body and the top half jet bearing. I'm not sure I would do this job with the carbs on the car?

Anyway, search doesn't show me but as I was typing something similar appeared on jet assembly adjustment. I want to start and tune and I believe I can start it and warm it by controlling one carb? I'd like to know what that preliminary adjust on the carbs should be?

Thanks for your help. I tried posting pictures of my car from my I phone unsuccessfully. It's a 61 CT320 L. It's in terrific original condition showing 34,000 miles.

Charlie
AKA Chasman3

 

[gonzo]

Correct. Adjust jet 2.5 turns out from fully seated. Considered a "rich" setting for the HS 6 carbs. Did you center the jet/ jet bearing on each carb? To confirm centered jets, lift the piston in its chamber, then drop. The piston should make a clunking noise as it bottoms-out and contacts the carb bridge. If the piston does not freely move up and down in the chamber, the jet may not be centered and the needle is sticking. All the best synchronizing the carbs. I use the two wires method to show where the pistons are relative to each other.

 

[Chasman3]

Thanks. It all makes sense. Yes I centered all the way up and all the way down for “click”.

Should I connect both carbs to start and warm then disconnect for tuning?

Thanks again

Charlie

 

[gonzo]

Thanks. It all makes sense. Yes I centered all the way up and all the way down for “click”.

Should I connect both carbs to start and warm then disconnect for tuning?

Thanks again

Charlie

Assuming all other functions are a "go" - spark, timing and valves etc. - then just get the engine started and up to operating temp. with carbs connected. When op temp is reached, disconnect carbs so they work independently from each other, back off choke set screw(s) and begin syncing. There's lots of good info / tutorials on the web. for this.

 

[Chasman3]

Assuming all other functions are a "go" - spark, timing and valves etc. - then just get the engine started and up to operating temp. with carbs connected. When op temp is reached, disconnect carbs so they work independently from each other, back off choke set screw(s) and begin syncing. There's lots of good info / tutorials on the web. for this.

Worked like a dream. Fabulous drive yesterday except... I pulled the new plugs and they too were black. This morning one fouled on cold start. When I removed the chambers the jet are nearly to the top. Yet it still must be rich. The engine is tight and no smoke. Plugs are Champion from Moss. Ignition electronic, high performance coil. I will say I had a number of trial and errors centering the jets. I have an aligning tool in the shopping cart. I did not replace jet heads, bearings or needles but wondering if that's the next step? It looks like needle removal is painful! But my thinking is if the jet head(S) are worn it allow more fuel to pass.

 

[gonzo]

Well, could be worn jets and /or incorrect float level. Or, fighting air leaks though worn throttle shaft(s) making correct mixture adjustment very difficult.

 

[Chasman3]

Well, could be worn jets and /or incorrect float level. Or, fighting air leaks though worn throttle shaft(s) making correct mixture adjustment very difficult.

Yes it’s a list of rule outs! I’m getting really good at removal and assembly! I think Jet heads are next. Not sure about the upper and lower bearings.

 

[gonzo]

Agreed. Jet centering tool will help, although with could be accomplished with the piston and needle trail and error. Bent needle(s) could be an issue too. So check. Unlikely upper and lower bearing(s) are worn.

I'm rebuilding a pair of HS6s now with delrin bushings and new throttle shafts installed and will be centering those jets soon.

 

[Chasman3]

Agreed. Jet centering tool will help, although with could be accomplished with the piston and needle trail and error. Bent needle(s) could be an issue too. So check. Unlikely upper and lower bearing(s) are worn.

I'm rebuilding a pair of HS6s now with delrin bushings and new throttle shafts installed and will be centering those jets soon.

Agreed. Jet centering tool will help, although with could be accomplished with the piston and needle trail and error. Bent needle(s) could be an issue too. So check. Unlikely upper and lower bearing(s) are worn.

I'm rebuilding a pair of HS6s now with delrin bushings and new throttle shafts installed and will be centering those jets soon.

I passed on the tool. And starting down the replacement rabbit hole. Just took my time and eventually got the “feel” for centering and slowly tightening the gland at the same time. I find it like tuning my guitar! The carbs are 100% correct. Now I’m searching for directions on choke install and adjustment. Odd that there is zero printed in the Triumph Tr4 workshop manual or the Complete Official Triumph Tr4 & TR4a. Only thing I found is the proper setting for fast idle Fig 5. Jet and throttle adjustment. But nothing on jet control link adjustment.

 

[gonzo]

Great to hear 100% correct adjustment and fine tuning.
On my AH 3000 with HS6 equipped carbs, the choke set-up is a very simple adjustment of the fast idle screws on the cam when the choke cables are actuated. My engine doesn't require much choke to start from cold anyway...