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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - To ream or not to ream

I‘m having g difficulty restoring the H4 SUs from my TF. What is a better option? - reaming the body and fitting O/S shafts, or inserting bushings and using standard throttle shafts? Also, what is the best bushing material? Where can I get bushings or can I get them made?

It seems the reamer is impossible to find, unless of course, someone has one to rent. Moss is back ordered, and the maker Cobalt, will not sell me one on the grounds that it is a priority label (I guess Moss).

I had detected a slight ovality in the piston - from roughly 1.487, to 1.490". Is this enough to require any machining? Also, there is a bit of Piston movement inside the bell.

My machinist is a motorcycle guy and has rebuilt many Amal carbs, and this usually requires a sleeve in the piston. That is his thinking.

Is there any documentation on how to rebuild the H4 SU?

Gord Clark
Rockburn, Qué.
Gord Clark

I think there is a good You Tube video by Joe Curto on how he does the SU throttle shaft replacement/rebushing. Beyond my skill levels so I outsource this type of work to him.
John Quilter (TD8986)

I agree with John … send them out. Joe is very good and you’ll get a complete rebuild. Magic
gl rombough

GL Rombough: Agreed, Not cheap or fast but they come back looking like new from Burlen Ltd. and are basically plug and play.
John Quilter (TD8986)

Thanks all but I've had at good look a "sending them out". For purely political reasons, I trying not to do any commerce with the US (at least, for now ... let's see what happens). The main Canadian re-builder in Victoria is asking $800 to do my H4s. Add to that two taxes and shipping and we're at about $1,000.00

On my retirement income, that's simply not in the cards!

John Twist also has a good video on carb body rebuild. Have a look at
https://www.youtube.com/watch?v=mEaQJcwa60I

But hey ... he makes it look so simple. He has all the special and hard-to-get tools like the two reamers. Not all of us have a tumbler or sandblasting equipment or chemical cleaning baths.

Much as I appreciate your contributions, in fact, I didn't get any answers to my questions. So its back to square one.

I have several sets of H4s in various conditions. So I'm going to see what I can cobble up. I'll buy the Burlen kit Number: MRK2205G and take it from there.

Gord Clark
Rockburn, Qué.
Gord Clark

Gord, I respect your efforts to support and defend your native country.

With regards, Tom
tm peterson

Tom:- I'm not a political guy, but once in a while, y'gotta do wut y'gotta do.

Your sentiments appreciated.

gc
Gord Clark

Gord,

I totally agree with Tom Peterson and understand your response.
As for your carby query have a look at the following link - may give you some ideas.

https://www.triumphexp.com/forum/tr4-and-tr4a-forum.7/su-carb-bushings-throttle-shafts.1546822/

Some years ago I re-bushed for a standard shaft using bronze bushes off the shelf from a local bearing supplier.

Good luck,
Ian
I Bracher

If you use bushes make certain you round the inner ends to match the bore of the carb. If you leave them square there will be an air leak and you will have probs with tick over.

Jan Targosz
J Targosz

Gord, I cannot believe that their is no one local to you that can re-bush throttle shafts on SU carbs.

Look for your local British car club, and get in-touch with them. If still no luck, you can contact me privately. I am in Ontario, and I think I can get them done for you.

CR.
CR Tyrell

This thread was discussed between 07/04/2025 and 26/04/2025

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