Healeys with Mikuni Carbs

[steveg]

Anyone doing this? I'm in the process of installing HSR 45s on my Healey. Quite a few Triumph owners use Mikunis.

 

[GregW]

Why yes, I did it. Triple HSR42's.

 

[Bob_Spidell]

'In the process?' Looks like they're ready to run to me!

What's the advantages to these? Hard to tell function from form, are they constant or variable choke? Is this a kit? Did the offset air cleaners come with them?

 

[Jerry]

Tried them on my mini. Too much gas at lower rpm. but at high rpm, sounded like a Harley taking off!

 

[steveg]

Properly tuned, they should provide near-Weber power with better-than-SU mileage. Accelerator pumps provide livelier pickup.

All these claims have yet to be verified by me - will report back as I learn more. Car runs OK with as-delivered carbs, but some tuning is required. Extensive tuning information available online. Requires reconfiguring distributor for manifold vacuum.

It's a kit from > Vintage Performance Developments - Performance products for vintage street and track cars <

Tons of info on that site.

Kit was just over $1100.

Because my DMD manifold uses horizontal carbs, I had to do a number of mods which aren't necessary with a stock manifold.

V-performance sent me this pic of a Healey undergoing installation - Plenty of room for K&Ns without my extensions. The rings shown on mine attach to the carb venturi with set screws:

 

[Bob_Spidell]

Thanks for the info, Steve.

 

[gonzo]

A set of Mikunis and headers is now on my Healey wish list. Thanks Steve for sharing. Let us know how the new carbs work out.

 

[steveg]

The Mikunis don't have a fast idle setup, so I built this hand throttle from a lawnmower throttle and some aluminum angle:

 

[vette]

Nice work.

 

[BoyRacer]

I like your engineering.

 

[gonzo]

Nice clean set-up. Me like. Is this fast idle cable operated separately from choke for cold start ups? When would fast idle be used?

 

[steveg]

The Mikunis have only a mixture-enrichment device - similar to Weber DCOEs. Rather than running the mixture enrichment until the engine's warmed up, as soon as it starts, I pull out the hand throttle to 1500 rpm or so, then push in the mixture enrichment. Trying to keep extra fuel off the cylinder walls. So yes, it's separate from the mixture enrichment.

It's like a motorcycle - you enrich it to start, then once started hold a little more throttle until it's ready to go. Since these carbs were originally made to replace SUs on Harleys, that's probably how they do it.

 

[John Turney]

That's kind of like the electric enrichment carb on early 3000 Mk II's before they found out how much trouble they were.

 

[steveg]

I always wondered about the complexity/unsatisfactory issues - Jaguar used the thermal carbs even going back before the war.