Fall 2019 Wrap Up and Mikuni Update

Greetings from NW Ohio, where we have had 4 inches of snow already ! Fortunately I started my fall "putting Tillie to bed" routine early this year (mid October), so no worries about cold weather and Triumph abuse. :-)
A nice October week-end afternoon drive with wife Rhoda and dog "Happy" turned out to be the final TR6 voyage for 2019.

Happy dog needed some treats, so the first stop was our favorite pet store where "Barking Spots" are reserved for canine owners' vehicles...Miss Tillie fit right in!   

The roads along the historic Maumee River are always a favorite journey...especially this year since I recently read some War of 1812 history. One incident I read about was Dudley's Massacre, and it was not a bright spot in American military history. Dudley and his troops where supposed to come down the river from Grand Rapids,  spike the British cannons on the Maumee (north) side of the river, then retreat back across the river to the American encampment at Fort Meigs. Unfortunately, after they successfully spiked the cannons, the Indians drew them deeper into the forest where they were surrounded and suffered high casualties. 

So what's a TR6 adventure without ice cream ?  We recently discovered this candy/ ice cream shop in downtown Maumee...a great end to our day trip adventure!

Want to mention the annual "Cars for Critters" car show that is held each September.  "Cars for Critters" is a fund raiser for the Ottawa National Wildlife Refuge here in NW Ohio. Where possible, cars are put in classes with wildlife names.  Such as, a Plymouth Barracuda would be in the Fish class, a Ford Falcon would be in Best Bird, and the Ford Mustang in Mammals, etc., and then they have best of the '40's, '50's and '60's etc.  Tillie won her class (Exotic/Foreign) among some stiff competition from other British cars. The weather was beautiful, great crowd, and everyone had a fun time.

So that leaves the Mikuni Carburetor update... the short version is switching from the ZS carbs to the Mikunis has been a positive experience...no stuck needle valves!!  I did change the main jets from 165 to 160 and the pilot jets from 22.5 to 20.  The air /fuel gauge was showing a rich condition (11-12) and my mileage was around 18 mpg avg.  After the switch, air /fuel gauge went to 13-14 and mpg jumped to 21 mpg avg. To be honest, I never really checked the mileage while using the ZS carbs so I don't have a base line to compare with. Tillie runs very strong after being warmed up...however, she is a bit cold blooded for the first few miles.
I had hoped to put Tillie on a rear wheel dyno this summer but it didn't work out , so look for a dyno report in 2020.

 Ok, now I'd like to share some information that some of you may not know...the difference between  Phillips head screws and JIS (Japanese Industrial Standard ) screws. I found out that trying to remove a JIS screw with a Phillips screw driver can be a real problem. Philips are made to "cam out" to avoid over tightening. JIS screws stop / reduce this cam out action. The big problem for shade tree mechanics like myself is these screw drivers look the same unless you look really closely. Or look at the head of the screw...if there is a dimple on the screw head (photo below) get out your JIS screw drivers. I ended up buying a set of JIS screw drivers to remove the float bowls on the Mikuni Carbs for changing the jets and was amazed at the difference. I ruined one of the float bowl screws trying to remove it with a Phillips screw driver. The JIS tool popped those screws loose with no problem.

So the moral of this story is, if you are working on anything that might be made in Japan, check for dimples on the screw heads!

We are almost to Thanksgiving here in the U.S., and of course December is fast approaching...then the year 2020! arrives already.
Best Wishes to everyone for an enjoyable Holiday season!

Spring 2019 / Goodbye ZS... Hello Mikuni !

Nope, I didn't give up and sell Miss Tillie...she's much too attached to our family for me to do anything that drastic!  However, sticking needle valves in the ZS (Zenith Stromberg) carbs did cause me to start down a rather drastic path concerning carburettors last fall.

Some of you may recall that I had a very qualified carb guru give my ZS carbs the once over trying to resolve poor idling and sticking needle valve issues. "The three darlings", as I liked to call them, seemed much better after the do over, but that lasted less than a year when the needle valve issue once again raised it's ugly head.

The "three ZS darlings"

ZS needle valve...brass color with plunger in the middle and a hole on either side 

 

Late summer 2018, I had to turn back home on the way to 2 different car shows because of stuck needle valves...wife Rhoda, being the ever sensible one, asked me, "Isn't there a more modern thingie available to replace the ZS thingies" ?
Well of course that got me thinking and I remembered hearing about Mikuni carbs.  A Google search turned up John Parker's company, "Vintage Performance Development"  http://www.v-performance.com/products/air_fuel.html.

A  review of the excellent web site convinced me that three Mikuni HSR 42 carbs might be the answer to my carburetor issues, which had been going on since 2014.

I exchanged emails with the owner John Parker who answered all my questions, so last fall I went ahead and ordered all the parts John recommended.

Left side

Rear view

Right side

 I order the optional tuning kit (recommended) that provides additional main, pilot, and needle jets allowing John to customize the Mikunis based on the performance modifications on my engine. This option not only provided a good starting point for tuning, but allows for any future changes.

I was able to reuse the "Goodparts" triple manifold  from the ZS setup.

The Mikunis are quite easy to install via rubber boots and clamps.

I cut the provided steel rod and used the provided couplings to link the three Mikunis. 

I needed to provide the fuel line, "T" connectors, and shut off valve (optional) to plumb in the fuel connections.  The cable running from the choke hardware to the fuel line clamp is to stabilize the fuel line ( my rube Goldberg setup ).  :-)

The reused "Ratco" throttle linkage did require a bit of modification to fix the pull angle as seen   below.

I bolted an extension to the original Ratco bracket to move the throttle cable out and more in line  with the throttle arm.

The final piece of the puzzle is the hardware kit John provided for the chokes a.k.a. "starter plungers". The chokes face the front of the car, so a special bracket is needed to be mounted on the front carb.

Rear view showing the starter plunger cables...note the main choke cable on top of bracket

John's kit provides 3 different length cables (one for each carb) to accommodate the different distances between carbs.

Finally, I needed a locking choke cable to replace the ZS cable.  It turns out the MGB choke cable was the perfect answer...right length and it locks on. I did need to turn to ebay to procure the MGB cable.

Plungers locked "on"

Final setup...this conversion is not what I would call "plug and play", but it is very well thought out, and the average car guy (or gal) can do the work themselves.

I only have driven Miss Tillie about 100 miles since finishing the Mikuni conversion, but so far it seems that I'm on the right path.  The idle is definitely better, and the power is strong all through

the rev range.  

 More Mikuni updates to come. 

Happy Summer Motoring !!