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Mikuni HSR 45 MM Install on my 142

Turborg

Turborg

Active member
Joined
Jun 22, 2003
Location
Northern Ca
I had a set of Mikuni HSR 42 MM on the green 72 142 that I really liked so I decided to install the 45MMs on my stroker motor. The conventional way to install these is to extend the throttle shaft enough that you can attach linkage with shaft couplers. I decided not to go that route and decided to fabricate a cable system. The linkage I am putting together will not be the final linkage but it is fast and easy and retains most of my HIF 6 linkage so I can reinstall the SUs if I can't get the Mikunis tuned. I have purchased and installed the float valve that can be used with a fuel pump(2.3 instead of the stock 4.1). I installed 22.5 idle jets to replace the 25s. I used 187.5 main jets to replace the stock 175s. I am going to try the stock needle as I have several sets of main jets. I have the parts to finish now. The pics I have are huge so I am linking to my album. Schroll down on the pics for info.
http://www.pbase.com/turborg/mikuni_hsr_45_install
Hope to be driving it by noon Sunday
 
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Not running yet but assembly worked out

I added some pics of the finish fabbing. Trial and error has shown I will have to make some changes on the final install. the carbs are syched and it is drivable to see if the Mikunis will work out. Need to hook up the gas and change a couple of fittings.
http://www.pbase.com/turborg/mikuni_hsr_45_install
 
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Finished the cable linkage

After a 2K shake down, I decided to take my engine apart to fix a rear seal leak, change the camshaft from vv-71 to vv 349, paint the engine, paint the engine compartment, and adjust the T-5 trans mount.

I finally got back to working on the cable linkage after the engine was installed again. I decided to fix the trans in the car after the engine was in. Feel good about being able to stab the two together by myself. Very little room to maneuver.

Two more cable linkage pics. Scroll to the bottom for text. Change the picture size to original to see details.

hope to have it running soon.
http://www.pbase.com/image/164956917
http://www.pbase.com/turborg/image/164956915
 
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Wow, the 71 ran out that early? The 61 I had was done by 5k, figured the 71 should have wound out a little better.

This dang VPD cam doesn't stop it seems, clear to 6500 so far, even looking at the dyno. Sure wish I knew what it was. Might have it checked when I do the build on that car, just to get an idea.
 
gsellstr said:
Wow, the 71 ran out that early? The 61 I had was done by 5k, figured the 71 should have wound out a little better.
Click to expand...

My friend Ian tells me that more cubic inches will tame a cam and I feel like that is the reason the 71 ran out of steam. I had one in my 122 that pulled to redline.
 
Progress on the install

I have finished the linkage install and the car is driveable now. I purchased this Speedhut setup as I was having trouble getting my Mikunis set correct.
165138856.jpg

This has the details.
http://www.speedhut.com/gauge/GR-AF...e-with-built-in-controller-8-5-18-(w--warning)
The car was very quick up to about 1/4 throttle and then would lean out. After installing the system it showed an AFR of 11 to 12 off idle, but headed lean as soon as the needle jet was controlling the mixture. I have more needles and jets ordered.
So far I am very impressed with the wideband o2 system and it will make setting the carbs easy. Of course it went on sale a week after I bought it!
 
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sorry for bumping this thread, but did you get it running properly? i wan't to build a b20 for 150+ hp . so i figure this carbs could be a good choice for me.
 
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