I run one on my 1986 ,love it, great trouble free performance.

 

Had one in my FLSTN from ‘02-‘19. Worked great for me. For my bike it was jetted a bit rich from the factory. As always YMMV.

 

I have a had a well jetted and tuned CV on Harleys and the Mikuni.
The CV is a good carb, but you cant go past a Mikuni.
Throttle response is better than the CV, they realy wake the bike up just make sure you read and understand the tuning manual.
They can be a pain to jet and tune correctly but it is worth it.

 

It is worrth if you can buy it really cheap. It makes so little diffrence that spending big $ doesn't justyfy it. But this is only my 2 cents.

 

Aussie is correct. Make sure you understand the the tuning manual. I just went through a rebuild and and tune on my HSR.

 

I will NEVER again use anything else than the wonderful Mikuni HSR

Perfectly happy since I installed it twenty years ago

 

Love the mikuni but could they please just fix the slide slap?! Couldn’t be hard to address if they wanted to. Little rollers in a channel on the slides etc. something ! Haha.
Some of us came up in the school of hard knocks and had to build or fix our things with little to no money so the habit of paying attention to odd noises is permanently engrained no matter what vehicle, new or old and that slide slap straight up f*cks with me almost on purpose haha

 

Jake, I have never heard a sound from mine, and I might not get it right - but as you suggest rollers, do you have an older version of their carbs without the roller bearing slide ?

 

Huh? Mikuni has bearing slides now? Haven’t seen or heard of that one? My mikuni def is just a slip fit in a track for the slide

 

Jake, the .."..now..." is funny...!
My HSR was installed around 2003, and the bearings-HSR was not a new release even at that time.
The previous TM 40 and the TM 42 or at least early versions of the TM 42 had no bearings.
HSR`s never came without the 8-roller-bearing-slide.

Maybe you post a pic of your carb ?
I think you might have the old TM Mikuni, not a HSR (check added picture comparison) ?


When installing the Mikuni, it replaced my Lectron.
Aside the need of almost daily adjustments on the Lectron, due to the lack of a true idle system, I once had the (non-roller) slide stuck on the Lectron.

Too bad when you have no kill switch to shut off the reving engine and the ignition switch on the left side, while you need the left hand to pull the clutch lever.
Final solution after fiddling around with the Lectron for two years was the Mikuni and I could not be happier. Best street carb ever in my 35 years HD.
The Lectron is a great race carb, but a street bike really needs a proper idle system... (and a roller-bearing-slide is not a useless thing either).......lesson I learned...

As said I never noted any sounds from the HSR on my bike (87 Evo/oem cam/ HSR 42/ Venturi w."coffee filter"/ built staggered´s w.V&H "Quiet" baffles), but here is what Mikuni states about it :
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Slide rattle:

Most HSR carburetors make a soft "ticking" noise at idle. This ticking is the result of the normal pulsing of the air in the intake system. This pulsing is caused by piston and cam action. The ticking is not a sign of wear or incorrect tolerances. It is normal.

During the intake cycle, when an intake valve is open and the piston is moving down, a partial vacuum is formed in the cylinder, intake manifold and behind the carburetor's throttle valve. The normal pressure on the out-side of the carburetor's slide then pushes the throttle valve back in the carburetor body. This movement can cause a "click".

Near the end of the intake cycle and below a critical rpm, which varies with cam design, a positive pressure forms in the cylinder, intake manifold and behind the throttle valve. This positive pressure forces the throttle valve forward in the carburetor body. This movement can cause another click.

So, the throttle valve being "pushed and pulled" by the variations in manifold pressure at low (idle) rpm results in some ticking. As soon as the throttle is opened and the throttle valve is raised, the ticking stops.

Cams that have been designed for high rpm performance usually close the intake valves much later (in crankshaft degrees) than the stock cams. The later the intake valves close, the greater the pressure on the back of the throttle valve and the louder the ticking may become.

Exhaust systems with no baffles, like long open straight pipes, also tend to increase the reverse pressure on the throttle valve.

By the way, it is the late closing of intake valves that cause "reversion" in high performance engines. Reversion is the word most commonly used to describe the fog of air/fuel ejected from the mouth of the carburetor when the throttle is opened at low rpm. Reversion disappears when the engine rpm becomes high enough that the intake valves close before the piston can push air/fuel mixture back through them.

Factors that affect slide rattle:

1) Cam design --- the later the intake valves close (in crankshaft degrees) the higher the rpm before reversion and therefore slide rattle stops.
2) Exhaust systems without baffles, particularly long, straight open pipes, increase reversion pressure.
3) Windshields, fairings and unrestricted air cleaners (like the Screamin' Eagle) echo any noise coming from the intake system.
4) Throttle valve to carburetor body clearance. There is some minor variation in the amount of play between the throttle valve and carb body.
....A "loose" throttle valve and a "big" cam can combine to make the normal ticking sound louder.
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