Mikuni HSR 42 : V-Twin Forum: Harley Davidson Forums

Will-Run · 08-30-2009, 08:52 PM

Hey Scott.
Will a Mik42 feed an S&S 107-T with headwork, cc ed, tightened up squish, 10:1 static with Wood 6h, If one stays a grand south of 6.?.
I'm looking for awesome throttle response.

Thank you much for your time and wisdom.

rcsoftail · 08-30-2009, 11:24 PM

I am running a hsr42 on my 106 with r&r heads, 10.5:1 compression and s&s600 cam. It runs great. Moved the needle up one clip, using a 170 main jet and a 60 accelerator pump. I am sure I would get a little more wide open throttle power if I had a hsr45, but already had the hsr42. Everything except for wide open throttle should be the same between the hsr42 and hsr45 due the nature of a flat slide. If you have a choice, go with a hsr45, but I wouldn't spend the money if you already got the hsr42.

Dyna494 · 08-31-2009, 03:40 AM

Quote:

Originally Posted by rcsoftail

I am running a hsr42 on my 106 with r&r heads, 10.5:1 compression and s&s600 cam. It runs great. Moved the needle up one clip, using a 170 main jet and a 60 accelerator pump. I am sure I would get a little more wide open throttle power if I had a hsr45, but already had the hsr42. Everything except for wide open throttle should be the same between the hsr42 and hsr45 due the nature of a flat slide. If you have a choice, go with a hsr45, but I wouldn't spend the money if you already got the hsr42.

Would you recommend the HSR 42 or 45 on a 80 with screamin eagle headwork.

(Don't know exactly what other headwork but the motor has 80 HP and 74 ft lbs torque)

Thanks

Hillside · 08-31-2009, 06:08 AM

Quote:

Originally Posted by Will-Run

Hey Scott.
Will a Mik42 feed an S&S 107-T with headwork, cc ed, tightened up squish, 10:1 static with Wood 6h, If one stays a grand south of 6.?.
I'm looking for awesome throttle response.

Thank you much for your time and wisdom.

That carb will handle that engine, as long as peak hp numbers are not a large concern.

Scott

rcsoftail · 08-31-2009, 01:48 PM

Quote:

Originally Posted by Dyna494

Would you recommend the HSR 42 or 45 on a 80 with screamin eagle headwork.

(Don't know exactly what other headwork but the motor has 80 HP and 74 ft lbs torque)

Thanks

I think the hsr42 is a nice size for an 80 incher, even with head work.

4XLT · 08-31-2009, 02:26 PM

mine works well

Will-Run · 08-31-2009, 05:47 PM

Quote:

Originally Posted by Hillside

That carb will handle that engine, as long as peak hp numbers are not a large concern.

Scott

At what rpm with this motor, would the 42 become the stopper?.

Hillside · 09-01-2009, 06:51 AM

I'd bet that it would show signs of it at 5300-5500 on that 107", but usually that is enough anyway.

Scott

dog155 · 09-01-2009, 08:00 AM

Think about how many times you would be revving your motor into the 5500 rpm range.Most of us ride well below that,unless challenged.Even then our Harley motors are torque monsters,my belief is without mega cubes, optimize what you have for the riding you do the most.Too big a carb will hurt off idle performance.

Will-Run · 09-01-2009, 07:16 PM

Quote:

Originally Posted by dog155

Think about how many times you would be revving your motor into the 5500 rpm range.Most of us ride well below that,unless challenged.Even then our Harley motors are torque monsters,my belief is without mega cubes, optimize what you have for the riding you do the most.Too big a carb will hurt off idle performance.

Solid truth.
Thanks.

TheNowhereman · 09-02-2009, 10:55 AM

You'll get decel popping coming out of your ass but, it will work with normal riding habits.
Better just get the 45 and be done with it.

tjglide · 09-02-2009, 10:23 PM

Quote:

Originally Posted by TheNowhereman

You'll get decel popping coming out of your ass but, it will work with normal riding habits.
Better just get the 45 and be done with it.

Can you please explain why decel popping would be worse with a smaller carb? I am experienceing decel popping with my MIK 45 right now.