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Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 6:39 pm
by KTHO
Yes, No issue at all...
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 6:56 pm
by jparent
What are the jets that you have installed:
Pilot Jet
Needle Jet
Jet Needle
Main jet
what is your altitude
is this a fresh built engine with any mods,
Thanks for the pic, looks fantastic
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 6:58 pm
by jparent
Are those spacer blocks in between intake and carbs?
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 7:33 pm
by KTHO
Yes to clear the steering shaft
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 7:40 pm
by jparent
What jest do you have installed?
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 7:44 pm
by jparent
Correction: what Jets do you have installed
Re: HSR 42mm Carbs
Posted: Tue Oct 12, 2021 7:58 pm
by KTHO
Got the HSR from Vintage Performance with all jet pre set no issue on hi altitude, here is a more detail image
Re: HSR 42mm Carbs
Posted: Wed Oct 13, 2021 10:58 am
by jparent
I was just curious as to what jets you have in them, I got the same kit from vintage performance and had to totally re-jet, what is you altitude?
Re: HSR 42mm Carbs
Posted: Wed Oct 13, 2021 11:00 am
by jparent
Is your engine rebuilt? if so, is it all still stock or did you build it up a bit?
Re: HSR 42mm Carbs
Posted: Wed Oct 13, 2021 11:42 am
by KTHO
Altitude is 2 m
Re: HSR 42mm Carbs
Posted: Wed Oct 13, 2021 11:44 am
by KTHO
Engine is stock...
Re: HSR 42mm Carbs
Posted: Thu Oct 14, 2021 10:34 am
by jparent
Do you remember what
pilot jet
needle jet
jet needle (and what slot)
and main jet
that are installed in yours?
Re: HSR 42mm Carbs
Posted: Thu Oct 14, 2021 11:33 am
by KTHO
I've have to check is was long ago when I install the carbs...are you having problem with your??
Re: HSR 42mm Carbs
Posted: Thu Oct 14, 2021 7:13 pm
by jparent
A bit of a hesitation, but I also had to order other jets, Its running ok, but also think that part of that could be from an old worn out engine, also I have a 123dist. I installed as well,
But I was really curious as to what jets were in yours
Re: HSR 42mm Carbs
Posted: Mon Aug 21, 2023 5:41 pm
by augsburger
These are NOT off the shelf bolt on carbs. Imperative to install an O2 sensor for tuning carbs. (How I found out my SU's were leaning out w/ new NOS M39 needles) Need to make sure valve adjustment was correct. Then timing. Then carbs. The timing curve on my 123 was a bit modified from JT's stock settings but not much. I was having the same problem jumping on the accelerator from a downshift causing a carb backfire. I solved it with rejetting and jet needle height adjustment. Here is what I wound up with and my car is now a completely different car....YOU will have to find your own numbers for your car. This is just what I wound up with.
Main 190
Needle and seat 2.3
Needle jet Y-8
Jet needle 95
May seem complicated but not too bad. Waaay better than SU voodoo for me. I can have them off and back on in minutes and would estimate a 25% power increase. My head is a NOS iron head which I was convinced needed porting, but I got them to work without having to "drive around" the backfire. NO further issues and they sound awesome as well. I can just imagine what a stroker with these carbs would be like. My next project! Cheers!!