Old School and Other Rotary Old School and Other Rotary Powered Vehicles including performance modifications and technical support

tuning rx2 1974 hitachi carburetor

Old Jul 2, 2005 | 02:43 AM
  #1  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
tuning rx2 1974 hitachi carburetor

I am having difficulty tuning my hitachi carb from an rx2. It seems to be leaning out. I have messed with the adjustment screws, but if anyone has a diagram or anything that would help me much. There's a big flathead screw in the center (don't know what it does), a 10mm screw (might be the a/f mixture screw) and over by the throttle linkage there's a smaller screw with a flathead insert for the idle screw only. But I don't know how each should be set. Normal driving is a bitch. It seems to be leaning out just driving normally partial throttle. It will stutter unless more gas is applied. I managed to richen it up so when WOT it doesn't stutter, which it used to. Please any help is appreciated. This new carb is crazy difficult to tune compared to the nikki. Thanks
Reply
Old Jul 2, 2005 | 12:57 PM
  #2  
Jeff20B's Avatar
Lapping = Fapping
Tenured Member 15 Years
iTrader: (13)
 
Joined: Aug 2001
Posts: 15,725
Likes: 91
From: Near Seattle
I rebuilt an Hitachi last week and it ran very smooth even before adjusting any screws. Maybe that carb of yours needs a rebuild?

By the way, the Hitachi carb is for a 13B. Does your RX-2 have a 12A? If so, just get another Nikki (maybe from Sterling).

If you decided to get another Nikki, would yopu be willing to sell the Hitachi? Do you have any pictures?
Reply
Old Jul 2, 2005 | 01:18 PM
  #3  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
probably does need a rebuild. from what i can tell its seems that the car stutters so maybe a theres not enough pressure forcing the fuel out of the one jet. one is flowing more at idle than the other.

yes its a 12A i still have my nikki in my rear hatch, as well as tons of water just in case anything goes wrong where i need to do a carb swap on the highway or something

i would sell the hitachi IF it was mine to begin with, i put it on to test it out, im on a trial period. if i liked it then i might buy it. it seems that this one is too much of a handful im gonna have to go back to stock nikki and my original clutch fan im sure. lame

and sorry no pics. =(
Reply
Old Jul 2, 2005 | 01:54 PM
  #4  
Matt22's Avatar
Fear The RE
Tenured Member 15 Years
iTrader: (10)
 
Joined: Dec 2001
Posts: 2,743
Likes: 2
From: Oregon, USA
why woudl ypou have to swith back to your original clutch fan?
Reply
Old Jul 2, 2005 | 10:34 PM
  #5  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
Ok I thought it was listed, but I'm in arizona constantly in 100-120 degree weather. The e fan I have installed doesn't cover my entire shroud thus my cooling is pretty shitty.
Reply
Old Jul 2, 2005 | 11:58 PM
  #6  
Matt22's Avatar
Fear The RE
Tenured Member 15 Years
iTrader: (10)
 
Joined: Dec 2001
Posts: 2,743
Likes: 2
From: Oregon, USA
why not buy a better e-fan? should be better than the stock fan, well i would think at least.
Reply
Old Jul 6, 2005 | 12:33 AM
  #7  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
This isn't helping. I need a diagram of this carb to find what the hell I am tuning here. Does anyone have one? Does anyone know who has one? Anything. I'm running out of options here.

And matt22, I don't have money for an efan, I need help with the carb, I could care less about the fan.
Reply
Old Jul 6, 2005 | 01:16 AM
  #8  
staticguitar313's Avatar
R.I.P. Icemark
Tenured Member: 20 Years
iTrader: (2)
 
Joined: Sep 2004
Posts: 4,229
Likes: 1
From: gilbert, arizona
where in Az are you?
Reply
Old Jul 6, 2005 | 01:46 AM
  #9  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
Avondale
Reply
Old Jul 6, 2005 | 01:51 AM
  #10  
jays83gsl's Avatar
1983 GSL, 1987 323 "GX"
Tenured Member 05 Years
 
Joined: Jun 2004
Posts: 2,265
Likes: 0
From: Las Cruces, NM
You need to pull all the damn cacti out of your carb!


Make a mark to see where the screws are, and try messing with them. If you're lean, then un-lean it.
Reply
Old Jul 6, 2005 | 01:59 AM
  #11  
IanS's Avatar
Ricer
Tenured Member 15 Years
iTrader: (4)
 
Joined: Jun 2004
Posts: 4,424
Likes: 1
From: Washington, Iowa
yeah man "un-lean" it.
Reply
Old Jul 6, 2005 | 02:08 AM
  #12  
jays83gsl's Avatar
1983 GSL, 1987 323 "GX"
Tenured Member 05 Years
 
Joined: Jun 2004
Posts: 2,265
Likes: 0
From: Las Cruces, NM
Yeah, make fun of my terminolgy smarts
Reply
Old Jul 6, 2005 | 03:13 AM
  #13  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
Guys don't ***** my thread I need help. Lol
Reply
Old Jul 6, 2005 | 03:43 AM
  #14  
IanS's Avatar
Ricer
Tenured Member 15 Years
iTrader: (4)
 
Joined: Jun 2004
Posts: 4,424
Likes: 1
From: Washington, Iowa
OK, I talked to tougeFB on aol, and I told him that I thought that there might be some old gunk or some sort of buildup in the jet or possibly in the fuel line itself that could be causing the restriction. I am not sure how the Hitachi carbs are set up but if it is anything like the nikki, then this seems like a possible culprit to me.
Reply
Old Jul 6, 2005 | 09:09 AM
  #15  
Hullie's Avatar
My Deuce Coupe
Tenured Member 05 Years
 
Joined: Aug 2004
Posts: 409
Likes: 0
From: Bay Shore
And the Remedy is...........
Reply
Old Jul 7, 2005 | 10:37 AM
  #16  
tougeFB's Avatar
Thread Starter
10AE>ALL
Tenured Member 05 Years
 
Joined: May 2005
Posts: 167
Likes: 0
From: AZ
No help? Bummer. Bump
Reply
Old Jul 7, 2005 | 11:59 AM
  #17  
Crit's Avatar
No distributor? No thanks
Tenured Member 15 Years
iTrader: (6)
 
Joined: Oct 2003
Posts: 3,438
Likes: 6
From: Outskirts of Road Atlanta
If you having spotty performance on a carb you've never rebuilt, you need to rebuild the damn thing. It'll take you an afternoon at most, will rule out the whole "junk in the carb" possibilty, and let you look for stuck, broken, or misinstalled hardware from a previous owner. You need to take it off and go through it. It won't take long.
Reply
Old Jul 9, 2005 | 01:53 AM
  #18  
Rx4 whore's Avatar
Junior Member
Tenured Member 05 Years
 
Joined: Jul 2005
Posts: 49
Likes: 0
From: Australia
stop whinning & have a play with it - its the only way to really learn & you may drop your ***** doing it.


ohh, and the 'not enough fuel pressure' bs that you wrote earlier, it is a gravity/vacuum fed carby - as long as there is fuel in the bowl & no blockages & there is suction through the venturies - then you will have fuel entering the manifold/motor.


the hitachi's are a good (stock) carby (as are the nikki's) - make sure your secondaries are opening (this applies to both makes)


if the g ggur gur gur stuttering is when you are taking off/accelerating, then you may need to adjust the accelerator pump. get it idling nicely before you start playing with it 1st

have fun

Last edited by Rx4 whore; Jul 9, 2005 at 01:58 AM.
Reply
Old Sep 5, 2019 | 01:52 PM
  #19  
74dogcruzer's Avatar
Junior Member
 
Joined: Sep 2019
Posts: 12
Likes: 0
From: Las Vegas
I have a couple truck hitachi's....

Originally Posted by Jeff20B
I rebuilt an Hitachi last week and it ran very smooth even before adjusting any screws. Maybe that carb of yours needs a rebuild?

By the way, the Hitachi carb is for a 13B. Does your RX-2 have a 12A? If so, just get another Nikki (maybe from Sterling).

If you decided to get another Nikki, would yopu be willing to sell the Hitachi? Do you have any pictures?
I have a couple Hitachi's from my truck collection, dying to do the Nikki mod set up on a RB mani... Will it still have good results. Thinking long runners is good thing...
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Andrew7dg
1st Generation Specific (1979-1985)
3
Aug 6, 2017 01:41 PM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 07:45 AM.