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Discussion Starter #1 (Edited)
Stock Hitachi carby trouble-shooters guide for Sierra & Samurai

I'm wanting to switch to a CV carb for my 1990 hardtop, but i'll have to hold off for now while I wait for spare $ to brew. I also want to 100% confirm the legality of the conversion before I go and spend any money unnecessarily... so i'll stick with the stock Hitachi carburetor for now.


As i'm just a newbie to Suzuki mechanicals, i'm hoping to gather a trouble-shooters guide a 'backshed mechanic' like myself can use to keep the Hitachi carb well maintained - things like how clear fouled jets (hopefully without removing the carb), general issues of the unit (if any), adjusting idle speed, rich/lean adjustment... i'd love to go off a photo of decent size and have the adjustment screws clearly labelled and identified - but that might be asking a bit much.

I'd also like to know if a Hitachi carb is one in it's own, or are there various Hitachi carb models/variations I should be informed of?


I've pulled up a few dead links searching for a topic like this, and diagrams either too small or vague to gain visual reference. So any expansion of details would be greatly appreciated.
 

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Discussion Starter #2
Here's some pics of my WD40-covered carb! Hopefully somebody can label the numbers for me:






... some more from another perspective:






There may be more screws, but that's all I can see with easy-ish access
 

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well those are some very nice pics... but that's not the hitachi carburetor.

I did notice that what looks like your accellerator pump is not hooked up to anything.
 

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Discussion Starter #4 (Edited)
Yeah, my bad - i'm getting confused between the Aussie Sierra and US Samurai... I just assumed they'd be running the same carby for some reason.

This model is actually a Suzuki carburetor, not sure of the exact spec, but factory issue in Australia at the time.


After a fiddle (1) is obviously the idle speed adjust, (2) is fuel/air ratio, (3) and (4) are the hot and cold water choke adjustments.



I'm getting to know them well now - after another week of procrastinating a fix my carby has shown a bad temper and is running like junk, i've now 'obviously' got a vacuum breach in the system - i'd suspected the unknown old fuel tank dreggs and gunk I dragged through the carb a few weeks back, or maybe I was running too lean.

My non-stalling idle speed is varying hot and cold between 1300 and 2500 RPM, i've had to wind up the idle speed so i'm not stalling in city traffic (soo embarrassing at lights when idle speed is whirring at a rough 2500RPM with louder free-flow exhaust!! Just waiting for a cop to pull me over!!!). It also seems to be fuel-lean in acceleration, with a rich running splutter occasionally when shut down.

I've tried spraying a carby cleaner aerosol around the topside manifold gaskets to check for a breach (during my break at work), I'm yet to get to the underside intake manifold / block gasket area to see what that does. It seems the best improvement is when sprayed directly into the carb for a short burst 'before' starting - it starts rich, but the stalling disappears... for 15 - 30 seconds.

I assume my carb's dead so i've got a rebuild and tune booked for Monday by the locally recommended carburetor specialists.



I've been told now by various Sierra owners/repairers that these factory carbs are the best to run in Australia. Webers are on par - but no real improvement to a well tuned factory spec carb (apparently, don't quote me). Harley parts in Oz are WAY over-inflated, so too servicing costs, and parts aren't as easy to come by as in the US, and i've now officially been informed a HD CV conversion WON'T pass RWC due to various mod compliance issues (in QLD, AUS) - so whammy that too.


Just filling in the FYI, and hoping for some in return, maybe. I'm now curious about the Hitachi carb. I guess the Japanese carb guru can fill me in when I see him in a couple days.
 

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I would say that thats an Hitachi carb, there are a number of different versions. I'm no expert but I'm pretty sure that:
1 is either the idle speed adjuster or a fast idle adjust for when its running on choke
2 is the idle mixture adjuster
3 is an idle up valve of some sort
4 is the throttle stop screw

The thing that looks like an accelerator pump looks to be connected on the side away from the camera.
 

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I'm pretty sure that's the aisin carb that the non-U.S. countries got. It's not as restrictive as the Hitachi but it doesn't keep the emmission polutants down as well.

Now that you know what carb it is, you will be able to get the correct rebuild kit and find the correct info on it.

here's a step by step pictoral on breaking it down

SJ413 AISIN CARB No.I (photo)
SJ413 AISIN CARB No.II (photo)
SJ413 AISIN CARB No.III (photo)
SJ413 AISIN CARB No.IV (photo)
SJ413 AISIN CARB No.V (photo)
SJ413 AISIN CARB No.VI (photo)
 
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