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Choke mechanism - Is it Ok?

Posted: Tue Nov 15, 2011 3:21 pm
by stephenpolhill
Hi, I have rebuilt the choke mechanism & jet on my new HS4 carb. I have put a new (non-waxstat) jet on the HS4 and used the jet linkage from my HS2. The two carbs are opposite (HS4 float is towards the rear/flywheel side of the engine, opposite to the standard HS2). It seems to work properly but I need someone to have a look at the video and let me know if the part the choke cable links to is up the right way and if the whole way it moves is correct.
Many thanks, Steve :)

Video link - http://www.facebook.com/video/video.php ... 7494081882
If this doesn't work, let me know.

Re: Choke mechanism - Is it Ok?

Posted: Tue Nov 15, 2011 6:28 pm
by simmitc
When you pull the choke cable, the jet should move downwards. Push the cable back in, and the jet rises. The throttle stop screw (or idle screw) should be set just clear of the cam, then cam should open the throttle slightly as the cable is pulled.

Re: Choke mechanism - Is it Ok?

Posted: Tue Nov 15, 2011 6:51 pm
by stephenpolhill
Okey dokey. It looks ok so ill wait to put it in the car to see :)

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 17, 2011 8:33 pm
by bmcecosse
With the float bowl on that side - when you accelerate the fuel will be thrown back away from the jet - weakening the mixture, and equally when you slow/brake the fuel will surge forward causing flooding. It's on the forward side of the standard carb for good reason......

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 17, 2011 11:13 pm
by stephenpolhill
Ah...

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 17, 2011 11:16 pm
by bmcecosse
It may be ok - try it and see .

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 17, 2011 11:23 pm
by mach2
Ive got a backwords HS4 and its fine for me :D

Re: Choke mechanism - Is it Ok?

Posted: Fri Nov 18, 2011 12:07 am
by stephenpolhill
It makes sense though, I see where the problem lies.
Maybe it'll come in use, I can't accelerate hard so I save fuel.. ;).
I'll see what happens and cheers for the heads up

Re: Choke mechanism - Is it Ok?

Posted: Fri Nov 18, 2011 12:27 am
by bmcecosse
An HIF 38 is a far better carb all round.......and none of these worries.

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 12:34 pm
by stephenpolhill
BMC - I have a new 'right way round' HS4 its way. This is because the cables didnt quite reach the new carb linkages & in case of any issues, I wanted to be able to swap straight back to the old HS2 rather than changing cable lengths.
I will transfer the AAA needle over to it (if it hasn't already got one!) & see if the linkage fits to it. Finally on the way to getting it running :lol:

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 4:19 pm
by bmcecosse
A new long throttle cable costs little (but buy two so you have a spare) and gives a smoother action anyway - and can always be used with the original carb. Choke mech can be swapped side for side on the HS4 - or the cable inner can be extended slightly.

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 5:09 pm
by stephenpolhill
That was an option. I did bear in mind the possible issues you mentioned about float being on the wrong side. Now I have 2 carbs with one as a spare which is good. As mentioned I'd rather have a Carb the same way round as previous but bigger than one the wrong way :p

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 9:19 pm
by mike.perry
If you had twin carbs then you would have a float chamber on each side anyway.

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 9:38 pm
by chrisryder
a very good point mike.

i like my HS4 having the float chamber at the front. it makes it look more normal to the untrained eye...

not that it would be easy to mistake my car for being standard:

Image

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 9:56 pm
by bmcecosse
That's one reason the twins don't work very well - one carb floods and the other starves when the car accelerates........ On a Mini - one carb always stutters when cornering hard. The HIF carbs are a BIG improvement.

Re: Choke mechanism - Is it Ok?

Posted: Wed Nov 23, 2011 10:03 pm
by stephenpolhill
Certainly interesting..

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 24, 2011 11:48 am
by mike.perry
bmcecosse wrote:That's one reason the twins don't work very well - one carb floods and the other starves when the car accelerates........ On a Mini - one carb always stutters when cornering hard. The HIF carbs are a BIG improvement.
Maybe those conditions apply on the race track but they don't seem to affect my car on the road

Re: Choke mechanism - Is it Ok?

Posted: Thu Nov 24, 2011 5:25 pm
by bmcecosse
You are just not accelerating hard enough........ it is a marginal thing.