10 replies to this topic

[minimuk]

Hi,
Just wondering if it is a good idea to replace the existing HS4 Carb on my 998cc engine with a HIF38 carb (just bought) will this enhance the engine preformance or will it be of better use on a 1275cc engine (which I am building at the moment).
thank you

[AVV IT]

It will make no difference as they are virtually the same carb. The main difference is that the HIF38 has an integral float chamber, whereas the HS4 has the float chamber bolted to the side. The HIF38 is the basically the same size as the HS4, but an updated metric version of it. (the HS4 being 1" + 4/8" = 38,10mm and therefore virtually the same size as the 38mm HIF38.)

The HIF38 will be suitable for a standard 1275, but even a mildly modified 1275 really requires a HIF44.

Edited by AVV IT, 10 August 2011 - 09:22 PM.

[Dan]

The 998 will be a bit more economical with the HIF than with the HS assuming they are both properly set up and tuned, but that's it really. As said they are the same size carb.

[bmcecosse]

You could take the time to 'Vizardise' the HIF 38 - and then fit it!

[AndyMiniMad.]

I wouldnt bother! As you are building a 1275, then the best carb to get would be an Hiff 44....

[minimuk]

Thanks Dan, AVV IT and bmcecosse, to re-cap, not much difference in preformance but Hif would be economical and ok for 1275, but that would be a standart 1275cc only.

Edited by minimuk, 10 August 2011 - 09:38 PM.

[minimuk]

AndyMiniMad,.. HIF 44.....makes me think...I have another option and got the gear to build a twin HS4 carb, what would that do to the 998, and what would that do to an 1275cc?

I wouldnt bother! As you are building a 1275, then the best carb to get would be an Hiff 44....

[AndyMiniMad.]

Twin carbs are a pain....Only my oppinion of course.... but a single hiff 44 will fuel anything upto and including a 1380....But remember that bolting on a carb or carbs wont give you any real performance increase unless you get the head sorted. I do like the look of the twin carb set ups and they do help the throtle response....but are harder to keep in tune.

[minimuk]

Twin carbs are a pain....Only my oppinion of course.... but a single hiff 44 will fuel anything upto and including a 1380....But remember that bolting on a carb or carbs wont give you any real performance increase unless you get the head sorted. I do like the look of the twin carb set ups and they do help the throtle response....but are harder to keep in tune.

Makes sence to me, HIFF44 is all in one rather then fetling wiv tuning every so often, I agree the twin set up's are looking good.
thanks for the advise.

[lolipop]

HIF has built in cold enrichment too compared to HS.

[minimuk]

HIF has built in cold enrichment too compared to HS.

This might sound thick but what do you mean by that,petrol stays cooler so less use for same output?