Pilot screws are 3+1/2 turns out front and rear

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TravisZack
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Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

As in the title, I'm cleaning up my carbs and just checked the pilot screws for the first time. 3 1/2 turns out front and rear, should I set them back to factory? The bike had some loud cans on when I bought it so maybe the PO has tried setting it.

I run a standard air filter and headers with Arrow pipes. I would say the bike seems to be running lean, but I'm no expert. I'm happy to play with them and get them right but it seems to be quite a way out. I don't really want to mess around with jetting at the moment.
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popkat
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by popkat »

At 3 1/2 turns out it sounds like it needs to go up in size on the pilot jet.
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VTRDark
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by VTRDark »

With 45 pilots the Honda manual says to set the front to 3 turns out. I wouldn't want to run with them that far out though as there is less pressure on the fuel screw spring and it would most likely work loose on my bike :lol:

I agree with Popkat if you require that many turns out go up a size on the pilot jet. But if you went richer on the needles you may find that 3 or less turns would be OK on the fuel screws. :roll: You should find out what else is going on in the carbs. What makes you think it's lean and at what revs and throttle opening.

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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

Everything inside the carbs is standard. I only mention it could be lean as I sometimes get that surge forward when rolling off the throttle, I don't know though I could be talking rubbish! It's been a while since I rode it to be honest so need to get back on again before I start tuning, they just seem a long way out.
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popkat
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by popkat »

TravisZack wrote:Everything inside the carbs is standard. I only mention it could be lean as I sometimes get that surge forward when rolling off the throttle.
Is there any play in the throttle cable, you should have a couple of mm, if you have none it's easy to get the surge you describe, it's easy to inadvertently hold it open a little. Personally I like no play in the cable but you do have to shut the throttle, you get used to it,
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2014 CRMC Post classic Superbike champion.
2014 CRMC Post classic senior production champion. On a Suzuki Katana 1100
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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

Yeah I set the cable slack when I last had it apart, it's got a little play in it. I think I'll rebuild it as is for now then try the workshop manual method for setting the pilot screws.
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Varastorm
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by Varastorm »

TravisZack wrote:Everything inside the carbs is standard.
The early VTR carbs came from the factory with #45 pilot jets standard, but later models were fitted with #48's.

The plugs should give you a good indication of your fuelling.

Have a look inside, its the only way.

Also have a look at the excellent Cyborg links :thumbup: http://www.vtr1000.org/phpBB3/viewtopic ... 18&t=31348
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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

Ok, apologies for yesterday, I've had a better look this time and seen some numbers..

Front:
Image

Rear:
Image

I had the needles out yesterday and it is all stock under there. It's an '03 so I'd call it a later model but looks to have the 45 pilot's. I've been having a read but I'm more in the mode of getting the bike back together at the moment, and I assume I'd need it running before I really know what to start playing with? It's not an area I've paid attention to before.

If there's any suggestion at this point before I reassemble and hit the starter I'd be very appreciative :thumbup:
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Varastorm
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by Varastorm »

Ideally it should have the #48's in but if you don't have them you'll just have to put it back as is & look for some :thumbup:

The setup I ran with for years was this:-

http://www.superhawkforum.com/forums/te ... -up-24769/

It was spot on with the standard velocity stacks, stock filter & straight through exhaust.

If you want to keep the #45 pilot jets have a look at my Ducati stack mod, they are required for that :thumbup:
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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

Ah yes thats a thread I've dipped in and out of! If its that straight forward to get a baseline then I ought to be doing it while it's all here in front of me.

Found the jets on eBay so will order them. Am I right in thinking you just remove the washer from the front needle and leave the rear in place, then you only need to start buying new washers if/when you start fine tuning?
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Varastorm
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by Varastorm »

TravisZack wrote:Found the jets on eBay so will order them. Am I right in thinking you just remove the washer from the front needle and leave the rear in place, then you only need to start buying new washers if/when you start fine tuning?
No, you need swap the front washer for a 1mm washer. The rear Std washer stays but that also has a 1mm washer :thumbup:

So, 1 x 1mm washer front & 1 x 1mm + Std washer rear. 1 front 2 rear :thumbup:

This setup should be used with the #48 pilot jets :thumbup:

Also make sure the jets your buying are genuine Keihin.
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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

ah ok that makes sense, it's the only bit that was worded a little awkwardly and I was wondering how they'd be raised without doing any raising :roll:

Do you know where to get Keihin jets other than the states? EBC sell some that are supposedly exact copies for flow rate etc, and they could be here on Tuesday. I don't even know what difference, if any, I'm gonna feel from doing this to be honest.
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kev64
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by kev64 »

Read Hawks Carb tuning guide, I got 48s fitted, removed the front needle washer only
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TravisZack
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by TravisZack »

Hawks guide is what I was referring to, it's written as if you don't put any washers in, just remove the front one. So you guys have done it both ways... who's right :wink:
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macdee
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Re: Pilot screws are 3+1/2 turns out front and rear

Post by macdee »

i think what he is saying is to remove the front washer and replace with a .040 washer and then leave the rear washer and add the extra .040 washer as well

Then you need to shim up the needles. While they have a very good profile, they are a little too long for performance. The question here is how much do you shim them. Around .040" is a good starting point but will need to be tuned to each bike. Also there is more to it than just shimming both needles .040". One of the set up tips from HRC is to use one more shim on the rear needle than you use on the front (this tip might be helpful to try on bikes with an aftermarket kit also). So what I do when setting up a set of carbs is remove the stock thin washer that is under the front needle and leave it in place on the rear. With this method you actually end up with the front needle approx. .030" higher than stock and the rear .040" higher than stock which seems to work well.
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