OK carb guru's what 's up here.

[RustiePyles]

I’ve never seen this done before, this will reduce the effect of the diaphragms eh? I’m curious to see how you do this.



Yes please!

It was a pretty common practice with CV equipped Harleys. As a matter of fact the screamin eagle stage one kit was just a main jet, drill bit, and a slide spring. I have a plethora of various slide springs from my Harley dealership days. I'll use a digital kitchen scale and an adjustable square to match a set. The slides are set up from the factory for a smooth throttle response, this does not always equal efficiency and or performance. By enlarging the draft hole in the bottom of the slide (usually by 1 wire size bit) and decreasing the spring pressure you will increase the speed at which the slide raises and decrease the amount of less than atmospheric pressure needed to raise it. There is a point of no return where the slide becomes either erratic or totally non-functional. So I'm not encouraging guys to go at their carbs with a drill index and hardware store springs, because this does take a practiced hand. I have hundreds of hours on a dyno tuning CV carbs. but If its something you're interested in we can definitely start a conversation about it. The slides and springs on my 80 have been altered for about 10 years now and it runs like a scalded dog.

 

[RustiePyles]

Also worth noting, as with all things CV carb related. What works in KS at my elevation may not work so well at another location/elevation. If I recall the HD Screamin Weasel kits were actually regional. Kits were sent out with different springs and drill sizes to different regions based on elevation. So doing it from scratch means making very conservative changes and testing. But I drilled my 80 in Virginia at sea level and have never had any issues since I moved back to Kansas.

 

[Jan_P]

I keep a couple of new pairs of Vise Grips (regular and needle nose) in the tool box for stubborn screws. With an exposed head and heat if needed, 99% of the time you can crack them loose. Damages the heads tho so only good if you’re replacing the fastener or don't care what it looks like.

Sorry to be anti .. but it did not work for me
I tried that .. both on the head and on the stump sticking out .. after drilling the head
I bought a couple of different sizes vice grips
Since these can be handy at welding jobs.
Applied
Heat ( gas Torch ) and oil ( light ) different sorts in many steps
I also have a good set of pipe wrenches

https://www.bahco.com/int_en/swedish-model-90---pipe-wrenches-pb_140-147_.html

The largest i have ca 2 ft length ( to large here )
But those grip hard and are used on process tubing in industry and so
they wont slip.
Also tried nut pliers
https://www.biltema.se/en-se/tools/hand-tools/pliers/special-pliers/nut-pliers-2000018144

Only chipping away on whatever I could get a grip on
Of course also making a slot with a hacksaw blade for a flat screwdriver or correctly
a bit . To Weak

If i remember correctly
about 2 per 8 came out as supposed
3 with the pliers oil and heat
1 with a screw extractor
2 drilled out by hand tool .. I was lucky enough to not hit the thread

The Milwaukee Milwaukee M18 5/16"
Here cost more than half the price I payed for my first XS 650 ..but OK that was some years ago
Milwaukee surely fine tools but mostly for professional shops here.
So since the saying " You get what You pay for "
So the Milwaukee M18 5/16" might be the solution

 

[bosco659]

Sorry to be anti .. but it did not work for me
I tried that .. both on the head and on the stump sticking out .. after drilling the head
I bought a couple of different sizes vice grips
Since these can be handy at welding jobs.
Applied
Heat ( gas Torch ) and oil ( light ) different sorts in many steps
I also have a good set of pipe wrenches

https://www.bahco.com/int_en/swedish-model-90---pipe-wrenches-pb_140-147_.html

The largest i have ca 2 ft length ( to large here )
But those grip hard and are used on process tubing in industry and so
they wont slip.
Also tried nut pliers
https://www.biltema.se/en-se/tools/hand-tools/pliers/special-pliers/nut-pliers-2000018144

Only chipping away on whatever I could get a grip on
Of course also making a slot with a hacksaw blade for a flat screwdriver or correctly
a bit . To Weak

If i remember correctly
about 2 per 8 came out as supposed
3 with the pliers oil and heat
1 with a screw extractor
2 drilled out by hand tool .. I was lucky enough to not hit the thread

The Milwaukee Milwaukee M18 5/16"
Here cost more than half the price I payed for my first XS 650 ..but OK that was some years ago
Milwaukee surely fine tools but mostly for professional shops here.
So since the saying " You get what You pay for "
So the Milwaukee M18 5/16" might be the solution

Not meant to work every time. If they are stuck so bad that the Vise Grips won’t budge them you will end up drilling and tapping anyway.

 

[5twins]

I don't know, maybe I'm just lucky, but I've always managed to get these screws out. I use a combination of heat (heat gun), penetrating oil, and a proper fitting #3 J.I.S. screwdriver bit in a T-handle holder. If the T-handle won't budge them then a couple of whacks with the hand held impact driver will usually break them free. I feel the T-handle is a very important part of this operation. You can exert tremendous downward and turning pressure with one of these, to the point of actually stripping the head. You have to learn to be careful with that, lol. If the T-handle is starting to turn and bugger up the head without turning the screw itself, you need the hand impact first. This is my bit holding T-handle of choice .....

https://www.amazon.com/Felo-0715732350-4-Inch-T-handle-Holder/dp/B000E62NIC

 

[650Skull]

Here is my go to.........no need for hand held impact driver or T bars.........this works every time.

Threw away my Impact driver

Has a ratchet for a screw setting so it wont over tighten. I set the setting so the ratchet is working and the drill wont turn. I slowly increase the ratchet setting and each time i run it in the srew for 10 seconds or so. As the ratchet settings increase so dose the amount of force through the ratchet.............This will vibrate on the screw enough, that when you get to the drill operating as a screwdriver the screw has broken loose............no damaged screw heads and it works on screw heads that are damaged that couldn't normally be got out with a hand held screwdriver. Can get a lot of leverage as well so the Phillips head/JIS is well bedded into the screw.

Any cordless or corded drill with a screw ratchet should work

 

[bosco659]

Here is my go to.........no need for hand held impact driver or T bars.........this works every time.

Threw away my Impact driver

Has a ratchet for a screw setting so it wont over tighten. I set the setting so the ratchet is working and the drill wont turn. I slowly increase the ratchet setting and each time i run it in the srew for 10 seconds or so. As the ratchet settings increase so dose the amount of force through the ratchet.............This will vibrate on the screw enough, that when you get to the drill operating as a screwdriver the screw has broken loose............no damaged screw heads and it works on screw heads that are damaged that couldn't normally be got out with a hand held screwdriver. Can get a lot of leverage as well so the Phillips head/JIS is well bedded into the screw.

Any cordless or corded drill with a screw ratchet should work
View attachment 185439

Nice trick. I’ll have to try that for sure. Thx

 

[gggGary]

https://yamahaxs650.com/product/fuel-line-t-piece/

 

[grizld1]

Glad you posted a warning to the unknowing on modifying slide action, RP! Folks, take note: there's more to the tuning than just getting the slides to rise as fast as possible without destabilizing.

 

[XSLeo]

For my Harley I bought a carb tuning kit that came with a new spring and a drill bit and an assortment of pilot and main jets.
I did everything the instructions called for, I did take a long time trying to decide about the drill bit. I had heard stories about bad results from drilling slides.
After a few days of thinking I figured the seller had years of experience doing this and decided to trust him.
I very carefully looked at the hole in the slide before and found it looked very good, maybe a burr around the hole from when it was made.
After I used the drill I looked at the hole. It didn't cleam away all the color from the hole but it did make the hole look better, all the same diameter and no visible burrs around the holes.
Along with the muffler and air cleaner changes it runs great. Did lose a bout 2 MPG did it runs so much better it was worth the loss of MPG.
So If I was to try it on my XS650's I might bet a bit that won't make the hole bigger, just one that can clean it up some. Maybe a larger bit to slightly bevel the ends of the hole to remove any burrs. This just to smooth the air flow through the hole.
I have found that the airflow through the carbs have a great affect on slide function. This was very notable when swappng the stock air boxes for p[ods. The K&N stlye short tapered pleated element pods caused an off idle flat sopt and surging st steady cruise. Swapping them for the longer straight foam pods elimanated these issues. The only thing a can think of is that the K&N stlye pods caused more air turbulance through the carbs thus cusing a poor/unstable vacuum signal for the slides. The foam pods did not do this.
Leo