Bonneville America Forums Forums Technical Forums Performance Mods Drilled out slides today........

I drilled out the slides today and removed the mini filter that Triumph installs on their bikes. I replaced it with a glass replacable filter from JP cycles. After drilling the slides you could tell the difference. The throttle response was quicker and there was less burbling when down shifting. If you haven't done this modification yet get off your duff and start drilling ......Angelis

please enlighten me... what is this drilling you speak of. The stock carbs are crap I was thinking of repalcing them, but if a mod helps I'm all for it.

Actually Gurdy the carbs aren't as bad as you think. For the horsepower and torque our engines produce the carbs work just fine. You just need to open up your intake by removing the the stock air breather and rejet, drill(drill only if you have a 2004 or earlier bike),and balance the carbs. Also a good set of exhaust pipes will really wake her up. You can find information on all of this on this site. By the way the Freak Kit is the one you want to use to use to replace your stock air box. It sounds expensive and complicated but it's no different than HD's Sceaming Eagle Phase 1, or Yamaha's Phase 1 modification, we just have to use the aftermarket since Triumph does not have a kit available........Angelis

Here's some info....

web page

From one of our astute members....

It shpuld be noted to those thinking of doing this that in 05' the bike came with the slide holes drilled bigger already. Whether this is true of ALL twins i'm not sure, but in researching this for my 05' speedy i found that it at least was larger already.I assume the america too, but i'm not positive. Maybe someone else has the full scoop.

angelis745,

I did this mod as I was wrapping up the "Big-Bore" installation (see pic below). Because of that, I am not able to give any before & after commentary because of the many different mods I did together.


(done with a 7/64th drill bit)


But, it just seems like a logical thing to do on all the Triumph twins (with the exceptions of 05's and newer models.

Actually I've done the mods you mention -Freak kit, AI gone, And the long TOR's. Ok the pipes could be better as far as performance ( sound & exhaust flow ). I'm thinking of going to the Septre's. With this done I think the carbs are horribly slow to respond to the opening of the throttle. Will this mod help?

OK going to the website answered that question...

Go with the scepters or epcos.

Hey Derek
The guy is Dan Cunningham.
The website 'Triumphant' is also his handle on this site.
Cheers

I guess I assume too much. Usually when someone links to a website on here for a specific item, I explore the site out of curiosity to see if there is anything else of interest. Here is the home page of Triumphant's web site.

web page

He's got info on other oft-discussed issues as well....

(sorry for digging up an old post)

Wow, I'm famous! **blush**

I haven't been on here in months, mostly because it's too f*ing cold here in MN to ride from Oct through March and even most of April.

I'm glad people find the info I posted useful. I didn't come up with any of the ideas on my own though, I got every one of them here. I just posted them to help other people do the same stuff that I found to be so beneficial to my bike.

Now Dan, don't let it go to your head. Next thing you know you'll be Pat, and you don't want that.

But seriously...it's so much easier to have a site like yours and Pat's to refer people to rather than trying to explain it all out in words, or by having to dig back through the forum using the search engine. So thanks again for laying it all out so it's easier to understand.

True... if I become like Pat I'd never forgive mysef... who would?

Right now the bike is up for sale, but Pat has graciously offered to host my info if/when my bike sells so that it's not lost. I told him I'd be honored to have him host my data. Hmmm... that can't help his ego, you know... the fact that I used the word "honored".

Great Dan, there's another 6 pounds of air in Pat's head!

yeah drilled slides today took bike for run wooooooow it is beeeetttteeerrr now THANKS FOR INFO !!!!!!!

I know I am going to regret this but..........

WTF is a "slide"? Is this doable during the Ga Raly?

it's inside the carb, carries the needle I think... Totally doable there if Chy has the right drill bit. 10 minute operation.

Drilled my slides out this afternoon to 7/64. Might be a little crisper on acelleration, but hard to tell. Popping on decell was a bit less. Rest of my setup is 45 pilots, 135 mains, snorkel removed, Unifilter, 3 1/2 turns out on air mix screws.

Gurdy,
Our carbs are fine, they are just choked down to meet EPA standards. Drill the slides, gut your airbox and rejet after you free up your exhaust.

Hey Derek ....I had a feeling you were gonna drill those slides.

Whats next? A hole in the bottom of the airbox and the uni-filter?

I've thought about doing that ever since I ran with Budweiser in Albq who's done that drill the bottom of the airbox mod. I suppose it would allow me to run 1 or 2 sizes larger on my main jets. Might as well go for the gusto though and run the Freak IMO.

Already have the Unifilter. Really it shouldn't be much different as far as how much air flows through compared to the stock paper filter. I just put in the Unifilter so I wouldn't have to buy an air filter every 12,000 miles(maintenance schedule said every 8,000 miles though back when I bought my Unifilter).

It seems from loosely reviewing the stats on bikes that the average main jet size for all those with the freak is somewheres around just under 150 or so average. A few are way up there higher and in some cases you throw out the numbers (Dinqua) cause they are so far outside the norm with big bore and amals and any number of other variables.

Those with the snorkle out and no drilled hole versus those who do have the hole is a much closer tolerance of main jet size. either way 130 to 135 seems to be tops with or without the drilled out bottom of the airbox.

Nuthin scientific in all this of course and each bike is different yet close enough to simply tally up numbers and reach an acceptable starting point.

I think if we ran the numbers on pilot jets the average would be 43 depending upon the sample size you take. More seem to have stuck with stock pilots regardless of pipes or airbox mods overall.

Once again no claim to anything or proof of anything cause its esy to skew the numbers.

Its clear to see that if we want to we can tinker with jets and airbox mods till the cows come home if we want to.

It'd be nice to be able to dyno every time you effect a change eh?

But then again we are supposed to ride these from time to time.

Hmmm. I have just over 1600 on mine and I have had it for two months effective today.

Your rackin up the miles!

I am going to San Antone Texas for a family function this weekend. I wish I could take the bike with me. It would be fun to putt around San Antonio for a few hours.

A bikini bike wash....

Now ......that sounds interesting.

You have to get the family to schedule the functions outside of April and October. Two best months for riding out here, and plenty of biker type events to go to. Now IS the time to rack up the miles before it gets too hot.

The original post regarding this tech tip was made by me about two years ago.
I obtained the "carb tweak" from "Dale" the owner of Specialty Spares after purchasing my exhaust & jet kit from him.

Site Link:
http://www.specialtyspares.com/pages/1/index.htm

*It’s also on a site dedicated to our carbs (see link below)

Just one thing...some how, the second part to this MOD is missing, so here it is...

After drilling the vacuum port to 7/64 don’t simply de-bur the hole, chamfer it with an even larger drill bit.
YOU WILL notice after MOD when you crack the throttle on your TBA/Speedmaster (after warmed up) it will NOT choke out. TBA/Speedmaster(s) without MOD will gasp and/or choke out.
Also, throttle response will be as good as you can get!
I have been told by many other “old school racers” since, that this is an old common racing MOD.

CV Site link:
http://images.google.com/imgres?imgurl=h...hl%3Den%26lr%3D

Member
G@ry J@mes

ok what means CHAMFER ????? my dictionary too small!!!!

Hole that has been Chamfer'ed

thank you !!! was thinking about this but was not sure !!!!
next job for saturday

So, its safe to say that many who have done this mod have not used a one size larger bit to add a chamfer?

I am sure that the point of the chamfer is to ensure a clean hole. Going back and adding one after the fact is not going to add anything extra to throttle response that is not already there with a 7/64 opened hole. If you did not add a chamfer going back afterwards and adding one is not going to improve anything.

I used this....