Aftermarket Carburetor Cap and Idle Screw Install

Braaaptor

Member
Dec 1, 2009
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Hamlet, NC
Well, I finally got a carburetor cap kit for my '02 Blaster. So, I thought I'd do a tutorial on how to install one of these carb. cap and idle screw kits. This kit is designed to replace the factory TORS brick sitting on top of the stock carburetor. Pardon any redundant info.

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Here's the kit. I got mine from Moose Racing, as I'm a sucker for anodized aluminum in matching colors. 8-| Vito's and Motion Pro also offer these kits, although they are a bit less flashy. And therefore cheaper.

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First, remove the stock cap and cable from the carburetor. Take the carb. off your Blaster...

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Note the filled-in hole on the left side of the carburetor, next to the fuel inlet. It is NOT drilled OR tapped. Yet. It soon will be. DO NOT mistakenly drill out the similar hole on the opposite side of the carburetor. It is factory-threaded, but the idle screw won't work if put in on this side of the carb.

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Using a grinding burr (shown here) or a hand file, you'll need to remove the taper from the lip of the un-tapped hole on the carburetor. This is done to ensure that the lock nut for the idle screw has a flat surface on which to seat.

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Here's the intended result. One clean and very flat flange. Work slowly, and be careful if you're using an air tool. The grinding burr will cut aggressively, and it is easy to take off too much aluminum. Also, DO NOT use a mounted stone when grinding aluminum. The aluminum will load up on the stone and may cause it to fly apart.

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Once you have the flange ground down, it is time to use the drill bit supplied with the idle screw kit. Shove a rag down the venturi of the carburetor to help keep metal shavings out. Using a drill press (or a very steady hand) drill all the way through the hole, until the drill bit emerges into the throat of the carburetor. Again, work slowly and patiently. A vise really helps here, too...

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Now that you have a neat hole in the side of your expensive carburetor, it is time to thread it. Using the tap supplied in the idle kit (and some lubricant), thread the tap into the hole and spin it home. Make sure to cut new threads all the way into the throat of the carburetor. It is a good idea to check for burrs after you get done, especially inside the carb. You don't want the throttle slide getting stuck on a rough edge.

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Almost done with Part #1! Just blow out any wayward aluminum shavings, thread the idle screw into the fresh hole...

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...and you're done with the hardest part. Here's the end result. The idle speed will have to be set once you get the carburetor back on the quad and the engine warmed up. Turn the screw to the proper setting and jam it in place with the lock nut. Just make sure to get ALL pieces of aluminum out of the carburetor before re-installing it. You don't want any metal shavings getting into the crankcase. Part 2 is coming up. I'll cover putting the new cap on the carb. in a few minutes...
 
Part 2. The cap install:

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Lay everything out on the workbench, making sure that you haven't forgotten anything.

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It works best for me if I install the provided throttle cable onto the cap and slide first, before attaching the cable to the throttle lever on the handlebars.

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I forgot to install the straight ferrule on the cap in this pic and the next, but you can still get the idea of what the finshed cap should look like.

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With the new carburetor cap/cable put together, go ahead and reassemble it on the carburetor. Then, the carburetor can go back on your Blaster. If you are using a Moose kit like me, the factory carb. cap lock bracket can be removed and discarded. See Pic. Vito's kits can re-use the lock bracket if desired. This part is only there to help prevent the carb. cap from unscrewing due to vibration. More Yamaha paranoia, if you ask me.

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Route the new throttle cable along the same pathway as the stocker...

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...and attach it to the factory thumb throttle assembly.

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Once you are sure that the cable is mounted properly, be sure to adjust it for about 1/4" of free-play. That is, the throttle lever on the handlebars should move about 1/4" before the throttle slide inside the carb. follows suit. Turn the handle bars lock-to-lock to ensure that the throttle doesn't bind, and if all is well, THAT'S IT! You are ready to ride once again, TORS free!
 
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I love good info like this.Im trying to laern everything I can about Blasters and stuff like this helps alot.YOU GOT REP.
 
How much did that cost you for the kit and throttle cable?

I paid about $ 65.00 for the whole thing (w/shipping) on ebay. You can get a similar kit from Vito's Performance for about $ 45.00. The Vito's kit works just fine - it simply comes with a plainer-looking carb. cap and a stock-style throttle cable, instead of the more expensive anodized cap and braided stainless cable found in the Moose Racing setup.
 
dont suppose you remember what size drill and tap you used? ive already got all the other parts besides the idle screw so just gonna buy one of them and do it myself
 
Watch this space in the near future...I am getting ready to install a Vito's carbuertor cap kit on a buddy's 2000 Blaster, and when I do, I'll post similar info again. Hopefully with some better pics and more detailed instructions.
 
Sounds great! Where have ya been man? lol

Well...let's just say I have been distracted by a woman in my life for the past 8 months! ;) She's still here, but we make time for each other to do what we like to do in life, so now I'm back at working on (and riding!) the Blaster!
 
dont suppose you remember what size drill and tap you used? ive already got all the other parts besides the idle screw so just gonna buy one of them and do it myself

J4M1E333 you will need a #6 Drill bit and a 16MMx .75 Tap. This is the information provided by the Moose Racing Carburetor cap kit & idle.
 
Hey do u have a pic of the port on the other side of the carb that has to be blocked off when you remove the oil injection?? I just read through this to see why my air screw doesn't work and Im thinking that the port for the oil injection is not blocked off.

EDIT
I found where it was lol. It is blocked off.