Rocky Mountain Dirt Riders

After wrestling my new studded tires with bibs onto the rims I am now installing the carb heater. Looks fairly straightforward but I cannot find a 6.8mm drill bit. Searching online I see that the equivalent can be a 33/64" or a 17/32 drill bit for the M8x1.25 tap. Where would you folks look for this bit size? Princess Auto was no help so I will go looking at other shops tomorrow. It is a one time use into a very soft metal so I am looking for a cheap bit. Thanks

Acklands has a decent variety but may need to order in. Thomas Skinner also can get any size if they don't have it in. Good luck!

I have a metric tap and die set which also has a table with the recommended drill size, and a selection of bits.
If you want to borrow it, or just bring the carb by we can do it on the bench, did mine not too long ago.

Malcolm,

That would be great. I will send you a PM with my contact info.

Ron

I found the required bit in a $9.99 bit set from Canadian tire.

A standard bit is close enough...
Use the smaller one then try the tap, if it won't bite, drill out with the larger one, but probably won't have to, as aluminum is forgiving.

Take care not to over drill the hole depth, you don't want to get into something that means a new carb to fix.
Take your time and measure with a caliper.

I have a 2 spare carb heater kits (one is missing the glow plug) if anyone is interested or needs parts.

I would also suggest you use a drill press

I installed mine before Christmas. I used a cheap Canadian tire drill bit set and measured the outside diameter with my calipers to find one close enough. It is an easy and very forgiving job.

That being said, the price of a case of old Milwaukee is a cheap investment to get Malcomzilla to do it to a much higher level of precision...

What about installing the KTM carb heater on a Mikuni carb? Any advice?

Long before purpose built dirt bike carb heaters, I used to use the thumb heater for a snowmobile or atv. Back then i would just zip-tie one to the carb body (float bowl as i recall). I think some thumb heaters now come with an epoxy to glue them in place. Would be easy to replace the ktm heater element with a thumb heater.

**Edit** I may have used 2 heater elements, one on the left side and one on the right .... can't remember exactly, sorry.

When I get a 2 stroke I'm going to use up my supply of depends well meaning friends gave me. Just insert a warm rock and wrap that sucker around the carb.

thirtyseven wrote:When I get a 2 stroke I'm going to use up my supply of depends well meaning friends gave me. Just insert a warm rock and wrap that sucker around the carb.

You don't need the rock. Should work good!

I drilled out my Mikuni following the instructions that came with the KTM carb heater. However, the hole depth cannot be deeper than 13.5 mm and the instructions say 16.5 mm so keep that in mind. I ended up with a couple of washers under the heater element and then tightened up. I hope it works.

Almost time for the carb heater again. Just checking the thread for notes and tips.

Just finished installing the carb heater on the Mikuni. 13.5mm works fine. I drilled the hole as far to the outside as I could and it worked great. Plugged straight into the wiring harness.

I have enough issues with carburation that I don't want a little snow to make it that much worse.

Pictures show the work