Recently broke a cheap bit in the starter jet drilling it out one size. Not any info on how to get them out and possible fixes. Everyone that says they got one out never said how. So this thread is to place the info. and pics here of my fix.

Used small tap to thread into starter jet (it was damaged with broken bit in it so no risk, however, it came out without damaging the actual jet). Once tap was threaded in good, used an old school slide hammer puller. To light bumps with the slide hammer and it came right out. See pics below, it's actually quite small and barely in there. I think a touch of heat and pliers would pull it right now.

Pics of stock jet.




I did not have a donor carb just yet so we decided to look through old carbs at jets. Found a small jet that didn't even need to be tapped to get in. Just screwed it in. This was bigger than I thought I wanted, but my mindset was that if screwing in a jet works, I could order a smaller one since I knew what carb it came off of. Ended up just staying with this for now, it's beat up so eventually I'll order a new one. Bike fired up this morning IMMEDIATELY at 35 degrees F outside.

First two pics are the new (old) temporary jet. Last pic is of the stock push in jet.





This was so easy that I cannot believe noone has come on and shown it. Once you get it out, your options of fixes are unlimited. Do what I did, take a donor one out of an old carb, make your own jet, JB weld then drill hole. etc. etc.

Hope this helps someone in the future that made the mistake I made.

 

Heres smaller pics of the stock jet. The actual jet hole is in the thinner part towards the bottom.

 

And here is the stock vs the temporary jet.

 

I tip my hat to you. You figured out a way to fix it. My question is was that an old pilot jet, with the screw slot and the number it appears to be so.

I think the reason why this has not come up is because most people haven't had the problem. Others that did asked how to deal with it, but those who didn't have the problem had no idea... we didn't need to figure it out.

If for some reason the JB Weld is affected by the chemicals in gas (had that happen with some other epoxy) you could clean it out, solder the hole up and drill again. The solder will be unaffected by gasoline for sure.

 

Yes it's an old pilot jet from a yamaha mikuni carb to a Rhino (UTV I hadn't heard of them). I hadn't ever seen the carb before. Just pulled carb parts till we found a small one. I haven't JB welded yet, but I'm pretty sure JB is gas proof. I'd check before doing it. I don't think it needs it tho. Once I order some new jets I'm hoping they just screw in, if not I'll tap it. Right now I'm leaving it alone because it's running good. Bike fired to life instantly while 35 degrees out this morning and has started easily all day. I want to play with my mixture screw and jetting but I'm just going to ride for now with the if it ain't broke.. philosophy.

 

JB should be fine. Many fuel tank holes, large and small, have been fixed with it!

 

That may be true today, but if there is some change in gas formulation it may not hold in the future. Use it while it works, but soldering up the hole would work too. I don't know the numbering system for the Mikuni jets, but if that 70 represents a #70 hole, that is around .0.7mm which is around .025" so not far off drilling and may work perfect as is (I got the values from Jets-R-Us web site). If the jet is secure I'd leave it alone. I will remember this tip should a problem ever happen with any others. It would be interesting if the hole could be tapped in a bit, probably needing to finish with a bottoming tap to get threads deep enough. Still better than trashing the carb.

From my understanding the starter jet only really affects the starting fuel mix, with the pilot jet taking over most of the load after starting. That was what the drilling of the starter jet was for - quick easy starting, it made the mix just a shade richer. Actual running is controlled by the pilot and idle mix screw, then the slide (at least on two strokes for sure), transitioning to the needle/needle jet and finally the main jet.

 

It is possible to Tap then screw in a jet. That was what I was going to do till I found a smaller jet that screwed right in. I didn't want to tap it just yet until I knew this worked. That's my plan going forward though. For Now I'm leaving it because it works so well. I need to take carb off soon to install Dynojet kit because I dont like the JD jetting some previous owner did. I might tap a new jet in at that time.

And yes, this jet is only open when choke is on.