VM29 Smoothbores Jet block

[nickr234]

so i just got a set of VM 29 Smoothbores for my bike. i took them apart and it apears that one of the infamous jet blocks got stripped.

So what i did was i smeard some JB weld on the needle jet. ran it into the jet block very slowly let it set for a little bit, then took it out slowly, put a little more of the same jb weld i made on the needle jet again and then ran it slowly in, let it set, then ran it slowly out. repeat for about 3 hours.

end result: i get a new set of threads that can handle about 2-3 ft/lb of torque before re-stripping (i tested it the first time i made them).

after i let the jb weld cure for about three days i then bought a pack of the lightest threadlock they have (thread sealant). and then ran the needle jet in the threads with the threadlock.

And now here is my question. Do you guys think this will stand the test of time. Or will the threads breakup under the vibration of the bike. The gas shouldn't effect the JB weld, at least that is what the maker of JB weld says. Also that thread sealant should keep the gas away from the threads if it does actually eat the JB weld away.

Thanks for your time and ideas,

Nicholas Ryan Rasmussen

[Testarossa]

I suspect that it will last for a couple of years. I once repaired a leaking coolant bypass fitting in the intake manifold with JB weld. Forgot all about it until one day when I was pulling a load, uphill and had to really give it the beans. The repaired tube burst loose and finally forced me to make a proper repair.

Those carbs will be subject to a lot of vibration. In case you are unsure about your repair, or your JB Weld does fail you down the road, I have a more permanent repair. I am a machinist, and I mill out the old threads on the jet block. Then I turn a brass insert on the lathe that is press fit into the jet block. This brass insert has the proper threads for a Mikuni needle jet. I have done my personal set that are in constant use to this day. I have also done another set for a member on another forum. Mine are holding up just fine with about 2000 miles since the repair.

Here's a link to a thread on another forum that shows the repair: http://z1ownersclub.com/topic/4253971/1/

BTW all of the jet blocks that I have had my hands on and I do mean all, have terrible threads. It seems that the castings must have had lots of impurities because there is a ton of porosity visible when you mill out the old threads. I you have any that are good, be extremely cautious when you screw in your needle jets.

Send me a pm if you need more information about my repair.