Stripped pilot threads

The pilot jets in my carbs(Mikuni VM28)have always seemed to just barely fit. Only a couple threads caught before the jet was seated. Well today while rejetting that last thread let go in one of the pilots. Should I try to repair or will I need to replace the carb? If I can repair what are my options for such a small hole?

Any help will be appreciated.

You may be able to use a glue of some kind.Try an autimotive suply store .Maybe a locktite product?If it a permanant type glue it wont matter once you have the jetting right you shouldn't have to change it again anyways.Theres a posibilty you could get a heli coil.Shoot a message to wiredgeorge he works on carbs all the time.

I believe you can fix it. Not positive as I haven't done it but I think a 4mm .7 pitch insert will fix the thread. You will have to drill the old thread out using a drill bit recommended by the insert manufacturer. Then thread the insert in and I suggest using some red loctite. That should fix it. Be careful with the drill to keep it dead-straight as there isn't much material to work with.

Where can I find the inserts? I looked around on the web and cant find a 4mm insert at autozone or pepboys. Is there a specific store I can check out?

bharper6649 wrote:

Where can I find the inserts? I looked around on the web and cant find a 4mm insert at autozone or pepboys. Is there a specific store I can check out?

I got the same recommendation from WG about my float bowl screws a while back, and he mentioned "Recoil" systems, so I tried it. Great system. You can buy the "kit" which comes with the tap and insert and insert tool. You use your own drill. I buy my ReCoil kits from Maryland Metrics . I've bought two different ones now....

Sorry, I forgot to mention Maryland Metrics. When you call, ask for Scott and tell him I sent you (George Lesho aka wiredgeorge). It is best to order the kit which includes a tap (special size), the install gizmo and some inserts. I suggest you take the suggested drill bit very seriously and don't use some other size that looks right (don't ask how I came by this knowledge). You can also buy more inserts (refills) for the kit. I keep 4mm and 6mm kits stocked and need to get a 5mm kit and an 8mm kit at some point. They are also a great source for stainless socket head stuff as well as metric orings. They are the only place I know that can get 20mm (thin) countershaft sprocket nuts, 12 x 1.25 taps and dies (comes in handy for cleaning thread on shock mount studs) and metric exhaust studs.

I missed my opportunity to call the place, so I will have to wait until Monday to order the kit. I didn't see prices anywhere. Can anyone give me an idea of the cost for one of the kits.

Thanks for all the help!

Bryan

Probably will be Tuesday. I can't recall pricing... sorry. I just buy replacment inserts and the kit was ordered quite awhile back. Here is a price I found on the net:

www.storesonline.com/site/600195/product/RE-35040

You can do a google search as follows:

+M4 +Recoil +"thread insert"

This search will turn up various sources for the Recoil kit. Other insert types are Helicoil, Timesert and Keysert.

bharper6649 wrote:

...Can anyone give me an idea of the cost for one of the kits...

The Recoil 4x0.7 (53040) kit I bought in January cost $33.28, and I got an extra 10 inserts (the kit came with 10 as well) for an extra 4.46. Shipping was 7.52. Grand total of 45.26. I emailed the sales email address, got a price and used the online form to submit.

I ordered another different sized kit via their online form a couple weeks ago, and while looking for the price, I noticed they never billed me for it and I haven't got anything yet... drat... I'd better contact them...

i messed up a hole on one of the arms that pulls the needle assy up on my vm28's. i filled the hole in with quicksteel, let it set then drilled it out. worked like a champ. been using the carbs on my 77 kz1000 for a couple years now with no obvious side effects. maybe you could do this...then tap it out. with no more pressure then is on these jets, it should work. good luck.

The recoil kit worked like a champ. The hardest part was cleaning the shavings out of the pilot hole.

Thanks everyone!

Thanks for getting back and providing feedback. I wasn't sure how the insert would work as I haven't done this repair, oddly... with all the hundreds of sets of carbs, I have yet to see one with stripped thread in the pilot well. I thought it would work as the tap isn't very much bigger than the hole was. Did you have to drill any or were you able to just use the tap to cut the thread for the insert? I use the 4mm inserts all the time for float bowls so I buy them in bulk. LOTS of stripped float bowl bolt hole thread...