R90/6. Idle jet was snapped in half by the po. I managed to get it out but the threads are a little damaged. ( I don’t think it was me…)What would be the proper tap for the threads to clean them up, or is this baby a write off ?~T
Use the thread pitch gauge in your tap and die kit. But you will either need to buy or grind a bottoming tap. depending on how deep the thread damage begins, you may start with a taper tap then switch to the bottoming tap. either way it is a delicate operation and the tap(s) should be started with your finger tips to get them started in the remains of the old threads.
You could take the idle jet out of the other carb and measure the diameter and thread pitch. Then look on line for standard thread tables. I would expect it will be a metric fine thread.
Measuring thread pitch is tricky, is it possible that the thread is really M6 x 0.75. Different carb but here is some evidence that Bing used M6 x 0.75 threads Carburetor reconditioning - Salis Parts Salis Parts (bmwclassicmotorcycles.com)
Let me double check and feel like a goof. Though feeling like a goof is better than spending unneeded tap money !Thanks all,~T
If it is really M6 x 0.70 you can always buy a correct sized bolt and cut it to approximate a tap... https://www.instructables.com/Make-a-tap-from-a-bolt/
Did you try simply reaching out to Bing to ask them the thread pitch? They are generally very helpful and support the customer base pretty well.
https://www.amazon.com/75-Metric-Hand-Tap-Bottoming/dp/B008HSQXFI 2 for $18 This is one of the few times I wouldn't worry about the skinny tap snapping, given how soft the carb body material is
水龙头和死去的化油器different from regular taps and dies. Don't make assumptions as Helicoils usually aren't an option.
I just took a jet out of a spare carb and measured.M6x0,75 is what it measures. The idle MIX screw measures M7x0,75, I pulled that one as I was already in there. Both 'Metric fine', acc DIN, and Germans invented the DIN norm and stick to it.Paul.
I'd prefer to make a chaser out of a bolt if all you're doing is reforming the thread. A tap is apt to remove more material than you really want to, especially in whatever zinc alloy Bing uses.
If the damage is at the top of the thread how about just boring it out with a drill bit and leave the good threads under it? A lot of times threads are longer than they need to be.
