Butterfly valve screws stripped

Drew85 · Mar 4, 2014

A few years ago I put 1300 venture carbs on my vmax, I swapped everything over(including the butterfly valves) from the vmax carbs to the venture carbs. Now that I'm rebuilding the carbs and putting in morleys jet kit in I noticed some of the butterfly valve screws are stripped. I figure the best way to fix them is to drill out the hole and tap to the next size bigger. What size drill bit, tap, and screws would I need to get the job done? Should I put the venture butterfly valves back in these carbs? The vmax and venture butterfly valves have different numbers on them.

gamorg02 · Mar 4, 2014

which screws? not a lot of screws on the carbs that have the room to go up the next size.

wildweasel_pt · Mar 4, 2014

He should be mentioning the 2 that hold the butterflies on the stem? The venture carbs are smaller in bore (34mm) so i wonder how were you able to fit those butterflies on the carb bodies if thats the case. I should expect that vmax butterflies are somewhat bigger comparing to venture. Dannymax will be able to sort this one out.

sdt354 · Mar 4, 2014

1300 Venture engines have 35mm carbs. The screws are staked in place by the factory and will booger the threads when removing unless ground carefully. Think about what happens if a screw goes down the intake? Over size is cutting it close. I 'd think the throttle plates would be the same. Dano would know more.

Drew85 · Mar 4, 2014

Yes I'm talking about the 2 screws holding the throttle plates on the shafts. The venture carb bodies I have use the exact same part numbers as vmax carb bodies.

mabdcmb@yahoo.com · Mar 4, 2014

Not sure what size those screws are. A lot of times you can find a SAE screw that is just slightly larger and re-tap it for that thread pitch. Sometimes it works, sometimes not.

For instance, my CR5 has a oil level check bolt that threads into the side of the case. After 20 plus years of oil changes the M6 threads weren't holding. I tapped the hole for 1/4-20 threads and was able to use it that way. I know the butterflies use smaller screws but, it may be possible to do without having to drill.

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dannymax · Mar 4, 2014

Put the Venture 35's back in, you will be fine. Don't be concerned about the numbers stamped on the plates, even VMax's have different numbers sometimes.