stripped carb bowl hole - best thread insert?

[bren]

Sadly, I've discovered a small leak from the carb bowl that needs fixed. One of the screw holes is stripped out. I tried cleaning it up with a tap but I don't think it had quite enough meat left to hold it.

One of the carb bowl screws was replaced by a PO, and they didn't add a lock washer. I'd like to blame them but I very well could have overtightened it and stripped it out myself.

Anyway, the holes are through holes, is anyone experienced with thread inserts? would a helicoil work here? it's not very thick so I don't know. I've never used one before.

 

[Syd]

Any chance of using a longer bolt with a suitable nut? Not ideal, but if there's enough room it may provide a suitable outcome

 

[bren]

Any chance of using a longer bolt with a suitable nut? Not ideal, but if there's enough room it may provide a suitable outcome

yea. that's what i ended up doing. I'm not wild about it, but it does work. I picked up a #6-32 bolt 3/4" long and a nylock nut at home depot. Just gotta remember to keep an 8mm wrench in my kit

i also gotta take the bracket off the bottom now to get the bowls off. but I guess that's my stupid tax for stripping a bolt out.

 

[Nessism]

There looks like enough meal for a helicoil. Measure to be sure, but most likely M6.

Edit: brain fade set it. The common VM carbs are 4mm and BS/CV are 5mm. What carbs are we talking about? I see 450 in your signature. Those carbs are a bit odd, particularly the early version. Could be 4mm, but that is inconsistent with most other CV's.

Edit2: PN is 02112-0412A

​So that does reference 4mm x 12mm long

 

[bren]

There looks like enough meal for a helicoil. Measure to be sure, but most likely M6.

yea, there might be. I'll revisit it at some point. I've still got a broken cam cover bolt to deal with eventually so I'll probably do them both then. fingers crossed I just won't need to take the carbs apart again for awhile.

the carb bowl screws are m4-0.7's. the above hardware was like 5 bucks for a set so I went with that.

 

[zed1015]

I helicoil them back to M4 but the stripped out thread is the correct size to run an M5 tap through so you could do that and fit m5 bolts.

 

[chuck hahn]

Ive had that happen. i just retapped the hole one size higher and drilled the hole in the bowl bigger. belive it was 5MM Done in a few minutes

 

[bren]

Yea I thought about that too. I looked for some m5 hardware but couldn't find any locally that had a small enough head to fit. I'd have to order a bolt online. I do have a m5x0.8 tap so it's an option in the future

 

[chuck hahn]

allen heads..............local fastenal store