Should be plenty of meat there for a helicoil Bob. I think that's the way I'd go.
That’s what I was thinking. It’s a pretty small screw, 3 or 4mm? Not sure.
Do they even make heli coils that small?
Should be plenty of meat there for a helicoil Bob. I think that's the way I'd go.
Hey, peanut, had same issue many years ago. I simply retapped the stripped bowl screw hole to 8-36, not an easily found size, but used in gunsmithing. You could do it with 8-32 std. 4mm is about .157" dia, #8 machine screw is .164" dia, just enuff to get usable threads. 0.7mm pitch is almost 36 tpi.
http://www.shender4.com/thread_chart.htm
It's just barely larger, so you can opt for the helicoil later. I don't recall having to drill out the bowl hole, I think it just barely slipped in there.
Let the screw cut its own threads, use a litle pressure to ensure it goes in, and if you slowly reverse the screw before starting, you can feel the screw drop into engagement with what remains of the old threads, then you start it in.
Careful, this is really a band-aid...
By the way, I meant to add. I am so sick of parts that don’t fit. I try to buy OEM stuff or real Mikuni parts, I always make sure I check the figment charts, but WTH? Three bogus parts on one little carb? Nearly $40 pissed away!
It’s just so frustrating!
I was just fooling around and grabbed a little SAE machine screw out of my cabinet and it fells like I could screw it in, a little tight but......
Anyways, I’m gonna think on it.
Yup, they do. Amazon has em'. Might also get lucky at your local auto parts or hardware store.Do they even make heli coils that small?
Stripped screw; do a search in here there's a SAE that's either tap n go or it's just enough oversize htat it can just be threaded into the stripped hole.
Gaskets; I feel your pain, just spent about 1/2 hour or more "fitting" a set of keystone gaskets jhad to remove the flash/fur from every hole in addition to the perimeter trim. Reused the needle jets but it took some work, they had suffered a bit on the way out cause they were REALLY stuck in there.
Sorry; but withseveralLOTS of trips to the parts tubs I was able to get these 78-9s back together.
Not show carbs but they will go on the 79 in the shed that's getting a wake up drill "real soon" to see if I got 'em right.
View attachment 116928
Better than a week ago.
In a pinch one can "convert" a taper tap into a bottoming tap. Just grind the end off till there is only one or two flutes left showing some taper.That's the hardest hole to repair. The choke casting on the body blocks the hole so a tap won't go through very far. Along with the standard Heli-Coil tap, you'll probably need the bottoming tap as well .....
https://www.mscdirect.com/product/details/99005134
Mailman; did you look at these?
650 central
Carb Kits
For the 1970 & 1971 Models. Each kit contains:
float bowl gasket, a complete float valve, choke plunger & spring,
slide needle and all jets(42.5 &130) to rebuild (1) OEM Carb.
Order Two.
#CMXS48-1917 ..... $17.50 each