Questions about my oil pump

[Mailman]

Thank you all for your input. I really appreciate it. Jim I know I was on board with going the heli coil route last night, and your advice comes from your extensive background. I know that your suggestion is probably the surest repair.
After much deliberation I think I would like to at least explore a less aggressive approach first and then make a final decision.
Thanks again to everyone who weighed in
Bob

 

[Mailman]

Gary, I’m going to give the approach you suggested a try. Gotta think like a Dr.
Try the most conservative approach first,
if that doesn’t work.....then break out the knives!
Thanks for the suggestion.
Bob

 

[gggGary]

I kinda think when a Japanese MC maker used a phillips head where a socket head or hex head bolt would "normally" be used there was a reason. IE the "average dealer mechanic" is much less likely to strip the threads with a phillips screwdriver than with a wrench or 3/8" socket wrench.
especially when you frame it in "40 years ago" think and typical motorcycle shop practices of those times.
I know that as a lad changing my thinking from cast iron and steel to aluminum parts took some "adjustment". I'll just say that Honda's "noodle strength" phillips head cover bolts, saved me a lot of stripped out aluminum threads............

 

[Mailman]

Yeah , I can see that. Much harder to twist a screw than a bolt. UNLESS some knucklehead puts a torque wrench on it and twists like he’s TRYING to strip it!

 

[YamadudeXS650C]

Gary, I’m going to give the approach you suggested a try. Gotta think like a Dr.
Try the most conservative approach first,
if that doesn’t work.....then break out the knives!
Thanks for the suggestion.
Bob

Sounds like a good plan, Dr. Bob.

 

[Jim]

Jim I know I was on board with going the heli coil route....

No worries Bob. As I said in my disclaimer, because of my aircraft background I always default to the most guaranteed fix. There are no curbs to pull over to at 30,000ft. I understand we're talkin two wheelers here and there are indeed curbs.... Still, it's a mindset I reckon I'll take to my grave... too old to change now.

I'm sure some of the fixes being suggested will work just fine.

Cheers.

 

[Mailman]

Thanks Jim, I quite understand the perspective you are coming from. Taking shortcuts on aircraft repair is rather frowned upon! Haha!

A little update as to where I’m at. I ran around like a chicken with my head cut off all morning trying to find a bottoming tap. No joy, it’s too specialized. I did pick up some new button head 6mm screws that are 10 mm longer than the existing screws.
The existing screws have threads that have a rather rounded edge to them.

The new screws have nice sharp threads, and when I ran one down in the hole it felt more snug with no wiggle to it.

Now here’s the part I’m exited about, with the cover on the oil pump I used my digital caliper to measure the depth and came up with 24mm. My old screw was 20mm long so if I cut these screws to 23mm I will pick up an additional 3mm of previously unused threads and with these new screws fitting better to boot, I think I’m going to be ok.
I also really scrutinized the threads in the case
I really can see no evidence of them being stripped, no cross threads, they still look sharp. There is some gunk that looks like burnt
oil residue, and some accumulated stuff in the bottom of the holes. I will clean all that up.

I may not even need the bottoming tap. I might just clean everything up and give it a go with my new screws.
But now I’m out of time until the weekend. I’ll keep you posted.
Bob

 

[robinc]

Cheering for you Bob!

 

[TwoManyXS1Bs]

Bob, use your caliper and measure the OD of the screws. A full sized 6mm screw would come close to 6mm (0.236"), but they're not usually available that big. A good one would be over 0.232", and some could be as small as 0.220". It's an industry thing, intermixed with poor quality, with how the screw is made and the callouts for sharp/rounded/flattened thread peaks.

In critical fits, I always measure my screws.

Have a look in here:

http://www.xs650.com/threads/tap-and-die-sizes-for-rebuild.31642

 

[Jim]

Good point 2M... less contact area is gonna stress the threads even more. Let's hope they're beefy.

 

[MaxPete]

go for it Bob ....gently.

 

[gggGary]

DIY bottoming tap; flat grind the end of a garden variety, tapered tap back "aways"
keep the tap cool while grinding, lots of water dips.
Go easy on the blue juice a little dab 'll do yah.
Jim; if god had meant helicopters to fly he'd of designed em with wings.

 

[Jim]

flat grind the end of a normal tapered back "aways"

Yup, that's how I got most of mine...

 

[MaxPete]

HELICOPTER = fatigue test surrounding with an oil leak.

HELICOPTER = large number of parts combined with a great wad of lock wire - flying in close formation.

re: Bob's oil pump: these things seem to be pretty reliable and so it isn't likely those bolts will be undone again until sometime later this century - so I suspect with the longer SHCS and deeper threads, he"ll be OK.

 

[Jim]

Jim; if god had meant helicopters to fly he'd of designed em with wings.

HELICOPTER: A collection of nuts and bolts flying in loose formation.

 

[5twins]

Some good quality, reasonably priced M6 taps .....

https://www.ebay.com/itm/Bosch-1609...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

I got some, tried them, and they're very nice.

 

[xjwmx]

Is the situation now it's put together but you're worried about it? What I would do is try to tighten them in situ with a screw driver and if they don't strip before what I would consider proper tightness by feel, I'd say good to go. You can tell when a screw is tight, can't you?

If it didn't pass that little test, I'd either get a new cover, or have a machine shop helicoil the old one. If it's really worth this kind of worry, it's worth having a pro do the helicoil.

 

[Mailman]

Some good quality, reasonably priced M6 taps .....

https://www.ebay.com/itm/Bosch-1609445717-6mm-x-1-00-Plug-Tap-4-Flute-USA-2PCS/391157024367?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

I got some, tried them, and they're very nice.

Thanks 5Twins I just went and looked at those. They do look like a good value.

Bob, use your caliper and measure the OD of the screws.

I did this and I can say with absolute certainty, that my caliper is inconsistent at best. I don't understand , I bought the best Chinese made caliper that $12 and free shipping would buy on eBay. All joking aside I'm a little surprised by how inconsistent this thing measures. I read that article you posted a link to and while I can appreciate that there are differences in screws, I can't begin to imagine how the home mechanic figures out what type of screws they have and how to match them up. I will tell you this, if I screw the original screws in the holes I can wiggle them, not a lot, but I can. The new screws go in without being forced and are snug.

 

[Mailman]

Is the situation now it's put together but you're worried about it? What I would do is try to tighten them in situ with a screw driver and if they don't strip before what I would consider proper tightness by feel, I'd say good to go. You can tell when a screw is tight, can't you?

It is presently apart awaiting a good cleaning and reassembly. I will not be using a torque wrench when I put back together. I plan to channel my inner TimeMachine and use my "calibrated fingers."

 

[Jim]

if I screw the original screws in the holes I can wiggle them, not a lot, but I can. The new screws go in without being forced and are snug.

Bob, it's a crude way of going about it.... but if the new screws have less wiggle, they're probably just as big in diameter or bigger. Other variables (such as thread pitch variations) can also have an effect... but if they're "snugger" than the old ones, you're probably OK.