cam chain adjuster housing stripped threads help

[Greenmachine]

I have a 1981 xs650 I had a guy from the xs650 australia club member rebuild my engine as it was a basket case and was missing a hell of a lot of parts and he has plenty of access to the parts needed. I have put only 114 k's on it and the cam chain adjuster hosing is pissing oil. There is 6 bolts attaching it to the barrels and I found the 2 bottom threads are stripped in the barrels. I bought a helicoil kit but due to the engine mount on the case where it connects to the upright of the engine I can not drill them out without pulling the barrels out.
I ordered a flexible drill shaft to try do it without pulling the barrels out. I really don't want to have to pull it all apart again. So my question is, Is there some kind of product I can use to be able to get the bolts to tighten them enough?

 

[TwoManyXS1Bs]

Yeah, not much room in there for traditional tools.

For things like this, I like to pursue a sequence of attempts that start with minimal effort and damage, increasing in severity, to all-out war. Kinda like removing broken studs.

First thing I'd try is a slightly larger bolt.
Take a 1/4" long shoulder bolt, cut to length, and thread it to 1.0mm pitch.
I have adjustable/expanding threading dies that allow me to choose finish diameter.


A 1/4" bolt shank would be about 6.3mm.
An expanded M6x1.0 die could cut oversized threads, giving you bolts that should self thread and grip into the remaining threads. This threading can also be done on a lathe.

The next size up is a M7.0x1.0 bolt. You'll need to tap the holes with an M7x1.0 tap. If done carefully, tapping threads synchronized with the existing M6x1.0 threads, cutting oil, frequent withdrawals and cleaning, it can be done without having to first drill the holes to 6mm.

These 2 bandaid fixes will keep the holes small enuff so that a future fix with helicoil is possible...

 

[Greenmachine]

toomanyxs1b's Thank you for the reply. My tap and die kit skips m7 but I played around with a longer bolt without retapping and I think I will have just enough threads to get it to tighten and think using gasket glue as well as a gasket I will get away with it I hope. I'll cut the longer bolts to size and see how I go. If that doesn't work, while I have already pulled the motor out I might be best to disconnect the cam chain and move the barrels up enough to drill and use helicoils without having to pull the barrels above the pistons and make more work for myself.

 

[MaxPete]

EEEEyyyyeahhh...you've got yourself a bit of pickle there Greenmachine.

I am with 2M on the hierarchy of tactics in the removal of recalcitrant fasteners:

• persuasion tools (wrenches, screwdrivers, sockets etc.)
  
• chemicals;
• gripping tools (vice grips);
• metal removal tools (like drills);
• profanity;
• violence;
• heat.

Pete

 

[xjwmx]

I bought a helicoil kit but due to the engine mount on the case where it connects to the upright of the engine I can not drill them out without pulling the barrels out.

Don't remember offhand how long the original bolts are or how deeply the threads go, but it looks like there's a possibility of just using 10mm longer bolts. That would certainly be the most minimal effort and damage. Barring that, since it's aluminum maybe you could turn your helicoil bit by hand. Maybe weld a nut to the end and use a ratchet handle. Push hard with the right and turn with your left.

 

[Greenmachine]

Don't remember offhand how long the original bolts are or how deeply the threads go, but it looks like there's a possibility of just using 10mm longer bolts. That would certainly be the most minimal effort and damage. Barring that, since it's aluminum maybe you could turn your helicoil bit by hand. Maybe weld a nut to the end and use a ratchet handle. Push hard with the right and turn with your left.

Today I did just that, I used longer bolts and cut them down to the right size( about 5mm longer) There was enough good thread in the bottom of the holes and it tightened up perfect. I put a new gasket on and also coated each side with permatex form a gasket sealant ( which is meant for that purpose) Feeling very confident with the repair.

 

[xjwmx]

Whoot. Nice that it worked out. Now fuggit about it.
I read somewhere that 6 threads is about all you need, with each thread having less force on it when tight until you get to about the 6th one that has almost none on it. I'm sure there can be other considerations, but just for holding something on at least.
I find that to avoid stripping small bolts choking up on the wrench helps a lot, at least it reminds you not to pull like an ape. IOW holding the wrench near to the bolt.

 

[XSLeo]

An Idea I just had as I read this thread is you could remove the adjuster body. Clean out the holes very well. Find studs the size of your bolts Like used on the valve rocker adjuster covers.
If you get the holes and the studs very clean you can coat the threads with an epoxy, I like JB Weld, thread these studs into the holes. Careful to get them straight. Let set till epoxy gets cured. If done well these studs will hold any torque you would put on the studs.
Then acorn nuts on the studs to hold the adjuster body on.
You might be able to use the JB Weld to make new threads. Very clean hole, coat with a light layer of oil or grease, this will act as a release agent. Then coat the bolts with the JB Weld. thread in, let cure, unscrew bolt.
If done right the bolt should come out leaving the JB Weld in the hole with perfect threads. I haven't tried this yet but the directions tells you it works.
This is with the regular JB Weld, not the Quick set. The Quick set isn't as strong.
Leo

 

[xjwmx]

I remember some product that is just for making threads like that. JB might be better or worse. A good parting agent might be a layer of smoke from a candle. It's used for some lead casting of little things with metal molds.

 

[MaxPete]

Normally, full thread strength depends on what material is tapped (the assumption being that the male part is always made of steel).

For a steel bolt/stud/screw threaded into a steel part, full strength is normally reached at one thread diameter. So, a 6 mm bolt needs to only thread into steel about 6 mm to be resistant to stripping out and an M8 bolt would need about 8 mm of thread etc. in steel

However, most of our bike engines have holes tapped into aluminium components like cylinder heads, engine cases etc. and for a thread tapped into aluminium to reach full strength, most experts agree that you need 1.5 - 2 x thread diameter.

Thus, a 6 mm bolt needs 9-12 mm of thread if it is screwed into an aluminium component.

 

[xjwmx]

It would depend on the torque you need to give it. Which has to be why your recommendation is based on the diameter of the bolt.

 

[MaxPete]

It would depend on the torque you need to give it. Which has to be why your recommendation is based on the diameter of the bolt.

Well, no actually it doesn't depend on the torque. The "full strength" I am talking about is the pull-out force of the threaded fastener regardless of the torque used to install it. The torque is there to create an axial load in the fastener which presses the two components being joined, together. If the force separating them exceeds the pull-out force - the parts will separate but more importantly, the threads will strip out of the female part.

 

[xjwmx]

You're blinding me with science. There are several places in the xs where there are about six threads. The neutral sensor for one. It won't strip until you try to apply too much torque, so I say whether it strips or not depends on the torque you need to apply. Good enough for me, whose differential equations are very poor.

 

[Greenmachine]

Thanks guys, plenty of good options there I might need to use if this initial repair doesn't hold, and great advice for others in this predicament. My bike probably won't be on the road for a few weeks yet ( rewiring a lot of it) and then I will find out if it holds well and not leak oil. Not a lot to do now to get it registered and then HAPPY DAY'S riding

 

[peanut]

EEEEyyyyeahhh...you've got yourself a bit of pickle there Greenmachine.

I am with 2M on the hierarchy of tactics in the removal of recalcitrant fasteners:

• persuasion tools (wrenches, screwdrivers, sockets etc.)
  
• chemicals;
• gripping tools (vice grips);
• metal removal tools (like drills);
• profanity;
• violence;
• heat.

Pete

I think you might have missed out the 'introductory profanity' at the outset pete as in
' Feck me........ I don't believe it !

I' trying to imagine the excessive force required to strip out 2x M6 threads .....I don't get it ?

Whats the worst that can happen if a bolt is not tight enough .....so you lose a couple of 5 cent bolts from vibration. the whole plate isn't going to suddenly burst and explode off the bike along with the cam chain .
You'd be warned of the loose bolts by the oil leak long before and potential damage was done.

previous owners have a lot to answer for

 

[MaxPete]

Greenmachine: when installing things, you might consider some gasket sealant and the best stuff IMO it a product called Hylomar Blue which is used in the aircraft industry. It seals great, never hardens and seems to be TOTALLY resistant to oil and fuel.

It is likely available at airports that service small planes or online and a little dab-‘l-doo-ya. It cost a bit more than the usual automotive products but man, it works.

 

[Greenmachine]

I think you might have missed out the 'introductory profanity' at the outset pete as in
' Feck me........ I don't believe it !

I' trying to imagine the excessive force required to strip out 2x M6 threads .....I don't get it ?

Whats the worst that can happen if a bolt is not tight enough .....so you lose a couple of 5 cent bolts from vibration. the whole plate isn't going to suddenly burst and explode off the bike along with the cam chain .
You'd be warned of the loose bolts by the oil leak long before and potential damage was done.

previous owners have a lot to answer for

This engine had been robbed of a lot of parts before I got it and due to the missing parts I was not confident in rebuilding it myself so I contacted a fellow from the Australian xs650 club "Peter Kommer" who has been rebuilding and selling motors for a number of years so I thought he would be a good man for the job. Also here in OZ you have to pay $1000 for a non running engine and I picked up the motor and frame for $500. I worked out very quickly he doesn't have or know how to use a torque wrench, On my first test ride (maybe 20km's )there was oil dripping from the bottom of the engine and had already lost some nuts from the bottom. I replaced and re torqued them. I gave it another 90km test ride and it was pissing oil from the cam chain adjuster lower bolts. I found they were totally stripped out. So left me in this predicament.
He lives approx 1000km's from me so it wasn't worth the trouble getting the motor to him so repaired it myself. Only the 2 bottom bolts were stripped the other 4 were fine. I'm sure he either stripped them or at least would have known about it and counted on me not coming back that far to have him fix it.

 

[Greenmachine]

Greenmachine: when installing things, you might consider some gasket sealant and the best stuff IMO it a product called Hylomar Blue which is used in the aircraft industry. It seals great, never hardens and seems to be TOTALLY resistant to oil and fuel.

It is likely available at airports that service small planes or online and a little dab-‘l-doo-ya. It cost a bit more than the usual automotive products but man, it works.

I had some "permatex form a gasket sealant" on hand which has the same properties as you described with Hylomar Blue

 

[peanut]

I gave it another 90km test ride and it was pissing oil from the cam chain adjuster lower bolts. I found they were totally stripped out. So left me in this predicament.
He lives approx 1000km's from me so it wasn't worth the trouble getting the motor to him so repaired it myself. Only the 2 bottom bolts were stripped the other 4 were fine. I'm sure he either stripped them or at least would have known about it and counted on me not coming back that far to have him fix it.

How bad is the leak ?
It may be best to just ride it as it is for the time being and just top up the oil regularly. An oil leak ain't going to bust the engine unless its pouring out....Old .Brit bikes with vertically split cases mostly all leaked oil for half a century and they ran fine .

Maybe just ride and enjoy the bike until your next planned restoration /repair date when you can remove the engine and do a proper repair

 

[XSLeo]

MaxPete, I agree that it takes a certain amount of threads to hold the max load of a bolt. I'm pretty sure the 5-7 ft.lbs. of torque that most of our 6 mm bolts get is well under the amount it takes to strip out the threads.
Leo