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Magua
29th January 2009, 09:33
Finally made a start on my engine last night with the help of Xwhatsit (legend).

All of the engine bolts came out out of the head with varrying degrees of difficulty except one for. This bolt was determined not to move. After applying what felt like all the force in the world it made an allmighty crack and started to spin, but still with great difficulty. It's pictured below and not looking too great. What could cause those few threads to fill in as they have? Threading from the case?

Both Cylmer and Haynes manuals tell me just to 'lift the cylinder up and off', whereas mine seems to be rather stuck. Other than continually whacking it with the rubber mallet/block of wood are there other avenues to follow?

Max Preload
29th January 2009, 10:48
Those few threads have filled in with the top section of thread from the engine case. Helicoil time.

Magua
29th January 2009, 11:38
Those few threads have filled in with the top section of thread from the engine case. Helicoil time.

Lovely. So I imagine a Helicoil, to rethread a hole, would need to widen it a little. Which means I'll have to get a new bolt made?

vifferman
29th January 2009, 11:59
I dunno if you need to helicoil the hole - dpends how knackered it is. Probably best in the long run (do the job right, do it once. etc.)
Yes, to fit a helicoil, the hole needs to be drilled slightly larger. But (however!) the helicoil means the thread size is the same (no new larger bolt needed).
Don't forget to clean up the threads of the bolts before you replace them.

Does the barrel have bits (a skirt) that poke down into the case? If not, then it should eventually come off. Just be sure you spread the force over a large area so you don't crack/bend fins.

The Pastor
29th January 2009, 12:17
man that is a dirty thread!

xwhatsit
29th January 2009, 12:44
man that is a dirty thread!
Yeah. It feels gritty but it's not hard -- I wonder if it's some sort of gasket gunk crap.

@Max Preload: That's what I thought too but when I've pulled threads out like that generally you can see that the threads are separate, if you get what I mean. Sometimes you can get your fingernail underneath and peel the whole thing out. With this, those flat bits look like they're part of the same steel, completely seamless and filled in.

Helicoil on a cylinder head bolt thread in the crankcase? Will it be strong enough?

The real PITA is the stuck cylinders. Can't do anything without getting that off.

Magua
29th January 2009, 13:06
I've been bashing away at the cylinder with my rubber mallet. All I've achieved is to chip away at my mallet.

vifferman
29th January 2009, 13:27
I've been bashing away at the cylinder with my rubber mallet. All I've achieved is to chip away at my mallet.
Hmmmmm......
Hmmmmmmmmmmmmmmmm.....
Try putting a block of wood against the barrel and giving it a sharp whack with a hammer/the rubber mallet/a small sledgehammer. You need something that's gonnna break the base gasket loose. Alternatively (or as well), if you can gently poke/tap a very slim knife blade into the gasket (not either side, in case you damage the face), you might wound it enough to make the fucker let go its grip...
Looking at your pix, if you levered the barrel upwards where the fins have webs between them, it's unlikely to snap or bend them, so that's another possibility.
The main thing is whatever you wallop/lever is walloped/levered over a decent area and/or is supported or strong enough that it won't bend or crack.

Ixion
29th January 2009, 13:30
The thread looks munted, but there may be enough left to hold.

Is the head separately bolted to the barrel ? If so you can try putting a bit of wood on the top of the piston, and bolting the head in place. Turn crank, piston comes up, and bit of wood meets head pushes head up, head pulls barrel up. Make sure you have the cam chain off so the valves don't try to open. Best not done on a built up crank.

Edit Are you sure you have removed ALL barrel holding down bolts/nuts? Really sure? really really ? Go take another look. Get someone else to take a look.

vifferman
29th January 2009, 13:36
'bout time you showed up Les. :yes:

xwhatsit
29th January 2009, 13:54
Edit Are you sure you have removed ALL barrel holding down bolts/nuts? Really sure? really really ? Go take another look. Get someone else to take a look.
I had a separate look, but then again I'm the guy who didn't bolt his cam sprocket up tightly enough and caused quite enough spectacular damage for his own wallet.

Head bolts go right through to the crankcase. No separate bolts, apart from the camchain tensioner garbage, of which there is only one. Very simple little motor.

We weren't particularly enthusiastic about jamming knifeblades and such into the gasket surface, part of reason for taking it off is to replace the slightly leaking base gasket and scratching the mating surfaces isn't likely to help.

Ixion
29th January 2009, 14:00
Do you have a heat source? Heating the area around the joint may help.

MSTRS
29th January 2009, 14:06
I'd be putting a piece of wood on the crankcase and using a loooong lever inserted under the bottom fin, gently prise the cylinders upwards. Once off, you will know whether the crankcase thread is stuffed (helicoil had it). It is an easy fix for a proper engineering shop.

Max Preload
29th January 2009, 14:13
Edit Are you sure you have removed ALL barrel holding down bolts/nuts? Really sure? really really ? Go take another look. Get someone else to take a look.

I second that. Nothing down behind the camchain tensioner guides?


@Max Preload: That's what I thought too but when I've pulled threads out like that generally you can see that the threads are separate, if you get what I mean. Sometimes you can get your fingernail underneath and peel the whole thing out. With this, those flat bits look like they're part of the same steel, completely seamless and filled in.

Try spinning a nut over it - I think you'll find it moves up the bolt ahead of the nut. Or give it a scratch with a scriber - that'll show if it's soft.


Helicoil on a cylinder head bolt thread in the crankcase? Will it be strong enough?

Plenty - but it has to be done properly - any misalignment and it'll majorly upset the head torquing.

Magua
29th January 2009, 23:50
I wanted to use this, simple solution. Then I read the fine print, doh.

The Pastor
30th January 2009, 10:08
I wanted to use this, simple solution. Then I read the fine print, doh.
thats there to provide a saftey cover for them if somone uses it on a brake bolt and then the brake fails etc.

if the thread fails, what damage would it do?

Magua
30th January 2009, 10:50
Damage to the head from uneven torque?

Max Preload
30th January 2009, 11:53
Damage to the head from uneven torque?

At the very least a leaking head gasket.

Magua
30th January 2009, 18:53
Nothing I have tried has worked, it's like they used cement cement instead of gasket cement. Soooo, I'd like to keep it on.

I went and bought a new engine bolt today, it screws into the hole that the munted thread bolt came from with ease. I'm that thinking that maybe I will just add some of the thread repairing goop and leave it at that.

xwhatsit
30th January 2009, 20:44
How are you going to get the camchain tensioner out?

mikeey01
30th January 2009, 21:45
Nothing I have tried has worked, it's like they used cement cement instead of gasket cement. Soooo, I'd like to keep it on.

I went and bought a new engine bolt today, it screws into the hole that the munted thread bolt came from with ease. I'm that thinking that maybe I will just add some of the thread repairing goop and leave it at that.

So barrel still stuck on crank case?

gatch
30th January 2009, 22:51
I'm that thinking that maybe I will just add some of the thread repairing goop and leave it at that.

Id run a tap down it first to see if any of whatever is on the bolt, will easily be removed, ie could be more broken threads in there.. If your tap comes back coated in shit, then Id give it the helicoil, definitely, for the sake of a $20 repair kit and 20min of your time, you can save yourself the repair bill from when your head gasket leaks..

my 2c..

Magua
31st January 2009, 09:10
How are you going to get the camchain tensioner out?

We've already taken the tensioner out.


So barrel still stuck on crank case?

Yep, bugger wont move an inch.

mikeey01
31st January 2009, 09:56
Yep, bugger wont move an inch.

Can you take a pic of the bottom of the barrel / crank case and post up?

Here's something to try....

You'll need some heat, a good heat source!
Get a gas torch (local mitre 10 little blue gas bottle with nozzle tap etc) or at least a hot air gun (ages for the hot air gun) heat evenly around the bottom, once it's all hot enough (you'll know when) place a slight bit on tension under the barrel, it's acting like a lever, not a wedge! Why I say lever is you've got some tension on, a wedge won't budge and you'll break fins :(
Now with a rubber / nylon mallet whack the barrel all over, (whilst tension is held between the cc & Barrel) on the side etc. The intention here is to shock / crack the seal / bond.
Yes you'll need some force.

There are other ways, such as using steel bars front and rear and passing them through / around the barrel between the lower fins, using the bikes own weight to lift etc or the studs and some steel as a puller, but by the sounds of it your not tooled up enough.

The easy way out for you just might be to take it to your local garage, any good mechanic will be able to get it off! Well rehearsed at this sort of stuff they are :)

Looking at the stud that came out and the ali left on it, the thread is buggered and I'd be surprised if you'll now be able to get the required torque down on the head. Heli coils are not so hard, if your concerned about doing it then get the local garage mechanic to do this as well, they do em all the time!

If ya lived locally I'd get the barstard off for ya!

crazyxr250rider
31st January 2009, 14:36
Somthin' tells me your being a nana with your hammering,remember the bigger the doubt the bigger the clout....Serious.

xwhatsit
1st February 2009, 02:23
We've already taken the tensioner out.
No, we took the camchain tensioner tensioner out (the little spring and associated paraphernalia), but we didn't take the tensioner blade out. The tensioner blade is the bit that wears from the chain rubbing against it and that's the bit that will potentially need replacing.


Somthin' tells me your being a nana with your hammering,remember the bigger the doubt the bigger the clout....Serious.
Somewhat concerned about breaking fins off. It's an aluminium barrel with spindly little fins.

Ixion
1st February 2009, 14:09
With enormous hesitation and trepidation I second the suggestion that you are maybe being a bit too gentle.

I have known watercooled barrels to corrode n place (GT750 Suzukis sometimeshave to have the barrels smashed off :eek:) but this is a simple air cooled twin. The barrel can't be locked in place (assuming, again, that there is no hidden screw or such (down inside the chain tunnel? - UPWARDS from underneath ? )

The fiche shows several dowels on the barrel joint. My guess is that the barrel has been replaced using a hard setting gasket cement and this has set around the dowels .

What is needed is leverage, not hammering, to break the joint free.

Jap bikes often have a 'ledge' or similar where a lever can be used to prise the joint apart. I'm not talking here about sticking things in between the mating surfaces , but of using a lever between a 'sticky out bit' of the barrel and the crankcase.

Quite moderate leverage will break free a glued joint when even vicious hammering will fail.

Magua
1st February 2009, 15:35
Done. Renegade Master came over, we jacked the bike up and tied the barrels to the roof, lowered the jack to increase the tension and gave it a few good whacks.

The barrels look to be in good condition, no scaring, same goes for the mating surfaces. The piston rings look fine to my untrained eye, no breakages. They can be pushed around the piston with ease, I understand this is normal?
Edit: the tensioner looks good too, doesn't look worn.

hayd3n
1st February 2009, 16:32
looks like its been a s/s bolt in a alumunum head not a good mixture

Max Preload
1st February 2009, 19:43
The piston rings look fine to my untrained eye, no breakages. They can be pushed around the piston with ease, I understand this is normal?

Correct. Measure the end gap when installed in the bore and the clearance on the piston grooves.

Ixion
1st February 2009, 19:50
Good stuff. Piston rings are normal for a four stroke. Two strokes will normally be pegged.

A suggestion. DO not repeat the 'stickj it down with super gungy gunge' idea when reassembling.

A new gasket and a light coating of grease should suffice, if the surfaces be sound and true. Or at most a light (that's LIGHT) smear of Hylomar of some other quality jointing compound. NOT that vile orange silicone stuff.

If the mating surfaces are damaged, best to try to remedy it. And use a torque wrench on the head.

mikeey01
1st February 2009, 20:31
Done. Renegade Master came over, we jacked the bike up and tied the barrels to the roof, lowered the jack to increase the tension and gave it a few good whacks.

Great stuff and good on ya Renegade master for helping out! :niceone:



Or at most a light (that's LIGHT) smear of Hylomar
Yep that's great stuff...I've used it for years and I swear by it. Sometimes goes by the nickname blue.

xwhatsit
1st February 2009, 21:38
So at the end of the day you mostly suspect a combination of those crispy-looking exhaust valves and a very tired camchain causing rattles and perhaps erratic timing?

What a clever idea with the ropes :laugh:

Magua
2nd February 2009, 08:29
So at the end of the day you mostly suspect a combination of those crispy-looking exhaust valves and a very tired camchain causing rattles and perhaps erratic timing?

What a clever idea with the ropes :laugh:

Sounds about right combined with those seals between the manifold and carb, yep.



Question, using a helicoil you have to drill out the hole first. Wouldn't I lose a lot of files into the bottom end of my engine? :S

xwhatsit
2nd February 2009, 11:58
Sounds about right combined with those seals between the manifold and carb, yep.
Ah yes they did look pretty flat, didn't they.


Question, using a helicoil you have to drill out the hole first. Wouldn't I lose a lot of files into the bottom end of my engine? :S
If you're very careful... I did a helicoil into my cylinder head while it was attached to the engine. Is it a blind hole into the crankcase? Or does it go all the way through? If it goes all the way through you might be in the poo, but if not, you could use some rags to stuff up the gaps around the pistons.

Or maybe drain the oil, bolt the engine to your roof, and drill upside down? :woohoo:

The Stranger
2nd February 2009, 12:11
What could cause those few threads to fill in as they have?

Galling or cold welding.

xwhatsit
2nd February 2009, 13:05
You mean this stuff? http://en.wikipedia.org/wiki/Cold_welding


It is now known that the force of adhesion following first contact can be augmented by pressing the metals tightly together, increasing the duration of contact, raising the temperature of the workpieces, or any combination of the above.
That all sounds good, and the scraping of metal on metal when the bolt was screwed in would scrape away the oxide layer, but what would cause the vacuum needed to actually start the welding process?

gatch
2nd February 2009, 17:34
Question, using a helicoil you have to drill out the hole first. Wouldn't I lose a lot of files into the bottom end of my engine? :S

yep as the other dude said if its a blind hole your sweet just keep your spindle speed low so chips don't fly everywhere, if its a through-hole, can you fit a vacuum cleaner nozzle in there ? did that at work once, worked sweet, when you use the tap you can cover it in grease, just go a few turns at a time, back it out, wipe off grease and go again..

Magua
2nd February 2009, 17:51
yep as the other dude said if its a blind hole your sweet just keep your spindle speed low so chips don't fly everywhere, if its a through-hole, can you fit a vacuum cleaner nozzle in there ? did that at work once, worked sweet, when you use the tap you can cover it in grease, just go a few turns at a time, back it out, wipe off grease and go again..

Vacuum cleaner nozzle? It's a through hole.

Edit:. that's a photo of a different hole, they're not through holes. I don't trust myself with a drill though, think I'll have to get it to an engineer's shop.

speedpro
2nd February 2009, 20:11
You'll need to get the little tang off the bottom of the helicoil without dropping it in as well.

The reason the thread seized up is the same reason the barrel was hard to remove, it's been together a long time. A good way to ease future disassembly problems is to put loctite on all the threads. Not only does it lubricate the threads as you assemble it but it holds the thread tight and the loctite stops corrosion. You only need 222 or whatever it is now. I like to use Loctite on the base gasket as well. Just the faintest smear of something like 555. I like the loctite gasket compounds as they don't set except in the joint and therefore can't flake off and block an oil gallery to the head which historically has been a bit of a problem with hondas being worked on by beginners. As has been said - keep away from silicone goo, it's wrecked many a good engine.

edit: Honda fed the oil up one or more studs on these motors I think, it was a typical thing to do anyway. so you have to be double double careful. Just take the cases apart, it ain't hard and it eliminates a lot of potential problems. Nothing like giving it a good flush out with the garden hose to get rid of swarf etc.

speedpro
2nd February 2009, 20:19
Vacuum cleaner nozzle? It's a through hole.

Edit:. that's a photo of a different hole, they're not through holes. I don't trust myself with a drill though, think I'll have to get it to an engineer's shop.

This stud hole has an oil gallery feeding it, see the hole to left within.

Magua
2nd February 2009, 20:26
This stud hole has an oil gallery feeding it, see the hole to left within.

Yeah I noticed. Funny that the bolt that came from the hole with the broken thread has an "oil control washer", but no oil gallery.

gatch
2nd February 2009, 20:41
oh thats a bugger, i thought it would just be straight into solid metal, forget the vacuum thing... :shifty:

Magua
3rd February 2009, 11:30
Yeah I noticed. Funny that the bolt that came from the hole with the broken thread has an "oil control washer", but no oil gallery.

It's looking like I've lost one of those damn washers, and it's not as simple as popping up to the bolt shop to get another.

Who can I get to make me another?

Edit: Nvm, I'll go to the wrecker. Duh!

xwhatsit
3rd February 2009, 14:15
It's looking like I've lost one of those damn washers, and it's not as simple as popping up to the bolt shop to get another.

Who can I get to make me another?

Edit: Nvm, I'll go to the wrecker. Duh!
Hahah, you need more ice-cream containers.

So I'm confused. The dodgy hole doesn't have an oil gallery, and is a blind hole? If so, that's a piece of piss. Don't have to worry about the tang on the helicoil either (don't most people just leave them in place if space permits?). I kept drilling a little bit, then dunking the drill bit in a tub of old engine oil, which meant most of the swarf stuck to it and kept the drill bit lubed anyway. Same deal with the tap. It's really not hard to do, you just have to keep the drill bit dead straight so you don't round out the hole.

But to buy a kit is about $50 -- getting the hole coiled by an engineer would be similar, although you don't get to keep the drill and tap that way. Time to drop the engine out! At least it'll be lighter now :D

Magua
3rd February 2009, 14:30
Hahah, you need more ice-cream containers.

So I'm confused. The dodgy hole doesn't have an oil gallery, and is a blind hole? If so, that's a piece of piss. Don't have to worry about the tang on the helicoil either (don't most people just leave them in place if space permits?). I kept drilling a little bit, then dunking the drill bit in a tub of old engine oil, which meant most of the swarf stuck to it and kept the drill bit lubed anyway. Same deal with the tap. It's really not hard to do, you just have to keep the drill bit dead straight so you don't round out the hole.

But to buy a kit is about $50 -- getting the hole coiled by an engineer would be similar, although you don't get to keep the drill and tap that way. Time to drop the engine out! At least it'll be lighter now :D

I think I will take it to a shop, know of any? I've bought a helicoil (2 actually), but I don't trust my unsteady drilling hand. :sweatdrop

speedpro
3rd February 2009, 21:40
If you put a couple of studs back in you can use them to align the drill vertically. Get a mate to keep an eye on the alignment while you very carefully drill it out. I like to do this sort of thing in the drill press. It allows you to get everything square and you get good control over the drilling process. I start the tap using the drill press as well just to make sure the start is square. Once started I undo the chuck leaving the tap in the hole and remove the whole case or whatever and finish the tapping and helicoiling process.