Head Bearings

With those difficult to remove head race bearings with no lip, I think I've only heard it suggested to weld a brace across or drill out the bearing with a Dremel ( other brands available - LOL ). Chatting to one of my YouTube channel subscriptions  - a mechanical engineer ( currently building a 2 stroke engine with a lathe, and nuts and bolts restoring a CX500 ) he advised drilling 3 holes into the head stock from the back and punching them out. I had already thought of this, but thought too unorthodox and passed it over back when I was doing mine. Will definately try this on this on the next ever set I need to do. Just a bit of tidying up after with solder I would say. Anyone tried this ???

https://scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/16508088_1269174759828049_3285620700759673393_n.jpg?oh=87992382439d8d4d6bce14c2eccf681d&oe=5943B28D

Andy c suggested a rawbolt in bearing hole... that work. Tighten up rawbolt(anchor bolt) and get chisel otherside smack tip of raw bolt it knock bearing out

Is there a demo of that - don't quite follow ?

Think I'll just use a welder when I need to change mine next. Drilling holes in the frame that aren't factory does go against the grain for me.

The bearing has hole in middle the raw bolt (anchor) are used as masonry fixing..  basically  get correct size raw bolt for bearing hole. Put it into hole at bottom yoke   tighten til it locks tight  in bearing hole now go to top bearing  you can pass a slim drift through top bearing hole and now you can hit top of raw bolt and it should knock lower head race bearing out.... ive no demmo i am afraid.

Jameshambleton wrote:Think I'll just use a welder when I need to change mine next. Drilling holes in the frame that aren't factory does go against the grain for me.

I know what you mean, which is why I thought it unwise at the time, but when an engineer says do it ! -  Removing material to fix a problem isn't that unusual and perfectly acceptable if say you're honing a cylinder in a mild or wild fashion for one reason or another or lapping a valve back in, or even helicoiling a cylinder head or crank case,  So why not a short cut to a quick bearing removal ? A welder's heat could equally damage the frame if not done correctly, and it's fair to say most people can handle a drill and have easy access to one unlike a mig or tig welder. Definately going to give this a try next time.

wornsprokets wrote:The bearing has hole in middle the raw bolt (anchor) are used as masonry fixing..  basically  get correct size raw bolt for bearing hole. Put it into hole at bottom yoke   tighten til it locks tight  in bearing hole now go to top bearing  you can pass a slim drift through top bearing hole and now you can hit top of raw bolt and it should knock lower head race bearing out.... ive no demmo i am afraid.

Cheers wornsprockets. I see now, yeah sounds like it's worth trying as well. I almost want to get an old frame and give this technique a try. I have taken to buying bits of crap just to take it apart and see. Sell it on fixed Or in better condition !

spanner monkey wrote:With those difficult to remove head race bearings with no lip, I think I've only heard it suggested to weld a brace across or drill out the bearing with a Dremel ( other brands available - LOL ). Chatting to one of my YouTube channel subscriptions  - a mechanical engineer ( currently building a 2 stroke engine with a lathe, and nuts and bolts restoring a CX500 ) he advised drilling 3 holes into the head stock from the back and punching them out. I had already thought of this, but thought too unorthodox and passed it over back when I was doing mine. Will definately try this on this on the next ever set I need to do. Just a bit of tidying up after with solder I would say. Anyone tried this ???

https://scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/16508088_1269174759828049_3285620700759673393_n.jpg?oh=87992382439d8d4d6bce14c2eccf681d&oe=5943B28D

I suspect that this would be fine as far as strength is concerned - the hole are only small and the steel is strong, plus when the bearing race is installed the load is spread over the whole area of the race. Personally i would prefer to weld something onto it if required, I think I'd only go for the drilling option as a last resort (though it is a lot better than junking the frame because you can't get the head bearing race out!).

Yeah, even using a grinder directly onto the bearing race does minimal damage. Either of these methods leaves well over 95% of the seating material intact. A quick plug of the hole with solder and paint, will stop water ingress. No issue.

Hi,

I guess nobody has actually tried this rawlbolt trick yet? I found out I have flat spot on steering when dead straight, so it seems like I need to change my head bearings...

I have to see if I can find suitable size rawlbolt. I could borrow MIG welding machine and try welding a bead inside the bearing race and wait for it to cool and shrink. The problem is that I am not much of welder guy. If I go this route I better practice first with something where errors are less costly.

Oh well, plans for the weekend seem set...

BR,
Antti

That raw bolt trick seems like a good first try before welding even, nothing to lose.

Melitos wrote:I guess nobody has actually tried this rawlbolt trick yet? 

I have done that, but for much smaller bearing on an assembly I could heat in oven - the crankshaft bearing on a nitro engine.

I'm curious to see if it will work on the cb head bearings.

hh_12345 wrote:

Melitos wrote:I guess nobody has actually tried this rawlbolt trick yet? 

I have done that, but for much smaller bearing on an assembly I could heat in oven - the crankshaft bearing on a nitro engine.

I'm curious to see if it will work on the cb head bearings.

You might need a big over to put a cb500 in it 

You need a big raw bolt i have one in work i am going to use if it fit...raw bolt for heavy steel structural beam bolted into concrete

Rawl bolt trick is good for wheel bearings but it would be the biggest rawlbolt in the world for the steering stem.

I had someone run a weld round mine and it just fell out like magic. I had read about it but seeing is believing!

lawmand wrote:Rawl bolt trick is good for wheel bearings but it would be the biggest rawlbolt in the world for the steering stem.

I had someone run a weld round mine and it just fell out like magic. I had read about it but seeing is believing!

Any chance you're called David?

Yes James that's me seen you on the fb forum too

Thought I recognised that image from somewhere

Hi

I got mine off today with not too much wrestling. The upper one I could actually drive out with punch and hammer because there was just enough lip for the punch.

I was not able to find large enough rawl bolt. It'd have to be something like M36 thread diameter...

Also when I looked at the lower bearing race it was clear that welding was not an option with my skills.

Anyway the rawbolt method got me into thinking and I came up with following special tool.

OD 35mm steel pipe 4mm wall thickness. Cut wide V shape to one end, then cut axially on both sides (about 4cm was good for me, depends on actual OD of the pipe) and two sets of reliefs to help with widening.

Here the pics to help

First prototype. The axial cuts were too short, tool did not get wide enough to touch the bearing race. Also I noted that you need to shape the end with wide v-cut to get better grip from bearing race. Nevermind the machined section on the end, that is not needed.The machining was on the raw material that was the starting point for the tool.


This one did the trick! End cap was helpful when hitting with hammer but I'd say not a must. I had to support the V-gap with punch in order for the gap to not close when I was hitting with hammer from one end.

Patent pending...

BR,
Antti

Nice one, necessity the mother of invention and all that.

Good job. Thanks for sharing.

Thats what i like to see home made tools  to get the job done  good work antti 

.........if only there was somewhere to buy a tool like this!!!!!

Honda do a special tool for the bearings/races No's 07953-MJ10000 and 079463710500.

Have not yet had a chance to search the web for them