Author Topic: Oh Oh !!!!!!!!!!!! (Read 5522 times)

beelsamin · « **on:** October 06, 2007, 02:57:06 PM »

So with brew and tools in hand,not at the same time mind you,I started pulling the head off my K2.
Everything a piece of cake until I started pushing the rocker arm shafts out....both shafts on the right side(kick side) are broken right at the waist...what the hell...fade to long sip of nectar and scratching of head...how can both shafts be broken?
Made a mental note to go to SOHC forum and cry, and continued to dis-assemble the head,all bolts are out and am letting it sit before pulling it off..I'm afraid of what I'll find.Has anyone else found their rocker shafts broken ?

mattcb350f · « **Reply #1 on:** October 06, 2007, 03:45:53 PM »

Is your bike a 750K2? here's the diagram of the rocker arms and shafts

Is there more pieces than what's in the pic?

beelsamin · « **Reply #2 on:** October 06, 2007, 04:08:58 PM »

Number 4 and 5 are broken in half right at the narrow point.

rhinoracer · « **Reply #3 on:** October 06, 2007, 05:36:43 PM »

At this point I think you'll be way ahead getting a running motor from ebay.

beelsamin · « **Reply #4 on:** October 06, 2007, 06:51:02 PM »

Well that's not very encouraging,I would think the shafts are replaceable.A whole new motor because a part is broken?

MoTo-BunnY · « **Reply #5 on:** October 06, 2007, 07:36:25 PM »

weird.. . .what the heck would cause something like that?

mattcb350f · « **Reply #6 on:** October 06, 2007, 08:16:43 PM »

Well, before you give up on that engine I'd tare it appart anyway and see what else it needs. The broken rocker shafts may be the only bad parts in it. Still not sure what broke them, unless the valves are stuck and in trying to turn it over they broke in the process.

Anyway, keep an eye out in the Supershopper. Last week I saw a 750 engine for sale and this week is a frame, fork and engine. Here's the buysell.com link:
http://www.buysell.com/root/detail/Central_Ontario/Motorcycle_Parts_Trailers/4840/65453093/Honda_CB750_frame_and_forks_for_1969.aspx

rhinoracer · « **Reply #7 on:** October 06, 2007, 08:28:57 PM »

Quote from: beelsamin on October 06, 2007, 06:51:02 PM

Well that's not very encouraging,I would think the shafts are replaceable.A whole new motor because a part is broken?

I didn't mean a NEW motor!

You're taking it apart because the crank is jammed and you couldn't free it so there will probably be more damage than just the rocker shafts. The shafts would break like that if the rockers seized from overrevving or lack of lubrication. Pistons and bearings would seize too.

And even if not, gasket set +$70, bolt set +$25, rings +$60, bearings +$15 each x 9, valve guides +$30.

Add head work, at least valve seat cutting and lapping, head surfacing replacing guides, honing cylinders, sealants and assembly lubes.

I wish the best for you but just reassembling the motor will cost you more than a good used one. That's what I meant, didn't mean to sound rude

Terry in Australia · « **Reply #8 on:** October 06, 2007, 11:40:19 PM »

She's clagged mate, get yourself another one. Cheers, Terry.

toycollector10 · « **Reply #9 on:** October 07, 2007, 04:48:22 AM »

I'm afraid she's "coozed" mate. Or is that "Koozed". Those words idon't feature on Wikipedia dot com so I will tell you what it means.
It means that it's munted. Ooops, nothing there either. Stuffed, knackered, f*cked, maybe. Shot, "had it", buggered...it's completely worn out old son.

beelsamin · « **Reply #10 on:** October 07, 2007, 05:41:38 AM »

Both the shafts, although broken, slid out smoothly,there were no score marks at all,the rocker arms on that side also looked good,in short,apart from the shafts being broken,all looked good.
Anyway I'll be pulling the head later this morning and can have a look at the valves and pistons.

KB02 · « **Reply #11 on:** October 07, 2007, 05:45:05 AM »

Part #14461-300-020 and #14462-300-010.

Before you took them off, did you notice any bending or bulging of the rocker arms? I would only worry about them bending the holder to the point that any new parts put in would soon meet the same fate.

beelsamin · « **Reply #12 on:** October 07, 2007, 05:57:46 AM »

I really had no evidence that there was damage to the shafts until I pushed them out,I'll take a look at the rocker arms ,it does seem that the only way the shafts would break is if they were being torqued,and for that to happen,the rocker arms on both shafts would have to partially seize or seize completely at the same time....does this sound possible?

beelsamin · « **Reply #13 on:** October 07, 2007, 07:58:00 AM »

I've just pulled the head off and found a nasty rusty mess,all the chemicals I've poured into the cylinders over the past 2 months are still sitting on top of the pistons.There is a lot of rust on the cylinder walls so looks like an overbore for sure.I've put some Deep Creep on top of the pistons so hopefully I can get the block off sometime this week,then I can delve into the tranny. it looks like a fair amount of work but this is one K2 I will not let die.
So my next question is,does anybody know a good shop in the GTA (Toronto) that can do the machining I'll need?

justfours · « **Reply #14 on:** October 07, 2007, 10:17:17 PM »

Sure, its alot of work, but you seem to have the right attitude about it. Just be patient. I had almost the same situation when I started rebuilding my motor.I am assuming that your motor is seized from sitting and not mechanical malfunction.I tried weeks of soaking the pistons and they still didnt free up. In the end, I had to split the cases and use a wood block to hammer out each piston. Again, patience. I found a set of .5 oversized pistons on ebay and had the cylinders bored to fit.

I also had a broken rocker arm shaft. you should be fine just replacing it, but you could also try to find the top end of a later F bike. You dont need the head, just everything on top. The later cam towers and rocker shafts have screws that hold the rocker shafts in place. They have worked great on my motor so far.

It can be frustrating, but I assume you are doing this as a hobby and you love these bikes and want to know all you can about them. Well, there is no better way to get an intimate knowledge of these motors. Good Luck.

mattcb350f · « **Reply #15 on:** October 08, 2007, 08:29:57 AM »

Quote from: beelsamin on October 07, 2007, 07:58:00 AM

I've just pulled the head off and found a nasty rusty mess,all the chemicals I've poured into the cylinders over the past 2 months are still sitting on top of the pistons.There is a lot of rust on the cylinder walls so looks like an overbore for sure.I've put some Deep Creep on top of the pistons so hopefully I can get the block off sometime this week,then I can delve into the tranny. it looks like a fair amount of work but this is one K2 I will not let die.
So my next question is,does anybody know a good shop in the GTA (Toronto) that can do the machining I'll need?

The guy I'm using is doing my machine work as a favour to me. I'm not sure he's enjoying it yet

I'll ask him if he's interested in doing an other bike engine, as far as I'm concerned he's probably one of the best in the city. He's down on Islington, not far from the lakeshore.
Matt.

cleveland · « **Reply #16 on:** October 08, 2007, 09:27:53 AM »

Where are you located?

Tower · « **Reply #17 on:** October 08, 2007, 09:53:47 AM »

There's a few places out in Mississauga at reasonable rates (unlike those in Toronto) that can do the work. The closest to Toronto, that I've had work done at, is The Motorcycle Shop (TMS), off Dundas east of Dixie.

mattcb350f · « **Reply #18 on:** October 08, 2007, 12:51:05 PM »

Just thought of another shop, Northern Motorsports in Bradford.
http://www.northernmotorsports.com/
And here's the link for the one Tower mentioned:
http://www.themotorcyclestore.net/index.html
Matt.

beelsamin · « **Reply #19 on:** October 08, 2007, 03:28:19 PM »

Thanks guys,I'm just north of Orangeville and work in Brampton so any of the Toronto places are accessible.Just had a quick look at the motor and the pistons are really rusted tight,I'll give them a wack with a piece of wood every day meanwhile I've got SeaFoam deep creep sprayed on them.

Tower · « **Reply #20 on:** October 09, 2007, 12:22:26 PM »

@beelsamin, Had to search through my old receipts before I could post info on the other folks I've dealt with.

Tony's is a father and son operation on Steeles about 2 km west of Winston Churchill. They work out of a large garage in the back of their farmhouse. They've been in business a long time. Always a huge waiting list of customers (I guess that's a good sign). A little pricey, but they'll pick up, and do any repair you need, if you don't mind waiting (905) 878-4986

I've had good work done by Neil at Motorcycles International on Ridgeway Drive (s.e. corner Ridgeway and Laird) just west of Winston Churchill and north of Dundas. He works from a shop in the back of his store. He's got a lot of history in the motorcycle business. All work is on an hourly basis. (905)-607-2337. I was so happy with his work, I gave him a jar of my wife's Plum Jam.

beelsamin · « **Reply #21 on:** October 09, 2007, 02:37:25 PM »

Just got home from work and gave the pistons a couple of taps with a piece of 2x2 and actually got #1 piston to move an eighth of an inch,block is moving so maybe i will get the thing loose of the other 3 pistons before too long.I'd be really embarrased to take it for machining with the pistons still stuck in the block.That 1/8 inch is the most its moved in 2 months of trying.

Sam Green Racing · « **Reply #22 on:** October 09, 2007, 03:42:16 PM »

Take the lower crankcase half off before you start hitting the pistons, It could be that the crank is locked up as well as the pistons.
You could damage the crank if it's not allready damaged. Get the bottom end off.

Sam.

mattcb350f · « **Reply #23 on:** October 13, 2007, 04:18:58 PM »

Bump. How goes the battle beelsamin?
I see that 750 engine is still for sale in the supershopper for best offer..
Matt.

beelsamin · « **Reply #24 on:** October 14, 2007, 09:10:01 AM »

Matt,
Only one piston still stuck,should have it loose this week.I'll probably be lugging the motor into the basement ,my garage is not heated and I like warm

The guy in the ad is only offering the frame and forks not the motor,his ad was not really clear.Until I get the motor fully apart and can determine what all it needs I'm pretty well at a standstill.As far as the rest of the bike, everything is there,even had the original exhaust,which is in pretty good shape,usual rusty spots on the chrome but most of it is coming clean,some might require rechroming but want to wait until I get all the pieces needing chroming together and have them done at the same time.Have had a guy offer me a parts bike but he is very vague about what it is he has, and since he's an hour and a half away,I asked him for engine and vin numbers,all he knows is it's a 70's Honda 750 and he has to dig it out.At the same time,I'm renovating this old house we bought and find less time than I'd like to work on my baby

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Author Topic: Oh Oh !!!!!!!!!!!! (Read 5522 times)