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Messages - K2-K6

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Tricks & Tips / Re: Wots goin’ on here pls folks?
« on: Today at 11:41:08 AM »
With rings stuck it will compromise most stages of running as it's effectively sucking (drawing in the cases) as well as holding compression. It's more or less like having leaky cases in a way.

Dilution of crankcase gases with burnt blow by effectively reduces the volatility of the next charge phase.  This is what they do on exhaust gas recirculation systems in car engines, but only at specific load demands.

You'd need the rings working properly to make realistic assessment of the running as a prerequisite.

Humour / Re: I can see huge one
« on: Today at 09:59:15 AM »
"Roughly made by the barrel on the farm."

In Somerset with someone that took us to a farm at which they had a few different vats of different apple type ciders, which they would blend as you liked to make cider of your preference.  Cloudy and quite rough, but great tasting. They also said that they'd throw in a ham during fermentation to replcate things that would originally have been in cider from drowned rodent population (seemed serious but could have been for amusement toward us softy visitors) it tasted really good in spite of this.

Person that took us there also "distilled" it via freezing and then as it thawed the alcoholic element drains out first to make farmer's apple brandy  ;D

Tricks & Tips / Re: Wots goin’ on here pls folks?
« on: Today at 09:38:12 AM »
Lubrication breached, obviously!  But reason is important to correct.

As others, is it really supposed to be at 100 to 1?
Presumably water cooled?
Have you pictures of combustion chamber, piston crown and spark plug to see colours.
What is the spark plug identification/grade etc.
Looks like exhaust side of piston?

Humour / Re: Would you really
« on: February 24, 2021, 08:57:04 AM »
Yes, genuine parts Roy  ;D

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CB500/550 / Re: Cb 500 k1 with a k2 engine?
« on: February 24, 2021, 08:05:20 AM »
"Plus the current owner got the bike in 2004, never done any maintenance"

"He says he never has done any maintenance, only oil change every year. "

It looks like it's been kept inside,  with oil change each year. This is a very good starting point as many of then don't have this. For more detailed inspection, that's only possible once you get it and ride it, but for the money it seems quite an original bike and worthwhile to buy.

CB500/550 / Re: CB550K - engine rebuild (partial or full)
« on: February 23, 2021, 12:51:41 PM »
As Bryan says,  all ok.

To take it underneath that which is needed for good mechanical condition, it can tell us more about the conditions during running so far.

The outer two bearing surfaces show just a flattening of the original boring marks and exactly as you expect to find as witness marks.

The marks are consistent with the design in that the bore size has to have a tolerance in relation to the camshaft journal that avoids seizure and allows for oil film effectively not under pressure.  You can see from the wear marks how far up the "wall" of the bearings that the two depart and no longer touch each other. 
The centre two bearings show their witness marks travelling further than the outer two,  a little like judging plastiguage. Meaning the camshaft has worn into the bearing further on these two,  but a very very small amount.
This would happen if the oil film was unable to support the load as it should. Mostly this is associated with oil condition and specifically dilution/service interval in the engine's life so far.

It seems consistent with the amount of wear in the primary chain too. Those bearings (within the chain) are possibly the highest loaded individual parts in the engine with their lifing giving a good indicator initially of running conditions to that point.

As first stated, it's perfectly normal to see the bearings in the head like this and it's not a fault as such in the overall condition,  just that you can have more of a picture of progress so far in the engine's life.

CB500/550 / Re: CB550K - engine rebuild (partial or full)
« on: February 22, 2021, 09:22:44 PM »
I understood the thread focus was to assess if the motor needs to be split at this time to replace chains etc. Rather than avoid cost,  but more for Erny to get realistic appraisal of if and when it would be sensible to carry that out.

Obviously, the problem with the rocker shaft and it's effect on running brings that to urgent scheduling, but cam chain is ok and primary serms medium worn and so not absolutely required immediately if may be better to complete next winter.

As already noted through the thread,  camchain replacement is entirely sensible whether bad or not, if the crankshaft is coming out.

Clearly the two chains wear at very different rates,  but then they are completely different engineering solutions compared to each other.

"Please say yes that the mixed bearing option is an option albeit neither Flesh nor"

Nothing wrong with this at all from a technical point of view.  Quite common to mix bearing types according to load demand.

The taper is most beneficial on the bottom in absolute terms,  top just really keeps it from wobbling or falling out  :)

You get similar in MTB cycles with a complete mess of different frame, fork and bearing size. They don't have a fixed length stem though, so can be made up with all sorts of different components to fit various types of forks etc.

Project Board / Re: 1976 CB550F1 (what have I let myself in for) Project
« on: February 21, 2021, 05:40:12 PM »
Nice work, great when a project gets into the building phase too.

CB500/550 / Re: CB550K - engine rebuild (partial or full)
« on: February 21, 2021, 05:31:58 PM »
That sounds fine with no real wear at all.

It doesn't matter if it's tensioned or not as you are effectively comparing the chain pitch with the sprocket pitch, with no realistic slack it shows it's virtually as new. 

A chain can be tensioned as much as possible,  but if worn you'll still be able to pull the links away from the sprocket at the centre of it's engagement.  If you can't it's definitely good.

They move/slide slightly side to side,  all seems fine.

Some pictures on page 4 of that link show a little more details.

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The original "stack" height has a seal washer for the bottom race which the new kit may not have.

The original ball set standard equipment cannot be matched as far as I understand,  that's in tapered std manufactured.

Contemporary times for these, suppliers like Dresda had taper sets ground to match the Honda fit and sold as kits.

Referenced by Bryan in this thread to effectively give a drop in set. 

In the end I resorted to violence using a 15mm masonry bit with the SCS in hammer mode only it finally  let go! Thanks for the encouragement everyone!
I find this with most things that are well stuck or corroded.

Far from being the most brutal,  it seems just more insistent in applying vibration to the work piece and avoids the significant blows a heavy hammer will apply.

I've been using (by making up special adapters) this method for moving things in fairly light structures that I didn't want to damage.

CB500/550 / Re: CB550K - engine rebuild (partial or full)
« on: February 20, 2021, 09:05:17 AM »
Adding to the above, the chain disguises it's wear really well and is unlikely to fail. They just go on getting more and more loose but with the tooth form and design (the way the chain changes as it bends)  keeping it running quite effectively.

The limits for this engine are particularly, that it will end up touching the crankcase casting, and that it will make more noise when idling.

This one is not so urgent that you'd have to stop using it and change immediately,  but certainly to plan for work to get the parts and complete when convenient for you.

As Oddjob says, the cush drives need to be considered if you are stripping to change the chain.

Sounds good if you can outsource it to get a good finish.

Went to look at a local powder coater recently as son is working on bicycles,  they showed me some really nice work and finishes and not what I'd seen in the past.

Blue and gold always look good paired.

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