Honda SOHC engine rebuild

[Rob.b (Rob Birkett - RIP)]

Hello, I'm new here.

I live in near Nantwich in Cheshire and have owned my CB500 four since 1983, it has started to smoke, it uses about 1 litre of 10/40w oil every thousand miles, although it seems to run just fine.

I replaced the valve guides about 15 years ago in the hope that would solve the issue - it didn't.  It has not really matterd to me until now, but this bike is my only remaining bike and I want to start to use it as a regular (reliable) ride.

I'm not a very confident mechanic and so I was wondering if any members know of a good engineer preferably in the Northwest that could do some work; likely to be a rebore on the bike.

I have put up a Video on YouTube of the symptoms that may be of use.

Its at:    https://youtu.be/awYEY3Rb7JI

Any thoughts or suggestions would be much appreciated.

Thanks Rob

[Trigger]

Welcome to the mad world of the SOHC. Sounds sweet to me, a little smokey but looks fine for one of these old girls. 
Are the plugs oiling up ?

[SteveD CB500K0]

I need an "envy" smiley for that number plate.

Welcome.

Steve


Sent from my iPhone using Tapatalk

[Johnwebley]

wow,that sounds cool !!!


  at 9k,in 3rd all I hear is the wind in the helmet !!

[Woodside]

Is the bike in the black and white picture at the beginning the same bike.....just wondering as it has a 4 into 1 pipe
And your video it's a 4 into 4?

Sounds great whatever

[Rob.b (Rob Birkett - RIP)]

Hi all
Thanks for the responses so far.
I can't figure out how to make individual replies yet so here goes with a catch all reply.

First I am very pleased and surprised by the number and promptness of them.

1) yeah the plugs are not straw brown in colour, they are uniformly sooty.

2) the number plate on the photos is near to the real registration number, but thanks to Photoshop is much cooler than the DVLA ever made it.

3) I have built a set of deflectors and baffles for it now, its much quieter and far more tractable, engine performancenown feels like standard.

4) the black and white photo is from august last year, I took it just before I fabricated the four into four set up on the vid.

Cheers to you  all, keep it coming
Rob

[Trigger]

These engines are very strong, may just need the bores cross hatched and a new set of rings. Will not know until the top end is stripped. Out of interest, what sort of miles do you thing the engine has done ?

[Rob.b (Rob Birkett - RIP)]

Hi Trigger

The bike has done 38,000 since new. Some of those on low oil way back when I never imagined I would care about the bike in 2016.

I had thought that it probably would benefit from a short engine refurb but have no idea who to trust the work to.

Regards Rob

[Trigger]

I re-build SOHC's for a living but, am snowed under with work at the moment and nowhere near you 

[royhall]

Sounds great, but please don't do that again.

[Rob.b (Rob Birkett - RIP)]

Roy,

I promise not to do that again, it makes my toes curl to watch it.

cheers Rob

[Trigger]

Roy,

I promise not to do that again, it makes my toes curl to watch it.

cheers Rob

Toes curl? You nearly gave a few members a heart attack The 500 loves a oil and filter change with mineral oil every 1000 to 1500 miles

[paulbaker1954]

Hi
I am just rebuilding my engine on a new project i bought with a seized engine.

If you managed to change valve guides i am sure you could tackle a fuller rebuild.

Whilst i am time challenged in terms of helping i would be happy to help with phone advice, pm me if you want to talk

In terms of engineering i used a company just off the Irlam junction on m6 called micro precision to press out some horribly seized pistons, hone the bors and fix a broken off case stud and they are nice guys and did agreat job at a reasonable price www.mpeltd.co.uk

[mike the bike]

Armed with a manual, tools and parts, gaskets etc, I'm sure you could manage it yourself.  You can always ask for advice on this forum from people that's done it.
It seems a daunting task but it's the fear of the unknown that puts people off.
It does sound like the piston rings are worn.

[Rob.b (Rob Birkett - RIP)]

Hi Mike & Paul, Thanks for the encouragement, but I am still very reluctant to open the motor as I don't really know what I am doing and wouldn't know how to recognise problems if I was looking at them.  For example when Trigger advised that new rings and a cross hatch might sort it I had to google 'Cross Hatch' to find out what it meant.

When I changed the valve guides that was under the very close supervision of my brother, and it didn't solve the oil burning issue anyway.

I have owned the Honda for the past 33 Years, for much of that time it has been my second bike while I had a string of more modern bikes which were my regular rides.  The Honda has been off the road, but maintained for ten years (or more). Last August I sold my MT01 having decided to get out of biking while I was ahead.  I couldn't sleep the night the MT01 went as is was the first time in 46 years that I didn't have a bike, (big mistake I thought) then I realised that in fact i did have a bike - The Honda.  I got up at 6 am and the bike was running by 10, insured by 11, and MOT'd by 12.

Anyway the long and short of it I want to get the Honda working well and reliable, and I have little in the way of mechanical aptitude, I've read every CB500/550 related post on this forum and think I know who I am going to ask to book it in for a refresh.

Many thanks Keep it coming

Rob