Honda-SOHC

In a bid to fix my horrible sounding no 1 exhaust I emailed them along the lines of I bought these 2 years ago and surprised to see a baffle failure after only 2k dry miles

I have to say great service as they have replaced it at no cost but looking at their web site I have got to wondering....

They list single pipes for 2 3 and 4 cylinders but always show a single pipe for no 1 as unavailable

This has got me wondering if there was an original known manufacturing issue with no 1 and they have pulled my replacement unit from a full set which is why there is no availability of no 1 pipes

I believe DS use the same supplier as well but may be wrong

So I was just wondering if anyone else has heard of any similar problems

Recently I  have got rather interested in Compression level testing on my 500 4 mainly down to trying to diagnose some running issues.

The Technical official Honda 500 Maintenance Manual indicates a "good level" of 170 PSI and anything under 140 indicating worn rings, poor valve seating etc

So off I went with my pressure tester and got 135 PSI on all 4 pots and started to panic, why are these levels so low compared to the Honda spec given that I rebuilt this engine only 2k miles ago with new pistons and rings and honed bores and all measured up to within official Honda sizes for a standard bore (56 mm) engine. Also the engine runs well with no smoke etc indicating worn rings or anything else wrong.

So why the large discrepancy.

I think there are a number of factors at play here

1) The compression tester I used was a fairly cheap unit   but like many commonly available that has a long length of rubber hose. This significantly increases the volume of air being compressed and can drive down the readings on these small capacity cylinders as the additional volume of air is significant compared to the swept cylinder volume.

If you look at the Honda maintenance book picture the  guy there is using a rigid metal small bore pipe connected to the gauge NOT a rubber hose. Also the Honda manual says nothing as to whether this is a dry or wet test but logic would assume dry as nothing says otherwise.

There is an excellent post on the USA forum about this that end up getting very technical but a really interesting read for the highly technical amongst us.

http://forums.sohc4.net/index.php?topic=39971.0

2) This was a dry test so I put some oil down the bores and the readings whacked up to 175 but I think I put way too much oil in there which was why such a jump. I thin I should have added just a few small drops !!

So now to my million $ question on these 4s what would be a sensible "good" level to get when using the type of gauge easily available and thet we all use.

My experience seems to lead me to around 135 psi on a dry test and that it does not rise dramatically on a wet test with a few drops of oil would indicate a pretty good condition engine. But that said I wonder what an acceptable lower level would be to indicate a top end problem.

Be very interested in others opinions here and how this thread develops.

A) Does anyone else have and readings from their bikes that may help?

B) Does anyone know what sort of increase is OK between a dry and a wet test?

Help....

I have been trying to chase down a problem with my bike that started with cylinder 1 sounding like a tractor.

I have checked the exhaust and no loose baffles to be heard.

Next step was to check the plugs and oddly number 1 looks ok but the others all look a bit rich. This a bit odd as carbs have been fully rebuilt with ultrasonic cleaning and all new jets etc so not convinced I have a carb issue.

Next I checked the compression and am only getting 135 psi on all pots. Again a bit odd as she has had new pistons and rings but maybe my bore measurements were off!! On putting some oil down the bores compression climbed to 175 so that would seem to confirm a piston/ring problem. But again why would this cause this noise only from cylinder 1

I think I have come to the conclusion that I need to at least pull the head and block and check all over again.

But before I reach for the toolbox I would appreciate and ideas anyone else has having listened to the sound

As I said in the first sentence the issue is the rough sound from cylinder 1

I have posted here on YOU TUBE.
http://www.youtube.com/watch?v=R-Xa4GgAUno

http://www.youtube.com/watch?v=WscXzWjlIQU

The first vid you can hear the rough sound and in the second I disconnected spark plug 1 so you can hear the difference.

Just been doing some more investigating on my odd sounding no 1 cylinder and decided to check compression. I am getting 135 psi on all 4 pots so no drastic difference on no 1 cylinder

That said are these readings a bit on the low side as the maintenance manual mention 177 psi

I should add that engine had a full rebuild 2k miles ago with new pistons and rings and I also regrouped all valves in etc

I should add that this was a “dry” test ie no oil put down bores etc

Anyone ever used JMT gel battery?

Are they any good?

Just had a bit of a root around the garage and I have the following available if anyone is interested pm me

1) Full 500 four clutch , good plates in spec, springs, basket, lifter, shim etc

2) Two aftermarket coils CML612 units.They are 5 Ohm primary and 17 Ohm secondary. I bought them last year but never used them as I ended up going full Boyer kit

3) Two original coils working but worn. The outer ht coverings are a bit brittle and have cracked at the entry to the coils but they do work fine

4) Another contact has an original NOS K0 seat in mint condition. Apparently they are as rare as hens now. I can put you in contact here if anoyone is interested


PM with a sensible offer if anything is of interest. They are all on fleabay but rather a forum member benefited

Just noticed my 2 year old battery (Nitro YB12A-A) was struggling on cranking. I keep it topped up with an optimiser.

Just checked and it needed a massive top up so must have been halfway down cells - agggh!!!

Topped up and back on charge but will it be buggered having got so low or will it recover?

Interesting that I heard using optimisers tends to dry em up, anyone confirm this.