Author Topic: Running like a dog Part II  (Read 4160 times)

Offline K2-K6

  • Grogu
  • *
  • Posts: 5234
    • View Profile
Re: Running like a dog Part II
« Reply #30 on: September 11, 2019, 03:34:50 PM »
Yes,  top of piston #3 watercooled 750 Suzuki triple.

You'd have to say it's inventive  ;D at a guess.

Offline paulbaker1954

  • SOHC Pro
  • Posts: 696
  • I'll just be 5 minutes dear!!
    • View Profile
Re: Running like a dog Part II
« Reply #31 on: September 13, 2019, 10:44:48 PM »
Ok head off AGAIN and checked valve leakage by putting petrol in combustion space-no leakage but I am guessing that if it was top of stem that got bent putting cover back on that would be expected as the bend would be above the guide (opinions please).

Taking head to local machine shop for valve check and overhaul next week so will know more then
If you think there's light at the end of the tunnel it's usually another train !!

2016 Yamaha MT09 Tracer
1971 Honda CB500 Four K0

Offline matthewmosse

  • SOHC Master
  • Posts: 2161
    • View Profile
Re: Running like a dog Part II
« Reply #32 on: September 14, 2019, 12:51:49 PM »
If you can remove the valve cap and see if it comes out freely that might be a good first indication. Depends on having the right tool to get the collects out though. Possible without correct tools but can be a fight.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline matthewmosse

  • SOHC Master
  • Posts: 2161
    • View Profile
Re: Running like a dog Part II
« Reply #33 on: September 15, 2019, 09:35:06 AM »
Dab of grease on them to refit too. Its compressing those valve springs that's hard work without the right tool, a bit of gp100 for stanchion with hacksawed slots to give access and a G clamp was what I resorted to last time. What has held me back from going near the job again is having the confidence to assess the guides condition, it's one thing for them to slide freely by hand without excess play but that might not translate to smooth operation at 9,000 rpm. I have one cb500/4 engine I rebuilt from several scrap ones that has this issue.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline paulbaker1954

  • SOHC Pro
  • Posts: 696
  • I'll just be 5 minutes dear!!
    • View Profile
Re: Running like a dog Part II
« Reply #34 on: September 16, 2019, 08:35:45 AM »
Paul I have the genuine Honda spring compressor for getting the valve springs out. I can pop round after work one night and we can get them removed within around 10 mins if you'd like. It would be around 8.45pm though.

Hi Ken
Thats a very kind offer but I am going to drop head off at my local machine shop for them to do the work as am going to use the opportunity to have all checked, valves reground in etc whilst head is off

I think better to get valves professionally checked rather that rolling them around on glass as I suspect the bend if there is may be only slight but enough to cause them to stick when warm.

« Last Edit: September 16, 2019, 09:54:31 AM by paulbaker1954 »
If you think there's light at the end of the tunnel it's usually another train !!

2016 Yamaha MT09 Tracer
1971 Honda CB500 Four K0

Offline paulbaker1954

  • SOHC Pro
  • Posts: 696
  • I'll just be 5 minutes dear!!
    • View Profile
Re: Running like a dog Part II
« Reply #35 on: September 20, 2019, 07:18:13 AM »
Paul I have the genuine Honda spring compressor for getting the valve springs out. I can pop round after work one night and we can get them removed within around 10 mins if you'd like. It would be around 8.45pm though.

Hi Ken
Thats a very kind offer but I am going to drop head off at my local machine shop for them to do the work as am going to use the opportunity to have all checked, valves reground in etc whilst head is off

I think better to get valves professionally checked rather that rolling them around on glass as I suspect the bend if there is may be only slight but enough to cause them to stick when warm.

Welll just my luck!!!!!!

 machine shop called me yesterday all the valves are good and no bends anywhere in sight

Having head skimmed and valves lapped in anyway whilst it’s there but......

That means still no nearer finding the cause of my running problems and think I have exhausted all things to check

This is soooooooooooooo frustrating!!!!!!!

I have now checked and tested the following.....
Carbs stripped and idle circuits checked, no pilots blocked
Good even compression on all 4 cylinders
Complete ignition system back to Boyer for testing and no issues
Leads and plug caps tested and all ok
Valves checked for any bends, leaks etc -all good

Am really now clutching at straws but have one final theory

I put  2 small lengths of nitrile fuel tubing on the tank petcock and connected these using 2 right angle elbows to the carb hoses. I cannot see any kinks in the tubes when installed that would cause a fuel cut off to carbs 1 and 2 but is it possible that by using these right angle connectors that I am somehow upsetting the fuel flow as they have a smaller bore than the hose of course

[ Guests cannot view attachments ]

See my other post today about petcock behaviour

This may sound crazy but I am now really clutching at straws. I seem to remember a post from another member about these bikes being very fussy about hose routing and dimensions

Whilst all is apart am going to get rid of these connectors and put some new hose direct from carbs to petcock to eliminate this as a possible cause
« Last Edit: September 20, 2019, 07:51:49 AM by paulbaker1954 »
If you think there's light at the end of the tunnel it's usually another train !!

2016 Yamaha MT09 Tracer
1971 Honda CB500 Four K0

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal