My 500 4 is poorly

[K2-K6]

I'd agree with Trigger, it doesn't at first impression appear to be running any problem with the engine.

It just looks / sounds like you've lost part of a baffle. As above I'd try to investigate that first and certainly not pull the motor apart at this stage.

Would you be able to get a camera down the pipe or try it with another pipe to get a better appraisal?

As a slightly off beat method could you swap the 2 and 3  pipes or another combination,  even if you have to stick them on at odd angles, to see if the pipe sounds the same on another cylinder.

[K2-K6]

http://forums.sohc4.net/index.php?topic=131905.0

It's obviously a 750 pipe,  but gives more insight of what is happening inside these exhausts.

[Trigger]

Took me yonks to find this again >> https://www.youtube.com/watch?v=G2W68pThPCc

[paulbaker1954]

You old boys worry too much  . 135 psi on a dry test is fine for a non rebored engine. I would not even bother if I was getting that result, the engine has only just run in and hasn't had time to really coke up to seal.
The futting noise sound like a exhaust problem, that is where I would start. Block the end of number one pipe with a rag on your had and see what the change is.

Hi Trig
I have opted to do a top end rebuild anyway (just love the fun !!) just to check there is nothing horrendous happening internally and I want to clean and rebuils carbs again anyway.

I will then get the bores measured again just as a sanity check and if they are still in original spec(ie under 56.1) I will leave the existing pistons and rings since they are pretty new (2k miles) anyway. That sais what I don't get is why the Honda repair manual quotes 170 psi and says that anything below 140 indicates bad bores/rings/valve seats etc.. Honda says nothing about testing wet or dry in their repair manual.

As for the damned exhaust I swapped 1 and 2 over (I had to laugh at the exhaust angles !!!) before I started stripping but was really hard to tell if I still had the phutting on n0 1 as I was getting a lot of phutting from around the exhaust ports. I think it was hard to get a good seal on the copper gaskets with the weird exhaust angles.

[Trigger]

If you were getting smoke and too much pressure from the breather that goes to the atmosphere and it is 140 or below on a wet test, then it is time for a rebore.
Another good way to test psi is, start with number one. Plug the tester in and start it up, you should see the psi go up as you rev the bike. But, I would be more than happy with 135 across all four.
What was the piston skirt to bore clearance ?
Don't believe everything you read 

 

[paulbaker1954]

Took me yonks to find this again >> https://www.youtube.com/watch?v=G2W68pThPCc

Interesting I have opened a ticket with CMSNL along the line of this pipe is only just 2 years old any only 2K miles of dry use and a baffle failure !!!

See what I get back !!

[paulbaker1954]

If you were getting smoke and too much pressure from the breather that goes to the atmosphere and it is 140 or below on a wet test, then it is time for a rebore.
Another good way to test psi is, start with number one. Plug the tester in and start it up, you should see the psi go up as you rev the bike. But, I would be more than happy with 135 across all four.
What was the piston skirt to bore clearance ?
Don't believe everything you read 

Cant remember what the clearance was as I measured the bores and they seemed on spec at 56 and as they were new NOS standard pistons assumed all OK. I did check the ring gaps before I installed them and they came up again in spec for an unbored unit.


One further point on the damned exhaust issue I forgot to mention is that I forgot to post my plug pics. Plugs were pulled after a good run around ie not long idling.

Order is back to front in the image ie 4-3-2-1 and there is a lot of variation which is why I wanted to do a carb rebuild again but I wondered if the very lean look of plug 1 (ie the one on the right of pic)has anything to do with my problems

[hairygit]

A very weak mixture can cause a few problems, and detonation (Think Nurse Julie's 400/4!)

[paulbaker1954]

Took me yonks to find this again >> https://www.youtube.com/watch?v=G2W68pThPCc

Interesting I have opened a ticket with CMSNL along the line of this pipe is only just 2 years old any only 2K miles of dry use and a baffle failure !!!

See what I get back !!

Should have added that there are no rattles or odd noises when I bang or shake the pipe

[paulbaker1954]

Now here's a great result ---- thumbs up tp CMSNL !!!!!!!!!!!



Subject: Re: Problem with Exhaust
From: Gert Pruisscher
Date: May 1, 2018 12:19:46 
Dear Mr Baker,

Thank you for your order and sorry for the inconvenience.

We never had this issue before, and I agree it's not something you can expect after 2000 miles.

I will send you a UPS shipping label, so you can return this exhaust. We will examine it and send you a new replacement exhaust.


Please give me your address where UPS can pick up the exhaust.



Kind regards,


Gert