Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: singleoverheadbraincell on October 03, 2012, 11:01:12 AM
-
I have this bike only about a month now and have been tinkering with various things up until now, except the carb settings. I did suspect that it was ticking over a bit high (around 1400) and checked the manual which verified that tickover should be 1000rpm (550K). I turned the thumb screw outward to lower the idle only to discover to my horror that the engine started to sound like it was a diesel. My initial thought was that it sounded like a small end bearing. The noise disappears though at revs around 1400 or above so I set about adjusting the timing chain. I adjusted the timing chain using the method (described in this forum) of putting a little bit of tension on the chain with the kickstarter after TDC on cylinder#1. Anyway, this seemed to help it a little bit but the noise has not gone away. My only solution (at least for the symptoms) is to raise the idle to around 1400.
I haven't yet cleaned or balanced the carbs and I know this could help matters and I know also (from my reading) that these bikes are prone to a bit of low end rattle but I'm just not sure it should be as noisy as this. I understand the cam chain can be changed with the engine in-situ by attaching the new chain to the old chain and drawing it round and I would be prepared to undertake the surgery - I'm just wondering if this would improve matters or would I need also a new tensioner (these are pricey!) I don't really mind living with the issue (by keeping the tickover around 1400) as long as the chain doesn't break, which would be a disaster. The bike has 44k on the clock and I just changed the oil/filter using 10W40 mineral oil.
Any thoughts/feedback most appreciated.
-
Hi your best bet is to give it a full service then at least you will know everything has been done, i have a 750 and believe me they can sound like a bag of spanners in a tumble dryer when the carbs need balancing etc ;), cheers Mick.
-
With Mick on this even worse without the clutch pulled in.
Cheers
Bitsa
-
Forget the book, any tickover below 1200 is a dream, just about guarantee if you give it a full service then check the carbs it will get loads better
-
I just changed my camchain.
I don't think it needed doing that badly, but as the head was off then NOT to do it would have been silly (along with changing the rings).
You can do a proper rivet job with the chain if the barrels are off - it's a real fiddle with the head in place.
It didn't quieten it down that much.
I'd echo what everyone else has said though.
I have vacuum gauges (I have a selection of boxer type engines) and it's stunning how much difference it makes at idle.
800 revs ?
I cannot get a reliable tickover at less than 1200/1000. It stumbles and catches ( and sounds horrible when cold)
-
It is worth bearing in mind that all of these 500/550s sound rough at low revs even when they are set up correctly and all parts in good order. I had a genuine 7000 mile engine with replacement cam chain, tensioners etc and it sounded like all the others I have heard, i.e. like a bag of nails, but increase the revs slightly and all extremely smooth. 17 years later and it sounds exactly the same, no worse.
I don't think they are really designed to run at low revs. When I adjust the tickover there seems to be a sweet spot which I run up to. My rev counter is broken but I think it is about 1200 revs. Just remember, if you have the tickover too slow you won't have as much oil going up to the top ;-)
(maybe you can get them to run slower with stock airbox, exhaust and electronic ignition)