twinegar wrote:Does anyone see a problem with backing the pilot screws out another turn and do another test drive or maybe close the choke a little to enrich the fuel mixture?
I can't see any harm in that...but wouldn't the plugs tell you if you are running lean ??
This statement you made earlier "When the noise starts the engine RPM increases and then returns to normal when the noise ceases."is the key...but I just can't fathom the cause...
I hate to think about it but what about a sticking valve? If it sticks open a little too long that would account for the lifter noise. I am stumped too. My 750's are a lot easier to figure out.
I must admit, a while back I had one sticky valve that when I did a lot of town riding in +90 deg. weather would do the same. Before I decided to look into it further, it went away never to re occur....I put it down to carbon buildup on the valve stem &/or lack of use...But I did change my oil to full synthetic. What oil are you using ??
Penzoil 10 / 40. What is the benefit of synthetic oil? Did your lifters get noisy when the valve stuck?
It is supposed to be around 60 tomorrow night so I might take it out and see if the noise occurs. If it doesn't correct itself I guess it wouldn't be too much trouble to pull the head and clean and check the valves for bent stems. I burn premium unleaded in it but who knows what the previous owner used. With 14K the head probably has never been off so it would be a good time to change the seals also.
twinegar wrote:Penzoil 10 / 40. What is the benefit of synthetic oil? Did your lifters get noisy when the valve stuck?
Yes it was noticable at traffic lights but as soon as I got some air in the fins it went away...
Synthetic is more stable than dino oil, doesn't age as quickly & lubrication properties are arguably improved. Before you go into the head I would do a leak down test, pressurising the cylinders. It's a lot easier & tells you if you have any combustion chamber/cylinder problems. If you have a bent valve/s, that will show up for sure. Also going full synthetic "may" (and I say may) make the problem go away, if it's dry valve guides....
twinegar wrote:Thanks. I will check in with the results in a couple days.
EMS ( Mike ) may be onto something there too. Revs go up when it occurs.... Hmmm.. could be resulting in compression efficiency changes due to blow by or reduced piston drag.
A leak down test will show that up also....Keep us updated, this is a tough one for sure....
Pennzoil (car) oil? If so, get rid of it fast! First of all, its not even that good of a dino oil for cars, and second, Xs have a wet clutch so the friction modifiers in it can adhere to the friction plates in the clutch and cause slippage. I also don't think Xs have lifters like non OHC motors do. No pushrods, no lifters. Good luck. BTW, I run Amsoil synthetic in the 82 and the Hayabusa. Great oil, lasts longer, cools better and holds its viscosity much longer under harse conditions. Until I rebuild the 79 I use Valvoline motorcycle specific engine oil in it, available at many auto parts houses.
So how do I make the change to synthetic? Drain the oil hot leaning the bike to both sides and then fill with the synthetic? Change the filter too of course.
I always change it when its hot and let it drain for awhile too. Until my engine troubles were sorted out, I wouldn't change to a full synthetic just yet. Its around $9-$10 a quart! I'd use any good motorcycle specific engine oil (no friction modifiers) and once my motor was ok, then change to synth.
I think I will stick with "Dino-oil" and just find one without the friction additive. I wouldn't be able to afford synthetic in all my bikes. Would anyone know a good named brand of oil?
You are right that it has no push rods but it does have lifters or shim buckets as some people call them. I also erred in the post title by using "tappets " instead of "lifter". Boy am I living in the past.
You need to at least go with a motorcycle-specific oil. Honda's brand is quite adequate. But please use 20-50w. These engines get extremely hot and they seem to like the 20-50w. Now I've never heard of an oil-related failure that had to do with running car oil vs m/c oil or dino vs synthetic, but there are additives in the m/c oils that car oils don't have anymore. Ive used Golden Spectro for years in my '79 (it's a semi-synthetic blend - Honda has one too). I just switched to Amsoil m/c-specific oil this year since I have a friend that's a dealer now. It consistently rates near the top in oil tests.
You are wasting your money on premimum gas. I have over 100,000 miles on CBXs of all years and have never run premimum. These engines were designed to use low-octane fuel and if everything is right, they will never 'ping' on regular.
Well I guess you are never too old to learn something new. I have been using Penzoil for over 30 years and even in my bikes. I guess to be safe I will go with Honda brand dino-oil and use their synthetic in the CBX's. I hope they sell it by the case. Be funny if the new oil in the CBX fixed the problem. It makes sense that less friction on all those moving parts would reduce the heat signature. I will admit that I was a little dubious about changing to a different oil but apparently I am the only one here not using bike oil. Thanks for correcting a behavior that could have damaged my toy collection.
