What can you say from these plugs?

[Ant132]

Hi,

These are the plugs out of my CB400N, i took them out and replaced them due to experiencing a 'lumpy' ride, it was lacking power and stuttering. Wouldnt rev up as easily and cleanly as before.

https://i101.photobucket.com/albums/m62/ant-147/Photo0285.jpg
https://i101.photobucket.com/albums/m62/ant-147/Photo0288.jpg
https://i101.photobucket.com/albums/m62/ant-147/Photo0289.jpg
https://i101.photobucket.com/albums/m62/ant-147/Photo0286.jpg

The bike would judder at low speeds and generally just feel 'off'.

The only things ive done recently were chain tension and ever-so-slightly lowered the idle speed as i felt it was just a tad too high, but i dont think that these are related to my problem.

So, just wondering if anything can be said from these snaps, although i appreciate the quality isnt the best and you should also note that the electrode colour is lighter in real life. It looks to be an off-white in real life.

As always, help much appreciated!

Ant

( Also, i havent tested the new plugs yet because im waiting for my air filter to dry out. Figured i might aswell give the obvious things a going over while im at it )
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[Bikeless]

They look fine to me although may be a little old/loose where the threads have discoloured.

[P.addy]

the spacing seems alright, colour is waaaay clearer than mine and looks pretty good to me.
How old are they, could just be nearing the end of their life mate...for about a fiver, replacing them just to see isnt a bad loss!
My GS500 felt like it was limited at about 7000rpm, was just the plugs were damn old and pretty shit.
New set seemed to clear it up and runs sweet as a nut..until i blew fuses everywhere

So how old are they?

[neatbik]

Look fine to me too, possibly a little rich but nothing i would worry about.
Were they torqued up correctly?

[lonner]

they look slightly rich to me .

but in good condition.

if anything they look like they were a bit loose from the gasket compression and the blackening of the threads and would cause lack of power plus shitty running.

did you get a pit pit pit noise from the top of the motor as that would be the cause

[Ariel Badger]

Plugs are fine, loosen the chain back, it is very easy to overtension and wreck a gearbox.
____________________
Bikers make great organ donors, get 115 on your licence today.

[Ant132]

Thanks everyone!

New plugs have made a definite difference, however it still doesn't feel 100%, but definitely alot better than before. I will slacken the chain back off and see if it makes any difference.

I also made sure that the plugs where torqued up correctly and the plugs were about 3 months old. Am i right in thinking that really isn't that old? I do quite a few miles though.

Ant
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[lonner]

[chris-red]

It's more on the mileage surely. If you did 100,000 miles a year I doubt a set of plug would last 2 years. I change mine every year because I rack up the mileage and need a major service every year.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[Vincent]

If remember right, there's something about the carbs on these bikes - some seal or other part that causes a lot of runnng problems. Same with the Super Dream.

[Ant132]

Thanks everyone.

Like i mentioned in a previous post the pluygs didnt really cure the problem. However, i cleaned the carbs yesterday and i have noticed a significant improvement.

However, now i have found that the idle speed is lower. Now idles a little too slowly and i have to rev more to pull off. Is this right?

I know the simple answer is to re-adjust the idle, but is it right for the idle to have altered like this?

Another thing, changing from first to second feels clunky. Havent felt this before

Thanks again, Ant
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[lonner]

[Noxious89123]

Clunky gears is likely down to chain tension.

It can make alot of difference to gear changes.
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[Ant132]

Thanks again for replying guys!

I balanced my carbs today and whilst they were slightly out of synch, it has not cured my problem Chain has also been set back to how it was. (Slightly loose is better than slightly tight, right?) Anyway the gear change prob has disappeared.

The problem im having is that say im going along at say 30/40 on a straight, even road - The bike feels like it is on a bumpy road and it almost feels as though its being held back by something. If i drop a gear i can accelerate like it usually does, i dont feel as though its lost any power as such but it almost feels like the brakes are being applied, and you have to be heavy with it to make it move. (Ive also checked the brakes and they are fine)

Strange one. Im meant to be going on a run Sunday, but i want the bike to be 100% before i commit.

Ant
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[Walloper]

Have you checked the air filter is clean/ Fuel filter is clean/ And all the electrics are clean and free of crud or moisture?

Plugs looked good. n general the porcelain around the centre electrode should be dry-sandy-brown the electode should be dry dark gray and dull not shiny. The oil and stuff may not be so much of a problem as it's only on two or three threads.

You could run off the fuel and fill with a clean tankfull. (Grasping at straws now.)
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Ant132]

[Ant132]

Actually, I cleaned the air filter only about a week ago and it was fine.

On the airbox lid, it says 'clean filter and then soak in gear oil, rinse excess out then refit filter'. I never rinsed it in gear oil, but then again, i never have done. Is this necessary and would it cause problems?

Thanks, Ant
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[Walloper]

Oil in an air filter matrix is a method similar to old 'Oil Bath' systems where the oil serves as a trap for smaller particles of dirt/dust that can increase engine wear.
The principle is the same as Oil Bath the oil coats the filter fibre as opposed to the air being directed against the surface of the oil bath.
One type of filtration relies on the effect of air speed and centrifugal force to separate dirt from the air stream.
As the air is forced to change direction in the filter housing the dirt particles, being heavier than air, fall/are thrown into the oil and are trapped. This cleans the air to the engine.
At service time you wash out the contaminated oil from the filter and re-charge with fresh oil. You are more orless doing the same with a filter sponge. There are even special oils on the market to do this.
I don't imagine not having oil on it would cause the kind of faults you report. The filter does provide a restriction to air flow through the engine but the fuel metering alows for this. f anyhing your machine may run better with less restriction.
Some fools remove the filter to increase performance. That is OK if limited to race track or if you don't mind the expense of early wear.
Another ting to do is an expensive path of, 'if in doubt whip it out'.
Change out the least expensive links in the chain Plugs you have done, HT lads would be a good 2nd.
I am not sure what engine you have there but Sound Engineering Practice would dictate a few simple steps.
Check wear in drive to other ignition components. (The bit what controls the spark.) Is it mechanical or electronic, does it rely on a signal from the crankshaft to determine when to spark?
If there is slack/flappy-ness there then you will get rough running as load changes during operation.
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[steven_191]

generally speaking, any lumpy running on any engine load is normally down to

-plugs
-leads
-coils

at low revs and higher gears, you accelerate, which applies a lot of load to the engine. this is when you will notice the problem most. as the engine revs up higher the problem may seem to go away but thats only because theres no real load pushing back against the engine.

check those 3 (id recheck your plug just to see the condition again) and make sure they are all good. these can be checked/tested and not cost you anything so its worth a go. as long as you have a tester that is.

other than that, start looking toward mixture, air leaks in the induction system, leaks in the engine (head gasket, plug, exhaust etc) and see how that goes

definately get your carbs balanced as that will make a massive difference on running. (if you have more than one carb)

[Ant132]

Thanks Walloper and Steven, for some reason i missed your posts so sorry for the delay in getting back to you.

Anyway, the carbs have been balanced now with no real improvement. I will check the coil, leads and plugs again to be sure!

Another thing ive noticed is that it seems better in low revs when its cold but when it even slightly warms up its back to normal. Yesterday i was in alot of traffic, stop/start (no chance of filtering ) and in first even with only a tiny bit of momentum going the bike felt really 'snatchy' if you know what i mean.

Thanks, Ant
____________________
1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200