Swapping Sparkplugs depending on your ride.

[Wolf]

Takes that time on just about all bikes, especially 2stroke singles come on... I can change my plugs quick smart if needs be, about a 4/5minute job.

Well.... On the LS400 you have to remove the petrol tank to get to the plug which means unbolting the seat then unbolting the tank.

As to my other bikes, pretty quick.

I'm not sure what my personal record was for removing a plug from the Zundapp, cleaning the shit out of it and getting it back in the bike - there was a truck bearing down us at the time so I didn't bother checking my watch.

[Ixion]

I would disagree with their assessment of the reason for the seizure. Too soft a plug may hole a piston it will very rarely cause a seizure. (apart from a seizure due to debris from the holing)

IIRC you had an earlier seizure caused by insufficient oil. Unfortunately, after a seizure, even though the engine frees up and appears to run OK, in fact there is hidden damage. Specifically, the piston (less likely the barrel) can be distorted. This predisposes to another seizure if the engine gets hot enough for long enough.

Basically I think the seizure was an inheritance of the earlier seizure. I don't think the barrel was pulled then was it?

However, two strokes often do need plug changes for different conditions.

I always found it easier to use the hard plug permanently and accept the risk of fouling at low speeds. I you ride it hard that situation does not arise anyway

[Ixion]

Well.... On the LS400 you have to remove the petrol tank to get to the plug which means unbolting the seat then unbolting the tank.

As to my other bikes, pretty quick.

I'm not sure what my personal record was for removing a plug from the Zundapp, cleaning the shit out of it and getting it back in the bike - there was a truck bearing down us at the time so I didn't bother checking my watch.

I once pulled the plug on a Bantam, cleaned and replaced without stopping the bike or getting off. Going downa long hill, splut, pouf,blurggh, "bugger that's a whisker".Plug spanner in pocket, pull clutch in ,reach down, HT off unscrew plug, remove, dewhisker, replace, clutch out, ringa-dinga-dinga, continued merrily on my way.

[F5 Dave]

Yeah RDs & RZs were hella reliable, it’s just when they pushed the envelope with KR1s & RGVs that you were extracting 55hp from 250s, I mean that is 220bhp/l.

Tune your GSXR to that see how reliable it isn’t.

My RZ was very reliable despite being ported & high compression ratio. Had to lower it when they went from the good old leaded super to the piss they called ULP when they did the change over though.

Stupid politicians. Next it will be ethanol with it’s unpredictable throttle response, don’t get me started.

[F5 Dave]

I once pulled the plug on a Bantam, cleaned and replaced without stopping the bike or getting off. Going downa long hill, splut, pouf,blurggh, "bugger that's a whisker".Plug spanner in pocket, pull clutch in ,reach down, HT off unscrew plug, remove, dewhisker, replace, clutch out, ringa-dinga-dinga, continued merrily on my way.

Half your luck on the YZF. With the slant cylinder arrangement the carbs are in the breeze once you take the fuel tank & airbox off, so that is nice for tuning. But the down side is to get to the sparkplugs then you have to pull the carbs, the coils, mounting plate & move the radiator out of the way. Long life iridium plugs are worth the extra dollars in that case.

With a previous seizure the alluminium from the piston smears on the cylinder & makes it easier to pick up on.

[vifferman]

What a lot of bollocks! Use a 10 instead of a 9, oh please!

Yes you can run too hot a plug, but 9 is pretty cold. Now let’s get one thing straight, the plug temperature doesn’t affect the cylinder temperature directly....

I revisited this thread to say just that, after thinking about it.
Surely the plug 'heat' relates more to whether there are problems with it fouling, and possibly to pre-ignition, than to cylinder temperature? As I recall from the '70s, that was the main concern then.
Never had any problems with it myself (only owned one two stroke, and it was VERY reliable), but always carried a spare plug just in case, and many bikes had extra plug holes for that very purpose.

[Motu]

I've certainly seen holed pistons from a plug just one heatrange higher,but a standard plug has never been an issue for me,dunno about if the bike was modified though.I might go for a plug one colder if I was going to be pushing at max revs/throttle for long periods.

I clanked when I walked Ixion with all the plugs and plug spanners for the daily grind on a Bantam.I had some old favorites that had run for days in the past...I'd sort through my collection on the side of the road and select the best I had....maybe dribble some petroil (bet the young guns don't see the spelling) and set it on fire to burn the oil off,put it back in,pray for a miracle.

A lot of Bantams turn up at classic trials,I just can't believe how well they do and how great that little motor is - it wasn't a nice motor when I had one,they were a nasty piece of shit!

[Ixion]

..

I clanked when I walked Ixion with all the plugs and plug spanners for the daily grind on a Bantam.I had some old favorites that had run for days in the past...I'd sort through my collection on the side of the road and select the best I had....maybe dribble some petroil (bet the young guns don't see the spelling) and set it on fire to burn the oil off,put it back in,pray for a miracle.

A lot of Bantams turn up at classic trials,I just can't believe how well they do and how great that little motor is - it wasn't a nice motor when I had one,they were a nasty piece of shit!

Yes, once one found a "magic" spark pug that seemed to run a while one treated it like a precious treasure. Until the day (never long delayed) when progress home was in 5 mile bursts interspersed with plug cleanings.

The early 125's (until about 1954 I think) with the "funny shaped" barrel, were shit. The later 125's were OK and the 150's were actually good.

Especially after taking 1/4 inch off the head with the Wolf electric drill with a milling cutter in the chuck (hey it worked !) , and replacing the brass bush in the points plate with a needle roller bearing .That was a key, because a lot of the problem with Bantams was that stupid bush. The points cam was on a long spindley extension of the crankshaft, the laughable main bearings meant that the crank end described a path that could only be matched by a drunken monkey on acid.This fonged out the standard brass bush (with no provision whatsoever for lubrication) within a few hours running So ignition timing varied from TDC to BDC to sometime next Thursday, and all points in between. On successive cycles.

Oh, and of course naturally one completely removed the contents of the silencer. Assisted by the fact that the end cap was screwed on, and the baffles removable for cleaning "Honest officer they were there when I started out. Must have vibrated loose".

[sAsLEX]

Takes that time on just about all bikes, especially 2stroke singles come on... I can change my plugs quick smart if needs be, about a 4/5minute job.

pfft you try change the plugs quickly on a CBR250! need tiny monkey hands to get to the third plug as it can only be accessed from the far side!

[inlinefour]

I never need to change plugs as they are set up for all conditions. Was the plugs that caused the problem different to what the manufacturer recommended or something?

[Ixion]

I never need to change plugs as they are set up for all conditions. Was the plugs that caused the problem different to what the manufacturer recommended or something?

Only relevant to two smokers of course

[inlinefour]

Only relevant to two smokers of course

Never had to change any of the plugs on any of the 2-strokes that I have owned

[Waylander]

Get a cruiser. Takes me a total of two minutes to change out the plugs. Easily accesable cause there are no plastic pansy bits getting in the way.

Cursed myself with that one. Need to either get new plugs or spend a good long time cleaning the old ones. Was Idling and running like it was only on one cylinder. Pulled the plugs and they are black as night. Ohwell just one of those little tiny things that you always find after the major work is done.

[Motu]

Yes, once one found a "magic" spark pug that seemed to run a while one treated it like a precious treasure. Until the day (never long delayed) when progress home was in 5 mile bursts interspersed with plug cleanings.

The early 125's (until about 1954 I think) with the "funny shaped" barrel, were shit. The later 125's were OK and the 150's were actually good.

Especially after taking 1/4 inch off the head with the Wolf electric drill with a milling cutter in the chuck (hey it worked !) , and replacing the brass bush in the points plate with a needle roller bearing .That was a key, because a lot of the problem with Bantams was that stupid bush. The points cam was on a long spindley extension of the crankshaft, the laughable main bearings meant that the crank end described a path that could only be matched by a drunken monkey on acid.This fonged out the standard brass bush (with no provision whatsoever for lubrication) within a few hours running So ignition timing varied from TDC to BDC to sometime next Thursday, and all points in between. On successive cycles.

Oh, and of course naturally one completely removed the contents of the silencer. Assisted by the fact that the end cap was screwed on, and the baffles removable for cleaning "Honest officer they were there when I started out. Must have vibrated loose".

Mine was the 150 ''Major'' in a swingarm frame,as a learner you learnt a damn sight more than how to ride! Yeah,the points plate bush,tell me about it! Also my flywheel came loose on the steel boss,that took a bit of finding.I found if I loosened the 3 points plate screws it would start....then I had to wedge a screwdriver in to make it go....finally I made some spacers to put behind the plate to set it at an angle so the stator didn't pole - fix the symtom not the cause eh? Another points plate and flywheel and the bike ran great for the next owner,but never for me.

My wife had a 175 and she used to pull the motor down and replace gears and all sorts of mysterious things,she was only a teenager then,I was always too scared to open up my Bantam at that age...out classed by a girl!