Metal-clad spark plug caps.

Those amongst us that were bikers in the 70's when men were men and bikes leaked oil all over the place, should remember the troubles caused by the metal-clad plug caps used on Hondas and the like. After a few thousand miles any moisture or light rain used to cause cylinders cutting out due to internal shorting.
Wise dealers changed them even before delivery for all-plastic ones to avoid trouble.

I thought I'd seen the last of the b******s, but they're back on Chinese bikes folks...
There's no need to change them, the metal cladding is fitted with tiny bent-over tabs and can be removed, leaving a normal cap behind.
They were fitted to screen interference from the plug and stop radio and TV interference, but nowadays with FM, UHF and digital transmissions this does not happen.
If you get misfires in the wet, remove the metal cladding or change to an all-plastic cap.
http://www.igijon.com/personales/nom...lugtrouble.jpg

I junked mine, and replaced them all with the Bosch Ceramic boots. Most good Foreign autoparts stores have them, or can get them. They are just like the ones used on the "Jacobs" wires. Desipate the heat, and wont melt under any normal useage. Had nothing but problems on any bike that had the metal encapsuled units. Bit of water and wear, and the bike stalls out. Than you fart around trying to get it dried out.

I worry enough about the chinese welding, dont want to worry about the spark output to boot.. No pun intended of course.. HAHAHAHA

my rmr 125 has one of these caps fitted and it runs like there is a fault with the coil. plug,coil,cdi,stator generator and pickups all changed and it still runs crap! do you guys think the cap could cause these coil like symptoms?

Tis possible , either change it or just take the cladding off - there is a "normal" plug cap in there !

cheers
just ordered a standard ngk cap so i'll see what happens! i'll post back with results.

Quote:

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Originally Posted by ske4798

my rmr 125 has one of these caps fitted and it runs like there is a fault with the coil. spark plugs,coil,cdi,stator generator and pickups all changed and it still runs crap! do you guys think the cap could cause these coil like symptoms?

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dude where did you order the standard ngk cap?? im going to buy one but i can't find a cheap price in the net.

Quote:

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Originally Posted by ishie

dude where did you order the standard ngk cap?? im going to buy one but i can't find a cheap price in the net.

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NGK LB05F. Shop locally maybe cheaper than "net" .

Quote:

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Originally Posted by ishie

dude where did you order the standard ngk cap?? im going to buy one but i can't find a cheap price in the net.

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straight off ebay mate, was only a couple of quid.

new cap....no change! seems to only run ok when i've been riding for at least 15 mins and even then its not great! rev counter is all over the place sugesting coil problems. however, i have changed coil,cdi,rectfier and pickups.

anyone any ideas?

Quote:

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Originally Posted by forchetto

Those amongst us that were bikers in the 70's when men were men and bikes leaked oil all over the place, should remember the troubles caused by the metal-clad plug caps used on Hondas and the like. After a few thousand miles any moisture or light rain used to cause cylinders cutting out due to internal shorting.
Wise dealers changed them even before delivery for all-plastic ones to avoid trouble.

I thought I'd seen the last of the b******s, but they're back on Chinese bikes folks...
There's no need to change them, the metal cladding is fitted with tiny bent-over tabs and can be removed, leaving a normal cap behind.
They were fitted to screen interference from the plug and stop radio and TV interference, but nowadays with FM, UHF and digital transmissions this does not happen.
If you get misfires in the wet, remove the metal cladding or change to an all-plastic cap.
http://www.igijon.com/personales/nom...lugtrouble.jpg

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Thanks for that, that's really interesting.