RD80MX - Spark Plug Cap & Plug

[pahannah]

Hello

Started to do some work on my Daughters 1981 MX80.  I am not mechanically minded so go easy

After replacing the petrol as it had sat over winter, got it running for a couple of minutes, it stopped then would not start again.

I checked the spark plug and its a really dark dry colour, sparking seemed quite weak.  Whilst doing that I noticed I would get a shock when touching the cap, which is the original metal one.  This then led me to checking the plug itself and the outer body looks corroded and touching with the plug cap.

Haynes specify NGK B8HS, The original Yamaha owners manual states also NGK B8HS, whereas the Original Service Manual stats NGK B6HS for UK.  Interestingly the one on the bike was a BR7HS, so I assume this is completely wrong as it is the resistor type.

A couple questions.

1) Is it fair to assume than as I could be shocked whilst holding the cap it has lost its insulation, and needs replacing, or will that stop with the correct spark plug?

2) I was going to buy the NGK B8HS, which 2 out of 3 references state that is correct. If that is correct does that mean the Cap is a resistor type, hence the non resistor spark plug?

3) Was looking  at a metal plug cap that Yambits sell as its close to original look, does anyone have any experience of this Cap?  ( I have heard all the general Yambits feedback on some items)  I have asked them what type this is resistor or not, it has 1k and the OHM sign so can I assume that is the resistance .  If not then what type should I fit, resistor of non resistor plug cap?

yambits.co.uk/classic-metal-spark-plug-cap-p-108090.html

4)  Any recommendations on spark plug cap types and where to buy them?

Thanks for all your help

Regards
Paul

[brigitte]

Hi Paul,

usually you have less trouble with a cap without the metal shielding. When you have a cap with built-in resistor, you use a spark plug without resistor and vice versa. But I never noticed a difference. I recommend the NGK LB05E, which is used with the little nuppie on the thread of the spark plug.

www.bts-motorradteile.de/de/elektrik/zuendungsteilezubehoer/zuendkerzenstecker/zuendkerzensteckerlb05efueranschlussmutterfestemrkopf.html

My German parts dealer has the B8HS for the RD80MX, but I don't know if it matches with GB-spec.

Regards

Brigitte

[copper99]

My YSR80 motor is essentially the same, I use B8HS plugs in that, along with NGK caps..I wouldnt fit the metal caps myself.

[markrd250lc]

I think on my DT50MX is a B8HS im sure its the same for the 80MX (DT/RD), i use NGK red HT cap.
Mark