Tyz250 Spark Plugs

[cubik2]

Hi there

Im a new TYZ250 owner... a 1994 model

Just wondering what other owners recommend for the spark plug ?

The bike came with a NGK BPR5ES and ran fine

I changed this to the NGK plus recommended in the manual BP6EV , except i used the X platinum tip version which was hard to find

After running the bike today i could have sworn it didn't run quite as well with the new plug, not quite the same power it seemed.

Nothing else has been changed or altered on the bike since the new plug.

I just wondered what plug everyone else used in theirs ?

I know the the R NGK plugs have resistance in them and i wondered if this made any difference to the running.

I have a Montesa 315 and it needs the R plug for example

thanks

neil

[woody]

Use the normal plug, the platinum tipped things are fine for constant high reving like motocross but can foul up when running at low revs.

I've had a few TYZ Yams and never fouled a plug in any, although can't remember what plugs I used now - probably BP6ES or 7ES. The TYZ I had from new I never changed the plug in.

[jon v8]

Woody is right,use the ordinary plug.The Platinum plugs use a wider gap and require a much higher voltage to fire them - which puts a greater strain on the ignition system to reliably make the spark jump the gap.The smaller gap of the ordinary plug keeps the peak HT voltage down.I have studied this quite a bit by using an oscilliscope to monitor secondary HT waveforms,(Mostly on LPG fuelled V8's in Range Rovers) by keeping the peak voltage down with ordinary plugs the leads and coils last longer.The emissions also stay right down which means a more complete burn in the combustion chamber - which is what we all want even if we dont have to pass an emission test.

[toemoss]

cubik2 I have a '93 and run an NGK BP6ES, if you have a service manual I would really appreciate the correct fork oil amounts. Thanks