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Beta 525RR ---- Plug Cap Isues ---- My Solution.

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Having just bought a Beta 525RR - (RFS Motor), Riding this bike is ace, far better than the WR450 I had before in every aspect.....apart from water !!

Every time it went through deepish puddles it would run like crap..thought it might be a crap airbox design so I inspected the seams and edged some silicon in there......still the same.

The spark plug cap was the next step as lots problems there.

Tried that, lasted about 2 days then the bike ran crap again riding through water.

I used to ride very deep water before on the WR .. not shy, and had properly `waterproofed`it, high breathers, cam breather rerouted to top of airbox, etc etc,

The WR would go where other would not dare, so long as it wasnt over the seat it would be fine.

The Beta is another issue .. I am finding myself avoiding water..

Being a Motorcycle Technician of 20 years I tried to solve the problem.....as you do.

My solution to the plug cap issue is this.

The standard plug cap is plastic with a large rubber boot at the bottom and a small boot on the top, the lower boot holds muddy water in the spark plug access like a sink with the plug in and starts to track to the HT lead as the rubber is a snug fit to the `orifice`, there is a drain on the cylinder head for water to escape from but muddy water doesnt flow well past the rubber boot and just sits there, for me causing the problem I had.

What I have done is used the rubber waterproof spark plug cap SD05FM, with this though the problem lies with the standard spark plug, you cant unscrew the nipple to accomodate the cap as its part of the plug.

NGK produce the standard plug DCPR8E, the Racing Irridium IX plug has a screw on nipple so I used the DCR8EIX wich is the alternative to the standard plug, unscrew the nipple and pop on your plug cap, nice snug fit and it wont rattle around.

The other bonus is that the plug cap is narrower than the standard one and now I can pour water down past the plug with the engine running and see it gush out the drain causing no faults at all.

This might or might not solve the resistor problem so will let you know.

This has been on for about 3 weeks now and every time I go out I can go swimming on the Beta, no problems, no faults and even seems to run a bit crisper.

Plug cap - SD05FM

Spark plug - DCR8EIX

If things hold up I will bump this thread later on in the year to give a report.


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I think I would have tried a simple zip tie around the plug cap to seal it better.... But replacing the cap works too.

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thx for a very nice tip!

I too like to go swamping and todate my beta has never missed a beat....Same as my KTM450.....And I do mean serious puddles..

On the UK KTM forum there others having problems with "rain stop play" so im inclined to think its more related to individual machine as opposed to manufacturer fault..

Lets see what other Beta riders say..

Safest option is to fit and inflateable bike jacket:smirk:

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I had my RS 450 in some deep water (about lower seat high) And never had any problems. I would like to know if just the spark plug change would be boost in performance

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