Is there a reason why this happened and can i prevent it??

[philhnottm]

Riding along A46 60MPh (ish) noted loss off top end power at nearly full throttle .

Thought it was going to heat seize so dropped off revs , then loud pop and scooter died.

Coasted to hard shoulder thinking I had blown hole in piston.


Finds out spark plug cap had blown off the spark plug. Only ever happened to me once before.

Noted at a layby stop 15 mins before elec start didn't work and lights were playing up. (don't know if connected)

All sorted now but a worry as just come up M69 and M1 with son on back.

However there is a god as when checking scooter over noted main exhaust bolt had come loose and cut a large grove in tyre almost through!!!!!!!!! . So if plug hadn't popped don't know what might have happened.

Thus chucked it in boot of Volvo estate and became car w@nk3r for the day and thanked all my mates who asked if I was going to Isle of Wight
Rode 50 so miles to BSSO racing at Mallory park and scooter ran fine

Any ideas please as wont to make sure ive sorted any problems before Mersea

Thanks

Phil

[ArmandTanzarian]

Mine came loose in the same way halfway across the Alps. Fortunately it hadn't come out far enough to cause tyre damage but it was a close thing. Luckily I noticed in a tiny village outside of a small DIY shop. I fitted a new bolt with liberal coatings of loctite. The bloody thing's probably stuck forever now.

[cezeta]

crude but it works, ive had the bolt come undone and dig into the rear wheel. i use a blob of gasket silicone on the bolt now. it can be scraped off with a screwdriver but keeps the bolt from undoing. i do the sasme on exhaust bolts.

[gaz_powell]

I always use a good flat washer on the bolt and a good flat and spring on the nut - never had a problem.

i always remove the cage nut arrangement where fitted as they can be dubious - can be a pain getting to the nut but it can be done on standard and sito.

Gaz

[diesel]

I think he needs advice on the plug cap issue rather than advice on how to tighten the exhaust nut, I too would be interested in hearing how the cap can "blow off" .

[Andy Pickering]

Ive had 2 caps do the same in the last 3 years, 1 I found had worn badly in the clip part which clips over the plug threaded part and the 2nd time the threaded part of the plug was badly worn.

Sent from my GT-I9300 using Tapatalk 2

[ArmandTanzarian]

The spring clips wear out and they just vibrate off. Buy a new cap and keep a spare for when it does it again.

[goldeneye]

I use the red silicon HT caps, the ones you need the little nipple on the plug, give a better "snap" on the plug. oh, and I carry a spare in case. the exhaust bolt, as stated, get rid of the caged nut arrangement and use a flat washer and a nylock .when setting off on a long ride too or from a rally, just go round the scoot and give things a tug to see if owt has come loose. easier to fix at home or on a campsite where people might have spares, or tools handy, and its a bit safer than at the side of the road.

[Rotor]

Have found different plug makers will have very slightly different end top nut as well (NGK plug with NGK cap works for me) now knowing it will come lose very soon....
P.

[philhnottm]

New plug and cap fitted Thought it had to be user error or a worn part .
Thanks for replies