Engine problems 900 Sprint EX

[mitchelinuk]

Hi, I've had my Triumph Sprint EX 900 for about 8 months, experiencing no problems up until this point!
Since I've had the old tyres changed I noticed a small decrease in power in the lower revs, plus sputtering, but once I'd ridden her for about 10 miles the problem disappeared.
I've just been out for a spin and the problem has escalated and is bot disappearing like before, with a knocking sound in neutral. She's abit retro (97) now, and done about 52,000.
Any advice would be great. Thanks mitchelinuk

[sailfish]

Check to see that your choke is closing completely and that the cable is not out of adjustment.

Clean all of the electrical connections on the coils, protect them with dielectric grease.

Replace the spark plugs.

If none of the above works, disassemble and clean the carburetors and check the filter in the petcock.

How long has it been since the valve clearances were checked?

[Roden]

You say there is a "knocking sound" in neutral, these lumps are generally quite noisy mechanically, is this a new noise you are hearing? Can you narrow it down to a particular area of the engine?

The alternator drive rotor is known to come loose and produces a rather distinct rattle which most times disappears when you turn on the headlight and apply electrical load. This could be your "knock" and if so is an easy fix.

Cheers,

Roden

[JimKraemer]

Definitely try Sailfish's suggestions. Especially since your trouble seems to disappear as the engine warms. These steps have definitely helped me in the past.

[trypcil]

How's the air filter? Perhaps with the weather change you've gone a little too rich with all the summer dust and bugs stuck in there - lean even, with the denser air now it's cooled off. Do you still have your fuel screws capped? Or perhaps you've got a stiff wheel bearing thru' improper wheel/tyre refitting(unlikely) - brakes binding maybe, does the bike push easy? Sail fish is right on otherwise - good luck.