gsf bandit 250 valve adjustment/mystery

[Dare]

Over the last few months my bandit has had a 'tap' sound from inside the engine, the problem is most noticeable at idle but at speed the engines note is a bit unsmooth and there might be a bit more vibration than usual (fuel consumption is also up from ~250k a tank to ~200 a tank but that might be me). I have tried to locate the sound by ear and with the bike still in one piece all i could decide is that it sounded lower down than the cam shaft (which is a good few inches above the spark plugs anyway). Lately the throttle has had some wierd flat spots and dips especially around idle that makes pulling from the lights interesting.

Bear in mind i'm very sensitive to this kind of thing so the bike is far from dying, I just want to fix it before it becomes a real problem.

Anyway I decided to do what I would do with my mini, which is pull it apart and check the tappet adjustments... Using the 600 & 1200 manual I set to work and a few hours later pulled off the valve cover, only to find that my screaming 250 doesnt appear to have adjustable tappets. The cam lobes sit directly in line with the valves, or so it would appear. So right now i'm thinking free up the followers somehow and spray some carb cleaner around the place, but that seems like it might do snap all...

Anyone else got any ideas? :crazy: I'm stumped!

[HDTboy]

Because your engine is designed for big revs, the tappet adjustment is by shims rather than rockers like the bigger bandits.

What you need to do, is measure the clearances, note what they are, remove the cams, measure the shims under the lifters, replace with appropriate size, and work your way backwards, remeasure, reassemble, ride.
If all that sounds a bit much, give me a yell and I'll do it for you.

[Dare]

Because your engine is designed for big revs, the tappet adjustment is by shims rather than rockers like the bigger bandits.

What you need to do, is measure the clearances, note what they are, remove the cams, measure the shims under the lifters, replace with appropriate size, and work your way backwards, remeasure, reassemble, ride.
If all that sounds a bit much, give me a yell and I'll do it for you.


Considering that until quite recently my attitude towards rebuilding the mini was a Jeremy Clarkson-esque 'if it doesn't fit get a bigger hammer' I think I should take you up on your offer =)

Check your PM's. Cheers! :apint:

[mops]

looks like an early bandit.
i had the late one with VVT (250's also).

for valve clearances you had to check in 32 places. 8 for exhaust valves (screw adjustment), 8 for intake 'LO' cam position (shim adjustment) and 8 for 'HI' cam position(shim adjustment). then intake sub-rocker to rocker clearance (screw adjustment).

i'm like so over adjusting valve clearances :)

you should just locate manual for your particular engine and follow it, but yes, your adjustment is via shim... or leave it to the pro's :)

[motorbyclist]

shim adjustment - swap and replace shims 'til it comes right

don't use carb cleaner whatever you do!


and you problem is one of carburetion and it might pay to look at the plugs:shutup:


(done this for a mate's bandit and without a manual we forgot about the 'vtec' so only checked 16 clearances:doh:)