Hi folks, decided that after 4 or 5 years of owning and riding my nc30 through all weathers in Scotland, that it was time for a full service and not just a quick filter and oil change etc.

The top end was starting to sound a bit tappy in the #2 cylinder. So i decided i'd do the shims. All inlet valves were between 0.13 - 0.20 roughly. Except one in the #2 cylinder which was at 0.38!
Reason i'm putting this post up is, i'm confused as to wither i'll need to do some work to the cylinder head to sort this valve.
Need to get another magnet to get the shims out to measure them, as the one i have is too big.

When i took the airbox off there was quite a bit of gunk around the #2 intake (looked like old sticky fuel). Possibly petrol getting sent back up the valve if it's not closing correctly?

Cheers for any help or advice in advance.

Worth seeing the valve and lapping them in. It is likely to have a lot of carbon buildup.

cool, thanks.

would this cause fuel to come back up the valves-carbs? or is there something else going on there?

geebus wrote:would this cause fuel to come back up the valves-carbs? or is there something else going on there?

Any noticable oil consumption?

Surely sticky stuff in the airbox would be oil? Don't the crankcases vent into the airbox? (it's been a while since I had an airbox on my NC!)

I'd do what CMSMJ1 says and pull the head to check the valve and seat.

Yeah, can be a little oil go disappearing. What's that from then?

geebus wrote:Yeah, can be a little oil go disappearing. What's that from then?

If the oil sludge is not on all valves then it is probably being sucked down the valve guides which may be worn or the seal there went hard. If it's on all the intakes then it could be the same thing and/or the piston blowby is pushing up a lot of oil mist through the crankcase breather.

lukemillar wrote:Surely sticky stuff in the airbox would be oil? Don't the crankcases vent into the airbox? (it's been a while since I had an airbox on my NC!)

I'd do what CMSMJ1 says and pull the head to check the valve and seat.

Yes, it's the rubber hose that goes into the airbox from the rear cam cover.

krisztian_andre wrote:

geebus wrote:Yeah, can be a little oil go disappearing. What's that from then?

If the oil sludge is not on all valves then it is probably being sucked down the valve guides which may be worn or the seal there went hard. If it's on all the intakes then it could be the same thing and/or the piston blowby is pushing up a lot of oil mist through the crankcase breather.

Only coming through one intake valve i think. As far as i can see anyway.
Just need a new oil seal you reckon?

one of these http://www.davidsilverspares.co.uk/VFR4 ... rt_150808/?
Would it be a good idea to replace the lot?

Thanks folks.