Hello I haven't posted for a while but need some advice.... Recently I noticed some oil on the valves when I had the carbs off the nc 30 .... I have just tried to start it today after winter hibernation and it has fouled the plugs up badly with oil .... My question is has anyone done the valve stem seals on theirs because of the same problem..? The bike has 48000 km on it so not sure if the seals have just hardened up or there is some wear on the guides as well ? Looks like a bit of a pain to do, but the plug fouling is also very irritating. Do the valve stem seals just push on or are they a press fit? Any tips or advice on this problem would be most appreciated.... Ta

Not had this issue but from memory it's a full top end strip to do them. Yes they just push on.
I would try the usual stuff before going down the top end strip-
Fresh fuel, clean carbs, good battery or jump from car, get the plugs clean with very hot blow torch. I have found that once they get dirty you need to get the electrode ground red hot and you will notice that there is yellow flame burning crap around the electrode. It can take a minuet or more to get the flame clean and free from the yellow burn.
I would clean plugs and fresh fuel and jump start first then clean carbs.

Ah cheers ... The bike is in good nick generally, the carbs were stripped late last year, this is when I noticed the excessive oil on the closed valves... Bike has had shims done, new fuel lines and only run on super unleaded. When I took the plugs out today they were a right mess so it's plugs out again tommorow and re clean em. I used the gas ring in the kitchen to burn the plugs off but with the bike being stood so long by the time it had pulled the petrol through it had oiled the plugs up again

Spin it over with the plugs out first.To blow some of the crap out.

Will do mate I'll report back tommorow when I get it going..... Think I'll be putting off the full head strip untill the weather improves ..... Thanks for the replies

Update .... Got it running today after loads more faff took a while to start running on all cylinders.... Ran it up to temperature then it started to missfire put the choke on again still missing so I think it's time for some sodding plugs again
.... Cheers guys

Yer they are crap. I have just got a set of Denso iridium plugs, they are supposed to be better- not tried them yet but others seem to rate them. Same sort of price as the ER9's

If you do need seals, Then I managed to buy OEM at a really good price from Partzilla as they are a common Honda part number

yamahaha wrote:Ah cheers ... The bike is in good nick generally, the carbs were stripped late last year, this is when I noticed the excessive oil on the closed valves... Bike has had shims done, new fuel lines and only run on super unleaded. When I took the plugs out today they were a right mess so it's plugs out again tommorow and re clean em. I used the gas ring in the kitchen to burn the plugs off but with the bike being stood so long by the time it had pulled the petrol through it had oiled the plugs up again

no need at all to run Super unleaded in it as the bike is designed for 91 plus. The only reason id consider Super Unleaded is if you are trying to avoid ethanol as some of the super blends (depending on country) have no ethanol, but then again some countries supers have loads of it as its a cheap quick octane booster.

If you want to test the valve stem seals stick a load of kitchen roll in each of the inlet / exhuast ports, get the rocker boxes off and pout some oil around over the valves and wait awhile.

Pain in the arse job to do as you gotta take all the top end off and the valves out and its expensive but if it needs doing then it needs doing right.

Hello, I don't know what the fuel is like where you live but here its crap, just recently had to replace fuel lines on two bikes due to ethanol content in petrol .... Fuel lines went like jelly plus it eat the tank gasket on my 94 fzr ..... You might be right about what fuel the bike can run on but super as you say has no ethanol where as normal u/l can have as much as 12% ethanol added without having to inform you in the UK ..... Which for me running old jap bikes with steel petrol tanks and ageing carbs with perishable rubber o rings in em it's a no brainer for me for the extra few pence per litre