Originally Posted by tallbikeman

If you have a new chain, new cassette then the problem may well be the derailleur. Check to make sure when you are in 8th gear that the derailleur is not to one side or another on that gear. The upper pulley determines this. I think you might leave a little extra travel toward 9th gear so the derailleur centers properly on 8th gear. If your upper pulley is loose or very badly worn it could lean to one side or the other or just plain wobble. I try to adjust my derailleurs so they are as close to the cassette as possible without running the upper pulley into the cassette gears. I believe this helps some with precision during and after shifts. This skipping will happen more with friction shifting than index shifting if everything is adjusted properly. Keep in mind to redish the rear wheel after putting a spacer in on the cassette side. I would check the dish with a dishing tool to make sure your bicycle will track right after installing the spacer. On your front derailleur check the cable to make sure it pulls very easily out at the derailleur. I'm assuming 1st gear is the smaller chainring? If the cable has stiction then this can impact derailleur function. If either derailleur has a weak return spring that might be the issue. The shifter might have some kind of issue that doesn't let all the cable out. I oil my chains all the time. I ride 4 bicycles in rotation and oil all chains at least once a month. When I start hearing the chain I have let it get too dry. These chain/derailleur problems are real whack a mole territory. I don't use a pressure washer on my bicycles because I don't want to breach seals on my hub and crankset bearings. Soap, water, a sponge and a garden hose to rinse off. Then back to oil on the chain. I'll try to remember to get that Nishiki serial number. I really like 1010 hi tensile strength steel for bicycle frames and forks. It has the ability to soak up vibration better than chrome moly steel in my opinion. The downside is a heavier bike. However at my age I'm not racing anyone anymore and the hills are not very big around here. So 1010 steel is fine in my book. My Nishiki is the most comfortable diamond frame bike I have at the moment. The Spiderflex seat is fantastic. No pressure sores, no pain, what is not to like. First seat that from day one has not hurt me or caused saddle sores ever and I've been riding 60 yrs. Not including recumbent seats of course. Also the ODI mushroom bar grips have likewise been a major find. I have much less hand numbness with these grips. I'm thinking about starting a thread about my experience with noseless saddles on this site. I'll keep you posted. If you have the time rebuild your headset just to keep your mind happy. Rarely is there a problem and I've pulled headsets apart that had been dry for quite a while and were still working OK. I used automotive wheel bearing grease on my headsets and it slowly works out of the headset onto the frame but this lets me know there is still grease in there. Let me know if you get this skipping chain fixed or not please.