Valve guides probably still need to be run trough whit a reamer. They build a lots of crap inside. For the valve springs i ment if they are close to the service limit. The service limits on the factory manual on some parts are too lose.

The scoring on the walls don't necessarily mean the previous owner hadn't have oil in it. It's on every 954 i have seen no matter whar are the miles. Alusil isn't a coating like nicasil.

 

Well it was about 2 quarts low and black as black gets when I got the bike and he said he was riding it 2 weeks before. He either took some oil out (doubtful) or he has not changed it in awhile. Yeah the alusil did not work out so good. U.S. Chrome's coating in nicom for the cylinder walls and is much stronger and wear resistant than any other plating coatings. With that and the piston coatings this engine should last much longer and wear better.

 

There has been lot of scoring issues whit the alusil in porsches etc. that use alusil cylinders. Actually the oem piston skirts are allso coated. Alusil needs special piston rings and coated piston skirts. Otherwise there would be aluminium against aluminium. I checked my oem pistons a while ago and actually i could see the remains of the black coating on some of the piston skirts. Don't know is this scoring issue because the coating isn't good or is it the Alusil itself that causes the scoring. But too low oil level and not changing them won't definetly help. But i haven't heard of any similar issues whit the nicasil plating and you don't need any coating on the skirts or special piston rings. The cylinders could look like new after 30000 miles depending on the use the bike is and maintance. Nicasil is very thought.

 

Okay, that's fine. You just don't want to do this



on the intake ports. Exhaust ports are fine because the consistency of the fuel vapor mix does not matter when it's going through the pipes.


The casting is very rough though. Just don't go crazy, and like Mika suggested, use his pictures as a guide - you'll do great.

 

I love YouTube, I found a video and it shows you how to disassemble a cylinder head with basic household tools. So I was able to disassemble the head yesterday and check a few things out. The first thing I looked for is to see if the valve guides are still in spec and I believe they are with no side to side movement of the valves and they all moved up and down rather easy. The next thing I checked was the valve seat itself and it was nice and shiny like it should be on every single valve. This should mean that a valve job is not necessary and I probably can just lap the valves in after cleaning. I kept everything in order and each valve, spring, retainer, and keeper will go back in the same location for consistency. So after work I am taking the head and the valves to my local machine shop for cleaning and double checking of the valve seat and valve guide clearances. If all is okay I am going to get new valve seals, header studs, bolts, and gaskets, and a new thermostat case gasket do the minor port job and have the head re cleaned, lap the valves in myself, reassembled and the head should be done. New valve seals are necessary correct the old ones should not be used right?

 

Well how pissed are you going to be when you have a leaking valve seal (that only costs $2) after you get everything done and put back together and the bike is running?


Yeah, replace 'em.




I've got to get my head done... I tried disassembling it - there's a valve that I CANNOT get to pull out... hahaha, it might be bent a little....

 

The valve seats don't need to be machined. The lapping of the valves will remove rest of crap that is on the seats. The valve seats are machined normally when the head is ported to get more flow or they look worn/deteriorated. They aren't exactly optimal from factory.

 

Where can you get the seals for $2? They were like $100 for all 16 on partzilla.

 

Honda CBR900 929 954 Viton Valve Seals Set of 16 New | eBay


$3.25 per seal - my mistake.

 

Do you have the oem workshop manual on .pdf? You could do the guides and seats yourself allso. On the manual are the instructions. You would only need valve seat cutters and the reamer for valve guides. I wouldn't polish the exhaust ports. The exhaust gasses still flow better if it isn't polished. My exhaust ports are the same roughness as the intakes.

I'm not totally sure about my valve seats but i think that they are bigger then stock seats.