Maintenance Cap O-Ring

[Sasmaster]

I’m preparing for a valve check and noticed in the manual that the o-rings for both the maintenance cap and the “window bolt to check for TDC” (I dont recall the actual name) are supposed to be replaced after removal and not reused. Problem is, i cant find these online anywhere.

Anyone know where to pick these up?

 

[dduelin]

Part numbers 91303-377-000 & 91344-PC9-004

2015 Honda NC700XD AC ALTERNATOR COVER | CyclePartsNation

 

[DirtFlier]

I've never replaced either of those on my last 3-4 Honda motorcycles. There is hardly any oil in that cover so why worry about a leak?

 

[dduelin]

There are threads about having to chisel the cap off however.

 

[670cc]

Although it goes against the specific steps of the valve adjustment procedure, I have stopped removing the cap for viewing the cam position on the right side of the engine. It is so easy to tell which TDC you are on by the looseness of the appropriate rocker arms. I suppose if it’s your first time or two, checking the cam visually might be a good idea, but after some experience, it’s really a waste of time. The only cap you’d need to remove is the one at the crankshaft, left side (while seated).

 

[Sasmaster]

Part numbers 91303-377-000 & 91344-PC9-004

2015 Honda NC700XD AC ALTERNATOR COVER | CyclePartsNation

Thanks much!

670cc - Good to know. This is my first attempt, and I think it may be the bike's first as well. I've no idea if the previous owner ever did it. Glad its a simple process though.

 

[dduelin]

I don't replace the O-rings every time myself but I think it is important to do it maybe every other time. The caps are torqued to relatively low torque values and what happens is the O-ring gradually deforms under heat and pressure. The cap is removed then replaced and instead of a compliant O-ring initially compressing and giving some 'feel' to the correct torque, the cap comes up metal-to-metal with little feel and we easily overtighten it past the 7 or 11 ft/lb setting, setting up a difficult removal next time. The O-ring should be oiled and the cap threads greased as well.

 

[potter0o]

I have done this three times now. I would inspect the rings looking for damage and replace them if they looked damaged or started leaking.

 

[DirtFlier]

Using the small viewing port on top is often difficult for first-timers because the marks "TF" or "TR" can go by quickly, almost without you seeing them! And don't forget to remove the spark plugs because if they are still installed, it's almost impossible to get the piston to stop at TDC!

 

[Sasmaster]

Good to know, Thanks!

 

[davidc83]

Using the small viewing port on top is often difficult for first-timers because the marks "TF" or "TR" can go by quickly, almost without you seeing them! And don't forget to remove the spark plugs because if they are still installed, it's almost impossible to get the piston to stop at TDC!

I have never removed a spark plug and no problems with stopping at tdc...and if I did, I would just crank it around again...less time to crank it around then to remove the spark plug caps, spark plugs and re-install them afterwards...dont recall removing spark plugs in the valve check maintenance procedure before...

 

[dduelin]

I have never removed a spark plug and no problems with stopping at tdc...and if I did, I would just crank it around again...less time to crank it around then to remove the spark plug caps, spark plugs and re-install them afterwards...dont recall removing spark plugs in the valve check maintenance procedure before...

It's hard to inspect the spark plugs without removing them, since spark plug inspection is part of the 16,000 mile service to me it's understood you remove the plugs to inspect them and also to make it easy to turn over the engine. YMMV.

 

[670cc]

I don’t remove the spark plugs because doing so and reinstalling them means the spark plug compression gasket has already been compressed. I’ve never had any spark issues in over 40,000 miles and I have no doubt these iridium plugs will last at least 64,000 miles. Like davidc83 said, I have no trouble stopping on TDC with the spark plugs installed. Why fiddle with plugs if you don’t need to?

 

[davidc83]

It's hard to inspect the spark plugs without removing them, since spark plug inspection is part of the 16,000 mile service to me it's understood you remove the plugs to inspect them and also to make it easy to turn over the engine. YMMV.

with today's spark plugs getting up to 100,000 miles on them (or more), and with EFI, dont see no reason to inspect them...if they aint firing, you going to know it, either not going to start (both dead) or extremely rough (one dead). My boulevard still has original spark plugs (100,000 miles on them).

 

[showkey]

Somewhat agree.^^^^^^^^^^ on the inspection is not needed.......but.........the inspection does give an opportunity to read the plugs, which gives an indication of the engines health ( assuming you know what to look for).

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Yes, the chances are very very low that a NC engine would need any work in the first 50-100k and the plugs would look like new in the first 50k if they were inspected.