Valve Adjustment intervals and reliability?

[dricked]

Ti valves on a street bike will last MUCH longer, they done live at +8,000 rpm. Racing application is different but I'm sure eventually they'll need replacing. The coating on mine actually deteriorated where the schim sits on the valve which caused a huge clearance and an audiable tick. Glad I didn't ignore it or I'd have introduced an intake valve to my cylinder.

I know you know this stuff Brian, just adding to the thread.

 

[yodude]

as far as on topic & op's first post goes..

+1 on post #13
http://www.gtamotorcycle.com/vbforu...-reliability&p=2467017&viewfull=1#post2467017

1. Follow MFG guide lines, they have spent a bunch of time figuring this stuff out.

2. Valve adjustment intervals differ between motor types.
For example something archaic might be every 6-8k, more modern super sports like a GSXR platform will be at 42k. Probable a new gen cbr RR platform would be around that 42k mark.

3. Lower Redline / longer service intervals just means there might be a ton of clearance or allowable wear between components. Also it could also mean that the technology in the motor might be outdated / old.

For example a Small block chevy from 1970 vs a new Small block chevy are totally different. (taking type of fuel system out of the equation) the new motor is way more robust, makes way more power and has tigher clearances.



If you are after something that has 'long' service intervals, you are after a motor that does not use flat tappe cams, more of a roller rocker type of valve system would give you a longer service interval.

Same as CHAIN DRIVE, VS BELT DRIVE VS SHAFT DRIVE. Weight, Cost, maintaince etc all play a big part.

 

[yodude]

1. Follow MFG guide lines, they have spent a bunch of time figuring this stuff out.

2. Valve adjustment intervals differ between motor types.
For example something archaic might be every 6-8k, more modern super sports like a GSXR platform will be at 42k. Probable a new gen cbr RR platform would be around that 42k mark.

3. Lower Redline / longer service intervals just means there might be a ton of clearance or allowable wear between components. Also it could also mean that the technology in the motor might be outdated / old.
.

& depending on application or intended purpose, a pushrod, hydraulic valves ohv engine is viable even today,

harley's went there a looong time, for one

 

[Brian P]

Ti valves on a street bike will last MUCH longer, they done live at +8,000 rpm. Racing application is different but I'm sure eventually they'll need replacing. The coating on mine actually deteriorated where the schim sits on the valve which caused a huge clearance and an audiable tick. Glad I didn't ignore it or I'd have introduced an intake valve to my cylinder.

It wore out at the top tip of the valve, not at the valve seat?

That's interesting, I wouldn't have thought wear would happen first in an area with ample lubrication.

The service manual warns against the traditional use of lapping compound to seat the valves against the valve seats, because it will go through the coating on the valves.

 

[dricked]

It wore out at the top tip of the valve, not at the valve seat?

That's interesting, I wouldn't have thought wear would happen first in an area with ample lubrication.

The service manual warns against the traditional use of lapping compound to seat the valves against the valve seats, because it will go through the coating on the valves.

Yep, surprised me as well but maybe with the constant pounding from the cam? You can see the valve on the left looks polished and the valve on the right has chips out of the coating. NM, forgot this site has image issues. You can envision it

Yes, no lapping with Ti valves. When I installed the new ones I just made sure the seat was in good shape and the old valve didn't have abnormal wear. It isn't the ideal way of refurbishing a head but the valves arrived Tuesday afternoon and I needed to leave Thursday morning for St. Eustache. I started the bike at 7:30 Wednesday night and got packing!

 

[Flywheel]

Have you ever put a micrometer on your 'bond' paper? Standard office 20lb bond/50lb offset is nowhere near .006" (45+ years experience with the stuff).

Not to mention some "bond papers" sell in 20#, 24# and 28# versions. Also, weight is not a reliable indicator of thickness (caliper). Watermarks and surface finish, or even engineering tolerances can make a difference. Caliper can also change over time as brands are sold/licensed to other manufacturers, or when new print technologies become prevalent. For instance, many paper brands with traditionally rougher/uneven finishes are now slightly calendered to accept digital print toners and electrostatic inks more readily. The physical properties of paper also change if it becomes wet, or absorbs oil. It's a neat material with many uses, but a feeler gauge is not one of them.

 

[Neil_V]

Got the bond paper out tonight... all seems well. going to recheck in the morning with feelers.

 

[Iceman]

I just buttoned mine back up. My buddy still has my bond paper from the last time he borrowed it so I had to resort to feeler gauges.

Sent from my SM-A500W using Tapatalk

 

[Brian P]

Got the bond paper out tonight... all seems well. going to recheck in the morning with feelers.

Cool pic ... haven't seen inside the top of one of those before. Timing chains are on opposite ends of the engine ... presumably so the front and rear heads can be the same part, just turned the other way. The chain drive to one camshaft and gear to the other one reminds me of Toyota 2RZ-FE.

 

[Neil_V]

Cool pic ... haven't seen inside the top of one of those before. Timing chains are on opposite ends of the engine ... presumably so the front and rear heads can be the same part, just turned the other way.The chain drive to one camshaft and gear to the other one reminds me of Toyota 2RZ-FE.

Precisely.

I've also always liked the second cam on a DOHC head being run by gears or a second small chain. I've always felt it simplifies the timing procedure when you can sync and lock the cams in place first.