Valve Clearance

[jimjr21]

What clearance have you checked and set your valves to? How many miles on bike at time of service?

Factory spec is .04-.06mm.

I feel this is way too tight of clearance. Any thoughts from anyone else?

[SpudRider]

I am getting ready to check the valve lash on my RX3, but I haven't done it yet. CSC specifies the valve lash as 0.04-0.06 mm for both valves. Initially, I though this valve lash was too small for the exhaust valve. However, I am going to follow these specifications for the first few inspections/adjustments, and if the bike continues to run well, I will stick with them.

However, it is interesting to refer to the AJP PR5 Owner's Manual. The last page of the manual, page 34, lists the following specifications for valve clearance.

http://issuu.com/ajpmotos/docs/ajp_pr5_user_manual_en

Intake: 0.05 mm
Exhaust: 0.08 mm

The AJP PR5 employs the same Zongshen NC250 engine, and Delphi EFI as the Zongshen RX3.

[No1Vic]

I see member Katflap set his valves to 0.06 which made the engine better especially from cold appearing to have cured cold start stalls, I'll be setting mine to this value once there's a few more miles on the bike.

[SpudRider]

I have inspected, and adjusted the valve lash on my RX3. All four valves were tight. I set all of them for a clearance of 0.06 mm. The bike is running great, and I am getting about 70 mpg every time I fill the fuel tank.

[AZRider]

Originally Posted by SpudRider

I have inspected, and adjusted the valve lash on my RX3. All four valves were tight. I set all of them for a clearance of 0.06 mm. The bike is running great, and I am getting about 70 mpg every time I fill the fuel tank.

Being very old and very conservative, I took the middle ground and set mine to 6 thou. I'm not easy on the throttle and consistently get around 70 mpg. I'm very happy.

[rjmorel]

Originally Posted by AZRider

Being very old and very conservative, I took the middle ground and set mine to 6 thou. I'm not easy on the throttle and consistently get around 70 mpg. I'm very happy.

6 thou or .06 mm ? 6 thou = .152 mm .002 thou = .06mm Not picking on you AZ but just saw Spud did his at .06mm and yours is 3 times more clearance. ????? I can here your valves clattering clear over here but then noisy valves are happy valves I've been told. )) rj

[AZRider]

Originally Posted by rjmorel

6 thou or .06 mm ? 6 thou = .152 mm .002 thou = .06mm Not picking on you AZ but just saw Spud did his at .06mm and yours is 3 times more clearance. ????? I can here your valves clattering clear over here but then noisy valves are happy valves I've been told. )) rj

Being old school British I have a hard time accepting the metric system and still mix up the terminology. You'd think that after almost 40 years in the States I'd have it down by now. You're absolutely right, l should have written mm, my bad. Fortunately, my feeler guages are smarter than me and it all worked well in the end.

[Weldangrind]

Originally Posted by AZRider

Being old school British I have a hard time accepting the metric system and still mix up the terminology.

You'd be downright confused as a Canadian. We're officially metric, but so much is still expressed in either US or Imperial.

[AZRider]

Originally Posted by Weldangrind

You'd be downright confused as a Canadian. We're officially metric, but so much is still expressed in either US or Imperial.

You may be metric now, but when I emigrated to Toronto in 1968, metric was a gleam in Pierre Elliot Trudeau's eye. Or was that gleam for his wife?

[3banger]

As an engineer in the states I can't believe I still have to deal with standered units. They should have died 40 years ago!

[KirkN]

Originally Posted by rjmorel

but then noisy valves are happy valves I've been told. )) rj

It's: SLAPPY valves are happy valves!


My pushrod 250 called for 0.002" intake and exhaust. I couldn't bring myself to do only 0.002" on the exhaust. I went with 0.003" intake and 0.004" exhaust.