Grand Prix 250
Main Motorcycle: KTM 1290SA
Join Date: Nov 2018
Location: Louisiana, USA
Other Motorcycle: Triumph Tiger 1050 ABS
Extra Motorcycle: BMW R80RT
You're looking for justification to not bother with the scheduled valve checks. They are scheduled by the manufacturer for a reason. The 1050 is not known for rapidly closing up valve gaps and some people have certainly skipped checks without consequence. I checked my (new to me) Tiger 1050 at around 22,000 miles because I had no idea if the previous owner had it done. The clearances were all roughly between mid-range and max-range and at least a couple had clearly been adjusted previously. I don't know if they changed much but as they were all in the ideal range, I doubt it. I MIGHT skip or delay the next check (but probably not as I'd like to see if they are changing.)
If you KNOW your bike has had the valves inspected previously and the current check is not terribly overdue, you could probably roll the dice and be fine, especially if you also KNOW the clearances were set properly at the last check/adjust. It's unlikely you have this information, however. Even if it was checked before, If one or more valves were right at the lowest clearance but in spec and therefore not adjusted, they might be very tight now. You might notice hard starting if they close to zero or you might not notice anything until one valve either washes out or fails, trashing the cylinder if not the entire engine. ...Likely? Probably not! Your choice.
If you're reasonably handy and take your time, the valve check can be done in an easy day, along with sparkplug and air filter change and other maintenance. Then you'll know for sure. If the valve clearances need adjusting, the cams need to come out (as you probably know) which makes for a more complex job with more things to risk screwing up, but it's still not terribly challenging. You would need to order shims in that case too. If it comes to it, make sure you can leave the bike for a week mid-service and order a complete shim kit if you find you need it. You can then either keep it for next time or sell it on to the next guy doing the same job.
MSF Ridercoach, IBA member
KTM 1290SA, Triumph Tiger 1050, BMW R80RT, Suzuki Vstrom 650, Suzuki DR350