The question might be what is it about the design that requires the short interval. How hard could it be would depend on shim under bucket v adj. nut rockers and access. But you knew that.
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The KTM RC390 thread
- Thread starter CafeRay
- Start date
The question might be what is it about the design that requires the short interval. How hard could it be would depend on shim under bucket v adj. nut rockers and access. But you knew that.
Roomie
Banned
Ever been out of the city where we don't have street lights? Pitch black night.... I'd love even a small led or ring where the ignition is. It's a bugger to see. Other than sitting still though you're correct lights aren't necessary on controls.
Not if you finished high school. Wouldn't surprise me if some of the reviewers are still working on it.
You have to feel for the manufacturers ... they come out with a solid bike, yet the critical Internet public will still find a list of nuances, eh?
Does any company still use adjustable nut rockers? At a 10k redline, there must be shims under buckets, but that's not rocket science and not that much more work once you gotten down to get the valve train covers off.
It's not rocket science but can be fiddly and there's more room for error. Real world Saturday morning valve adj. + sourcing the specific shims you need could work into a whole day and beyond. I think those reviewers complaining about 6k valve adj. intervals imagine it being that much of a bother. I know I do. I don't keep as much track of what all OEMs are doing in the bumpstick dept. but did note that the NC700/750 has nut adjust rockers. Of course that's a real world bike.
Sticking within manufacturers spec, changing from the tightest to the loosest values can change things a lot. On an old 450, IIRC when everything was loose (within spec), it was tame with decent midrange,tightening up the exhaust side (within spec) brought on a rush of power (relatively) as the revs climbed. Changing nothing else but valve lash made a 15 km/h difference on top end speed. It surprised the hell out of me, but I repeated the experiment many times and got similar results, obviously other bikes may experience different results.
Edit: I guess the comeback is that NC700/750 is low revving, but luckily remembered Brian P. telling me how easy it was to adj. CBR125R valve. A quick google reveals adj. nut rockers. Not that it's a competition or anything
oops, meant to edit, not quote myself. Under a lot of strain today. Damn hardwood floors ugh.
Edit: I guess the comeback is that NC700/750 is low revving, but luckily remembered Brian P. telling me how easy it was to adj. CBR125R valve. A quick google reveals adj. nut rockers. Not that it's a competition or anything
oops, meant to edit, not quote myself. Under a lot of strain today. Damn hardwood floors ugh.
You are starting to talk to yourself. Time for beer.
Ducati is making a big deal about VVT this year, but this has been in cars for 20 years. Also, why do all bikes not have hydraulic valve adjusters? It's not rpm, the Honda S2000 had a 9,000rpm cutoff 15 years ago. I don't think any bike has GDI yet.
I think it's convention, and about costs. No one would by a car if it required 10,000km valve service intervals or new belts every 5000kms.
Hydraulic lash adjusters take up space and add weight and cost.
Plenty of car engines don't have hydraulic lash adjusters. Lots and lots of Toyota and Mitsubishi engines don't, and I know there are others. They're shim-bucket, just like most bike engines. If the valve and valve seat materials are correctly chosen and the cam profile is correct, there's no need for lash adjustment.
Variable valve timing is a benefit if the engine is going to see a wide range of RPM when under load. A bike doesn't weigh much. It doesn't need to get lugged down going up hills or on takeoff from a stop. It costs something to do it ... and it requires the clearance pockets in the pistons to be sized for worst-case; on a high-performance high-compression engine, there simply may not be enough clearance between valves and pistons to make it worth the tradeoff that lowering the compression and adversely affecting the shape of the combustion chamber would cause.
Direct-injection in cars is being driven by environmental / corporate average fuel economy / CO2 emission regulations. It's expensive. The regulators have not (yet) seized on the fact that a good many larger motorcycles use as much fuel as a good many cars. I am also not sure how nicely the present direct-injection hardware plays with very high RPM. Normal port injection need not be synchronized with the intake stroke, but it's critical with DI. At 15,000 rpm, the 180 degree intake stroke is completed in two milliseconds.
Plenty of car engines don't have hydraulic lash adjusters. Lots and lots of Toyota and Mitsubishi engines don't, and I know there are others. They're shim-bucket, just like most bike engines. If the valve and valve seat materials are correctly chosen and the cam profile is correct, there's no need for lash adjustment.
Variable valve timing is a benefit if the engine is going to see a wide range of RPM when under load. A bike doesn't weigh much. It doesn't need to get lugged down going up hills or on takeoff from a stop. It costs something to do it ... and it requires the clearance pockets in the pistons to be sized for worst-case; on a high-performance high-compression engine, there simply may not be enough clearance between valves and pistons to make it worth the tradeoff that lowering the compression and adversely affecting the shape of the combustion chamber would cause.
Direct-injection in cars is being driven by environmental / corporate average fuel economy / CO2 emission regulations. It's expensive. The regulators have not (yet) seized on the fact that a good many larger motorcycles use as much fuel as a good many cars. I am also not sure how nicely the present direct-injection hardware plays with very high RPM. Normal port injection need not be synchronized with the intake stroke, but it's critical with DI. At 15,000 rpm, the 180 degree intake stroke is completed in two milliseconds.
The pattern is always the same ... why does it take for Brian P one sensible posts to read 5 or so absolutely out to lunch posts?? Talk about keep defending a good bike, before the naysayers finally give up ... LOL .... Wonder which part of the bike would be questioned next, any clue?
DI pumps are fairly bulky and power hungry, no? DI was apparenltly first invented in 1902 in France. Man, automobile tech takes forever to develop.
To throw more sticks on the RC fire--that tail section is basically steering wheel foam. Once the upper layer rubs through/tears, it'll crumble quickly.
DI pumps for gasoline engines don't draw much power nowadays.
As for the tail section ... Normal seats are also foam, it's just that this one is bigger to cover the whole tail! As long as the cover material is durable, it shouldn't be a problem.
As for the tail section ... Normal seats are also foam, it's just that this one is bigger to cover the whole tail! As long as the cover material is durable, it shouldn't be a problem.
Aren't you gonna spring for 500 bucks Corbin? .... LOL .... the list is getting longer, eh? ....
- ****** front end design
- concerns over trellis one piece frame
- too short valve adjustment intervals (half of a bike has to go apart)
- stock brakes are soft
- missing small led or ring where the ignition is
- seat will crumble due to soft foam
I am sure you guys can come up with more ...
What about bulk? A battery sized unit isn't that big of a deal in a car. I'm curious more than anything else, since nothing really gets explained these days, just: AWESOME NEW REVOLUTIONARY ACRONYM!
More teasing MXS than anything else on the tailsection. Video makes It look like a closed-cell foam, like you'd find in certain anti-fatigue mats. Mind you, Corbin & Co exist mainly because manufactuers don't take seats seriously.
I'm sure the RC will do fine, despite the sharp corners it may have. The Japanese were pretty unapologetic about offering genuinely terrible bikes in the past and they still sold in droves. The RC seems like a more serious attempt right out of the crate and that can only lead to pressure on the competition.
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