Ben thanks for the reply and the leap of faith on actually making the swap. I had been thinking of a possibly easier way of changing cam timing by splitting the cam, re-indexing it, and rewelding it. It would save several precision steps. It would still need to be held precisely in the bearing surfaces (like in an an old head that was shimmed up). What do you think?
pekingduck, re-indexing is not what it needs, it needs more meat on the skinnier 1 and 2 lobes to get the right duration
Ben
(03-14-2020, 04:36 AM)Ben70_imp Wrote: [ -> ]pekingduck, re-indexing is not what it needs, it needs more meat on the skinnier 1 and 2 lobes to get the right duration
Ben
I thought they had just rotated the same lobe contours, but didn't realize they changed the ramps and/or lift. That's even worse.
Here it is:
skinny lobes
fat lobes
They open at the same time, 1 and 2 cyl lobes have been shaved to close 10 degrees earlier.
I think material can be added and then machined down to match 3 and 4.
I plan to find out some details early next week. Will keep you posted.
Ben
That is some serious craft Ben.
Wow, thanks Ben. It looks like they may have ground the original lobes! That's not like them - still, it would have been a quick-and-dirty way to do it. I know that in the recent past, they've un-crated bikes at the US warehouses, taken engines apart, made a change, re-assembled and re-crated bikes.
Sorry, either you misunderstood me or vice versa. This is the original intake cam showing one end, then the other just to illustrate the difference. My plan is to make the skinnier lobes look like the fat ones. I dunno if we are on the same wavelength?
Ben
(03-14-2020, 09:33 AM)Ben70_imp Wrote: [ -> ]Sorry, either you misunderstood me or vice versa. This is the original intake cam showing one end, then the other just to illustrate the difference. My plan is to make the skinnier lobes look like the fat ones. I dunno if we are on the same wavelength?
Ben
I understand. The profile of the lobes was changed, not just the timing as I had originally thought. Was just speculating if Honda made a change to the cams by regrinding flatter ramps after production had started by modifying existing cams as a cost cutting measure.
Wondering how late into the design/production timeline it was decided. The original engineer's discussion on the Honda Global site is gone. You'd think the designers/engineers would have ground the identical, slightly more radical profiles on all the lobes, not just on 2 cylinders. This just sounded like a cheap way of getting a little harshness without a performance benefit.
Well, yeah, but as I understand it the decision was made pre-production. I seem to remember some chatter I read about it just being too smooth, st1300 like.
And if you changed them all, you wouldn't get the dissonance. 1 and 2 are next to each other in the firing order, so it would be more effective at creating the desired effect than evenly spacing the "different" power pulses.
As it was, early reviews spoke glowingly about almost everything about the bike but that it lacked Character. Too refined, etc. yadda yadda...
Don't get me wrong, I love the bike! If someone hadn't let the cat out of the bag I would have just accepted the buzz, and have for some time.
I joined this forum in fall of 2016 and at about that time PowerDubs was just starting his journey. I followed that but ended up just trying the swap to see if even lobes would give the desired effect, secretly hoping the power would stay the same.
It appears that it works for my purposes and if a dyno wasn't available I may have never known I had lost some power. Acceleration to pass, etc. was good and just overall smooth.
However, I want to try to bring it back to where it was before some aesthetician got hold of it.
Ben
I didn't know about the designed-in dissonance until I had sold my 2013 and bought a 2014 to be rid of the buzz. But the 70mph freeway rpm is so low it kills the top gear roll-on power the 2013 had. Wish I had known about the cam cure before - would love to have kept the 2013.
Keep us posted on your cam regrind results. Cams are the same for all years. Any idea what cam grinder you might use?