Sunday, October 2, 2011

Ride report and observations on my design

I just got home from a ~150 mile ride on the VX. 1/3 of that was on twisty roads, mostly empty. I had a good chance to really gas it, take some fast corners, slow corners, do some major down shifting and braking. I put the bike through its paces for the first time. I had my ignition set to limit revs at 6200 rpm. The bike definitely has a lot of raw power. It pulls very hard and it was hard to even get the throttle to wide open without hitting that rev limiter. I'm limiting revs for the purpose of break-in. I'm following my own hybrid break-in procedure based partly on MotomanUSA's style, but a little toned down. I definitely put massive load on the engine, varied the load, did a lot of heavy engine breaking, but also did some freeway miles. I wanted to avoid the freeway, but ended up using the motorcycle ride to see family, which was long overdue, and one thing led to another and I ended up riding home in the dark and on the freeway.
Main observations on my own design:
1. Footpeg position is wrong and is too far back.
a. My crotch was jammed up on the tank the whole time
b. Too much weight on my hands
c. since my bike is so skinny, there's nothing to clamp my knees on to relieve the pressure on my hands.

2. Seat needs more and stiffer foam.
a. Front of seat needs to be higher and I barely use the back 1/2 of the seat.

3. Clutch is not fully disengaging. (couldn't get neutral the whole ride and it was almost impossible to get from 1st to 2nd unless I was power shifting.

4. Front cylinder is running a little too rich. (I was only monitoring the front cylinder with my Innovate MTX-L air/fuel ratio gauge. Front cylinder was at 12.2 - 12.8 at 1/4 to 3/4 throttle. WOT I'm in the 13.2 - 13.8 range. WOT looks good. I probably need to raise a clip on the needle.)

5. Rear shocks were very bouncy. I couldn't get the rear end planted in corners. I exercised about 3" if not 4" of travel on the rear shocks. I've got massive preload on the springs right now and have my rebound damping at 3 out of 4. I probably need stiffer springs.

6. Front shocks were spot on and I didn't notice a thing wrong.

Thoughts on Item #1 and #2:
I went for a racier look and ergo and installed rearsets. The combination of this and the seat change ends up with me humping the tank all the time. I can't take any weight off my arms because the pegs aren't under my center of gravity; they're significantly behind my center of gravity. I'm sure pegs being under my center of gravity is a key design element, here. Pegs are also a bit low. I felt like I could easily lean the bike way over, but was already scraping my boot. I wasn't even trying to corner hard and was dragging peg. The seat is also slanting forward. I thought this was somewhat important in order to provide something behind me to keep me sliding back. This is a concept I came up with based on false information. At no time during my ride was there so much power that I was sliding off the back. Ha! If only. That much power and you're wheelying, not sliding off. I think a flat seat is the right thing. If I put very stiff foam at the front of the seat, raise the front to go up the tank, and flatten it out front to rear, and move the pegs under my center of gravity, the riding position would be majorly improved.

I love the crouched feel, so I need to bring the pegs up a hair. Sounds like a redesign of my rearset mounting bracket since I've moved them as far forward as my current setup allows.

Thoughts on Item #3.
Man did the clutch kill me. I just put in new friction plates and springs. I've rebuilt the exterior clutch mechanism on the engine, and have a new cable and lever. My left hand stopped working since it was so hard to pull in the clutch. I'm also not getting full disengage. I spent 2 hours working on everything trying to get it to disengage and finally went on my ride, hoping to "break-in" the new plates and see some improvement. Nothing improved. Time to pull the clutch cover and mess with the springs. What a pain.

Item #4: To do: Go for a ride and monitor rear cylinder. Adjust clip needle position.

Wow, the VX has some awesome torque!