recently installed a 905 12 bar, changed it around a bit so it sits a little past 12.

but now, when it's on it, the bike doesn't wanna stay straight, at idle, it just wobbles left,right,left,right, until it wants to fall.

why is this? what could cause it?

A. tire pressure
B. angle of the flat bar
C. angle of the side bars
D. other

..?

 

come on.....ANYONE?

 

So when you scrape the bar the bike doesn't stay straight?

If so, the bar probably isn't scraping straight and flat.... put the bike on the bar and see if it sits flat to the floor... if it doesn't the angle may need adjusting or it may be wonky.. put a tape measure from the triple tree center nut to each corner of the 12 bar .. should be pretty much the same measurement for it to be straight...

if the bar seems straight then your subframe is probably bent.

But also, you might be scraping too slow? faster you go the more stable it usually is... (within reason) but from what you're sayin I think the bar or subframe is wonky....

 

i really hope it's not the subframe...i had a pretty bad coaster wreck z while back that bent the round bar but the subframe looked fine....i guess i need to re-evaluate it.

p.s. when i scrape, not all of the flat plate touches the ground....lets say the scrape/flat bar is 3 inches thick, only the lower 1inch gets scraped.....can that be why?

 

mine only scrapes the back half of the bar too...feels normal to me.

 

If I park my bike on the bar it wants to fall, but it scrapes perfectly fine, even for long fast scrapes.

 

it is better if the top of the bar hits the ground not the bottom

 

+1
You dont want the bar to dig
Whenever I put a new bar on ,the first thing I do is lift the bike up to the tail section (requires 2 peeps)and use vise grips to hold the bar in place.
Get it so the bike is obviously balanced and check the bar contact surface.

 

is the plate bar warped...(...I had that on my first FI and it took me forever to figure out why it wouldn't stay strait

 

if you bent the round bar you probably bent the subframe.

 

i remember when i had the tail section off, i looked at it and it didn't look bent and at least not by the naked eye....anyway, i hope not.

the digging into the ground makes sense...i'm gonna see if i can re-angle the plate...maybe put a spacer (nickle?) in the top-half or sumtin.

 

stuck a dime, nickle, and a penny behind each bolt. wasting a total of $0.32 cents

but it's hella better now. it sorta helped the wobble but didn't fully fix it. tho it DID make it scrape on the top half now which is gangsta.

also, when i went a little faster than idle with my weight ON the bike(seat stander), it wouldn't wobble anymore.:YEAH

 

I wrecked scraping last week and my 12 bar bent to the right but its still level when its at the 12 position... but I will find out if its fine next time I scrape