penske shock ? and air box?

OK so I just got this bike 1998vfr800 70k pretty nice condition previoius owner toured and took care of it. It has a hose off the rear shock going to a Penske tank looks like an old car ignition coil. I assume this is like an expansion can off the rear shock? The rear is so set too tight if I hit a bump at over 40 it is bouncing me off the seat must be set for like someone 250 lbs. I am only 140. My question is can I just bleed some gas off the little can. ALso is this Nitrogen as well if I need to add any. I have never see this type of gas can thing on a bike before so any info is appreciated. 2nd ? is the bypass door on the airbox is dissconected from vaccum some how I have tore down far enough to tell yet but should this be working (closed when idle) and maybe could this have been dissabled becuse it has a k&N and 2bros pipe. I know on other bikes we just cut out some plastic so maybe they just dissabled the door to create same effect. THanks for any info would be great. I am not new to bikes or engine work ect. just new the vfr but I love it so far and will probably be neglecting the other bikes for a while. Also I know I need the manual, I havent had time to get to the shop yet. Also I was looking for like a sticky thread for basics specs and stuff I don't know if you all have one here or not.

 

Look on the spring to see if there is any writing on it, odds are the spring rate is too heavy for you and you will probably want to change the spring rate out (or change the preload). I would not mess with the external reservoir unless you have some special tools to work on it, that is what that external can is.

Considering the age, if that shock has been on ten years or so you might want to send it out when you get a different spring put on it and get the shock rebuilt- new seals, oil, and nitrogen refill- it basically makes it into a new shock for you. Given enough time even the best shock seals get leaky and lose nitrogen and the oil goes through too much wear and has to be changed, might as well do it at the time you change out the spring.

Can't tell you much about your other problem, don't know much 'bout them newer VFR's.

 

I will check out the spring tonight. The preload did not look tight as there was only 1.5 inches of thread left above the spring I suppose I could loosen it a liittle to see what that did, it would also lower me a little too. I put a guage on the external can valve and it was empty. I have a friend the does HVAC and he has nitrogen I could get him to fill it. Does anyoen know how much pressure is avgerage, normal I dont want to overfill? Then I could see if or how fast it leaks out.
I would rather not send off my shock in the middle of ridding season. I'll see if it hold gas but your probably right on the seals gone.
OH and I just realized the guy who had the bike before me toured on it so he probably got the heaviest spring for him and 100 lbs of gear.

 

if you did not use a screw on gauge, consider yourself lucky that it was empty.

 

Ditto that. The Penske manual calls out 150 PSI for a similar shock used on an SV650...

 

Ok so today I stopped in the local suspension shop and he said it should have been like 125 psi in there so yea I guess it was empty. I am going to pull it off and take it to them to get the right spring and recharge and check it out. So then should be riding right. You learn something new everyday.

 

When I first found out about how much pressure was used, I was happy I didn't find out the hard way...

FWIW, if you Google "penske motorcycle shock manual", you'll find a site you can download a manual from. I'm at home on a dial-up connection, and it takes to frikkin' long for all the graphics to load... Anyway, your shock is probably an 8900 Series. After you look through the dis-assembly/assembly procedure, you'll probably be happy to pay somebody else to do it.

I guess it's like everything else; if you do it every day, it gets easier.