Suspension Question
 

Alright, this is gonna sound retarded, but i come from cruiser country. I have owned several cruiser, mostly rice burners. But i have also riddin rigid frames too.

My question is, i just got my superhawk. Its a 98 with 21000 on it... I figured the shocks would have been worked in a bit but after a 800 mile trip... holy crap. I was sore, mostly due to poorly maintained southern arizona freeways. Does anyone know if there is an adjustable air shock to replace the rear coilover? I ask for adjustable because I want to be able to change for sports riding, but be able to soften for longer rides or to and from work. This is a daily rider so i would perfer something softer.

i wish i could tell you. i just dont know that much about suspension. those roads must definitely not be that great if you get sore from riding on them.

No airshocks available for the VTR (can't believe I just type that LOL) so either have the stocker rebuilt to your needs or get an aftermarket (ohlins, penske, wilbers, etc before they're gone too).

Your forks need attention too. Do a search for huge amounts of info.

Much better to spend $1150 on a Penske, Ohlins, or Elka triple adjustable, the reason being that they have high speed compression valving which helps immensely over sharper bumps. The high speed circuit in the shock has a bypass that opens when you hit a bump. The gains from a regular double adjustable shock would be less noticeable.

Rebuilding the SH shock would be a waste of time and money.

Only a suggestion but worth checking the rear suspension linkages and swingarm bearings, to make sure they've not seized up. They need regular servicing as they come with little grease in them!

Chris.

Ok, well the reason i ask... i gues.. is that i have looked into getting a longer swing arm... I am a physics major... longer the swing arm the more weight on the shock... has no choice but to rebound more... But i used to be a car mechanic, and semi too. there are a huge selection of air shocks... if you can match yours up... only problem... they dont have coil springs on the outside... without those you have no bound control
Being from the lowrider side of the tracs this would make the compression very soft... but wouldn't limit the rebound
I wonder if i bought a air shock, maybe i could transfer the spring mounts from my stock shock to the airshock with a bit of mig welding. Someone with technical expertise would be a huge help.

I have lots of experience, but i guess i am looking for a second opinion for some comfort before i do it.

Well, I'm not sure what you are aiming for realy... But a longer swingarm on a vtr will give you a very slow steering bike with very strange characteristics... Adding an airshock in the mix... I'm pretty sure you will get a very strange bike... I think you would be better off with another bike as a startingpoint... The vtr is a sport tourer, not a tourer...

It's a totaly different posture and way of riding than a cruiser, you probably just have to decide if thats what you want...

I'd be leary of welding on a shock. Distorting the metal from heat could ruin it real quick.

The only way you could weld to a shock without ruining it would be to fully disassemble it, and most of the air shocks aren't serviceable so it would be tough to do. You might have better luck with making adapter brackets to fit the shock to your 'hawk. By welding, you might destroy the hard chrome of the shaft as well as the seals.

With that said, you will ruin the suspension action of the bike and the force curves will be all wrong with the air shock since it's damping is rudimentary and even the most basic motorcycle shock is pretty highly developed in comparison.

Unless you want to turn your VTR into an ill handling piece of crap, avoid the air shock and the extended swingarm.

Well, i am an engineer.. I am going to meddle with an airshock mount i got my hands on. It goes between the shock and the mounting bolt on the top and will change pressure with any air compressor. After some research i decided not to go with a longer swing arm. However, i am toying with a supercharger i got my hands on... I have some demon wishes for this one... also looking into a throttle body setup in place of carbs... an engineer friend of mine that came from MIT is gonna help me with it... We are going to try it on a 600 cbr and go from there.
Hopefully i may have something for all you superhawk fans within the next couple months to increase horsepower by about 30...and cheap too.

I did find something that may work from penske though.. would be a custom airshock just gonna cost me a bit more. I will let you guys know.

Why?

Edit: Never mind... I missed the "I'm an engineer" part.

Since you are an engineer, you'll have no problem understanding the force curves you need for proper rear wheel damping and could probably come up with a new linkage to optimize the air shock.

And using the throttle bodies off something else to replace the carbs is easy as well, all you need is a programmable ECU and a fuel pump, don't forget that the FI systems use a combination of the cam position sensor and crank sensor to fire the injectors. With the supercharger are you using a roots type or a centrifugal? Are you going to use a map sensor with a higher range and big fuel injectors or are you going the rising-rate fuel pressure regulator route?

Of course i am kidding about all of this. What kind of engineering do you do?

The RC51 makes 30hp more, too and would make a great swap for that cool cam drive gear whine.

MIT friend or not... What works on a CBR600 will probably not work on a VTR... a twin and an IL4 (especially a smaller 600) has totaly different characteristics... The amount of fuel and air in gulps for two 500cc cylinders doesn't resemble the smaller pulses for four 150cc cylinders...

Also start with one thing... figure out the suspension first, then fiddle with the engine... The suspension in stock form isn't as good as a Race Replica bike... but it's atleast safe for the user... Trying out an airshock might not be... especially with no rebound dampening, softer characteristics and a quite potent v-twin with loads of torque on tap...

Engineer or not, theory and practice are two different things... I'm an electronics engineer with atleast half a degree in applied mechanics and
loads of experience in calculating different scenarios...

And while I may try out using a fork from another bike, I choose a similar bike and fork... same would go for the rear shock... an upgrade or another shock from a similar bike... But choosing an entirely different one (airshock) or re-engineering the internals workings of said fork/shock, that I would leave to a pro with experience in that field... Less chance of getting hurt that way...

Thank you!

Not to mention the amount of cam overlap a N/A engine as compared to supercharged or turbo. Your lobe separation angle with a blower would be in the neighborhood of 114-120 degrees while you might use 100 or less for N/A depending on rpm, etc. So when you degree the cams you would open the intake way earlier (maybe 10degrees) and the exhaust maybe 2 degrees later or the same. I have at least 500 hours of motorcycle dyno time with 600 supersport engines alone and cam timing can totally change the personality and useful rpm range of an engine.

Back to the suspension, the original question dealt with ride quality over bumps which a triple adjustable shock addresses since it has a circuit that bypasses the normal damping for harsher bumps, thus improving ride quality. The cost? $1100 or so. Sounds like a lot until you ride a bike both ways.

I like low budget solutions, look at my flickr page and you will see that in my projects, but sometimes it is safer and easier to just spend the $$$$

Well let me start out with this much. I am into aerospace electronics. As far as the supercharger goes... we have looked into all of that(everything u guys went through). I have a lot of trust in my friend.. He designs jet engines so when it comes to stuff like this i tend to listen to him. There are a lot of things that we will need to work out to make it even feasable.. and it may not be. But thats half the fun is figuring it out. i am limited for time tonight but I will hop back on friday and divulge some of the details on our project. As far as the suspension goes, I am leaving as is for the time being. I bought a new saddle this weekend and it has already made a huge difference. Keep in mind i am transitioning from cruisers.

Instead of extending the swingarm, why not try moving the shock mount closer to the pivot point? Or moving the top mount to get a steeper angle on it?

A new seat? What color is the bike? Only certain ones have any potential.











(LOL, I'm just busting your chops!!) Welcome to the forum Oneup and I hope you have a lot fun "re- engineering your 'Hawk!

Gotta go, mine needs more wax.

I'm all about doing retarded stuff to motorcycles, I am very guilty of that. I was just giving you shit. It's all about having fun and making cool stuff. You should see what I am doing to my Superhawk. It is stupid.

well...quit teasing and show us :D

I'll try and post some pics up later today.

Pics of other stuff I've done are at www.flickr.com/photos/rossthompson you have to sort through a lot of bullshit but there is some good fab work.

Well... I'm guilty of that too...:D I was mainly trying to get you do do silly stuff that could benefit me aswell... :rolleyes:

Also I figured that part of your pains was the transition from cruisers, the riding position is altogether different...

Its a seargeant. Think thats how they spell it. Its black with red trim... Matches the bike perfectly.