Suzuki GR650 - back to work...

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

Ben, IIRC the GS box has the same "rubber stacks" that Teazer mentioned. I didn't look too hard at them before I cut the box to hell though........

The stock GR box has nothing resembling a v-stack. Hence, the reason why I ordered some.

 

[stroker crazy]

Re: Suzuki GR650- change is in the airBOX.......

People looking at filters for airboxes might be interested in this:

http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm

Crazy

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

I've seen that before- I think PJ posted it elsewhere? Either way, it does make sense if you think about it. That is also another reason I went with this whole idea - there are a lot of manufacturers of GS500 filters (when I say a lot, I mean compared to GR filters). And when the filter gets dirty, I should be able to find a clean one fairly quickly.

Thanks Crazy!

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

Ben, IIRC the GS box has the same "rubber stacks" that Teazer mentioned. I didn't look too hard at them before I cut the box to hell though........

The stock GR box has nothing resembling a v-stack. Hence, the reason why I ordered some.

My GS box was flat inside.Just the boots where they seal around the box openings.

People looking at filters for airboxes might be interested in this:

http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm

Crazy

I would rather run a different filter but not many companies make filters like I posted above.The ones that do make them are very restrictive and have to be huge to flow enough air to prevent a vacuum build up in the box.

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

I can check in the morning if I remember. I may still have the GS intake boots laying around.

 

[peteGSX]

Re: Suzuki GR650- change is in the airBOX.......

I still have an unmolested 450 airbox here, boots and all Rich...

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

Gonna toss some pics at ya'll so get ready.

GS500E air box 89-96
This is the carb side.The upper fitting is for the crankcase vent hose.The lower fitting is the air box drain.

This is the filter side with the end of the filter sticking out.It has a small bell mouth.I'll show this better in later pics.

This is the left side.It is a restriction and partially blocks the left carb from getting direct air flow.This recess is to fit the frame petcock and fuel lines.

Here is the inside of the carb boots.They do have a slight bell mouth but aren't very uniform or stable.They're pliable rubber.

Just for reference,I took some measurements of the stock GS air filter and air box opening.

Here you can see the slight bell mouth on the stock filter.

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

If you guys want,I can take pics of the inside of the box, looking through the carb openings, and air filter openings.I'll have to wait until tomorrow when I have some better sun light and sub gale force winds.

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

The 4th and 5th pics down- those are the same stacks we were talking about earlier. It doesn't matter so much that they flex a little bit, they still smooth out the airflow into the carbs.

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

The 4th and 5th pics down- those are the same stacks we were talking about earlier. It doesn't matter so much that they flex a little bit, they still smooth out the airflow into the carbs.

OK great.So what happens if they're longer or have more internal taper, like a longer VS with a bigger opening?I know the air speeds up.But what else happens?

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

I did a lot of looking into the science of stacks when I was working on my Honda. That was a while ago, so it's all a little fuzzy.......so there could be some outright BS in the following statements:

Normally a stack mounted on the mouth of a carb (with no air box) is a tuned length. That length determines where the peak torque happens in the rpm range. Shorter=high rpm's, longer=lower rpm's. If it's too long, it becomes essentially worthless. But since the GS has them inside the airbox, the volume of the entire box becomes part of that tuned length.

Remember- I could be 100% completely wrong in the above statements.

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

I did a lot of looking into the science of stacks when I was working on my Honda. That was a while ago, so it's all a little fuzzy.......so there could be some outright BS in the following statements:

Normally a stack mounted on the mouth of a carb (with no air box) is a tuned length. That length determines where the peak torque happens in the rpm range. Shorter=high rpm's, longer=lower rpm's. If it's too long, it becomes essentially worthless. But since the GS has them inside the airbox, the volume of the entire box becomes part of that tuned length.

Remember- I could be 100% completely wrong in the above statements.

I think that is about right on.When I did the mods to my GS, and removed the air box,the torque did move up the power band and got narrower.Before the torque seemed to build at 3000rpm and fall off at 8500rpm.With the mods,it kicks in quick between 4000 and 4500rpm and drops off hard about 9000rpm.So maybe I should look into a different air filter in the stock box,or stick with the flat pleated filter idear I was having and add longer VS.

Sorry Rich,I just realized I flip your thread around to my bike.

What exactly are you hoping to achieve with the air box mods?Smoother power band,low end grunt,top end screamer?I'm interested to figure out how we both can benefit from this.I'm off to do more reading.

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

No problem Ben! Helps to keep the brain juices flowing......

Since I'm trying to keep this bike as functional as possible, I wanted the protection that an airbox provides. Especially from 1) water and 2) dirty air messing up the cylinders (GR parts are tough to come by!). I firmly believe that mods elsewhere will improve the bike. Weight loss around the bike, free flowing light weight exhaust, eventually a Dyna ignition, etc, should cover any kind of hindrance from a "stock" filter.

 

[ben2go]

Re: Suzuki GR650- change is in the airBOX.......

No problem Ben! Helps to keep the brain juices flowing......

Since I'm trying to keep this bike as functional as possible, I wanted the protection that an airbox provides. Especially from 1) water and 2) dirty air messing up the cylinders (GR parts are tough to come by!). I firmly believe that mods elsewhere will improve the bike. Weight loss around the bike, free flowing light weight exhaust, eventually a Dyna ignition, etc, should cover any kind of hindrance from a "stock" filter.

I understand.GR stuff is hard to find and getting pricey.These bikes will be collectors items when we retire.

 

[stroker crazy]

Re: Suzuki GR650- change is in the airBOX.......

To quote Blair and Cahoon once again:
'In design terms, one can usefully conclude that “short and fat” is best with an optimum length criterion L of one diameter.'

Rich - if you're interested in reading their paper on bellmouth design I can send you a pdf.

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

Im not one to turn down knowledge. Want my email address?

 

[stroker crazy]

Re: Suzuki GR650- change is in the airBOX.......

Rich - your email address in a pm would be fine.

Crazy

 

[Swagger]

Re: Suzuki GR650- change is in the airBOX.......

Ooh! Ooh! Me too......hehe

Rich, I like the addition of an airbox to your bike, as much as I think open element filters and stacks are cool and work fine on race bikes, I think there's some ride-ability to be had on your path. I've been thinking along the same lines for the Anachronism (yeah I know) bike....

 

[Big R]

Re: Suzuki GR650- change is in the airBOX.......

First off-line thanks Crazy for that PDF. Very informative reading. Swag: I can certainly pass it along. Let me look around for your email address.......

Sorry for not updating this like I should be. Been kind of hectic around here. I started going over the tins for a new paint scheme - but these pics are all I took. The lines on the seat are just to get an idea for shape and will be changed around shortly.......

And the paint:

I'm proud to say that I have a Shorai battery in the mail too. I wanted one for the weight savings but also because it will clear up a little space under the seat. With the airbox in it's current spot, I need to move all my electronics.

 

[t71ford]

Re: Suzuki GR650- change is in the airBOX.......


Exciting news! The tank layout and paintwork looks great, too. Stoked to see it completed. You really need to update this thread more, though...

Let us know how you like that Shorai, too! I still like mine, and its getting closer to a year old. Cold weather performance is certainly not as good, but I have found that I can pretty easy boost mine with a 2 amp charge only--without damaging the battery at all. Once warm (er than 17 degrees) it has not been a problem.

Can't wait for more!