Hey everyone,

Progress on the buggy has been slow but it's pretty much finished. I've taken it apart and painted the chassis, I just have to reassemble and do a few odd jobs and its finished!

Pic:


First I'd like to say that this engine, with those pipes, is the single loudest thing I've ever heard in my life. It boggles the mind how a 500 can sound so AWESOME! I was going to put the stock pipe on it to avoid re-jetting, but the hassle of attaching the muffler and fabbing an exhaust is probably more than re-jetting. I've decided to keep the pipes 

This buggy will be used in very dusty conditions so I'd like the best filtration possible. I've read that the K&N Lunchbox is not all that great at filtering so I've ruled that out. I'll probably just attach a K&N filter to the airbox opening, as a sort of pre-filter.

Now the question. I've read all the articles I can find on re-jetting but nobody has data about using a straight pipe exhaust (understandably). Can anyone give an educated guess as to what jets I will need to get this to run well? I'd like it to be pretty perfect or a bit on the rich side. It's a 2007 model.

Cheers,
Andrew

No idea on the jetting but what about a cooling fan? Wonder if it will overheat pushing that thing woith higher drag at lower speeds than on a bike.

And it looks great by the way

Cheers mate.

I am a bit worried about the cooling, but the oil cooler I've put on is about twice the size of the original (it's at an angle so not very visible in this photo). I suppose if it's a problem I'll put fans on the back of the oil cooler and possibly a big one in front of the engine, or on the side. I'd rather not do that though, it would spoil the look.

I'm thinking somewhere between:
20-60-140
&
22-65-145

But I really have no idea. That's just from looking at the table and guesstimating.

I wonder if the factory exhaust could be turned upside down....(or factory headers or a complete aftermarket exhaust...).
Jetting might be easier.....


I like it ...makes me want to do something like that...

As long as you've got fans on a larger oil cooler I think you'll be safe. Looks amazing, I'd love to see videos of it running. Oh yeah good choice on keeping the stock air filter, it'll keep more dirt out than the K&N and also hold more dirt before clogging.

Looks like you are doing hand throttle?  What is the weight?  You keeping those wheels and tires?  I have many more questions but those are most pertinent as of now.  Cool idea.

I think the jetting would be the same as for stock air filter (if you will be using stock airbox) plus aftermarket full-flowing exhaust.

I have one weight question though: I see that the engine is mounted on the right side of the buggy. Did you put any weight on the left side to compensate for the weight of the engine and to make this bugger more balanced??

overall very nice project!

PS. one more question: what gearing did you go with?

The driver is  the counterweight...

There was a guy on the forum a million years ago that ran the mini-sprint cars ( no wings)  that used the GS500e engine.... Grumpy Old Man Racing...if I remember correctly...

That thing looks like it will be fun.

Hey all, thanks for the comments. I'll go with the jetting for a stock filter and performance exhaust.

QuoteLooks like you are doing hand throttle?  What is the weight?  You keeping those wheels and tires?

The hand throttle is just temporarily there for testing the engine. I haven't made up the throttle cable, though I have the pieces.
Not sure about the weight. Edge quote it as being 200-250kgs, but this one is 180mm longer than standard and the engine is pretty heavy . I'm guessing around 260 kgs.
Yeah, I'll be keeping those tyres. I won't be racing it so maximum traction is not an issue, I like sliding around and drifting so those tyres should be good.

QuoteI see that the engine is mounted on the right side of the buggy. Did you put any weight on the left side to compensate for the weight of the engine and to make this bugger more balanced??
PS. one more question: what gearing did you go with?

Hehe, well the plans recommend a slightly lighter engine. The engine is counterbalanced by the 25L steel fuel tank and car battery on the other side. However, with this engine I don't think it quite does it. I've read that it's not much of an issue because of the rear suspension. It doesn't allow the buggy to lean like with independent rear suspension.

I went with a 50 tooth rear sprocket and a 14 tooth front sprocket. Should go a bit...

Cheers everyone, I'll definitely post some more pics and a video when it's all done. Won't be long now!

Andrew

Pretty sure I'll be going with these jets, unless anyone has a better idea?

20 - 62.5 - 140

Andrew, I went with K&N lunchbox with slip on exhaust. Im not sure what jets Buddah put into these carbs but im sure I have it some where.  Im running a little rich , which I think is better IMO.

And I have not noticed any issues from the off balance weight. And I have only a 1/2 tank of fuel .

I'm pretty sure I'm going with UNI pod filters and 20 - 65 - 147.5 jets. I don't really know what I'm doing though.

Argh, it's so frustrating.

Woops double post

The mid jet is just the starter jet, for cold starts. No need to change it.

You probably should raise the needle a little.
As for the main jet  Don't forget to check your fuel level via  a clear tube. Setting it as the manual states, gave me a very high level making my jetting too rich. (is this the case with your carbs too, or are mine wasted??)

start with jetting for a lunchbox and a good pipe, given that you're using a better extractor system and a worse intake system, it'll probably balance out real nice.
buy your jets second hand from your local bike shop, then be real friendly with them and bring 'em back if theyre wrong. My (former) bike shop let me swap jets with em about 4 times while i taught myself what worked well.

Generally a free flowing exhaust and stock air box only requires a richer high speed jets. When you change your intake is generally when you have to change out all the jets.

Cheers everyone, it's been a real help.

I have another few questions though. This time on UNI filters.

I have measured the carbs as needing 58mm filters. The closest size UNI have is 2.25" which is 57.15mm. Will this fit over the 58mm opening? My instinct says it will, but I thought I'd make sure.
Also, will the NU-2453 filter fit a 2007 GS? The UNI website says its for 1990-2002... Have the carbs changed size?
Lastly, with the individual pods is it worth getting the 6" long ones? Or are the 4" ones adequate? (please, no jokes lolol)

The GS filter is 3/4 of the price of the dual pods, but the pods have double layer, so I'd assume they're better in VERY dusty conditions. CAN'T DECIDE! HELP!

Quote from: lamoun on September 09, 2009, 10:09:09 AM
The mid jet is just the starter jet, for cold starts. No need to change it.
You probably should raise the needle a little.
As for the main jet  Don't forget to check your fuel level via  a clear tube. Setting it as the manual states, gave me a very high level making my jetting too rich. (is this the case with your carbs too, or are mine wasted??)

not true! older models of GS (pre 2001) had 2 circuit carbs and used only 2 jets. newer models (post 2001) have 3 circuit carbs and therefore use 3 jets.

the mid jet regulates the fuel intake in the midrange.
the pilot jet(smallest number of those 3) is responsible for cold starts.
so if you plan to ride in cold weather you'll be better off if you do change it.
it will also reduce the actual warm-up time, so I say go for it.


if you are planning to run K&N lunchbox and open pipes then 22.5 65 147.5 should work just fine.
good luck

Quote from: Beelzeboss on August 28, 2009, 05:27:45 PM
Pretty sure I'll be going with these jets, unless anyone has a better idea?

20 - 62.5 - 140

When you pick out your main jets drop me a line. I have a bunch for sale over here.

http://gstwins.com/gsboard/index.php?topic=49716.0

Quote from: kml.krk on September 10, 2009, 11:42:02 AM
not true! older models of GS (pre 2001) had 2 circuit carbs and used only 2 jets. newer models (post 2001) have 3 circuit carbs and therefore use 3 jets.

the mid jet regulates the fuel intake in the midrange.
the pilot jet(smallest number of those 3) is responsible for cold starts.
so if you plan to ride in cold weather you'll be better off if you do change it.
it will also reduce the actual warm-up time, so I say go for it.


if you are planning to run K&N lunchbox and open pipes then 22.5 65 147.5 should work just fine.
good luck

DRZ-400 has the same carb as newer models. BRS (36mm instead of 34mm)
Take a look here.

http://gstwins.com/gsboard/index.php?topic=49927.0