Suzuki GN400 Scrambler/Cafe Hybrid

Thanks for the quick reply, guess ill look for another option. I cant stand the stock alloy wheels. It seem pretty hard to find stock hubs wheels for wire wheels. This might be stupid question but do u happen to know if any other suzuki models that came with wire wheels can bolt right up to the gn without modification?

Interesting! Thanks for the info, can't wait to see your finished product.

In fact, as far as wire wheels go... some GN400 models came stock with spoked wheels. I don't remember the model designation, but as far as I know, there is a GN400, a GN400T, and a GN400X. I just did a quick ebay check and if you search for "gn400 wheels" you'll find front and rear complete spoked wheels.

Honestly not trying to hijack this thread, but I have an '81 GN400T that had the cast wheels, but ditched them for 21" motocross hoops for my current project bike...
Just in case anyone is interested in the "build thread" -it's just a little blog, nothing fancy. GN400 kustomizers UNITE!
http://kustomgn400.blogspot.com/

Review of Sidewinder Sprockets Thread Posted

I mentioned earlier that I had a negative experience with Sidewinder Sprockets and that I would post a detailed review of this company. Sidewinder is the main reason I gave up on finishing my bike for Barber Vintage weekend, because without the sprockets they promised to deliver it wasn't going anywhere under its own power anyway.

Below is my in-depth write-up about this company; the most dishonest company I have ever encountered:
WARNING: Sidewinder Sprockets - False Claims of Made in America

Bummer about Sidewinder railroading your project. I also had a hard time finding ANYONE to make a custom front sprocket. The only advice I have is to call a company called "Rebel Gears" in Tennessee. I was able to buy a 18 tooth front sprocket (made by PBI) from them. I believe they have 1 left. I almost bought both just to have them, but I would bet it's still there as no one is buying custom sprockets for the GN except you and me. I don't know if 18 will work for you, but that's one of the only options I know of... the other would be to "make" your own. Tractor Supply has various loose sprockets available and one guy on the Yahoo Group "GN400" machined the teeth off a stock front sprocket and machined the inside of the Tractor Supply gear to match and had a welder combine them. They are hardened so the job was tough, but it can be done. Also try looking up motorcycle drag race sprocket companies. I forget the name, but if you google "offset motorcycle drag race sprockets" you may find the company I found once... they make offset countershaft sprockets for using wider rear tires for your drag bike. If anyone would know about hardened/heat treated sprockets (and modifying them) it would be those guys.
Hope this helps a little bit. -and thanks for looking out for the motorcycle community and posting the warning (very well done by the way...) about Sidewinder.

Definitely let me know what they say. It's not very often that I can actually help someone out!

I remember asking them who in the USA actually makes front sprockets and they didn't know. How is that possible? How hard could it be? Laser/Waterjet cut them out of steel, do a little finish machining, heat treat/harden. Doesn't seem like it would be that hard... Seems like everyone does rear sprockets...

Ok man...
Now I'm on a mission. Here's another place just in case:
Superior Sprockets. Located here in the USA (Oregon) 1-888-347-7267
http://www.superiorsprockets.com/
They will build you whatever you need... front/rear, whatever.

Cool!
I'm glad they still had it!
I dig your project by the way... Your craftsmanship is exemplary. -don't know if I spelled that right...

I know you will be using a mikuni carb, I was just curious if you ever looked into using the stock carb? I can't seem find much info on jetting the stock carb with pod filter.

skillz said:

I know you will be using a mikuni carb, I was just curious if you ever looked into using the stock carb? I can't seem find much info on jetting the stock carb with pod filter.

Click to expand...

I've exchanged a few emails with Jared at Holiday Customs who built the brat style Gn400 that was on Pipeburn. He said the bike required no jetting with the pod filter on the stock Carb. Says it runs great. I'm hoping I'm as lucky.

cierrecart said:

I've exchanged a few emails with Jared at Holiday Customs who built the brat style Gn400 that was on Pipeburn. He said the bike required no jetting with the pod filter on the stock Carb. Says it runs great. I'm hoping I'm as lucky.

Click to expand...

You should be fine as long as you know what to do. I have a K&N pod on my bike (stock carb) and it ran good before I started this project bike. Folks will tell you that the GN will not run well with a pod filter, but it can. The main reason I wanted to go with a Mikuni VM is because it's a slide carb and not a CV. (plus it's more adjustable) The stock carb uses a vacuum activated rubber diaphragm to raise and lower the needle. If this rubber diaphragm gets old (as they all are...) it dries out, develops pin holes, becomes thin... etc. You lose vacuum pressure with these holes and your bike runs like crap. I could pretty much read a newspaper through my diaphragm so I "fixed" it by smearing a thin layer of "Hondabond" on both sides of the diaphragm. The Hondabond remains flexable and plugs all the tiny holes so the needle raises and lowers like it's supposed to. I'm sure I've added mass to the whole assembly by applying the Hondabond so my throttle response is probably not as crisp as a shiny new carb... but as far as the jetting goes, I went to my dealer and bought an assortment of main and pilot jets. I tried probably 3 of each. To me, (right off the Blue Ridge Parkway in the mountains of Asheville, NC... anywhere from 2000 to 5000 feet above sea level) the best combination with the pod filter was the stock size pilot, and 2 sizes up on the main. There is also an air screw that is "capped" at the factory. This screw (or cap) is visible from the top of the carb. It's the little silver aluminum cap in front of the big slide cap. Poke a hole in the cap with an awl, then pry it off. You'll see a little brass screw underneath. I had to play with this screw a little, but after the pod filter, the new main and a tweak of the air screw the bike runs at least as good as it did with all the stock airbox junk. Your results may vary, but in the end... it's just a simple engine with a simple carb. I'm sure there are many carbs that would work on our bikes. In fact, over in the UK Vic Camp was putting Amal's on his SP370 race bikes which would run at 120 mph!

Anyway, all that to say... it is possible to run this engine with a pod filter.

Lots of great info....thanks!

Guess ill start with the stock and see we're that takes me! Thanks for the info!

I'm getting a GN400 for freezies but I need a manual... do you happen to have one from your build?

Search eBay for the seller e-Classic Bike out of New Zealand.


He has a lot of factory reproduction manuals for very good prices. If he hasn't got one listed, he says to message him as he has access to more.


They come printed on decent quality paper and bound with a plastic cover.

Go to this link:
http://autos.groups.yahoo.com/group/GN400/
It's a Yahoo group dedicated to the GN400. You'll have to "apply" to be in the group, but there is a ton of info there and everyone is very helpful. In the "Files" section there are a number of files that you can download for free that will result in a full manual. I've done this and combined all the files into 2 pdfs. misteroddjob is pretty much correct in that you'll need 2 manuals... the first one is for the Suzuki SP400 (not the 370) and there is a GN400 addendum to that. These 2 manuals will give you everything you need to be dangerous. I'd post them somewhere for download, but together they're over 150mb!

I remember reading a few pages back you mentioned that all of the early Suzuki GS (400, 425,450, 550, 750 & 1000) models have the same hub dimensions as the GN, so they're a bolt on swap. Does this mean that the spoke wheels from these bikes fit the GN too?

My GN came with gold mags and I hate it!

And what front disk are you using?

If you want a direct bolt-on swap, check ebay. Some models of the GN400 actually came with spoked wheels (instead of the gold cast alloy). There's always some on there.

Do you happen to know off the top of your head a capacitor that will work to replace the battery on the GN400? Mine is still 6v.

Any progress on this monster?