1981 Suzuki GN400 - Single City

[Hobie164]

I picked up a 1981 Suzuki GN400 and am tearing into it. I picked it up and rode it 40 miles home and then put another 60ish miles or so on it in the next few days so I could figure out where I wanted to head with it. With a racing background I want something fun that handles great and I can rip around town on. Here it is when I picked it up.



After a few fun days cruising and whistling at girls, who thought I was a total goober, I tore it down.

 

[Hobie164]

So while everything was off at powdercoat, polish and paint I tore into the motor to make sure all was well and replace all gaskets as well as do a little port and polish in the head, new piston and rings, and make sure the valves were all good.

 

[Hobie164]

This has all been happening over the past two weeks hence the post going up so quickly. In SoCal we haven't had much of a winter so I am trying to get this thing wrapped up quickly so I can have something to ride as the weather has been insanely nice and then start on my next build. But frame and all parts for the most part came back from plating and the reassembly begins.

 

[Maritime]

Rad, nice start. Looks like it will be a fun little scoot when you finish it up.

 

[Rich Ard]

I dig it

 

[Joe Suzuki]

Sweet! What's the spec on the tires? Vee Rubber or Heidenau in front? What's in the back? Sizes?

 

[JustinLonghorn]

Rad.

 

[Hobie164]

They

Sweet! What's the spec on the tires? Vee Rubber or Heidenau in front? What's in the back? Sizes?

Bridgestone Trail Wing TW40 Motorcycle Tire - 120/90r16 for the rear

Bridgestone Trail Wing TW40 Motorcycle Tire - 130/80r17 for the front

They both just barely squeezed in and as you can see the front has about an 1/8" on both sides. I am really excited about how it is coming together, The only major thing I have to finish is the exhaust but that should be fairly simple as it is a single!

 

[treitz]

Beautiful! Looks like the same color frame as the XS850 I'm building.

I don't think I've ever seen someone put a wider tire on the front than the rear. How do you expect that to effect handling?

 

[pjdave]

New frame section looks great. Looks fun to ride

 

[Erskine]

Indeed.

 

[Islandstar]

Nice looking bike. Where are those shocks from?

 

[Maritime]

They

Bridgestone Trail Wing TW40 Motorcycle Tire - 120/90r16 for the rear

Bridgestone Trail Wing TW40 Motorcycle Tire - 130/80r17 for the front

They both just barely squeezed in and as you can see the front has about an 1/8" on both sides. I am really excited about how it is coming together, The only major thing I have to finish is the exhaust but that should be fairly simple as it is a single!

Did the math wrong the section width is as stated 120 and 130 the section Hieghts of the 2 tires are calculated. I was having a dyslexic moment.

 

[treitz]

130/80 = 104mm width
120/90 = 108mm width Back tire is still wider then front but basically equal size front and rear for those who were wondering and thought the front was wider

Really? I did not know that. I thought the 130 and 120 represented the width. Good to know!

 

[Maritime]

Really? I did not know that. I thought the 130 and 120 represented the width. Good to know!

They do but the second number has to be used. the 90 and the 80 are percentages. But I may have screwed those up with my dyslexic brain. I need to google it to make sure LOL


Edit I did the math wrong so disregard my other statement, carry on.

 

[7aliveatlast7]

wow, i really like the new rear end you made for this thing, what a huge improvement! as far as the tire numbers go, the first number is the width, the second is a percentage of that width, and that percentage is your sidewall measurement, then the third number is the diameter. so for example, a 120/90/17 tire would be 120mm wide, the sidewall would be 108mm tall, and fit a 17 inch wheel.

 

[Maritime]

wow, i really like the new rear end you made for this thing, what a huge improvement! as far as the tire numbers go, the first number is the width, the second is a percentage of that width, and that percentage is your sidewall measurement, then the third number is the diameter. so for example, a 120/90/17 tire would be 120mm wide, the sidewall would be 108mm tall, and fit a 17 inch wheel.

Yep I had a bad brain fart on it . I used to buy tires for fleets for a living and know better. As far as this case goes it is 10 mm which won't really be noticed I bet

 

[treitz]

Yep I had a bad brain fart on it . I used to buy tires for fleets for a living and know better. As far as this case goes it is 10 mm which won't really be noticed I bet

That makes sense. Not a huge difference... I've just never seen someone use a wider tire on the front is all.

 

[Maritime]

OP can likely confirm but I am going to guess those sizes were the best he could do in that tire for his rims etc.

 

[jordanarmstrong]

Looks great so far. im interested to see what you do with the wonderful 6v system we have.