1980 Suzuki GN400 - cafe conversion

[ridesolo]

I don't know if you'll find one at a decent price but the fuel tank from the Honda CB400F (four cyl) is a good looking tank that follows that line. No idea if it could be easily adapted to the GN400 or not. The Honda CB500T tank is also one of the best looking tanks in motorcycledom, but can also be a bit difficult to find. All in all, though, I think that Duc is a good inspiration for you, great looking bike.

 

[Rider52]

I saw several Chinese replacement tanks at the WOW show that were painted similar to OEM paint schemes. One of them was the Ducati 750 style. It looked really good. I had one of the tanks a while back and I was satisfied with the quality. These are the longer tanks which remind me of the Yamaha RD60 tank. In fact, one of the tanks was painted in the RD60 style. They usually can be found at Amazon and EBay for $50-$80.

 

[Untame]

I saw several Chinese replacement tanks at the WOW show that were painted similar to OEM paint schemes. One of them was the Ducati 750 style. It looked really good. I had one of the tanks a while back and I was satisfied with the quality. These are the longer tanks which remind me of the Yamaha RD60 tank. In fact, one of the tanks was painted in the RD60 style. They usually can be found at Amazon and EBay for $50-$80.

Very cool. Looks like a crap shoot on getting one without dents. See them from India and Thailand.

 

[Untame]

Are these any good?

 

[doc_rot]

Not good, but likely adequate for this bike with a new rider. Anything will be better than the worn out stock originals. For a nicer shock for not much more money check out Hagon. Most suppliers will spring them for your weight and application when you order rather than a generic shock.

 

[Maritime]

Not good, but likely adequate for this bike with a new rider. Anything will be better than the worn out stock originals. For a nicer shock for not much more money check out Hagon. Most suppliers will spring them for your weight and application when you order rather than a generic shock.

+1 on Hagon they are good shocks for the $$$.

 

[Untame]

Not good, but likely adequate for this bike with a new rider. Anything will be better than the worn out stock originals. For a nicer shock for not much more money check out Hagon. Most suppliers will spring them for your weight and application when you order rather than a generic shock.

Thanks for the tip on Hagon. I will definitely look into them. (I did a lot of googling and didn't come up with this brand.) Besides I'm not really a fan of the remote reservoir aesthetic for my build.

 

[Maritime]

Thanks for the tip on Hagon. I will definitely look into them. (I did a lot of googling and didn't come up with this brand.) Besides I'm not really a fan of the remote reservoir aesthetic for my build.

Made in UK but have a US distributor. I got mine from Dime city cycles I think but they are on Ebay too/ https://www.ebay.com/sch/i.html?_nk...duLtEE5lyMZ6vf2efz9pVcmmXfZ0C7FIaArrqEALw_wcB

 

[Maritime]

https://hagon-shocks.co.uk/product/gn250-33012sa1/ for the 250 but would be very close.

 

[Untame]

I have been continuing to tweak the geometry, and here is what I am currently thinking for ideal handling and aesthetic:

- 19x2.15 Borrani polished aluminum rim laced on existing Suzuki front hub
- Avon Roadrider MKII 90/90-19 (25.4in diameter)
- 18x2.50 Borrani polished aluminum rim laced on existing Suzuki rear hub
- Avon Roadrider MKII 100/90-18 (25.3in diameter)
- 14in rear shocks
- Stock fork length with forks pushed up 1in and clip-ons above the top clamp
- This puts me at 27.3 degrees rake and 100mm trail

 

[Untame]

Got the Arctic Cat driveshaft bearings in over the weekend. Just waiting on sprocket shims so I can put the chaincase back together (should be here Wednesday). Then I can get the bike in the garage and start disassembly.

 

[Untame]

BTW... these Borrani rims look fantastic. I expect to get quite the learning experience lacing them up to the Suzy hubs.

 

[Maritime]

Looks good.

 

[Untame]

Anyone had custom decals made for your fuel tanks? I am thinking about getting a custom Suzuki "S" logo made as a decal to adorn the sides of the tank. Something super thin that I would clearcoat over after striping. Would be ideal if it was so thin that there was no perceptible edge after clearcoat.

 

[Maritime]

There are a few mwmbers here that do them. Sparkmoto (Matt) has hooked me up. He does switch gear, and wiring and other stuff too. Quality stuff. http://www.sparckmoto.com/ he pulled off an emegency set of Honda decals for me to save my Magna build for my boss.

 

[doc_rot]

I have been continuing to tweak the geometry, and here is what I am currently thinking for ideal handling and aesthetic:

- 19x2.15 Borrani polished aluminum rim laced on existing Suzuki front hub
- Avon Roadrider MKII 90/90-19 (25.4in diameter)
- 18x2.50 Borrani polished aluminum rim laced on existing Suzuki rear hub
- Avon Roadrider MKII 100/90-18 (25.3in diameter)
- 14in rear shocks
- Stock fork length with forks pushed up 1in and clip-ons above the top clamp
- This puts me at 27.3 degrees rake and 100mm trail

These numbers look good! You can always go to a wider tire on those rims too - ie. 100/90/19 & 120/90/18 which are the most common sizes for vintage bikes.

One other thing to consider at this point is the swing-arm. Ideally its around 11-13 degrees for good anti-squat and drive characteristics. I would guess you are in that range but you'll want to check out the chain run. As mentioned eariler you may need a chain slider. you can check this pretty easily by making temporary strut for one side with varying lengths to check chain run. Also check you have enough tire clearance in the swing-arm.

You may need a new rear sprocket as well because the larger rear wheel will change the final drive ratios. gearingcommander.com is a good resource for playing with drive ratios

 

[doc_rot]

Anyone had custom decals made for your fuel tanks? I am thinking about getting a custom Suzuki "S" logo made as a decal to adorn the sides of the tank. Something super thin that I would clearcoat over after striping. Would be ideal if it was so thin that there was no perceptible edge after clearcoat.

View attachment 238238

due to the surface tension of paint it will always raise a bit around sharp edges, so no matter how thin the decal is there will be a visible ridge. The professional way to deal with this is to cut and buff the clear after painting.

 

[adventurco]

I can cut decals here, and I have a good bit of vinyl in stock. You won’t find vinyl thin enough to not have a bit of an “edge”.

Maybe with a stencil decal and painting your design onto the tank with a couple of thin coats. Best bet is to just bury them in clear coat and wet sand it smooth once cured.

Now that I think of it, I did the stencil method on the CB360 and it worked great.


Sent from my iPhone using DO THE TON

 

[Untame]

These numbers look good! You can always go to a wider tire on those rims too - ie. 100/90/19 & 120/90/18 which are the most common sizes for vintage bikes.

One other thing to consider at this point is the swing-arm. Ideally its around 11-13 degrees for good anti-squat and drive characteristics. I would guess you are in that range but you'll want to check out the chain run. As mentioned eariler you may need a chain slider. you can check this pretty easily by making temporary strut for one side with varying lengths to check chain run. Also check you have enough tire clearance in the swing-arm.

You may need a new rear sprocket as well because the larger rear wheel will change the final drive ratios. gearingcommander.com is a good resource for playing with drive ratios

Just when I think I've got it figured out, you give me a bunch more to think about! LOL.

I had thought skinnier tires were more vintage, but I'll take your word that those sizes were most common for vintage cafe. Should I bump up the rim widths, or stick with 2.15 and 2.5?

Is the swing arm angle measured without a rider, or loaded?

I'll math those tire sizes tomorrow to see the impact on geometry.

 

[Untame]

A crazy idea I'm playing with... move the right side shock to the inside of the frame so I can tuck the exhaust in tighter to the bike. I know it would look quirky from behind, but I'm not afraid of a little quirkiness if it is in pursuit of better functionality. Kind of the spirit of original hot-rodding. For instance, some early hot rodders would swap in a Mercury steering column with column shift, then flip it 180 degrees to shift with their left hand. This was so they could keep their right arm around their girlfriend. Quirky, yes. Funcational, oh yeah.