77 GS400 to Cafe Project

Kenda K671 Cruiser ST Motorcycle Tire

41549
Front, 18" Rim, 90/90-18, Bias Ply, Tubeless, Blackwall

Kenda K657 Challenger Motorcycle Tire
41539
Rear, 18" Rim, 110/90-18, Bias Ply, Tubeless, Blackwall, H

this is what i put on my 79 gs425e....with no problems at all....around 120 for both from bike bandit........

Thanks for the info man. I had not considered that the rims would hold tubeless tires. Saved me looking for inner tubes!

Thanks
Mark

Aaaah you've encountered the wonders of skinny 18" front and rear rims! Ha!

The best bet for the front is to try to stay with 90/90-18 or 3.00-18 if you can. I have a 100/90-18 Pirelli Scorpion Trail on the front because I really wanted dual sports for the whole scrambler thing, and I can't get Shinko 244's over here which were the only ones that would fit better.

On the rear you can safely go 3.50-18, 4.00-18, 4.10-18, 100/90-18, or 110/90-18 which makes things a little easier. I couldn't get a matching rear for the front in the Scorpion Trail series but the Scorpion MT90A/T works well with the Trail front and I got a 4.10-18.

If I was doing a cafe I'd probably go Bridgestone BT45's as they do a 90/90-18 front and 110/90-18 rear or Pirelli City Demons as they do both a 3.00-18 and 90/90-18 front and a 3.50-18, 4.00-18, and 100/90-18 rear.

Also, I have a feeling you'll have clearance issues with the stock mudguard if you run that profile tyre too...

Pete, thanks for your detailed answer. My rims are both 1.85. Agree that anything wider than 90/90 on the front and I'll be struggling with a fender or chafing the bolts that hold the fender to the fork legs. I had been considering Avon Roadriders and they do have a 110/80 that may help for the rear wheel.

I just ordered an Acewell speedo/tach for replacement gauges so that I did not have to worry about messing with the speedo reading. I was going to calibrate the speedo against the speed indication from the TomTom GPS. I'm my truck the GPS reading is always 1 mph Lower. See if someone will lend you theirs for a day so you could confirm your indicated speeds.

Thanks again
Mark

Kenda K671 Cruiser ST Motorcycle Tire

41549
Front, 18" Rim, 90/90-18, Bias Ply, Tubeless, Blackwall

Kenda K657 Challenger Motorcycle Tire
41539
Rear, 18" Rim, 110/90-18, Bias Ply, Tubeless, Blackwall, H

this is what i put on my 79 gs425e....with no problems at all....around 120 for both from bike bandit........

rearsets are from omars rearsets? for ~$300 im thinking about fabbing up my own set

Zafe - Correct, The Raasks I got from Omars Rearsets @ $325. As I mentioned in the thread, they are very 70's looking but I would say if you note the mounting locations they use on the frame, you could certainly knock something up yourself

Mark

[pete]

Aaaah you've encountered the wonders of skinny 18" front and rear rims! Ha!

Went riding with a mate from work the other week... the front tyre on his 90 something CBR250RR is slightly wider than my rear tyre... ha!

Anyway, to the point... I'm going to assume like me you have the 1.60-18 front and 1.85-18 rear rims.

The best bet for the front is to try to stay with 90/90-18 or 3.00-18 if you can. I have a 100/90-18 Pirelli Scorpion Trail on the front because I really wanted dual sports for the whole scrambler thing, and I can't get Shinko 244's over here which were the only ones that would fit better.

On the rear you can safely go 3.50-18, 4.00-18, 4.10-18, 100/90-18, or 110/90-18 which makes things a little easier. I couldn't get a matching rear for the front in the Scorpion Trail series but the Scorpion MT90A/T works well with the Trail front and I got a 4.10-18.

If I was doing a cafe I'd probably go Bridgestone BT45's as they do a 90/90-18 front and 110/90-18 rear or Pirelli City Demons as they do both a 3.00-18 and 90/90-18 front and a 3.50-18, 4.00-18, and 100/90-18 rear.

One thing to watch if you do end up with a 100/90-18 front is that I'm being very cautious with my speed as the larger diameter affects the speedo ratio, so I'm not sure if it's reading accurately or if it's reading slow yet. I'm having trouble getting something accurate to compare it with.

Also, I have a feeling you'll have clearance issues with the stock mudguard if you run that profile tyre too... I'm running a modified dirtbike front guard on a home made fork brace/bracket on mine.

rearsets are from omars rearsets? for ~$300 im thinking about fabbing up my own set

Looking very very cool. I have a mind to do a retro retro euro cafe with a GS myself. I really like the megs upswept like that. Where did you get them and how much did they run? I'd be doing it on a four, but I'd like to do the same and stack them ala a Benelli Sei.

Thanks Cafe, though progress is slow! I'm happy the way it's turning out. The mufflers I found them jerryscycles.com who has lots of odds and ends mufflers
I paid $140 for the pair delivered.

Mark

Looking very very cool. I have a mind to do a retro retro euro cafe with a GS myself. I really like the megs upswept like that. Where did you get them and how much did they run? I'd be doing it on a four, but I'd like to do the same and stack them ala a Benelli Sei.

So the time has come to pick some tires to put on my cast wheels. The bike came with spoked wheels but I prefer the cast ones for the look I want. The cast wheels I have are both 18 inch from 450's. Looking at the space available between the rim and swing arm it looks like the largest tire I could fit would be 100/90 or 110/90 but that would appear to be so close. On the front 90/90 looks OK and 100/90 again pushing my luck. I would be interested to know what anyone running a 400/425/450 and 18inch rims have on.

Thanks
Mark

I like the whole look of this bike. Your vision of it is coming to fruition quite nicely. The tail lights are a perfect match for the shape of the tail section. I, too, started with an Airtech piece for my Honda XL250 project. It was intitially designed for a Matchless, but with a little modification, looks like it was made for the Honda. Looks like you might have to do what I did, and that was to stretch the seat pan area a couple inches to reach the tank. It's a very subtle modification, but looks so right after it's done. How did you get such a straight line on the leading edge of the knee dents in the tank?

Thanks nve2old. Yes I will be extending the seat area up to the gas tank. I believe the Airtech Laverda mold was based on a Lav 750 which had a long tank hence the relatively short seat. The Laverda 500 which is the design guide for my project had a longer seat so I should be able to keep the overall look I'm hoping for.

How did I get that straight line in the knee pad area?

I drew a line on the tank and used a straight edge (a rubber sanding block in this case) on the line. I bought a body hammer that had a mild point on it's ball and just tapped gently for an hour as close to the block as it would allow. It flet like nothing was happening for what seamed like 30 minutes and then the line appeared and got more defined very quickly. No need to hit the tank hard, just lots of little taps. The result was way better than I thought possible just as little patience and restraint needed.

Mark

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How did you get the line front of the banged in part to be so straight?

-Brian

[nvr2old]

I like the whole look of this bike. Your vision of it is coming to fruition quite nicely. The tail lights are a perfect match for the shape of the tail section. I, too, started with an Airtech piece for my Honda XL250 project. It was intitially designed for a Matchless, but with a little modification, looks like it was made for the Honda. Looks like you might have to do what I did, and that was to stretch the seat pan area a couple inches to reach the tank. It's a very subtle modification, but looks so right after it's done. How did you get such a straight line on the leading edge of the knee dents in the tank?

Nice to see you getting started again Mark

Let me guess about the battery tray... right in the rear in front of those new tail lights right? Haha

I like the idea with the brake/tail lights by the way, they should look well integrated with that tail piece.

......and Pete wins the prize for hide the battery!

The tail lights also integrate turn signals which will help keep the back end looking clean. Not sure what the Texas Vehicle Inspector will make of them but that's something to worry about (much) later.

Mark

[pete]

Nice to see you getting started again Mark

Let me guess about the battery tray... right in the rear in front of those new tail lights right? Haha

I like the idea with the brake/tail lights by the way, they should look well integrated with that tail piece.

That's a real nice looking build. I like the twins. So easy to work on. That bike would look really nice with a set of spoked wheels if you had them.

Sci85

Actually the bike had spoked wheels when I bought it. Cast wheels are my personal preference. As it stands, I'm thinking of having both available to switch around.

Mark