77 GS400 to Cafe Project

[Zafe]

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

[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.

[Englishman]

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

[lmrmllr89]

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........

[Englishman]

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

[Englishman]

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

[lmrmllr89]

I still had to use tubes....my rims wouldn't hold valve stems unfortunately....

[Englishman]

I still had to use tubes....my rims wouldn't hold valve stems unfortunately....

Ah, that was what I kind of thinking. Thanks for clearing that up for me.

Mark

[pete]

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

You have a 1.85 front? Must be from a 550 or 650 or something...

The 100/90-18 front is ok width wise, it's the extra diameter of the tyre that I think might be the problem. It's definitely significantly taller than the 90/90...

I've tried using my work iPhone to check the speed but the iPhone is far too slow with the Speedometer App to be of reliable use.

At this point I'm thinking my wedding anniversary present in March should be an Acewell...

And yeah, these rims definitely require tubes...

[Frank Z.]

Inspired and subscribed. Very nice work.
What performance mods to the engine planned?

[Kitten Tooth]

I always like the look of a bare frame. it kinda inspires you and just the frame looks cool even without a gastank on it.

[Englishman]

Inspired and subscribed. Very nice work.
What performance mods to the engine planned?

Thanks Frank. Seeing the overall form and shape emerge over the last few months certainly keeps me going through the less glamorous phases of the project when you are just restoring metal surfaces and nothing seams to change. Things coming together at a faster rate now.

Other than getting the motor breathing easier with the pipes and K&N's + the suspension upgrades done, I have no other performance upgrades planned. Now if a pair of Yoshi cams appeared on eBay..........

Mark

[Englishman]

I always like the look of a bare frame.

Isn't there a Country Song that starts with that line?

[pete]

Thanks Frank. Seeing the overall form and shape emerge over the last few months certainly keeps me going through the less glamorous phases of the project when you are just restoring metal surfaces and nothing seams to change. Things coming together at a faster rate now.

Other than getting the motor breathing easier with the pipes and K&N's + the suspension upgrades done, I have no other performance upgrades planned. Now if a pair of Yoshi cams appeared on eBay..........

Mark

Mark I gotta tell you I'm happy with the small gains my pipe and K&N's have given my 450. The 2 into 1 seems to have dropped the sweet spot down about 500 - 1000 RPM's compared to stock and she definitely breathes easier and rev's easier than I remember, and she's not even jetted right yet.

Now, Yoshi cams... mmmm... that would be some fun!

I also just found out there *might* still be a stage 3 Dynojet kit available for my 450.... waiting with baited breath to see if the local distributor can still get one and how many limbs I have to donate to get it...

[Englishman]

I also just found out there *might* still be a stage 3 Dynojet kit available for my 450.... waiting with baited breath to see if the local distributor can still get one and how many limbs I have to donate to get it...

Pete, would an 83 kit fit your 82? There are 4 for sale on the US eBay for $85!

Mark