TOPIC:

Yeah, my big Webike.japan order come in, pretty fast, only 5 days from order to delivery from JAPAN..

Below is the order:

PMC S1 low style bars.
PMC Heavy Duty engine mounts.
Adjustable SS side stand.
NHK S1 style steering damper.
Digital GPS Speedometer.

That side stand is very high quality, fully machined.

577nitro.

gpz looks good!
i have been very pleased with my 17 " wheel conversion on my 1980 z1r.
it is very stable at speed and in corners.so much so that a hiway patrolman caught my tipping up out of a corner at 89mph.
fortunately for me he caught me when he did,as i was just grabbing a hand full of throttle and was fixing to gobble up a straightaway




leon

Updating on latest incarnation, I've now fitted a ZRX1100 rear swingarm with a 20mm through bolt up grade. Bored and reamed the frame for a tight no slop fit; used a ZRX1100 rear axle which fit perfectly. I milled the thread end back to fit the 17mm hole and be as tight as possible. Also milled down the head of the bolt so it didn't look funny. It was NOT as straight in fit, I had to mill down the end shims about 2mm so it would snuggly. Also had to file back the swingarm a little too. Pretty happy with the results so far...should handle a lot better without the slop. I had to shim out the S1 style rear sets on the right side to clear the swingarm. Next up is a mounting the S1 replica bars. Probably looking at dropping in a set of performance street cams...nothing too wild at this point. Been looking for a late model bathtub head, but they are rare.

Ride report and update..

So I now have a full summer of riding on the GPZ1100 with suspension upgrades...wow what a difference! I LOVE riding this bike! I used it to commute to
work about 70% of time this summer, and have put at least 5000 miles on it. I ride 600 miles a week commuting, about 60 miles one way on back country roads.
Needless to say I really let're eat on some sections....rock ass solid at 100+ no problems. No slappers, wobbles, pogoing...nothing just stable as can be. Power is wonderful now that I have the Mikuni RS34's dialed in as well. It will pull redline in every gear...roll on is massive no need to downshift. It easily is making the same power as my ZRX1100.

Here is what my current suspension mods are sitting at:

1. ZRX1100 rear swingarm with 20mm through bolt (zrx1100 rear axle) upgrade, hole reamed slightly tight for zero slop per Dr. Gamma advice.
2. 1986 GSXR1100 front and rear wheels, for a 4.0 inch rear with a 150 mounted and a 2.75 front with a 110 mounted.
3. Critical step here..front and rear wheels perfectly aligned < than a 1mm off. They were at least 1 cm off when I first checked it! This is key to fixing slappers.
4. NHK high end steering dampener.
5. S1 style lower triple clamp from Motogp. Stiffened the forks.
6. ZRX1100 rear shocks overhauled by DMR Jamie Daughtery << great guy.
7. Installed RaceTek Cartridge emulators both forks with O rings for a tight fit..1.5 clicks in. per side.
8. RaceTek fork springs.
9. Critical point here, multiple weeks testing the perfect fork oil mixture for this setup. For me 20ml ATF with seal conditioner, 30ml 75-120w synthetic gear oil (for rebound), then the remaining 10-30w synthetic motor oil. Also 10psi air per fork. For more rebound add the gear oil in 10ml increments. Caution this only works in ancient NON cartridge forks. I use this same basic formula in my RZ350 also...works perfect.
10. Change the fork oil often, dirt and grit contaminate it causing leaking seals. I found a way to change the GPZ1100 fork oil in about 15 minutes. I use a an old Hyperlube bottle which as a cone sprout. It fits perfectly into the air valve hole (remove the valve) and I have pre measured the oil and just let drain in. cap it and use a bicycle hand pump to put 10psi in per side. ..and Bobs your uncle.
11.Lasty, a Fork Brace.

Before modifying the forks like above, they were worthless...bottomed on braking, zero dampening down right dangerous. Now, they work like modern forks, fork travel is around 3.5 to 4 inches max..no bottoming, no diving on hard braking, and great rebound dampening. They are far less harsh than my ZRX, that just beats me to death. I can go over a real bumpy patched road surface at speed 90+ and it just floats over it...never gets upset. I tried Dr. Gamma's trick of slapping the bars ar speed to try and induce wobbles and nothing...I did this at about 65mph...not 90 like he does..not that brave..

Ride report and update..

So I now have a full summer of riding on the GPZ1100 with suspension upgrades...wow what a difference! I LOVE riding this bike! I used it to commute to
work about 70% of time this summer, and have put at least 5000 miles on it. I ride 600 miles a week commuting, about 60 miles one way on back country roads.
Needless to say I really let're eat on some sections....rock ass solid at 100+ no problems. No slappers, wobbles, pogoing...nothing just stable as can be. Power is wonderful now that I have the Mikuni RS34's dialed in as well. It will pull redline in every gear...roll on is massive no need to downshift. It easily is making the same power as my ZRX1100.

Here is what my current suspension mods are sitting at:

1. ZRX1100 rear swingarm with 20mm through bolt (zrx1100 rear axle) upgrade, hole reamed slightly tight for zero slop per Dr. Gamma advice.
2. 1986 GSXR1100 front and rear wheels, for a 4.0 inch rear with a 150 mounted and a 2.75 front with a 110 mounted.
3. Critical step here..front and rear wheels perfectly aligned < than a 1mm off. They were at least 1 cm off when I first checked it! This is key to fixing slappers.
4. NHK high end steering dampener.
5. S1 style lower triple clamp from Motogp. Stiffened the forks.
6. ZRX1100 rear shocks overhauled by DMR Jamie Daughtery << great guy.
7. Installed RaceTek Cartridge emulators both forks with O rings for a tight fit..1.5 clicks in. per side.
8. RaceTek fork springs.
9. Critical point here, multiple weeks testing the perfect fork oil mixture for this setup. For me 20ml ATF with seal conditioner, 30ml 75-120w synthetic gear oil (for rebound), then the remaining 10-30w synthetic motor oil. Also 10psi air per fork. For more rebound add the gear oil in 10ml increments. Caution this only works in ancient NON cartridge forks. I use this same basic formula in my RZ350 also...works perfect.
10. Change the fork oil often, dirt and grit contaminate it causing leaking seals. I found a way to change the GPZ1100 fork oil in about 15 minutes. I use a an old Hyperlube bottle which as a cone sprout. It fits perfectly into the air valve hole (remove the valve) and I have pre measured the oil and just let drain in. cap it and use a bicycle hand pump to put 10psi in per side. ..and Bobs your uncle.
11.Lasty, a Fork Brace.

Before modifying the forks like above, they were worthless...bottomed on braking, zero dampening down right dangerous. Now, they work like modern forks, fork travel is around 3.5 to 4 inches max..no bottoming, no diving on hard braking, and great rebound dampening. They are far less harsh than my ZRX, that just beats me to death. I can go over a real bumpy patched road surface at speed 90+ and it just floats over it...never gets upset. I tried Dr. Gamma's trick of slapping the bars ar speed to try and induce wobbles and nothing...I did this at about 65mph...not 90 like he does..not that brave..

Sweet ride!

Great looking bike!!!!!

Isn't fun riding a bike you know won't try to spit you off at the most inopportune moment!!!!

Nice looking bike, very nice. And it's a brave man that tries to induce instability by whacking a handlebar end especially at high speed!

Rick H.

Rick H. wrote: Nice looking bike, very nice. And it's a brave man that tries to induce instability by whacking a handlebar end especially at high speed!

Rick H.

Thanks...yeah I started lightly on the whacking of the bars...and worked up to harder hits, so I knew basically how it was going to react. I would never have tried it in stock form.

So a question to those who have done the ZRX swingarm upgrade...because of the lower bracing I had to cut the Kerker pipe just past the collector and then fabricate a new curved section to clear the swingarm. I bought some 2.5 inch exhaust pipe off ebay and then made the flanges to fit it. It was bitch and took a lot of working and fitting to get it to clear. I tried to get a shop to help me but nobody wanted to try...too small a job or to scared... Did anybody have similar issues and how did you solve it?

The gsxr wheels looks great on there. I have deal with simular exhaust problems before. I usually just buy a mandrel bend and play around with slices of it till i get the clearance i need. then welder up. masking tape does a surprisingly good job of holding the pieces if you wrap it super tight all the way round.

What an inspiring project. I just started stripping the Mrs' GPz11 just Saturday. This build has given me a bunch of ideas. Thanks OP!