1973 Z1-900 Radial Tire Upgrade Update

Test rode my '73 Z1-900 with those Avon Radial tires for the first time this past Sunday morning. Liked the ride and the way it corners and feels now. More like a modern bike than a 30-plus year old bike. Added a rear disk brake system too.

See my link to this project below for pictures and details. Got to fix the front calipers, one of which is dragging way too much.

Post edited by: BohicaBob, at: 2006/05/23 10:37

:sick: That green-ness comes from envy. When my Z1 grows up I hope it is just like yours!

IMHO your bike is a perfect blend of stock and new (updated). Great job.

You did a great job on that bike. Now, even though it looks like a show piece, I hope you ride it like it was made to be ridden!

Your front radial tire looks like it is a lower profile than the traditional bias ply type. Was that intentional, or did it just turn out that way? It does look good.

It would help if you would shorten the links in your sig, they are pushing the text of the posts
off into the black and making it hard to read what you and others write.

Just put an = after the url but before the bracket,
then put the actual url between the = and the backet,
then put a phrase such as "KZ1000 Stage One" after the bracket at the end of the url,
then the /url.

Like this:

'78 KZ1000 Stage I -

Post edited by: steell, at: 2006/05/23 13:11

apeman: Don't worry about me! I'm a firm believer in riding my bikes and not creating two-wheeled figurines. I've owned my '73 Z1-900 since December 1974 and it's lived in three states so far.

The radial tire upgrade was thought-out, with some consultation with experts, including Avon tires. For example, I figured how much my bike was going to be lowered by both Avon tires from the Bridgestone SE11s (19" front, 18" back) that I had on this bike before the upgrade. I chose what kind of gearing I wanted, given that: the motor will be hot-rodded in the not-too-distant future (yet again); and, the 17" Avon radial rear tire has a smaller diameter than the 18" Bridgestone SE11. Since the 17" Avon front tire has a smaller diameter than the old 19" Bridgestone SE11, I will have the speedometer overhauled, refurbished, and recalibrated, but only after I get those pesky dragging front brake calipers fixed. Maybe a pair of new Brembo calipers would be a nice fix!

Post edited by: BohicaBob, at: 2006/05/23 15:35

Bob,

Just out of curosity, what happened to the hole, for the dip stick in the chain oiler tank, that was in your side cover?

Thanks

I patched that hole ages ago, ah, to reduce drag at speed. Want to buy a bridge?

Beautiful job...love the brilliant white!
If I may ask, what are you monitoring with your third eye...I mean your third guage? :silly:
Just curious, thanks.

Post edited by: neilage66, at: 2006/05/23 18:51

My 'third eye' is focused on a VDO Oil Temperature Gauge. It's a most useful thing to have, especially on a hot-rodded, air-cooled motorcycle that lives in Florida.

Post edited by: BohicaBob, at: 2006/05/23 21:15

BohicaBob: Looks great ! I really like those excel wheel and spokes. How did you figure out what size wheel and spokes to get ? I mean, I dont know where to start to figure out how to do this to my bike.

Decided on 17" wheels because of the wider array of radial tires offered in that size in the marketplace. However ...

Before I decided on 17" wheels, I measured the distance between the top of the KZ front calipers and the stock-size 19" front rim and I mistakenly concluded that the stock calipers would be able to be removed from a 17" front wheel. Not! Ditto with the '78 KZ1000 rear caliper situation on a 17" rim. You must have at least 1.5" of clearance between the mounted caliper and the inside of the rims. 18" rims will provide this minimum clearance.

So, if you go down the 17" wheel road, be aware that the stock front and rear calipers cannot be easily removed from the wheels.

I can remove the stock front calipers, but only after removing the inside brake bad from each caliper, and after compressing the piston in each caliper. When I purchased that SS rear brake line, I got an extra long one that allows me to be able to take the whole rear wheel off without removing the SS brake line from the rear caliper. To remove the rear caliper now, I remove the four brake disk bolts and remove the caliper and disk together as a unit from the rear hub, since there is insufficient clearance to remove the caliper from the wheel with the disk on the rear hub.

Hope the above information is of use to you, should you consider such a project. Also note that my '73 Z1-900's frame is not stock, it's been braced so it can better handle the additional loads that radial tires impose, especially 'at speed.' I also use an aftermarket engine bolt kit with much stronger engine mounting plates and bolts, to help the engine act as a frame brace too.

Those 17" radial tires make for a great ride.

BohicaBob: That is helpful info if I decide to do something like this. I think I meant to ask how do I find these wheel/spokes and how do I know which ones to buy. Are they application specific ?