Rear shock question for the ZX7 experts | GTAMotorcycle.com

Rear shock question for the ZX7 experts

smudger

Well-known member
Morning everyone,
I'm wanting to replace the rear shock on my 1991 ZX7 but even after many hours of reading other posts I'm still not sure which way to go.
I actually missed a used Ohlins unit on EBay last week listed at $399, rather silly of me.
Usage will be track only & I'm a biggish guy at 235lbs, options:

Replace with one from a newer ZX7
Replace with one from ZX10 - but what year will fit etc.
Find a used Ohlins or similar unit - anyone got one for sale?
Have current shock rebuilt (unlikley)

I cant afford a new Ohlins/Nitron etc but would go for a used unit.
I also dont mind changing the linkage or drilling out the linkage but dont want to be modding the battery box like some have.
Any help greatly appreciated folks,
Smudger
 
Go aftermarket OEM shocks suck. Some more than others granted but all suck. The biggest issue is generally heat the cheapie OEM stuff heats up then the dampening goes away. Aftermarket stuff is much better at offering consistent action. I have an Ohlins on my current ZX7 and it works perfect. I had an old Fox twin clicker on my old ZX7 and it also worked well allowing me to get a bunch of race wins out of that bike (its still running VRRA with the same Fox still in it although I hope new owner ha done a rebuild or two over the years). Just watch the boards and wait for a decent used aftermarket unit. I got my Ohlins for $250.
 
Thanks Kneedragger.

I've been offered a "Penske shock for a '91-'95 ZX7 with 3 way adjustment, hyperpro spring, remote reservoir & the spring has been kept covered with a shock boot so it is very clean and not damaged"
The guy wants $350 & I'm just waiting on pictures of the unit but if it looks ok then that'll probably be the one I'll choose.

Whats everyone's opinion of the Penske 3 way adjustable units?

Smudger
 
Never used a Penske on the 7 but have had a few over the years on other racebikes always been happy with them.
 
Have been using a penske on my old R6 since 2012. Worked good except for once a needle(?) Fell off inside and it was like a brick. Had it rebuilt and it's been great again since
 
I am using a Penske 3-way. Great unit and excellent support directly from Penske (Mike Himmelsbach). Only issue is that it gets a bit grimy inside so that it is hard to feel the compression adjustment detents. That's when I know it is time to send it in for service (about once every 2 years). There is a Penske rep in Niagara on the Lake that services them with speedy turnaround...just having a hard time laying my hands on their contact info at the moment.

Edit: I think it is Competition Tire that services them.

360 YORK ROAD, SS #4
NIAGARA ON THE LAKE
ONTARIO L0S 1J0
CANADA
(905) 684-7418
(905) 684-1774 (fax)
 
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and use the zx9 top mount for height adjustment. its longer. jeff stephens, who bought Sanford should have a couple. If he still has the bike
 
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Thx for the advice guys but unfortunately the guy who had the Penske for sale has not sent any pictures & wont respond to my e-mails so I'm thinking its not available lol.
Sooooo, does anyone have a suitable shock for sale or know someone who may have one for sale.
Penske will make a 2 way adjustment 8983 model shock for me at $925 which TBH isn't a bad price but if I can pick up a used one I'd prefer that from a financial point of view.
Smudger
 
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Is it worth rejigging a good shock for a different bike for this sort of thing? I've got a good Fox twin clicker for a '92 F2 kicking around I could let go for cheap. Anyone know if it is the right length to fit the 7? It would need to have the bottom eye replaced with a clevis at the least. Practical idea or not? I've been curious anyway.
 
Thanks for all your help guys.
Fugue: I'm not sure if it would fit or not.

Does anyone know if a shock (Ohlins) from a '87-'90 ZX750F would fit on the 1991 ZX7 - the shock is engraved: KA7113 & V-120?
It would definately need a re-build even it will fit as its pretty tired looking but of the price is right it may be an option.

Smudger
 
With my amount of knowledge it's hard to say what would work and what wouldn't , but you have to consider the proper mount point to mount point height, the amount of body weight plus bike weight that is suspended on that shock as well. If you don't get at least those two in the proper range the shock will be worse for you then if you were to rebuild the stock one.


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Anything that is the right length with adequate stroke and proper attachments should work, if it can be revalved and resprung to correct specs for the application. In determining the specs, weight of bike and rider are important, but maybe more important is the linkage ratio of the rear suspension, and its progressiveness - those factors strongly determine what spring rate and valving is going to work. It's not a simple thing to work out from first principles and you could expect multiple rebuilds before you get it spot on. Much easier to use something designed for the specific application, or that someone else has tried and found to work.
 
Thx guys, I ended up with a Penske that came off a '91 ZX7R & fitted that after cleaning, greasing & reassembling the back end of the bike & getting a nice new Dunlop Q3 rear tire fitted.
Now I'm fitting the track bodywork, seat unit was a doddle apart for the front mounts on the tank where someone had bent them out of the way so I've bent them back in place
The upper fairing to lower fairing is causing me some greif but its more down to me than the product as this is the 1st time I've ever fitted bodywork of any kind, car or motorcycle.
Cant wait to get it finished & then see if I still have the balls to ride on the track after a 9 year absence :)
Some pics below:

View attachment 36397
View attachment 36398
View attachment 36399

It gets very cold trying to do all this in what is basically a tent ha ha
All the best, Martin
 

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