My st90 got me through jr high. I loved that thing. But it was already 25 years old at that time. Then it broke and sat in a barn for 25 more years. Now my son is approaching that age, and I'm fixing it up for him. I got it running, mostly cleaned up, and it's a blast. Though it still needs work. Specifically the suspension is......soft. fFor the front end, I know what to do. I am in the process of replacing the fork seals and will refill the oil. For the rear, is replacing the shocks with stiffer shocks a thing? My central strut the coil spring goes over also has a hole worn or rusted through in it. I see that dratv has rear shocks that are stiffer and longer. Supposedly to raise the bike. I don't want it raised, just a little stiffer. Does anybody know of a decently priced shock that is the same size but a little stiffer?
I'm a noob. please help bring my childhood st90 back back to life. - rear shocks
- Thread starter Drew_P
- Start date
b52bombardier1
Well-Known Member
I put a set of shocks from Dr ATV on one of my CT90 bikes and I have been very happy with it. Its not like we have many choices here for length, stiffness and spring rate for our 50 year old bikes.
I'd take that $60 chance again on that set of Dr ATV shocks even though it says they are for a CT90. Email Jack and ask him about the fit for an ST90.
http://dratv.com/ctchreapstoe.html
Rick
I'd take that $60 chance again on that set of Dr ATV shocks even though it says they are for a CT90. Email Jack and ask him about the fit for an ST90.
http://dratv.com/ctchreapstoe.html
Rick
scooter
Well-Known Member
Length is measured with the shocks off the bike from center of bolt hole to center of bolt hole. As far as actual spring rate, I think those springs are progressive (meaning spring rate can vary with displacement). I’d just look for something that says they are applicable to the ST90 but if you need a number probably something around 85 lbs/inch for the smaller of the two rates. You might see a spring rate quoted with a slash between two numbers - they are the smaller and larger rate if the spring is progressive.
DAX-IT!!!
Member
You could try and find a place that reconditions motorcycle shock absorbers - you might pay a bit high on the price but if you want to keep it as it was and not risk taking chances on uprated/stiffer springs etc., it might be an idea worth pursuing; i'm sure there's a place over there in the States that must do that kind of thing - man, you can get anything in the USA....................... WELL, ALMOST !! 
kirrbby
Well-Known Member
If you decide you want to try these shocks that b52bombardier1 linked above, I have a set, that I'd sell cheap. They were way too stiff for me on a CT70. I'm 165lbs. Mounted them, then removed them. Basically brand new.
They might not feel as stiff on a ST90..? But I would imagine that they'd be similar, since it's a similar bike.
scooter
Well-Known Member
You could try and find a place that reconditions motorcycle shock absorbers - you might pay a bit high on the price but if you want to keep it as it was and not risk taking chances on uprated/stiffer springs etc., it might be an idea worth pursuing; i'm sure there's a place over there in the States that must do that kind of thing - man, you can get anything in the USA....................... WELL, ALMOST !!
I believe those shocks are very similar to a set of CT70 shocks and my tooling should should fit to do a rebuild if you want to keep the bike original.
I appreciate the offer. I finally got the front forks rebuilt and haven't had a chance to try it yet. I also have to keep in mind that ultimately this bike will be my kids and nephews not for me. But I'll keep you in mind.