Heavier rear springs

Hello, New here and 1st time motorcycle owner.
it's an 83 KZ750LTD twin in excellent condition, only 10,000 miles.
When me and my girl are on it together we occasionally bottom it out. Ive adjusted the stiffness and rebound of the shocks. Hasn't helped. Where can I get either heavier shocks or springs? 
thank you. 

YSS offers a good price-performance ratio on rear shocks!

Ikon also offers several choices, www.ikonsuspension.com/wp-content/upload...application-list.pdf



. I put a pair of Progressive shocks on my 750 twin, that were a bit stiff for me alone, but worked very well with a passenger.
 

I have RFY shocks on my KZ750 LTD, ones with an 8mm spring. They're a very cheap shock, I believe a Ohlins clone. They're made well, but can have QC issues on assembly which can be fixed with a re-assembly (mine had no such issues). I'd say they're a little too stiff - with full luggage they're perfect without any preload, so with just me they're a little too much. But a huge, huge improvement over the original springs which would dip around corners, and easily bottom out without any luggage at all.

Other options I looked at:

- Progressive suspension seems to be the preferred replacement as you can buy the shock body and spring separately to get the spring rate you want.
- Hagon are also good - most suppliers will assemble based on the bike so there's not just one overly-hard spring rate like the cheap chinese options. But not adjustable unless you get expensive ones
- YSS are similar to Hagon in that the cheaper models are pretty good for the price, built for the bike and non-adjustable.
- Harley Sportser shocks are available on ebay near-new, since many Harley riders swap out their suspension straight away.
 

I have heard that Harley Springs will fit but I wasn't sure. How would I know which ones to buy? And are they adjustable?

Thank you for all this information 

Is there a particular year or model of Harley sportster that I need to buy from? Or do I just measure from center of eyelit to eyelit?
I assume these are heavier springs?  Are they adjustable?  

Thank you 

Do I need to pull my existing springs off to get a measurement? And can I do it without a special tool? Like any sort of spring compressor?  I have no idea what kind of preload might already be on them?

It might be easier and may get better results ordering a new pair from a company that can exactly match what you need.

The problem so far is I haven't found anything that is for my bike that is listed as a heavy duty, or even having any sort of weight rating. Infact all I have found from progressive is a set of replacement springs. Not even including the shock. Maybe I'm looking in the wrong places. 

Something like the below should have enough "pre-load" adjustment on the spring to meet your needs "two up" but can be reduced when you ride solo (the adjustment only takes a few minutes if you maintain the threads on the adjusters)
 

wrote:

It might be easier and may get better results ordering a new pair from a company that can exactly match what you need.

I wish I knew which company to contact for that info.. thank you 
 

wrote:

wrote:

It might be easier and may get better results ordering a new pair from a company that can exactly match what you need.

I wish I knew which company to contact for that info.. thank you 


 

Ikon have this service as does Hagon. The YSS shocks Wookie posted above have more preload adjustment than stock type shocks {like hagon and Ikon}, the collar above the spring can be wound down to exactly where you want it to stiffen up the spring, they have a small grub screw to lock the collar off once adjusted,  they are a good shock and the correct length. Make sure you understand and know exactly what you want before buying anything... Don't be afraid to ask more questions..