• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • Like the new V100, GuzziTech is full throttle into the future! We're now running on an all-new server and we've updated our Forum software. The visual differences are obvious, but hopefully you'll notice the super-fast speed. If you notice any glitches or have any issues, please post on the Site Support section at the bottom. If you haven't yet, please upgrade your account which is covered in the Site Support section or via the DONATE tab above, which gives you full site access including the DOWNLOADS section. We really appreciate every $ and your support to keep this site ad-free. Create an account, sign in, upgrade your account, and enjoy. See you on the road in 2024.

Wirth spring won't fit into 1000SP fork cup

tontilitis

Just got it firing!
Joined
Aug 11, 2014
Messages
2
Location
East Coast Australia
After thinking about it for years I decided to choose a one-piece Wirth spring over a new pair of long springs from the 2-piece original set-up. After frigging around for 2 days (on and off) I've decided I've ran out of cheats to fit the standard fork bottom cup to the Wirth springs.

Wirth spring OD 26.2mm, Guzzi fork cup ID 25.0mm. I managed to fit the cup on one but the other leg has got me stumped.

I could not find any info on ill fitting Wirth springs anywhere on the net so thought it was a going to be a drop in fit.

I'm so close to shaving with a bench grinder a bit of outside meat off the lower part of the spring so it will fit the cup but thought I better ask around in case it's a stupid idea eg. it will weaken the spring?.

So what has worked for others, surely I'm not the first bastard with this problem?

If I knew I was going to frig around like I have I would have just bought a Cali II spring set.... it's always greener on the other side of the fence so they say. ;)
 
I put Wirth springs in my 83 SP-NT and they fit fine, work great! Also put in Bitubo shocks, the combo really firmed up the front end.

You are right, It should be a drop-in fit, suspect you got the wrong springs for your model year somehow. I just went an dug out the stock SP springs I removed, and they measure 26+mm, like your new ones. What year is your SP, maybe there was something different? Or perhaps it isn't actually the stock front fork?

Grinding material off the new springs would be a really bad idea. You'll probably need to return them and find out what really belongs in that front fork.
 
My SP is a 1980 model, it's the last of the first series and I've had it for 17 years. The bottom fork cups were way too small for the Wirth springs, the one that fitted was not snug it was bloody tight, the other cup was impossibl to fit. Emailed Wirth and asked why they didn't fit, I waited for a reply, in the interim I recieved an IM from someone in this forum and who felt 1mm should not be a problem to shave off. So I ground the length of the cup back. Wirth returned my email and did not express any concern about me grinding off the 1mm and apologised for the added effort I ensued to fit their springs. But now I'm curious of what fork cups I have, could they have come from a small blocks forks?

The forks feel stiff, not surprising as the older spings had near 10mm sag and I was tolerating them. I fitted FAC's a long time ago which were still quite good. Replaced the steering head bearings and I can now take my hands of the bars without fear of a tank slapper :) , even with the one wheel trailer in tow!

Bottom of my Wirth springs
 
Thinking more about it, I guess a little grinding at the bottom end of the spring can't hurt much.

I've had to do similar things. and have found several weird quality problems in my bikes. On my SP, when I went to change the headset bearings, the upper bearing was pressed on so tight I had to hammer it out. Kinda hard to adjust the bearings when the upper is a tight interference fit, so had to mahine the tube down.

Hope it works out OK!
 
Back
Top