activpop Posted April 20, 2023 Share Posted April 20, 2023 Looking for a source for two of these bolts. They hold the driveshaft onto the male gearbox splined shaft. There is a recess on the shaft where these bolts are supposed to fall, but I encountered resistance when I took them out and I knew something wasn't right. They're stripped now so I need new ones. I know SD has them in Germany, but want to get them just a bit more local. Anybody know of a source? Is Ace really the place? Link to comment Share on other sites More sharing options...
activpop Posted April 20, 2023 Author Share Posted April 20, 2023 Also couldn't find torque settings for these bad boys...at least not in my manual. Link to comment Share on other sites More sharing options...
docc Posted April 20, 2023 Share Posted April 20, 2023 Because the split yoke spreads when not under load, consider clamping it lightly so that the bolts thread in cleanly without crossthreading. Inspect VERY CAREFULLY the threads in the driveshaft yoke(s), front and rear. I have had to "chase" those threads to clean them up, but CANNOT recommend this as my driveshaft yokes, later, failed. I can look further at my notes later today for alternate sources. Ace probably isn't the place. (More likely McMaster-Carr.) My recollection is to use the standard torque for an M8, but to tighten in steps, going back-and-forth between the two pinch bolts as tightening one will loosen the other. Link to comment Share on other sites More sharing options...
audiomick Posted April 20, 2023 Share Posted April 20, 2023 I gather you mean thes bolts? https://www.stein-dinse.biz/product_info.php?products_id=3601 https://www.stein-dinse.biz/product_info.php?products_id=214963 The cheaper of the two has a -Z on the end of the number. At SD, that means "Zubehör", i.e. from a third-party supplier, not Guzzi original (as the dearer alternative appears to be). I dare say any (good quality) standard M8 x 30 would work, not the least because of the price of the cheaper of the two. At that price, it can't be anything all too special. My gut feeling is that docc's advice about tightening the bolts is more critical than the bolt itself. Bear in mind that the bolt isn't holding a huge load, it is "only" clamping the yoke on to the shaft. It has to be in good shape, and tight enough, but that is all. Going by the pictures, the spline has the usual groove that the bolt sits in. As long as the bolt doesn't actually fall out, the yoke can't come off the spline. 1 Link to comment Share on other sites More sharing options...
docc Posted April 20, 2023 Share Posted April 20, 2023 Going back through the archives, I see these reliable contributions: @luhbo: "Make sure you use 12.9 bolts and torque them to 40Nm." And this thread, posts by @Kiwi_Roy and @raz: Link to comment Share on other sites More sharing options...
activpop Posted April 20, 2023 Author Share Posted April 20, 2023 Great info docc! I found the bolts at MC as suggested. My question about Ace being the place was said sarcastically. I don’t understand how this seems to be a recurring problem with many folks removing those two bolts. It seems to be a no brainer to line up the notched part of the gearbox spline upon reassembly, plus I don't think you could get thread purchase if it was not lined up. When I had to separate my driveshaft during disassembly, I encountered serious resistance...it was frozen together. So unknown to me at the time, my tapping the rear section off with a block of wood and mallet probably unseated the front coupling and rested the bolt thread against the rear of the shaft notch. Hence the stripping of bolt threads. The female threads probably were unscathed, but I will check. 1 Link to comment Share on other sites More sharing options...
docc Posted April 20, 2023 Share Posted April 20, 2023 I cannot seem to find the applicable thread referring to my driveshaft fasteners, but here is the image of the "low head" socket head fasteners that came out of my 2000 Sport driveshaft (right) and the replacement Moto Guzzi part (left, from August 2018) with a "normal" socket head height and apparent "blue" thread locking compound (also seen in @audiomick's Stein-Dinse link, above) . . . Considering triple the cost of the Guzzi part, I believe I could apply my own thread locker . . . 1 Link to comment Share on other sites More sharing options...
activpop Posted April 20, 2023 Author Share Posted April 20, 2023 The bolts that came out of my 2001 are the high head. 1 Link to comment Share on other sites More sharing options...
gstallons Posted April 20, 2023 Share Posted April 20, 2023 DO chase the threads on the bolt holes to be SURE they were not/are not damaged. 1 2 Link to comment Share on other sites More sharing options...
activpop Posted April 20, 2023 Author Share Posted April 20, 2023 You can be sure of that! Link to comment Share on other sites More sharing options...
audiomick Posted April 20, 2023 Share Posted April 20, 2023 4 hours ago, docc said: ... the "low head" socket head fasteners that came out of my 2000 Sport driveshaft... If there is no good reason for the "low head", space for instance, I think I would prefer the "normal" head for that application. The low heads are pretty, and perhaps sit flush with the recess in the yoke. I have, however, had issues with a low allen head bolt stripping out in the socket in the head. One case in point are the bolts holding the flange for the carbies on the V35 Imola. Low head, M6 if I remember correctly, probably 8.8. Either the ones that were in there were made of plasticine, or the head is just too low for the torque. 1 Link to comment Share on other sites More sharing options...
Tomchri Posted April 20, 2023 Share Posted April 20, 2023 Thats why I used titanium bolts. Cheers Tom. Link to comment Share on other sites More sharing options...
motoguzznix Posted May 11, 2023 Share Posted May 11, 2023 I had the case when I torqued these12.9 screws with 43Nm the joint was still a loose fit on the gearbox output shaft. To overcome this I cut the slot in the yoke some mm deeper. Works.... The flat headed screws are useless - they won't stand the torque to be applied. 2 Link to comment Share on other sites More sharing options...
activpop Posted May 11, 2023 Author Share Posted May 11, 2023 2 hours ago, motoguzznix said: I had the case when I torqued these12.9 screws with 43Nm the joint was still a loose fit on the gearbox output shaft. To overcome this I cut the slot in the yoke some mm deeper. Works.... The flat headed screws are useless - they won't stand the torque to be applied. Are you referring to the low head? 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now