Hoosier Daddy
Earache my eye...
Re: della corsa CB350
Uhm..... WOW!
Uhm..... WOW!
vintage race CB350 - last 10% is the hardest
- Thread starter freedomgli
- Start date
freedomgli
Been Around the Block
Re: della corsa CB350
Here is a pic of the clutch pushrod seal retainer fitted and safety wired. I had to remove the neutral switch for it to fit. I measured the hole depth and then found a M6x1.00 bolt in my spare parts pile and took it to the grinding wheel to shorten it. You want good thread engagement but you don't want the bolt to bottom out. And wouldn't you know the bolt is stainless steel and I forgot to apply anti-seize compound so I've got to take it back out and redo it. I'll be a pro at safety wiring by the time this bike is finished!
Alternatively, you can make your own with a bit of scrap metal and a fender washer.
Here is a pic of the clutch pushrod seal retainer fitted and safety wired. I had to remove the neutral switch for it to fit. I measured the hole depth and then found a M6x1.00 bolt in my spare parts pile and took it to the grinding wheel to shorten it. You want good thread engagement but you don't want the bolt to bottom out. And wouldn't you know the bolt is stainless steel and I forgot to apply anti-seize compound so I've got to take it back out and redo it. I'll be a pro at safety wiring by the time this bike is finished!
Alternatively, you can make your own with a bit of scrap metal and a fender washer.
freedomgli
Been Around the Block
Re: della corsa CB350
More trial fitting of the steering damper. I'm considering mounting the steering damper to the head tube in front of the forks but I'm not sure there is enough clearance with CR750 fairing. It's hard to tell with so many things going on and not enough hands to hold everything in place at once.
More trial fitting of the steering damper. I'm considering mounting the steering damper to the head tube in front of the forks but I'm not sure there is enough clearance with CR750 fairing. It's hard to tell with so many things going on and not enough hands to hold everything in place at once.
freedomgli
Been Around the Block
Re: della corsa CB350
Sprocket cover shaved, drilled and sandblasted. Now it needs a good polish so it stays looking that good.
I don't have any pics yet but I did some trial fitting of the bodywork and front fairing probe and I started on the bracket to mount the fairing probe to the head tube using the weld-ons that Jon Sunter provided.
Sprocket cover shaved, drilled and sandblasted. Now it needs a good polish so it stays looking that good.
I don't have any pics yet but I did some trial fitting of the bodywork and front fairing probe and I started on the bracket to mount the fairing probe to the head tube using the weld-ons that Jon Sunter provided.
freedomgli
Been Around the Block
della corsa CB350
High crankcase pressure can build up when the motor is run at high rpm for an extended period (as in racing) if the motor isn't properly vented. The stock breather on top of the motor is insufficient for racing as some found out the hard way with race ending oil leaks. The keeper just keeps the clutch pushrod seal from becoming dislodged in the event of high crankcase pressure. It shouldn't be necessary on a properly vented motor but better safe than sorry. Combined with a vented oil filler cap I should have no worries.
I don't have stock instruments nor stock electrical wiring so no need for neutral switch. I never needed a neutral light to find neutral in all my years riding dirt bikes.
ducatiboy said:
High crankcase pressure can build up when the motor is run at high rpm for an extended period (as in racing) if the motor isn't properly vented. The stock breather on top of the motor is insufficient for racing as some found out the hard way with race ending oil leaks. The keeper just keeps the clutch pushrod seal from becoming dislodged in the event of high crankcase pressure. It shouldn't be necessary on a properly vented motor but better safe than sorry. Combined with a vented oil filler cap I should have no worries.
I don't have stock instruments nor stock electrical wiring so no need for neutral switch. I never needed a neutral light to find neutral in all my years riding dirt bikes.
freedomgli
Been Around the Block
Re: della corsa CB350
With my wedding coming up in a few weeks I haven't had much time for wrenching on the bike but I did manage to get my Honda 305 Super Hawk CB77 front hub drilled.
6 vent holes drilled in hub, 1.25 in. diameter each. I probably could have gone even bigger but it's good to be conservative and take small bites as it's harder to add material than to take it away. Hub was fixtured on tilting rotary index table. Because the hub has some curvature, we split the difference and drilled the holes at an angle of approximately 10° from vertical. The angle isn't really important. As they say, there are many different ways to skin a cat. It's just fun to think about how to do it the "best" way in your own mind. You can achieve pretty much the same results with a hole saw and a 1/2" Milwaukee power drill or by plunging straight down with your drill press. Now I just need to chamfer the edges a bit and then polish it up so I can send it out to Vintage Brake to get worked over for racing.
I also had the SL350K2 fork top bridge machined to fit my straight 35mm forks.
The SL350K2 originally came with tapered fork tubes and I wanted to use XL250 Motosport straight fork tubes. So the fork tube bore was enlarged from approximately 33mm to approximately 35mm. This allows me to adjust the front suspension ride height as I please. There was plenty of material available to make this small adjustment so there is no safety concern. Because the fork top bridge is a split clamp arrangement, it is imperative to achieve the proper fit. The lower clamp was carefully measured and the same fit was replicated for the upper clamp seen here. All it needs is a quick shot of some Alumablast paint and it will be looking better than new!
With my wedding coming up in a few weeks I haven't had much time for wrenching on the bike but I did manage to get my Honda 305 Super Hawk CB77 front hub drilled.
6 vent holes drilled in hub, 1.25 in. diameter each. I probably could have gone even bigger but it's good to be conservative and take small bites as it's harder to add material than to take it away. Hub was fixtured on tilting rotary index table. Because the hub has some curvature, we split the difference and drilled the holes at an angle of approximately 10° from vertical. The angle isn't really important. As they say, there are many different ways to skin a cat. It's just fun to think about how to do it the "best" way in your own mind. You can achieve pretty much the same results with a hole saw and a 1/2" Milwaukee power drill or by plunging straight down with your drill press. Now I just need to chamfer the edges a bit and then polish it up so I can send it out to Vintage Brake to get worked over for racing.
I also had the SL350K2 fork top bridge machined to fit my straight 35mm forks.
The SL350K2 originally came with tapered fork tubes and I wanted to use XL250 Motosport straight fork tubes. So the fork tube bore was enlarged from approximately 33mm to approximately 35mm. This allows me to adjust the front suspension ride height as I please. There was plenty of material available to make this small adjustment so there is no safety concern. Because the fork top bridge is a split clamp arrangement, it is imperative to achieve the proper fit. The lower clamp was carefully measured and the same fit was replicated for the upper clamp seen here. All it needs is a quick shot of some Alumablast paint and it will be looking better than new!
freedomgli
Been Around the Block
Re: della corsa CB350
I also fabricated a few different prototypes for the bracket that will be welded to the head tube for affixing the front fairing probe but I didn't like any of them. This entire build has been like that: I've done some things 3 or 4 times until they were exactly right. So back to the drawing board.
The latest idea is to take a piece of 1/2" thick steel plate and mill a groove on it's edge so it can straddle the seam on the head tube. This will allow me to fit the plate tightly against the frame so I can weld the bracket while staying clear of the VIN stamp on the head tube. I'll drill two holes in this mounting plate for the weld-ons provided by Jon Sunter (the weld-on lugs are just pieces of solid steel rod that have been drilled and tapped). The steering stops attached to the fairing probe seem to be designed for a bike with more fork offset than mine so the 1/2" thick plate will also allow me to affix my own adjustable steering stops (McMaster-Carr to the rescue once again!). The 1/2" mounting plate will also allow me to affix my transverse mounted steering damper ahead of the front forks.
I also fabricated a few different prototypes for the bracket that will be welded to the head tube for affixing the front fairing probe but I didn't like any of them. This entire build has been like that: I've done some things 3 or 4 times until they were exactly right. So back to the drawing board.
The latest idea is to take a piece of 1/2" thick steel plate and mill a groove on it's edge so it can straddle the seam on the head tube. This will allow me to fit the plate tightly against the frame so I can weld the bracket while staying clear of the VIN stamp on the head tube. I'll drill two holes in this mounting plate for the weld-ons provided by Jon Sunter (the weld-on lugs are just pieces of solid steel rod that have been drilled and tapped). The steering stops attached to the fairing probe seem to be designed for a bike with more fork offset than mine so the 1/2" thick plate will also allow me to affix my own adjustable steering stops (McMaster-Carr to the rescue once again!). The 1/2" mounting plate will also allow me to affix my transverse mounted steering damper ahead of the front forks.
freedomgli
Been Around the Block
Re: della corsa CB350
Yes and many other forums, too. I stopped going to CR a while back. I couldn't stand the old management anymore and I don't care for the new management, either!
I still have a Miata but it's on the back burner for a while. Saving up for new coilovers and a built motor.
gtxtom said:
Yes and many other forums, too. I stopped going to CR a while back. I couldn't stand the old management anymore and I don't care for the new management, either!
I still have a Miata but it's on the back burner for a while. Saving up for new coilovers and a built motor.
freedomgli
Been Around the Block
Re: della corsa CB350
While doing a trial assembly I discovered the forks don't fit through both the lower and upper triple clamps. This means either the either my fork tubes are bent or my triple clamps are. So now I've got to do a bunch of careful measuring with the dial indicator and v-blocks to see what the culprit is.
I'm hoping it's not the fork tubes since I've had the forks rebuilt by a local suspension specialist and I hope he would have mentioned whether the forks were not serviceable.
It's more likely that the problem is with the triple clamps themselves. I've got two sets of SL350K2 triple clamps (always good to have spares) and while neither one fits together properly, one is further off than the other. Rotating the fork tubes didn't make any difference in how they fit together.
So now I've got to decide whether to keep forging ahead with what I've already got (a friend recommended www.motorcycleframeman.com) or keep trying eBay to find a decent set of clamps that aren't bent or up the ante and get a set of fancy CB750 billet aluminum triple clamps.
While doing a trial assembly I discovered the forks don't fit through both the lower and upper triple clamps. This means either the either my fork tubes are bent or my triple clamps are. So now I've got to do a bunch of careful measuring with the dial indicator and v-blocks to see what the culprit is.
I'm hoping it's not the fork tubes since I've had the forks rebuilt by a local suspension specialist and I hope he would have mentioned whether the forks were not serviceable.
It's more likely that the problem is with the triple clamps themselves. I've got two sets of SL350K2 triple clamps (always good to have spares) and while neither one fits together properly, one is further off than the other. Rotating the fork tubes didn't make any difference in how they fit together.
So now I've got to decide whether to keep forging ahead with what I've already got (a friend recommended www.motorcycleframeman.com) or keep trying eBay to find a decent set of clamps that aren't bent or up the ante and get a set of fancy CB750 billet aluminum triple clamps.
broncoboy79
Been Around the Block
della corsa CB350
Me too. I just find those guys to be rude.freedomgli said:
freedomgli
Been Around the Block
della corsa CB350
I got some XL250 trees and they together fit fine. The only questions now are whether the stem length is ok (just eyeballing things it looks too short) and whether or not there is enough width between the fork legs to fit the CB77 drum brake. I'll find out this weekend when I get back to the workshop. I'll probably still send the SL350 yokes out to frameman to see if they can be straightened as I want to have spares ready to go just in case.
I got some XL250 trees and they together fit fine. The only questions now are whether the stem length is ok (just eyeballing things it looks too short) and whether or not there is enough width between the fork legs to fit the CB77 drum brake. I'll find out this weekend when I get back to the workshop. I'll probably still send the SL350 yokes out to frameman to see if they can be straightened as I want to have spares ready to go just in case.
freedomgli
Been Around the Block
Re: della corsa CB350
OK. So more mixing and matching and I've finally found something that will work for me. The SL350K2 lowers are fine. After some more figuring I discovered both sets of SL350K2 triple clamps I purchased from two different sellers came with the same mis-matched upper triple clamp! Such is life sometimes when you buy crusty 40 year old motorcycle parts from strangers who may or may not know what they hell they're talking about.
Anyways, I picked up a set of 1973 Honda XL250 Motosport triple clamps on eBay to see if they might help me with my triple clamp dilemma. Good news is the XL250 triple clamps are straight and true and the upper matches the lower. However, the steering stem is too short to fit my CB350 frame. Fortunately, the offset perfectly matches my SL350K2 lower triple clamp! So by mixing the XL250 upper with my SL350K2 lower I now have a direct fit 35mm setup that simply bolts on! No grinding, no need to press out the old stem to swap in the right one, no need to weld. Ahhh....... happiness.
XL250 upper clamp and forks, SL350K2 lower clamp and stem by addlightness, on Flickr
The XL250 steering stem nut is also pretty cool. It is an open nut style with a black rubber cap. I can either drill a hole in the rubber plug or simply remove it entirely, making it useful for routing a vent hose from the gas tank.
1973 Honda XL250 Motosport Top Triple Clamp by addlightness, on Flickr
So this obstacle is no more. I can keep forging ahead with the build. Big sigh of relief.
OK. So more mixing and matching and I've finally found something that will work for me. The SL350K2 lowers are fine. After some more figuring I discovered both sets of SL350K2 triple clamps I purchased from two different sellers came with the same mis-matched upper triple clamp! Such is life sometimes when you buy crusty 40 year old motorcycle parts from strangers who may or may not know what they hell they're talking about.
Anyways, I picked up a set of 1973 Honda XL250 Motosport triple clamps on eBay to see if they might help me with my triple clamp dilemma. Good news is the XL250 triple clamps are straight and true and the upper matches the lower. However, the steering stem is too short to fit my CB350 frame. Fortunately, the offset perfectly matches my SL350K2 lower triple clamp! So by mixing the XL250 upper with my SL350K2 lower I now have a direct fit 35mm setup that simply bolts on! No grinding, no need to press out the old stem to swap in the right one, no need to weld. Ahhh....... happiness.
XL250 upper clamp and forks, SL350K2 lower clamp and stem by addlightness, on Flickr
The XL250 steering stem nut is also pretty cool. It is an open nut style with a black rubber cap. I can either drill a hole in the rubber plug or simply remove it entirely, making it useful for routing a vent hose from the gas tank.
1973 Honda XL250 Motosport Top Triple Clamp by addlightness, on Flickr
So this obstacle is no more. I can keep forging ahead with the build. Big sigh of relief.
freedomgli
Been Around the Block
Re: della corsa CB350
New front end going together. All I need now is XL250 axle and then machine some custom axle spacers to center the wheel between the fork legs. Well, that's not all it needs but you get the idea.
Drum brake axle detail. Plenty of room for CB77 drum.
Paolo e Franco Tarozzi Fork Brace
The nice thing about the XL250 front end is the beefy fork brace available from Tarozzi in Italy. Finish quality on the brace isn't the best. It looks like it has a just a single light coat of flat black spray paint on it. But the build quality is spot on.
New front end going together. All I need now is XL250 axle and then machine some custom axle spacers to center the wheel between the fork legs. Well, that's not all it needs but you get the idea.
Drum brake axle detail. Plenty of room for CB77 drum.
Paolo e Franco Tarozzi Fork Brace
The nice thing about the XL250 front end is the beefy fork brace available from Tarozzi in Italy. Finish quality on the brace isn't the best. It looks like it has a just a single light coat of flat black spray paint on it. But the build quality is spot on.
freedomgli
Been Around the Block
della corsa CB350
Tarozzi lists specific part numbers for specific bike applications. They don't do it by size per se because the shape of the fork bottoms can differ so much. Go to Fast from the Past to see an application chart that includes the fork tube center to center dimensions.
Tarozzi lists specific part numbers for specific bike applications. They don't do it by size per se because the shape of the fork bottoms can differ so much. Go to Fast from the Past to see an application chart that includes the fork tube center to center dimensions.
freedomgli
Been Around the Block
Re: della corsa CB350
In October I got married, went on honeymoon, refinanced the house and bought a new car so I've been quite busy. But the dust is starting to settle and I was able to spend a little bit of time in the garage this weekend.
Finally got the front fairing stay mounted to the bike. Now I can start fitting the fiberglass bodywork. Once the fairing is drilled and fitted and I adjust the seat contour at the back to perfectly match the frame hoop then I'll be ready for paint and reassembly.
To make fitting fairing bracket easier I shaved the seam on the head tube by grinding it off, seam welding it back together and grinding it smooth again.
Here is the frame tab I made out of 1/2" steel plate to hold the front fairing stay. I know it's probably heavier than it needs to be but I wanted it to perform several jobs including mount for the steering damper and the adjustable steering stops using plastic cushioned leveling mounts typically used as furniture glides (not pictured). The front fairing stay from England has built-in steering stops but they're not adjustable and they're positioned for triple clamps with more offset so I decided to make mine adjustable.
Welding dissimilar thickness metals can be a challenge. So to spread the load and reduce the chances of burning through my head tube I first welded the frame tab to a rectangular piece of sheet metal. Then I welded the assembly to the head tube.
^^^ I had to be careful there not to damage the original VIN stamp. I'll have to play around with it a bit to see how much freedom there is in the steering damper heim joint. If need be I can always make a small clevis to change the orientation of the steering damper 90° so the bearing doesn't bind. Also, I'll probably shave the original steering damper bearing so that I have more freedom to carefully position the adjustable steering damper clamp where needed to ensure equal travel when turning left/right.
In October I got married, went on honeymoon, refinanced the house and bought a new car so I've been quite busy. But the dust is starting to settle and I was able to spend a little bit of time in the garage this weekend.
Finally got the front fairing stay mounted to the bike. Now I can start fitting the fiberglass bodywork. Once the fairing is drilled and fitted and I adjust the seat contour at the back to perfectly match the frame hoop then I'll be ready for paint and reassembly.
To make fitting fairing bracket easier I shaved the seam on the head tube by grinding it off, seam welding it back together and grinding it smooth again.
Here is the frame tab I made out of 1/2" steel plate to hold the front fairing stay. I know it's probably heavier than it needs to be but I wanted it to perform several jobs including mount for the steering damper and the adjustable steering stops using plastic cushioned leveling mounts typically used as furniture glides (not pictured). The front fairing stay from England has built-in steering stops but they're not adjustable and they're positioned for triple clamps with more offset so I decided to make mine adjustable.
Welding dissimilar thickness metals can be a challenge. So to spread the load and reduce the chances of burning through my head tube I first welded the frame tab to a rectangular piece of sheet metal. Then I welded the assembly to the head tube.
^^^ I had to be careful there not to damage the original VIN stamp. I'll have to play around with it a bit to see how much freedom there is in the steering damper heim joint. If need be I can always make a small clevis to change the orientation of the steering damper 90° so the bearing doesn't bind. Also, I'll probably shave the original steering damper bearing so that I have more freedom to carefully position the adjustable steering damper clamp where needed to ensure equal travel when turning left/right.
