New CB350 Project - Back Breaker

[tWistedWheelz]

Re: New CB350 Project - Ball Breaker

I am aware of the factory construction of stamped steel on the backbone and stamped steel that forms the neck of a Honda CB350 Mike, and if you read my post you will see where I offered the advise to remove all of that and replace it with steel tube to make it stronger than even the stock one would be, which does really need the reinforcement of a stronger backbone once you convert to a rigid design. I think Dave has enough info here to make an educated decision and further discussion is just unnecessary. He apparently is a skilled fabricator and has an understanding of what is needed. I am sure he is a reasonable man and will work well with the help of suggestion from others who have offered him the suggestions.

 

[dynamitedave]

Re: New CB350 Project - Ball Breaker

Thanks Brandon. I thinks been a little over blown as well. I do plan on adding some gussets later in the project. I will keep the swing arm in place. Ultimately it adds more strength since it completes a triangle and now it's going to hold the battery and the rest of the needed electronic will be placed just above the battery. The seat bars are angled because of where I wanted them mounted to the main downtube. They are welded to the wide area of the tube, directly above them the tube gets narrower. I will level the seat out with padding. I'm not planning on running a spring seat.
I'm not going to write more about the top tube. It's thick steel, fully welded, creates triangulation. I'm leaving the rest of the stamped frame in place to hold the spark plug thingies. Most of it's hidden and it's plenty strong. Once I get the mock up done I'll strip the bike, fully weld the frame, add some gussets and paint it.

 

[tWistedWheelz]

Re: New CB350 Project - Ball Breaker

Dave I think the real concern here is the fact that the factory stamped steel got its real strength from the welded creased seam, and you have eliminated that. I am not saying your design is bad, or wrong, only that you removed a good bit of strength from the stock setup. Since there is not real "tube" in the neck, remaking that area with sheet metal will never offer you good strength, especially on a rigid. I would suggest welding in a proper tube up there for the neck, then making your triangle with another piece of short tubing from the top of the new neck tube back to the backbone. This will tie it all up real nice and give you ample strength. The real problem with the factory construction of the stamped steel is its lack of strength, and without the crimped welded ridge, it is way too flimsy for your type of build. Like I said, that is just what I would do, and I think everyone who has worked on a similar project here would agree on that. It is something you may want to consider. As for the swinger end, well it does complete the triangle and if you welded in a tube piece on both sides from the bottom of the frame back to the swinger, it would also create the triangle and be more aesthetically pleasing than a swing arm. Just another suggestion though.

 

[tWistedWheelz]

Re: New CB350 Project - Ball Breaker

This is what I mean on the back end. The red will be the new piece of tube and the green (hard to see) would be a gusset that ties the triangle in tight and allows you to weld some of the cut off swing arm back to it for added strength. I think it would just look better and you could build a battery tray on the back side of the old backbone and mount other electrics to the side of it.

 

[dynamitedave]

Re: New CB350 Project - Ball Breaker

factory stamped steel got its real strength from the welded creased seam, and you have eliminated that.

I did eliminate the welded seam but I welded in flat strips to hold the 2 pieces together. You can't see it in any picture tho.

The gusset you drew in the picture is far too large and would look silly. I think if you guys could see what I really did and all the places I welded and added extra supports in person it wouldn't be an issue. I do plan on welding in a small gusset where you show it but I think the red bar is overkill unless I remove the swing arm which I doubt I will do.

 

[tWistedWheelz]

Re: New CB350 Project - Ball Breaker

Your build brother and by no means am I telling you what to do, I am only offering you suggestions. If it puts a smile on your face man, and it is safe, I am just as happy as you when it is done! I am here to offer ideas and receive them. I have learned a lot here and I only try to give back because of all I have gotten. Good on you for doing it your way man. To each his own and that is what a custom motorcycle is all about. If we built them all the same, they would not be custom at all. Keep up the work, I am very interested to see you final product!

 

[beard]

Re: New CB350 Project - Ball Breaker

i still vote no brakes period..
and the big shoes..

 

[tWistedWheelz]

Re: New CB350 Project - Ball Breaker

I'm leaving the rest of the stamped frame in place to hold the spark plug thingies.

I hope that the phrase you used "spark plug thingies" is a joke! And why not run a rear brake, all the stuff for it is still there. As far as the gusset I put on the illustration, well it was just to give you an idea. But if you think it looks silly that is your opinion and you are intitled to it, IMO a swingarm on a rigid not only looks silly but sounds silly too!

 

[dakine_surf]

Re: New CB350 Project - Ball Breaker

But if you think it looks silly that is your opinion and you are intitled to it, IMO a swingarm on a rigid not only looks silly but sounds silly too!

Bahahahaha +1

 

[dead bound]

Re: New CB350 Project - Ball Breaker

When did this turn into caferacer.net ?

Though, I would vote for a regular hardtail if it was in the poll.

 

[boisdarc]

Re: New CB350 Project - Ball Breaker

First, I love net warriors-but I've never met one in person. Having said that, I understand what you mean-a large empty void section of a traditional hard tail DOES look like crap. DRAGON from JJ always harped on that. You can fill that section with your electronics or battery or even an external oil filter or whatever. Some people(myself included) think that a non traditional hardtail made from a swing arm looks kind of lame and half way done. I think that the folks here looked at your pictures and their initial glance made them think that your hardtail is not structurally sound and they were trying to look out for your best interest. Everyone here that I have pm'ed or im'ed has been more than helpful and polite.

 

[overdraft]

Re: New CB350 Project - Ball Breaker

When did this turn into caferacer.net ?

HAHAHAHA! this made my day! i gave up over there cuz they seem to take pleasure in cutting people down.

i'm a cafe guy so i rarely roam over here, but if this is the bob and chop section then chop away! interesting stuff!

 

[fastbroshi]

Re: New CB350 Project - Ball Breaker

I doubt you're using this thing for land speed records or to rail at the track. You should be fine as long as the integrity of your welds is solid and your tires/wheels are sound. And I'm sure you're addressing the forks and steering bearings. If you were bobbing a Schwinn frame I'd be concerned however.

 

[dynamitedave]

Re: New CB350 Project - Ball Breaker

I looked at the bikes on caferacer.com. They are fugly. My bike is pretty.

I did some sheet metal work around the seat pan. I mounted the brackets that hold the electronic components that I need. I also put in some gussets.

 

[blue44067]

Re: New CB350 Project - Ball Breaker

my bike has a "half assed hard tail" too, just struts welded to my swinger and to the seat bars I really like your design. What is that tank from? One thing I've noticed with mine is that the back wheel seems to wander under the bike at high speed on gravel roads. I think its because I haven't welded the swing arm to the frame, and my struts are too small in diameter. Anyways, I like the look you've got going there.

 

[iagsxr]

Re: New CB350 Project - Ball Breaker

Considering some of what I've seen it's hard to understand why this bike started the unsafe dogpile.

SO safety dudes, assuming proper welding/fitment techniques, where's the fail point of the hardtail?

I can't tell from the pics how well the neck's tied back in. That's the much larger issue, but I get from this the OP at least understands the concept;

the backbone is welded in the neck along with added supports, it's welded to the existing pressed sheet metal frame and tied into the main structure with added support. The sheet metal I used is the same gauge or thicker than the existing sheet metal. It's much stronger than a stock frame which it needs to be since this is a hard tail.

I agree stock rake/stretched hardtaills look silly.

 

[dead bound]

Re: New CB350 Project - Ball Breaker

I looked at the bikes on caferacer.com. They are fugly. My bike is pretty.

I didn't mean anything about your bike. I meant the people on there are less than helpful when it comes to a build.

 

[dynamitedave]

Re: New CB350 Project - Ball Breaker

my bike has a "half assed hard tail" too, just struts welded to my swinger and to the seat bars I really like your design. What is that tank from? One thing I've noticed with mine is that the back wheel seems to wander under the bike at high speed on gravel roads. I think its because I haven't welded the swing arm to the frame, and my struts are too small in diameter. Anyways, I like the look you've got going there.

I think hard tails would tend to wonder on gravel most of the time. Your struts look a little narrow. I would use the same thickness tube as most of the frame. Lower rear tire pressure and a well balanced tire may help with the wondering of the tire. The tank on my bike is a stock '70-71 CB350 tank with a 2" section removed from the middle horizontally.

 

[Ringo]

Re: New CB350 Project - Ball Breaker

my bike has a "half assed hard tail" too, just struts welded to my swinger and to the seat bars I really like your design. What is that tank from? One thing I've noticed with mine is that the back wheel seems to wander under the bike at high speed on gravel roads. I think its because I haven't welded the swing arm to the frame, and my struts are too small in diameter. Anyways, I like the look you've got going there.

There could be several causes for this, but... did you replace the swing arm bushings when you got the bike? Worn bushings will give you a sloppy rear end. Welding the swing arm to the frame could help if this was your problem. Please do not deflate your tires. Underinflated tires can cause tire failure.

 

[dynamitedave]

Re: New CB350 Project - Ball Breaker

I need some parts. I am looking for a disk brake front rim with little to no rust and forks that are disk brake compatible and have little to no rust. Anyone have any extras?