CB350 Cafe Build - Project Mjölnir

[bloodbath]

Let me begin by introducing myself; my name is Ryan and I have recently begun a CB350 project bike and I would like to seek the advice of like minded enthusiasts throughout my project.


I'll start with everyones favorite part, Pics.

The project has been ongoing but slow since I purchased the bike for $400 in September of 2010. I am a full time chemistry student and I moved home and decided to commute to school so I could build a Cafe Racer. Here is what it looks like at the moment. As of today, I am officially on summer vacation and will now be devoting all of my time to the bike.


The Tank is off of a '68 benelli mojave 360 and the block of wood came off my child hood bed fame when I moved back from college and had to disassemble it to fit in my friends jeep.

In the next week or so, I am going to start constructing a mold for a fiberglass seat and cowl as well as an upholstered leather seat. After that, I'm respoking the wheels and putting on the Pirelli sport demons I have waiting (120/90/18 and 110/90/18).

In this picture, you can see the front shock I didn't spend 8 hours sanding, filing and priming.


Let me know what you think and feel free to ask me about details I'm planning. Any advice is appreciated.

 

[Big R]

Re: College Student - First Build CB350 K4

Looks good- and welcome to DTT.

2 questions though: did you lace up wider wheels to fit those tires? Sounds like they may be a bit on the bigger side for the stock hoops. And 2: I can't see it on my phone, but how smooth is the lower section of the for tubes? I mean, the section that the seals ride on.

I really like those tanks btw.

 

[Perdition]

Re: College Student - First Build CB350 K4

Welcome! You've come to the right place. Great choice on the tank.

 

[bloodbath]

Re: College Student - First Build CB350 K4

Looks good- and welcome to DTT.

2 questions though: did you lace up wider wheels to fit those tires? Sounds like they may be a bit on the bigger side for the stock hoops. And 2: I can't see it on my phone, but how smooth is the lower section of the for tubes? I mean, the section that the seals ride on.

I really like those tanks btw.

I haven't figured out the wheel situation yet. I have seen other guys running the 120/90/18 Sport Demons before, so I am not anticipating any real problems. The bottom of the fork tubes are actually very smooth. In the first picture, what you were probably seeing is the masking tape I used to keep primer off of the fork tube. I spent an entire Saturday filing, sanding and priming the left lower leg (there isn't going to be a single casting mark on the bike).


I am planning on welding the backbone up solid and add a tubular support on both sides of the bike between the downtube and the rear tubular section of the frame, arced in a manner that will protect the carbs from being kicked.


And I love the tank as well. In my opinion, it fits the frame better than the original and the indentations on the sides (when viewed from the top) accent the shape of the cylinder heads perfectly, it almost looks bespoke to the bike.

 

[bloodbath]

Re: College Student - First Build CB350 K4


This weekend, I mocked up a seat cowl using some brake line I had lying around. Wanted to get some opinions about the shape. I am going to use the brake line as guides to cut foam into the cowl section. I am then going to skim coat the foam with body filler, course sand it and then laminate the plug with Fiber Glass and Kevlar tape reinforcements along corners and large horizontal surfaces to prevent sag.

I think its starting to take on a sporty/aggressive stance and I dig it.


My main consideration is how high the seat cowl should be. I'm not really worried about sliding off so I think the above photo compliments the bikes stance better. sorry for the cropping on the lower pic.

Also, If anyone in the west Michigan area has a set of Cl 350 pipes, I'd love to buy them.

 

[blake57]

Re: College Student - First Build CB350 K4

what i did was make it shoot to level with the tank... look at my bike.. its in my sig.

 

[RC]

Re: College Student - First Build CB350 K4

Was the mojave tank a simple drop in? Would the petcock get in the way of the tach cable?

I'm definitely watching this thread! I can tell this is gonna be an awesome build!

 

[bloodbath]

Re: College Student - First Build CB350 K4

Was the mojave tank a simple drop in? Would the petcock get in the way of the tach cable?

I'm definitely watching this thread! I can tell this is gonna be an awesome build!

Nope, and sorry for the two day reply time, it needs some modification to mount properly, but it fits the backbone fine. I am not running a tach so I haven't actually thought about it, but I will check and take detailed pictures of the frame fitment tomorrow.

 

[VonYinzer]

Re: College Student - First Build CB350 K4

Those tires are too big. Other members can explain it in much more eloquent ways, but they are too big. Its actually dangerous to run them.

Other than that it looks like a cool project man! The first seat pic looks good.

Not exactly sure what you mean about the bracing and whatnot. For a stock streetbike, welding the frame solid is plenty. Also, as far as the carbs getting "kicked", could you explain further?

 

[CBdublin]

Re: College Student - First Build CB350 K4

Well as far as tires go the 120/90/18 is fine for the stock rear as long as you dont want a rear fender... and who really does on a cafe. I have the same size, as well as some of my friends. Also a good reference is this beautiful 350 dubbed alice on here http://www.dotheton.com/forum/index.php?topic=21933.50. Now as far as the 110 on the front I know most go for the 100 but I've seen it done on a stock rim. Its more of a look preference. I like the wider tires on these bikes but some find it less "cafe" but I dare anyone to look at that bike I referenced and not call it a cafe. I would say my own as well but its not done. None the less the tire is safe with no leaks but I can only speak for the rear. Some argue there is a performance loss which is probably accurate, but unless youre taking this on a proper track I doubt anyone would notice a difference IMO

 

[Big R]

Re: College Student - First Build CB350 K4

What sizes are the stock 350 wheels? 1.6" up front and 1.85" in the rear? Those Pirelli's are made for a 2.15" wide wheel and a 2.5" wide wheel (front & rear respectively). So both tires are going to be severely pinched in the beads. At best, your handling is going to be squirrelly in the turns. At worst.....well, the tires can cause all hell to break loose.

Not trying to give a lecture, but don't want to hear of anybody falling victim to their own creation. If you don't want to pay for custom wheels (I don't blame ya), at least look for some wider wheels from another bike that will lace up.

 

[RC]

Re: College Student - First Build CB350 K4

Nope, and sorry for the two day reply time, it needs some modification to mount properly, but it fits the backbone fine. I am not running a tach so I haven't actually thought about it, but I will check and take detailed pictures of the frame fitment tomorrow.

Please do!

I'm building my bike with the Mojave tank as well and I'm interested to see how to actually mount the effin' thing!

 

[bloodbath]

Re: College Student - First Build CB350 K4


So this holiday weekend, I began to craft my seat out of fiberglass. I am going for something like what is shown in the sketch below.

So I began by covering the seat section of my frame in masking tape, making sure not to have any negative cavities, otherwise un-molding the piece would be difficult at best. I then layed down one layer of fiberglass cloth, followed by a strip of fiberglass screen, another layer of cloth, another strip of screen, and a final two layers of cloth.

The resulting part was both strong and rigid and fit snug on the frame. I was able to pry it off with little difficulty using my bare hands.

I used polystyrene, hot glue and bondo to sculpt a "plug" for under the tank.

I am going to continue to build and sculpt my seat. I am going to work on the contour of the front section of the seat and start to build the rear cowl.

The main task is going to be squaring up the sides of the seat and building an internal hardwood structure to add strength while allowing a subtle flex in the middle of the seat. Then, several more layers of fiberglass and resin followed by extensive block sanding and surface prep. Check Back for more Images Tomorrow.

 

[dean owens]

Re: College Student - First Build CB350 K4

looking good. love to see that you're putting thought into the stop hump and not just throwing something on there.

 

[bloodbath]

Re: College Student - First Build CB350 K4


So today, I waxed up the back of my Mojave tank and layered on some fiberglass to make my rear cowl.

It came off surprisingly easily and didn't even remove the break-in sticker from the tank.

Finally, here is what it looks like, untrimmed, in combination with the seat pan and tank. Tomorrow, I am going to rivet the cowl onto the seat pan and continue to sculpt/glass in the seat pan/cowl combo.

A few more days of itchy fingers and bondo will produce a pretty beefy seat. Check back tomorrow for more progress pics. I'm pulling out all the stops and getting this project done.

 

[blake57]

lookin good bro. Keep it up.

 

[moetrout]

Great job and write up! This is the stuff I need to see to motivate me to make my own seat instead of forking out a couple hundred and buying one. Sure I could find the money to make that happen, but there's no fun and a lot less satisfaction. I've never worked with fiberglass before so I need to educate myself on that first.

 

[bloodbath]

This project is still alive. Here is the smoothed out frame with all excess brackets removed. Just got it primed today. Hopefully, I will be able to get some more done before the current lull in my schoolwork ends.

 

[bloodbath]

Time to Murder this bitch out. All black, front to back. The only bit of contrast is going to be all stainless hardware and possibly some components like the gear and foot brake levers which will be polished. I'm still playing around with the full color scheme, input is appreciated.