College Kid Cafe Racer Build

Hi Guys, I'm a college freshman majoring in mechanical engineering. I just bought my first motorcycle, a CM400T. I plan on building a cafe racer with it.
The first attachment is a picture of a cb750 that I wanna design the bike after, I like the seat and the stance on it. The other two pics are of my bike. It needs some work.
Now I've got some questions that hopefully you guys can help me with. Since the frame style is the same between the CM400T and the CX500, would the CX500 tank work on my bike? Also I've seen bikes with two rear comstar wheels, does anyone know how to make the modification to get a rear comstar wheel on the front? And when I was looking at the bike before I bought it, the clutch wouldn't go in, however the right crankcase cover wasn't tightened down all the way, would this be why?
Thanks!

There was so much fail with that first picture. Then I read the first paragraph. Then the first sentence of the second.

Stop. Just stop now.

don't run the kid off....

Comstars..... Some folks have pulled off a decent looking bike with them.... but its hard. They are ugly (my opinion) but they also crack.

Keep in mind that the picture of the bike you posted as motivation is going to be harder to ride and handle than the stock bike you have... so if you have not ridden before, everyone in here will advise you to fix it up and get it running before tearing it down again.

and for good reason.... tons of projects get started and then end up as a bunch of boxes of parts due to enthusiasm.

Dig around on the forum though... get some motivational pictures from bikes that are being ridden... pipeburn and the such often have bikes that were built artistically.

As for the clutch. The lever wont budge? If the side of the case was loose, more than likely it means that someone was in there and did not fix the problem (and made more problems).... Get yourself a manual, a box of ziplock bags and a couple of sharpies... pull the side cover off and take lots of pictures so you know where stuff went. The cable runs into the case on the other side of the clutch-pack (usually... ill admit that I have not been in that motor before... some bikes are weird).

Clutch cable pulls a small worm gear... pushes on a rod that goes through to the other side... (and a little ball bearing)... which pushes the cap on the clutch pack out to disengage it. More than likely, its just the cable though.

I assume you're looking at the cx500 tank with the knee dents? That tank will dwarf your engine. It's actually a fairly large tank.

Good advice above. Get it running. Ride it for a while. Then mod it.

Hey welcome to the forum.
I am currently in the middle of an ME degree as well. I also am building a bike.
Start with a timeline for what youd like to do first. Then triple it. I can promise the more you do the more you do.
I also agree with the other poster about the comstars. Not my style, but to each their own!
Look around this site and hondatwins.com and sohc4.net and youll find everything you'll need to know.

Alex, welcome to DoTheTon. You are an engineering student but want to build an "Art bike"? Think about it dude. Your inspiration bike is "pretty" but will function and ride like crap compared to stock. Most of the comments you receive will be well intended but probably a bit crass. Don't sweat it, build what you want but be informed. Reducing the performance of a stock machine to conform to a "Look" is not what usually gets folks excited to help in a good way. So, I salute you, dive in and learn as much as possible.

J-Rod10 said:

There was so much fail with that first picture. Then I read the first paragraph. Then the first sentence of the second.

Stop. Just stop now.

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Come on.....youre not down with the rear tire rubbing the fender all day long?? Or the fact that if you lean the bike a little it will scrape the pavement with pegs or exhaust??


To the OP,
even if you continue down the road to make you bike look like the CB in the 1st pic, you will need to seriously modify the frame of the bike because your frame is almost exactly like a CX frame, which I have done SO are your welding skills up to par? And how much $$$ do you have to put into this bike. Unless you actually have a CX deluxe/standard tank (the one with the knee dents) be prepared to pay anywhere from $150 to $250 for a tank if you find one, starting to get scarce.

Like the others have said, get your bike running right, ride it for a while and then decide (also get your wallet ready if you donut have resources or skills to fab)

ALso, your bike already has comstars on it.

J-Rod10 said:

There was so much fail with that first picture. Then I read the first paragraph. Then the first sentence of the second.

Stop. Just stop now.

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There's nothing wrong with telling it like it is.

This kid will end up with a working, good looking, better performing bike if he listens to the people here. There are experts of all shapes and sizes and more brain power than any other motorcycle forum i've even just visited.

Kid, take the advice that follows not as any sort of insult, but as motivation to do things in a controlled and correct manner so as to end up with something you can actually ride and be proud of, instead of just having something cool to TALK about.


Ok, heeeeeere we go!!

alex2445 said:

Hi Guys, I'm a college freshman majoring in mechanical engineering.

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Thanks for the warning.

alex2445 said:

I just bought my first motorcycle, a CM400T.

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Congratulations!! Did you ride it first?

alex2445 said:

I plan on building a cafe racer with it.
The first attachment is a picture of a cb750 that I wanna design the bike after, I like the seat and the stance on it.

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Whoa there.

First off you're not going to build a cafe racer from a cm400. You MIGHT get lucky and end up with something that resembles an authentic cafe bike.

Second, that cb750, aside from being a complete pile of classless, ill performing amateur crap, is not even close to a cafe racer. I don't even know what the fuck that is.

The seat is made for one riding position, the most uncomfortable one in the universe, and the stance is awesome, if you like shitty handling bikes that rub the 1929 Model A tires every time you hit a bump. If you're lucky it'll make ya crash, then you'll learn even faster than you will here. But i promise it will hurt more.

alex2445 said:

The other two pics are of my bike. It needs some work.

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Cool bike. Grab a beer soda and hang out with it for a while. Look at stuff. Leave shit alone. For now.

I really like how somebody mounted the drag bars, had to see that the controls were gonna destroy their super trick 'hookers n' dice' paint job, but just said FTW and did it anyway.

alex2445 said:

Now I've got some questions that hopefully you guys can help me with.

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OK, Shoot!!

alex2445 said:

Since the frame style is the same between the CM400T and the CX500, would the CX500 tank work on my bike?

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No to both.

alex2445 said:

Also I've seen bikes with two rear comstar wheels, does anyone know how to make the modification to get a rear comstar wheel on the front?

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Bikes with two rear wheels are called trikes. HA!

I actually like comstars, but putting a fat front tire on a cm400 is 'tarded. Leave em alone for now. Maybe even learn to ride a motorcycle before you modify it in a way that negatively affects performance.

alex2445 said:

And when I was looking at the bike before I bought it, the clutch wouldn't go in, however the right crankcase cover wasn't tightened down all the way, would this be why?

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Would this be why the owner sold it? MAYBE!!

Chances are, it's broke. Somebody maybe even like you got their 'future engineer' hands in there and didn't finish the job.

alex2445 said:

Thanks!

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No Problem!!

Nice breakdown DOHC!

Welcome aboard Alex, do heed the advice that has already been presented, there are a lot of very talented builders (both professional and home builders) on this site that will *attempt* to lead you down a path that is both safe and pragmatic. Some you may have to take with a grain of salt, but be prepared to do some homework and don't be afraid to ask questions.

Good luck!

Wow, maybe I shouldn't be on this forum....Lol jk! I'm actually going to apologize to you guys, for not giving you guys enough information right off the bat. I was about to go to a class, and didn't have a whole lot of time to give you the whole rundown. So, believe it or not, I am a bit more qualified to do this build here's why:
-I went to a career center my junior and senior years of high school for powersports small engine technology
-my junior year we went to the state FFA contest for outdoor power equipment and won 4th in state...my senior year we went again, and won 1st, and I won 1st out of the whole state.
-between my junior and senior year, I worked in a small engine repair shop and did basic maintenance and basic to advanced troubleshooting.
-I read engine theory for fun(although not lately)
-in my career center, I got best student in my lab for my junior and senior year.
-my senior projects were a paper over increasing engine performance(that I wrote first, then found citations for), and a suzuki dirt bike project(that I unfortunately ran out of time for in lab)
-I can stick weld(although it's been a while) and I can mig weld very well, I've even built shelving for a lady along with other various projects for myself.
-I have a 56" toolbox filled about halfway with tools(I know this has nothing to do with experience, but at least I have resources)
-I work for my university's research and development lab, currently working on multiple projects.
-I have read countless builds on this forum, and have enjoyed every minute of it
Now, here are some things that I don't have experience with, that you guys caught me off guard with.
-Yes this is my first motorcycle, so I have not ridden motorcycles before. I have only ridden dirt bikes, which I do realize is a different story.
-yes now that I look at that CB750 I do realize that it's more artistic than functional
-no I did not know that the comstar wheels can crack, I will certainly do more research into this.
So that's that, and if anyone wants to read my senior report on increasing motorcycle performance to kind of rate me, I'd be happy to email it to you, or post it on a forum.

Now, as for the bike. I do realize it's not the best bike to start with, but it was $450 and I thought it was an alright deal. I expected the owner to be older, but he was only a high school senior, so that's why the bike is a little bit mechanically under the weather. When I asked about the clutch, I was trying to diagnose the problem, I haven't had a whole lot of time to look at it. I know how clutches work, also. My plan is to get it running first, and gradually cafe-racer it, not just tear it all down, build it up and ride when I haven't an idea what i'm doing.
So again, I'm sorry for not providing a whole lot of information about me and my plan for this bike.

Lol - excellent catch up man. You mentioned riding dirt bikes. That puts you ahead of the game for learning to ride street bikes. You learn skills on dirt that the street doesn't always teach but are very valuable. The CM can be a great little bike, glad you are going to fix it before tearing it up.

Look forward to watching you put something together.

Step 1 to building a good bike: Stop looking at Pipeburn, and bikes that were built solely to be on Pipeburn and the likes.

If you build it to function, the looks will come with it.

I agree with a lot of what's already been posted here. Typically people show up here with a bike and expect a bunch of answers and exactly what to do and how to do it to get a desired look. Do your research, read the manual, try and figure out problems on your own and if you reach a dead end there will always be people here to help out. I am going to say most importantly that this being your first motorcycle, don't change the stance, riding position, etc. until you know how it handles and how it rides. Get her running, put some miles on it and go from there.

Same thing with swapping out parts,etc. If you want tank dents, do them yourself with a planishing hammer ($5, harbor freight) instead of buying a new tank for $200 - see my 360 build for more on that. Building a bike should be about doing everything yourself, failing a lot, and learning a lot on the way.

As far as the clutch goes, if the PO installed those handlebars without shortening the cables (which they almost always do), you probably have some loops of extra cable behind the headlight. Either find some stock bars to put back on, or invest in shorter cables (motionPro is a good source, but I make my own). Pull the side cover and make sure everything is assembled correctly and greased. Then follow the Honda Shop Manual (throw out the Clymer's) procedure for adjusting the clutch. Not sure about this particular bike, but most of these older Japanese bikes have some kind of steel ball in the clutch lifter mechanism that is easily lost and will cause the clutch not to work.

That being said, good luck, and please don't try and make this look like that CB750

Wow, I literally had to make sure I was on DTT after reading the responses!
Way to go guys!

Starting to sound like the old group on CR.

Can someone point me to where they saw a comstar crack?
Never seen that on a sohc or DOHC CB.
Maybe it is a CX or twin thing?

adventurco, I too agree with what's being said, especially had it been for someone who had no idea what a wrench even was haha. I just enjoyed the look of a lower bike(not slammed or anything), however you guys are all right, i have no idea as to how this will ride yet. My plan is now to get it running and ride it for a while, then start in on modifications. The bike did come with a clymer, however I will buy a honda manual. You guys are right, I shouldn't have asked the clutch problem, I just hadn't had a lot of time to look at it before I went back to my college, and I wanted to formulate a plan. I figure it is the crankcase cover not being torqued down, just wanted a confirmation on that theory.
The reason I wanted the cx500 tank was because the cm400t tank looks too tear-droppy to me, kinda like a chopper. I didn't want it for the knee dents, specifically. The PO did install the handlebars, not me, so I will look into the clutch cable not being short enough.

As for the whole pipeburn thing that everyone is talking about, I've read more on DTT than I have on pipeburn. That 750 was just something that I saw and kinda liked. I like the looks of a lower bike, but it won't handle well, then I will keep that in mind.

This weekend I'll be back home and will look more at the clutch and the other problems that it has.

Don't get me wrong, I'm not saying not to ask questions, its just much more productive when you've looked into it a bit and helps get to a solution. ;D You should be able to download a PDF of the manual somewhere online, they are all up somewhere all it takes is a bit of googling. The Clymer manuals have significant differences from Honda manuals, usually important stuff.

The cables should have a smooth, fluid route. Tight curves are bad for the movement and cause excessive wear to the cable itself. The GS came with handlebars 'installed' by the PO and I ended up having to shorten all the cables.

Let's keep the personal attacks to a minimum, gents.

And by minimum, I mean non-existent.

I honestly don't know how everyone here has so much time to spend on this shit, and I'm the unemployed one.

Cleaning this shit up. If anyone feels the need to puke all over their keyboards again, maybe open Notepad or something first.

Darn, missed all the crazy stuff going down..
On topic though, try looking in to a CB400T tank. Not "tear-droppy" and should fit on your frame, though you might have to fab a different rear tank mount. Shouldn't be hard if you know how to weld
If you were interested in the dual rear Comstar swap to have the same size wheels front and rear, I'd look into swapping an 18" rear Comstar from a CB400T also.
Also, welcome from another ME student!

This is a project thread - I would encourage all participants to treat it as such.

If you want to engage in general discussions about the merits of one person's education vs the other's, the laws of quantum physics, gay porn or other unrelated topics, feel free to do so in a thread you start.