'81 Honda CB650 Custom. No clue what I'm doing...

LSEmory

New Member
hello everybody,
been checking this forum out for a few years to check out what people are building and finally decided to take the plunge and picked up an '81 Honda CB650 Custom.
the first thing i should mention is that i have no clue what i'm doing. rode a motorcycle a couple of times years ago, but little to nothing about them and what i'm doing. so I'm definitely in over my head and learning on the fly.
i am a soccer player...so i decided to use the off season to make as much progress as i can. i have about a month left and the tear down will be finished today.
I've got quite a few ideas about what i want this bike to look like...but really i just want it to run and be able to enjoy it. i ordered carb rebuilding kits and started that process last night (thinking, somehow, it would be easier than it appears it will be.)
hopefully there are enough guys here that won't be annoyed with the many elementary questions i will have as i struggle through this project.
 

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realizing that, for what i'm wanting...this frame is far from ideal. anyone have any ideas on ways to modify this to make it flat so i can fit a 2-up cafe/brat seat?
 

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wrestled with the engine and frame for a bit last night...finally realizing the frame came apart and the engine comes right out. just heading out to finish it now.
 

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essentially this is what i'm going for, just with a bit longer seat. i know that what this bike looks like isn't nearly as important as how it runs and rides, but....for all the energy/money i'm going to put into it...it'd be nice if it looked decent.
 

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Welcome to the forum! We all start somewhere, and you won't be clueless by the time you're done. Just remember to search a lot before asking questions. That's really the only time people will get on your back on there.

My favorite pointer for first time builders... Label everything. Puts nuts and bolts in zip-lock bags with specific labels. Label your wires, etc. Makes for much less guessing when putting it back together.

Concerning your seat question... Modifying the frame to be flat is not simple. You would have to pay an experienced welder to modify the subframe. However there are quite a few people who have made brat style seats on that frame. Here are a few examples...

http://farm3.staticflickr.com/2853/9315479428_c260588817_b.jpg

http://s213.photobucket.com/user/2000Silverado4x4/media/CB650/2_0726_zpscf94ab88.jpg.html

http://smg.photobucket.com/user/burlymugg/media/DSC006033.jpg.html

This is accomplished by making a seat pan that follows your frame, then the seat foam is shaped to make the top of the seat flat.

Also, that reference bike is great, but it's always good to find reference bikes that are the same bike as you have. Helps you set more realistic expectations. For instance that bike has spoke wheels, yours aren't. Here are a bunch of CB650 brat style bikes: https://www.google.com/search?q=cb650+brat&safe=off&espv=2&biw=1270&bih=509&source=lnms&tbm=isch&sa=X&ei=JZKZVOidFJa5ogSKuoKIBQ&ved=0CAYQ_AUoAQ

Good luck with your build!
 
thanks hbc!

yea...i have been looking around for a few weeks now at possible solutions that wouldn't require any welding. i know i'm going to take it to someone to have a battery box fabricated and welded, so i am going to see how much it would cost to have the frame modified as well...but if its out of my budget this is my backup...

http://brothermoto.com/blogs/bikes/15095323-cx-1
 
i'm just taking inventory and seeing what parts i have that are usable and what i will need to replace.
i have been looking at pictures and trying to do as much research as possible...and one issue has me left me scratching my head.
...
air box vs pods? from everything i've read...its not straight forward by any means, but was just wondering if anyone could simplify it a bit and give me some advice. i love the look minimalistic look of cafes with the side cover removed and not much if anything at all in that space, but if not having the air box and replacing it with pods affects the performance of the bike and/or leaves me with a bigger headache down the road...
 
A huge headache, and not worth it IMO. Not just because of the performance issues, but because then you also have to move everything in that space (like the battery, etc. as you have already found). Just avoid that set of headaches for now.

It's a shame you didn't get a 1979, they have the seat you're after
 
Depends on how much more work you want to put into it :)

Anything other than your stock airbox, as previously mentioned, will require you to relocate all of those items as Plagrone said. But beyond that you will also spend a fair amount of time tuning your carbs after the swap. Large jets are necessary due to the increase in air flow.

If you're up for the challenge, by all means go for it. It certainly does improve the look of a brat style bike.
 
i run dual 34 mikunis and pods on mine

but i still had to relocate the battery as mentioned and some of the electrical components
 
i am just beginning to open the carbs to clean and rebuild them. i ordered the rebuild kits from DCC. it is the first time i've even touched carbs...so ideally i'd like to keep it as simple and as straight-forward as possible. while i much prefer the look of pods...if it makes this project impossible for me...

not only does the '81 650 custom frame make things difficult for the look i was going for in terms of seats...i've also seen some people having problems fitting pods as well. using the stock air box also makes the decision of where to put the battery pretty easy...but i really can't stand the look of the stock side covers...especially on this model.

like i said...i'm opening up the carbs tonight to see how difficult the rebuild is for me. next is the engine...a rebuild kit just came in the mail from japan. i'm pretty sure i've bit off more than i can chew, but hopefully i can get enough help to get through all of this without too many issues.
 
Frankly it doesn't sound like this is your dream bike (or the ideal bike for your desires). In which case I would recommend you built it up in the easiest, most cost effective way you can. i.e. stock air box, side covers, leave the frame stock, etc. Learn as much as you possibly can along the way. Then sell it for a little profit and buy a bike that better suites your desires for a stripped down brat style bike.
 
its not ideal, but i'm really determined to make it work. it won't turn out like the image i have in my head, but i really just want to get it up and running and be as close to what i want as i can get it for now.

one problem I'm encountering already, despite the direction i take this, is that the person i got the bike from gave it to me without the parts that connected the carbs to the air box. i've looked around...but can't for the life of me find the parts i'm looking for or really even explain what i'm looking for.
 
Intake boots is what you're looking for I think.

Maybe you should experiment with making your own side covers, that might work for you
 
i have some boots, but its the parts that are connected to the carbs and boots. whatever is covered by the piece adjacent to the side covers on the custom model.
i think i will try to experiment with some custom side covers, i've seen some people with some that look pretty decent. if i don't have to fabricate a new battery box, i can spend that time and money working on those.
 
http://www.cmsnl.com/honda-cb650-1981-usa_model7224/partslist/

Look through some of the carb/intake parts fiche and let us know what you're talking about. CMSNL is a super helpful website for people like us ;)
 
on the "air cleaner" image...
"11" is the big piece i'm missing, i believe. i have the case, "5," but whatever connects the system from the carbs to the case is missing.
 
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