Topic: 1980 cb650 few questions need help..

[antleo]

I am looking into doing a bunch of random things to this bike. starting with pod filters. I apparently have a set of cv carbs and was wondering if it is worth it to get the dynojet kit for it? I know the kit says to drill out those lift holes and im not sure i want to do that..

next i seem to be having a problem with my clutch (just assuming) When i go to get on it and i get to where the brunt of the power should be, the motor revs like it just disconnected from the wheel, and i dont exactly speed up how i should. Im assuming its time for a new set of friction plates and possibly springs?

one last question: are there any places that sell brake rotors?

My list thus far is: mac 4into1,emego pods, a gasket set, I would like oem, but will probably go with an athena kit(unless someone can suggest a good source for oem or a better brand), an oil reseal kit, ebc clutch friction plates as well as springs and brake pads/shoes, a steering bearing set, and a new seat cover..or I might make my own, im not sure yet.

[antleo]

why are pods ill advised? Genuinely curious, Id like to get rid of the stock air box to free up some room, it may go the route of cafe, im not sure. I was thinking about doing the jetting myself, but where should i start as a baseline? looking at my plugs right now i know im lean(possibly just the colder denser air). One other problem I have is i dont have the stock airbox lid( the one that actually covers the airbox, not the fancy outer plastic) right now i have a piece of steel with a  smaller hole in the middle drilled for it.

What about something like the kn rc-2362?  are those still just as bad?

http://www.knfilters.com/air_filter/1981/honda/cb650c/650

[antleo]

I understand how to do plug chops,  that's nothing new (racing motocross for 12 years)  but I was talking a baseline for after my random few mods. Such as any intake mod, and exhaust.  With my motocross bike I could normally find a baseline from someone running a similar setup and tune from there. 

What's your opinion on the kn setup?   Has anyone made a smaller airbox for the bike?  That may be a stupid question thinking of how it sits next to the battery box.

[cb650]

If your bike is a true 80 it wont have CV's     Unless someone changed the head or forced them on to the 80 head.   The carb spacing changed in 81 and went to cv's then.    The cvs have a big round top.  the 79 80 carbs look like sohc 750 carbs.  I have run pods on a couple of my 81's with out to much trouble.   On the 80 they interfered with the choke so I did keep them on.

[antleo]

I was curious about that. I'm not entirely sure, they are definitely cv carbs, but the frame is marked 80, I know my truck is a split year, so I figured it is possibly the same with the bike. Like this is a late 80 bike. But I'm not sure on that. As to the exhaust what would you suggest?  The intake is more to free up space,  but I think I should be looking at the battery more for this now that I really am looking at it.

[cb650]

post a pic of carbs and how they are mounted.

[antleo]

First disregard the dirtyness, I haven't gotten a chance to work on it or clean it up,  that's comping this week. It's getting ripped down, frame cleaned up and possibly powder coated. After doing some research I may pick up a set of slip ons of some sort, and use factory headers. New tires, fresh bearings in a few places,  freshen up the suspension etc.

Frame Stamped 9/79

It looks factory to me so I'd assume a head from an 81.

[SOHC4 Cafe Racer Fan]

Those are CV carbs. Perhaps you have a 81-82 motor swapped in.

[antleo]

I'll check my motor numbers and see. Will post back tomorrow. Motor is out of the frame and will be breaking it down some tomorrow.

[DaveBarbier]

If you're interested, I have a fairly complete seal, o-ring and gasket list on my build thread (check my table of contents for the link). I would go with OEM over an Athena kit. There aren't any kits available in OEM so you just have to search the part numbers individually.

I agree with getting a base line with the 3k mile service.

The clutch may need replacing but it could also just need adjusting. Could be too tight, pulling on the clutch slightly.

Also, if you need, I'm selling the top three covers (tappet covers and rocker covers) on eBay, as well as internal rocker cover components.

[antleo]

The clutch cable I have adjusted with a good bit of slack, as that was my first thought. And okay,  that makes sense. I'll check for each one individually gasket wise.   How much would you expect to pay for a top end set and seals?

I bookmarked your table of contents, it's very informative, I'll probably refer to it a lot. Thank you!

[DaveBarbier]

Glad to help. Just know that most of my build is a 550. I'm dropping a 650 motor in my frame this month so I'll be having more 650 stuff up there in the future.

I wouldn't know how much a top end Seal kit would cost. OEM isn't available as far as I know so I bought it all individually. More expensive than an aftermarket kit but it's worth the piece of mind, in my opinion.

[antleo]

Yeah,  that's what I was meaning,  buying individually.   And with these o rings,  would it be worth it to go to a shop and get them in perhaps a different material?  If I'm not mistaken, standard and cheapest is a viton oring

[DaveBarbier]

Cheapest would be Buna-n (nitrile, NBR). Viton is more expensive and it handles heat better. Both are good at withstanding oil. Viton (FKM/FPM) handles fuel better. Viton is a firmer rubber that has a texture to it which isn't the best for sealing in pressure situations. OEM, I don't think is viton, but I'm no expert.

For o-rings that weren't available I did go with viton where I could find it (McMaster Carr) but for the rest I used Buna N. Most hardware stores have Buna N o-rings in those kits.

Not sure that really answers your questions, haha. Try to get OEM if you can

[antleo]

That answers my question very well!  Thanks!   I guess I was wrong on the viton haha

[antleo]

What about the cam chain?  Is it possible to replace it without splitting the. Cases? Is it worth while?

[antleo]

Alright,  so I finally got my motor all apart, came apart pretty easy,  took about an hour. I'm ordering parts tonight, and cleaning everything else up until I get them. (as you can see, it's pretty dirty). The previous owner appears to have tried to stop the leak with some form of hard sealant. Possibly similar to job weld. So I chipped all that away from inbetween the fins. I took a good close look at my plugs and culture 1,3,4 all seem a little lean to me,  while 2 looks rich. They are all jetted identical, what causes this? The only other question I have at the moment, is is there washers on each head bolt? I pulled out a head bolt and a washer came out with it. The others did not. Ill have a manual with this set of parts and will be able to answer a lot of my questions.

[DaveBarbier]

Could be caused by a weak plug, old plug wires, slightly clogged jets, possibly a tiny air leak, etc.

Yes, all head bolts have washers. They're corroded and stuck in the head. I have a way to remove them which worked very well for me, check my TOC on my build thread

Looks completely normal so far for a tear down. Dirty, yes, but it'll clean up nicely. I use mineral spirits and a nylon brush because it's cheap and safe on rubber parts and paint (at least safer than acetone or carb cleaner on paint).

[antleo]

I saw that with the drill bit! I didn't know if it was all or just a few random ones. If I can't grab them with  something I'll have to try that.   Good tip in the mineral spirits! I'll try it. I may hit it with aircraft stripper as I've heard good things with that too.  I plan to repaint it while its part too (gunna end up black with stainless hardware I think)  so I'm not to worried about the paint.

Sent from my SM-G930T using Tapatalk

[scunny]

a magnet on a droopy thing works well to remove those washers, they sometimes need a wee nudge to release them from the head.

[RAFster122s]

FYI
A wooden stiff thin hardwood stick is going to allow you to give the washers a smack from a light hammer to dislodge the washers and it the tool slips it isn't going to gouge your covers or cases.

[DaveBarbier]

Just from experience in removing my stuck washers on my 650, a magnet will never work. I took a brass drift, flipped the head upside down and smacked what little lip I could of the protruding washer, not much. Didn't work. My drill method worked like a charm. Wood would have just disintegrated, haha.

My motor was left out in the elements for a few years, though. Which isn't that uncommon for the SOHC4s we buy

[antleo]

Got my orders placed today. only thing not shown is the rings from ebay.  Ill probably borrow my buddys spring compressor to remove the valves, but need my own haha. Will it be worth while to re-lap the valves? or just throw the new seals on and call it good?

[scunny]

give the valves a lap.

[DaveBarbier]

Yeah, it would be good.

I like this video from Jafromobile. It's not on a bike, but it's the same process. I like his explanation. Clear and detailed. This is assuming you've never lapped valves before. If you have, disregard .