CB360 project Daily Commuter!!!

Got my new plugs, threw em in. Now both ground straps are a lite goldish color like the last pic you posted, but with a light colored flaky scale. Insulators are very light tan. Base ring is not sooty now, but as turned dark gold in color.

My flat spot still persists, but it seems to be getting better. I have found that if I keep it at half throttle I can get up to 6k with no problems. At full WOT, if I keep it held there, it just stumbles at 4,500 and I keep it wide open and it goes right past the trouble spot. It only bogs and causes me to loose speed at 3/4 throttle. There is also a slight miss when cruising around 4,000 to 4,500. above or below is fine.

BUT!! Despite this, I went for a ride around my neighborhood and couldn't resist doing some hill climbs on the terraces where they are developing a new subdivision. This little thing gets it pretty good in the dirt!!
 

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Big Rich- they are new, Duro brand... they sure look like it tho! They were on the bike when I bought it, the PO got them from a tire shop in Oakland I think...
 
Ok, so I cleaned out my carbs again last night, and it seemed to run much better. Flat spot totally gone, awesome acceleration, freeway speed was much easier.. then I realized I had a huge vacuum leak due to one of the intake bolts working loose! Would I be completely of base with guessing that I'm over jetted and thats part of my overall running problems? I looked for numbers on the jets and saw none... it would make sense tho, as it has aftermarket exhaust that the PO out on, and I dont know what it had before... I would like to go with a short exhaust, ending about at the rear foot pegs...
 
the b ike looks great !! nice to sea the stock seat being used
but please loose those hideous, useless,clubman style bars :-\ put some standard type bars back on there, you will have much more fun and much better control of the bike
 
ShortyLaVen said:
I would like to go with a short exhaust, ending about at the rear foot pegs...

Definitely NOT a good idea. They 'like' a long system to work properly
Stock bars make front end 'light', flats probably work better, CB400f euro bars are real nice
 
Crazypj- you know I always value your opinion! How short would you go, if you were to do custom exhaust? I saw a CB360 that Kickstart Garage in Redding built, and I really like their setup a LOT. Theirs looks to end about halfway between the pivot for the rear brake lever and the rear axle. Mostly I'm more wanting the mufflers they have and am not really concerned with the exact length. Longer would be just fine, I just like the look of pipe all the way rather than the long cone with reverse cone tips.

Last night I rode to my shop (more tools there than at home) and it seemed to run great. I pulled the plug on the cylinder with the vacuum leak and this is what I got. Shouldn't it be running lean with a bad vacuum leak like that? At any rate, I pulled it all apart again to out new intake gaskets in, and I'm picking up new bolts for them as well. While I had it apart I opened the carbs up again to check my jet sizes. Some careful looking and cleaning shows 100 main and 68 pilot..
 

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It's showing a bit rich at lower throttle openings then leans out (thread base is black, insulator white)
As for exhaust, if you use small diameter it just looses a bunch of power everywhere. The 'looks good' very rarely actually works unless you're a major manufacturer with unlimited dyno time
I can pretty much guarantee all the 360's with short pipes won't go much over 80mph instead of the stock 92mph and mildly modified 105mph with decent exhaust
Do you have a link to the ones you like?
 
It does show more white in photo.. its a very light tan in person, not much different than it was before... Do those jets sound about right? The most interesting thing to me was that it ran so much better with the intake leak... other than idle it was great, and pulled as fast as I was willing to go in 5th and 6th (albeit maybe only 70mph or so, but it felt like it could go faster). The flat spot was totally, completely gone. I'm going to put it all back together tonight, I'll let you know how it goes.

Has for exhaust, here's the bike I liked. I really dont want to kill the performance of this thing, so I'm completely open to ideas and input.
 

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They will work, but not at that length. You will need bigger secondary main jets, no idea on size though with stock air boxes (maybe start at 105?)
Bike probably runs real shitty, cheap pods, too short exhaust, no fork brace I can see (33m forks REALLY need for brace)
Have you re-set fuel screw to 3/4~1 turn out? Aftermarket cab kits have a much 'richer' needle than stock Honda. The pilot (slow) jets are also a different size to genuine Kei-Hin
 
I started with srews 1.5 turns out.. I didn't make it to the shop last night, but I'm headed there right after work. Are the aftermarket jets parts of my problem? I have seen a few jet kits on ebay for cheap, maybe I'll pick one up.

Do you know what size O-ring is used for the bowl gasket? One of them split when I removed the bowls this time. I was hoping to steal one from work (we have a big selection)

Im still looking for the "right" mufflers I want.. I'm totally good with having my pipes longer tho. Maybe even a nice kick up at the back too, so they end above the level of the rear axle (like the stock lines but without the huge mufflers).
 
Crazypj- I found a post on hondatwins where you mentioned 70mmx2mm.. I found some here that are 2.75"x1/16" and 2.75"x3/32"... im gonna try both and see which ones fit better.
 
That must be a real old post, I don't remember it ;D
With fuel screws, out is richer, in is leaner
 
The 2-3/4 x 3/32 worked like a charm! Got it back together and running now. There still seems to be a vac leak, but it is somewhere ob the carb body, not the intakes. Not on the throttle shafts, and not around the diaphragm... I'll have to investigate more tomorrow. But it does return to idle a lot faster now! There is a slight pop/miss when idling but runs great otherwise.
 
Tops of carbs are often distorted, I think I posyed pictures of it.
If not, Trek97 probably has the info posted, shoot him a pm
 
Did some more testing, its nit the carb tops... you think there could be a crack in the body or something? Im thinking more about getting some Mikunis for this thing. I heard 28 or 30mm? If I went that route, are they pretty easy to get "right"?
 
Actually, stock is easiest to get right as Honda set them up already. However, if you are modifying the engine, intake and exhaust, then it is a different animal.

Unless you are racing, stick to the 28's. The smaller carb will have better driveability, IE: off idle, and part throttle response. Too much carburetor make idle and mid-rage difficult to tune.

Tuning any carburetor to a custom setup motor is always going to take quite a few sets of plugs and some time. It is trial and error.
 
I do definitely plan on custom exhaust. But I would prefer to keep the stock air boxes, or at least the side covers if I go with aftermarket filters. Just my personal taste, I dont like the emptyness with pods and battery box removed.

I noticed some other things I dont like either. The goop around the head cover (I mentioned it in a 1-800-Cafe-help thread) started to leak oil pretty bad. Winter is right around the corner, though, so I am planning on a complete tear down. Today I met some old timers that live in the area that are going to lend a hand. The way they put it was "parts are cheaper if you dont break em first." And it makes sense to me. I got the time, and this thing probably has 20k miles on it, so I might as well freshen it up while its still in fair condition. My best friend also picked up basket case CB450 that he's going to rebuild simultaneously.

So, onward ho!
 
Stock carbs are best for most situations, I use them on 120mph 378cc motors.
Got several sets on Mikuni's but they are a b**** to set up properly (I'm not in the majority who settle for 'close enough', I'll ride around the problems)
The smaller sizes work better than the bigger ones, I use 26~28mm with Yamaha RD250/350 (air cooled, reed valve) emulsion tubes, or, make my own emulsion tubes
Haven't put any effort into 'fixing' Mikuni's since I worked out what works for stock carbs (still have some experiments to try with stock ;) )
 
I'm running stock Keihin carbs that were modded by PJ with a MAC 2-into-1 exhaust. I hit 103 today, which so far is the best I've been able to do. Get the setup right and these carbs will do the job. Put the money in modding what you have and the right exhaust instead of a new set of Mikunis.
 
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