'74 CB360 cafe/fighter-ish project

Well, I have to strip the por-15 out of the tank, so I'm going to strip down the outside, too. I'm going to spray it black like the original tank was. Good thing its raining this week, I hate down down time on nice days.

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dp9 said:

Damn, I love the look. Oh well. What're some good, reasonably priced tires? I haven't even started to look at any yet, but want to get them soon.

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I'm looking at some DURO, they do a Dunlop TT100 copy.
It can't be any worse than the 35 yr old tyres I've been using and, being more modern construction/technology they may be on par with the originals?
(I know nothing of DURO tyyres)
The Conti's stick real good but I got them for the wider alloy rims, not sure what to do, fit narrower tyres that handle better or get used to what's on there and buy same size for alloy rims on second bike???????? : :-[

Re: '74 CB360 cafe/fighter-ish project - adventures in tuning

Been riding a lot this week, mainly because I don't have another means of conveyance. Its been in the high 60's-70's most the week. As you've seen from the pics I have big k&n filters and straight pipes that are a couple inches longer than stock. I'm using a 115 main jet and running PJ's secret spec air jet to lean out the mid range. It pulled great on the mid range and top end but would sputter and miss while cruising and was really bad while deccelerating. Low end was missing too. The bike starts on the first kick without any choke and the problems get worse as the engine gets hotter, so I figured it was a rich problem. I raised the float height 1mm to 19.5mm (PJ's recommendation) and adjusted the pilot jets to 1-1/2 turns out, then equalized the exhaust pressure (left cylinder needed to be adjusted out another 1/4 turn). The problems dramatically decreased, mid range and top end power was up too. Problems still showed up when the bike warmed up, though not to the extent. Today I swapped out the 115 main jets for 110's and equalized the exhaust pressures via the idle jet screws (ended up at the same number of turns). It was in the 50's today and the bike still popped, only every so often, at cruise. Barely misses on decceleration when engine braking now, only once or twice on the whole ride (about an hour). At cruize it still popped and missed a little, but less than it did before the jet change. Kinda felt like mid range and top end power was slightly down, but I'm not too sure. I would say its livable right now, but I'm going to sync the carbs with a manometer. Gatta find one first though.

...the saga continues.

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Today didn't go as well as yesterday. Bike didn't want to start or idle. It bogged and stalled if I cracked the throttle too hard from a stop. Really had to ease on the throttle to keep it running. With the 115's I could just rip it from a stop and it was balls to the wall. the idle jet screw didn't change anything. At cruise it did ok. Popped a little, but not much. I ordered some 112.5 main jets. I'm going to order some larger pilot jets tomorrow. The ones that are in there are 68's. For the time being I'm throwing the 115's back in.

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I found 110 main jets too small, 115 too big and 112.5 just right on my 378 with long exhaust
With shorter pipes and pods 115 may be about right?
I ran 120 mains on the 2:1 without silencer, wouldn't run at all mid-range though, broke up because it was so rich (but when it cleared, boy was it LOUD-and made almost 40HP)
Messing with intake and exhaust length makes carburation critical on 360's
Did you do plug chop?

PJ, I'd like to thank you for putting up with all my stupid tuning questions. You're the man.

I haven't done any plug chops yet. Gonna be doing those once I go back up to the 115's to determine if I need up the size of my primary main jets.

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Put the 112.5 jets in today. power is up in low and mid ranges. I think top end might be a little lean because power isn't what it was with the 115's. Idle is good, doesn't want to die when I come to a stop. Idle screws are 1-1/2 turns out and exhaust pressure is pretty much equal as far as my thumb can tell. it coughs a little at cruise, but they're not as severe as they were. I'm ecstatic with how its running now. Its not perfect, but its the best its ran since I've had it.

I bought a vacuum gauge from harbor freight and tried taking readings but the needle bounced around through a third of the gauge range. I guess that's not the tool you use to tune carbs.

The tank sealer is starting to flake off. I can see bits of it in the filters. I'm hesitant about stripping it out though because I don't know how to make sute I get all of it out.

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Couple days worth of riding on the 112.5's and I'm still happy with their street maners, but the loss of top end power compared to the 115's is becoming ever more apparent. I'm thinking about going back up to the 115's and going down a size on the pilot jets. Its 1/8-1/4 throttle that has problems coughing at cruise and wanting to die when stopping. I haven't done plug chops yet. I know, I know. It just seems that every time I take the bike out its to run errands and not to just cruise around.

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Hey PJ, couple questions (I know, surprise, right?). My manual lists primary, secondary, slow and pilot jets. Am I right in assuming the slow and pilot jets are the same thing (#36 jets I think)? And are they the ones I would change to addjust idle to 1/8 throttle? Or should I further adjust my float level (currently at 19.5mm)?

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Try 20mm with 115jet, it's cheap and easy.
Pilot jets are under plug and get fed through primary main jets.
You could try smaller pilots but I wouldn't know where to start as I've never had a low speed problem on my 360's
As for sync jumping around, just put a pilot jet into the line so it damps down the pulses

met a guy at a local cruise-in who used to be a honda mechanic back in the day. he said to try raising the needles.


I'm going to do that and then test ride it over to the honda dealer and pick up some new pilot jets. make sure i have everything for a full afternoon of tuning.


Thanks for the advice, I'll letcha know how it goes. whether you want to know or not, laugh.

also, would you guys still call this bike a cafe? i get people asking me "is that a cafe racer?" a decent amount and im not sure any more. best answer ive been able to come up with is that its a modernized interpretation of a cafe racer. thoughts?

Haven't been able to get to the parts store to pick up jets yet. I shimmed the needles with flat washers and the mid range and top end picked up a little bit, but not much. Also, the bike coughs at cruise. I'm going to take the washers out. I'm thinking about raising my float height another .5mm to 20mm and going to the 115 jets.

I realized I hadn't posted pics after the new tank, seat and pipes were on. Here ya go.







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I could have told you shimming the needles was a waste of time, but, you would have to find out anyway ;D
Now it's 'independent verification' for anyone searching
I like the forks more than I thought I would, may do one the same.
brake pedal looks a bit low though?

yeah, you're right, the washers didnt work. yeah, you're right, im stubborn. youre right, youre righrt, all hail PJ the 360 deity.



112.5 jets are in the box, 115's are in the bike.



ok, so with that in mind, what are your thoughts? 115 mains. your air jets. 19.5mm (+1mm from stock) float height.


idle to 1/8th, maybe to 1/4 throttle im having problems coughing at cruise. idle is low after warm up. wants to die while coming to a stop. mid range and top end are strong as hell. no problems there.






my (uneducated) thoughts are that i may need to raise the float height more. what would you recommend?

;D Not sure if your being sarcastic or not?
You can go to 21mm, but try 20mm first then do a plug chop
Probably a good idea to ride it where its coughing and check plugs, see if it's rich or lean miss
where are mixture screws set?
start at 3/4 turn from lightly seated, less than 1/2 turn and you need smaller pilot jets, more than 3 turns, larger pilot jets
If they need changing you'll probably only need +/- 2.5 though

i was drunk-posting last night. no disrespect meant. you have been right on with all of your advice, and it seems a lot of guys on the forum look to you for guidance with their 360's, so yeah, i think 360-god is a fairly applicable term. I think im a little upset that i know less than id like to about all this. slightly frustrating to have to keep deferring to someone more knowledgeable every time i encounter a problem.


mixture screws are around 1.5 turns out. that seems to be the idling sweet spot for the 112.5 and 115 jets, oddly enough.


its been close to 100 degrees out the past couple days, so i havent wanted to really lift a wrench due to the uninsulated nature of my garage. ill get to it soon though.

Damn, that's hot, where are you, Sahara desert ;D
I thought it may be something like that, I deleted over a 1,000 posts I made when I first joined, still not sure how well American's and Canadians take to 'British' humor
no harm done 8)

hey man i just picked up a cb 360 last night, shes pretty rough but i thought what the hell its my first project..i just started to tear it down to the frame a couple hours ago..so im just getting started. i was a pretty serious buell rider but had to get rid of the bike i had crafted into a badass fighter but now i get to build from the ground up..i just registered to the forum, i figured i might have a few questions along the way and thought who better to ask than folks with similar bikes..i dont have the title though so can anyone tell me how to tell what year it is..i had read they only made the 360 between 74-76 and after looking at some pictures i was thinking mine is a 75..any help would be greatly appreciated..keep up the good work on the bike man she looks beautiful

Get title as soon as possible and before you spend any money.
I have a couple of 360 frames without titles, makes them pretty worthless as its around $250 to get it titled (and you have to have bike running/road legal first)

Thanks for the compliment.


check out this thread and msg diesel450 about a title. He just helped me get one for an old car and everything worked out great. I'm not sure where you're from or how much the cops/inspection stations there care. I'm in NJ and we no longer have motorcycle inspections (thanks gov. Christie). the cops dont really care either. a friend of mine bought his license plate at a swap meet and hasnt had a problem in over 10 yrs. Of course not everyone is comfortable doing that. PJ is right, get a title soon.


I'll be glad to attempt to answer any questions you might have while working on the bike, but just so ya know its mostly second hand knowledge from all the time's I've pestered PJ about things I was stuck on (he's the resident 360 guru around here).


Good luck with build. be sure to start a build thread with lots of pics so we can see your progress.