Who rebuilds carbs in the GTA?

[cholland_]

So I've got a '75 CB360 I've been trying to get on the road all summer. After screwing around trying to get it to run right, I'm at wits ends.

The carb's got rebuild with a set of Keyster kits, then the bike got a new set of coils, points, etc., and the top end of the engine got rebuilt (new gaskets, valve seals and rings). Floats are properly set, valve clearances are set, timing's set, carb's were benched synced and no rips in the carb boots, blah blah blah. Since then, the bike's started perfectly and idled fine. But acceleration and cruising above idle causes bad surging that makes the bike unrideable. It sounds like a two-stroke lawnmower engine that a squirrel crawled inside. Plugs look relatively clean when pulled, just a tiny bit of carbon buildup.

I read some bad reviews about Keyster kits, so I threw all the old jets and needles back in. No change.

Basically, I'm out of ideas, and give up! I want to send off my carbs to someone who can properly set them up for a CB360, (no modifications - stock mufflers and air filters) and make sure everything's good, beyond my level of carburetor expertise. Any help at all would be appreciated!

There she is, lookin' all sad sitting around all the time.

 

[Big R]

Sounds like it just needs jetted properly. And believe me, you dont want to pay a shop to do that. What sizes are in it now?

 

[teazer]

CB360 carbs can be tricky to set up. Surging is either a rich mixture or a lean mixture. In this case it sounds like it's too lean at anything above 1/4 throttle. It could also be a poor electrical connection somewhere in the system allowing something to short or intermittently make and break contact.

If the plugs come out dry and white, it's probably fuel related. Above idle, those carbs rely on the needle jet and needle plus the slide to regulate fuel. One simple test here is to remove the air filters and run the motor in the shop (door open) and use a mirror and flashlight if necessary to see if both slides raise together smoothly as you blip the throttle. As revs go up, so should both slides. If one is down or is fluttering, that's where to look next.

 

[johnny gaijin]

i was experiencing surging on my 360, although not as bad as it sounds like you are, and my problem was just a slightly clogged jet. might be worth double checking.

 

[cholland_]

Thanks for everybody's help. I'll check it out when I get the chance. I doubt think its a clogged jet, however. I've swapped jets to the old ones and nothing changed. And it should be jetted properly, they were running okay before they were cleaned/taken apart.

Still looking for shops in Toronto, however. I've got a few automotive carbs I'd like to get actually restored... torn down, completely cleaned and all the zinc coatings, etc. redone.

 

[djelliott]

Just tossing out a few wild pitches here.

A) Are you positive the timing and points gap are properly set?

B) When the top end was redone is it possible the cam was installed a tooth off?

C) When the carbs were cleaned were you sure to blow out all jets and passages with carb cleaner and air?

Just a few things that came to mind. I hope you get it sorted out. It sucks chasing gremlins around. I was doing it all last night on an XS650. Got her running though. WOO! Good luck.

 

[teazer]

C) When the carbs were cleaned were you sure to blow out all jets and passages with carb cleaner and air?

The trick there is to squirt carb cleaner through a jet of drilling in one carb and then repeat on the other for comparison. Then move on to another jet etc. You may be surprised to see how different the flows are from one to another if there are partial blockages.

 

[Cat13]

Seriously check the timing and points gap. My 360 has been running like crap since I got her. We tried everything cleaning carbs another set of carbs different jets, carb syncing etc. Everyone said it was carb related till a friend of mine who has a 360 fixed the timing and points. It runs like a dream now. If you want I can PM you his number. Hes starting a honda tuning business.