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Bogging when cold

Posted: Thu Apr 05, 2018 6:20 am
by Katatonia
Hey everyone,

I have a CB 650 Z, which is currently running with a 4-1 exhaust and everything else stock.

I noticed when i was fixing it up during the winter that the previous owner had put ducttape across half of the intake, i had no clue why so i removed it.

Now when i start up the bike, i can't rev up fast when the engine is cold. It bogs awfully and almost shuts off. But if i do it slowly, once i get it up to full rev once or twice, it stops completely and runs normally.

Does this have anything to do with that tape, or the intake of air? The carbs are newly cleaned and synced. It might be a small issue, but really annoys me. I have still to check the plugs to see whether they are white or greasy.

Any insight or ideas are appreciated. Thanks!

Re: Bogging when cold

Posted: Thu Apr 05, 2018 6:33 pm
by Folsoml
Sounds pretty standard for a cold engine.

Re: Bogging when cold

Posted: Sat Apr 07, 2018 2:25 am
by GeorgeSweety
Hi Kat, the issue that is bothering you also bothered the PO, that is why he taped up half of the inlet, to enrich the mixture so the bike would start easier and pull away quicker. To me it would just make more sense to use the choke for a bit longer. If it bothers you that much put the tape back but I wouldn't recommended it.

Re: Bogging when cold

Posted: Sun Apr 08, 2018 8:02 pm
by michael_650
Sounds like a work around for choke plates that don't close all the way. Have you had them apart to visually inspect and make sure they operate smoothly and close completely?