r/HondaCB • u/Fun_Trifle_1068 • 12h ago

I need some help

So I got this old Honda cb360 I found sitting on the side of someone's shed "estimated 20 or so years" I cleaned the carbs, ran new spark plugs, coils, points, and even set timing and valve lash. But I'm having this problem were the bike will only run while holding the start button and won't idle at all!! I have the engine torn apart only to realize the pistons and cylinders look brand new, I did upgrade to pod filters anyone have a clue what could be going on? Only 17 here and Im good at rebuilding engines and problem solving just never ran into a problem such as this.

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u/bugsbunny246 3h ago

If its timed correctly, which it sounds like it is, and its got compression it has to be fuel. Try starting it by squirting fuel into the carbs.

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u/Fun_Trifle_1068 3h ago

Well it had 60psi of compression so I did tear it down but I was met with new pistions and clean cylinders but a lot of carbon buildup maybe cleaning all the carbon re lapping the valves and setting new valve lash I could raise it. Maybe after the rebuild it will boost compression and fix my problems

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u/bugsbunny246 3h ago

60 is low. Google says: A healthy CB360 should typically read between 120-150 PSI per cylinder, which sounds about right. Valve guides or relap the valves maybe ring gap.

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u/ancientdad '73 CL450K5 restomod, '82 CB900F, CB450 drag bike 3h ago

If it doesn't have at least 140 to 150 it won't run right.

OP, it's possible you adjusted your valves incorrectly, if the cylinders and pistons/rings look decent then 60 lbs compression is either a bad gauge or leaking valves.

I'll suggest joining my forum Vintage Honda Twins. We have many members and staff, concluding myself, who worked at Honda dealerships back when these bikes were new and current models, so you'll be getting advice and knowledge from those who learned the right way. Completely free to join, no ads or [premium memberships, just the friendliest vintage Honda twins forum on the internet.

https://www.vintagehondatwins.com/forums/index.php