[Giz]

Hi all,

I posted this on reddit but figured further crowdsourcing is a good way to scope for advice. I've recently purchased a 1973 CB250 and am trying to baseline the feel/sounds of this beastie.

There's a few sounds coming from the bike that sound odd to me. Being such an old bike I'm unsure if this is normal. I'd love for you veterans to give me your take on these.

First is a grind or shifting sound on a cold startup. You can hear it clearly in these two videos. A kind gent on reddit suggested this would be the starter clutch; I played the video to my local mechanic this afternoon and he concurred, noting it was not a big issue.

The other is a constant metallic jangling sound, almost like someone has some coins in a jar and is swirling them around; albeit somewhat muffled. Most notable on the left side carby. I've got a couple of videos of this one where you can hear it clearly. Again a fellow on reddit suggested this could be drivetrain noise which is fairly standard in an older bike.

Also as a side note, can the 1973 CB250 and CB350 effectively be considered the same bike except for the displacement? I've seen a lot of posts regarding the 350 and was wondering whether the same advice would apply to my 250. I've yet to receive my shop manual to be able to compare, so your advice would be much appreciated.

Thanks in advance

Cheers

Giz
1973 CB250

 

[ancientdad]

I'd agree that the first sound is the starter clutch, but not the typical slipping sound made when it isn't gripping fully - this is more like a bit of a chatter at it slows down after the engine starts. Seems to grip well and turn the engine over fine, so it's probably okay for the time being but I'd keep an ear to it to watch for changes in the future. As for the other sound, I'd say the cam chain could be a little loose - and the reason could be wear on the tensioner parts (center rubber roller, tensioner rubber roller) or it simply could just need an adjustment