Topic: Advance springs and fast idle

[550Resto]

Hey all, had a question regarding these 2 items. I have a 78 550k and wanted to see if the advancer springs are available to purchase somewhere or do I have to make due with the ones on the bike and perform the Hondaman fix?

Second question is when I first start the bike with choke applied it idles at 1200 and after it warms up some and I take choke off and then return apply it jumps to 3k. I was under the assumption that it would take the bike to 3k when choke is initially applied or is this correct in that the bike warms up some and then goes to 3k?

Thanks for any and all help!

[DaveBarbier]

Have you bench synced these carbs? Could have started too high. After the bike warms up completely...I mean after like a 10 minute ride...you can adjust the idle to bring it back down.

Unless of course you have an air leak and it's causing a racing idle. But that doesn't sound like your issue.

But yes, the PD46C has a fast idle cam in the choke mechanism which should raise the idle so you don't need to feather the throttle. Mine was disengaged by the PO so I adjusted it back to work as it was designed. It's not super easy to get to as it sits between the 2-3 carb and you need to loosen a locknut and use a flat head. Similar to a tappet adjustment.

As for the advance springs, they're not available. If you're going to full advance too soon then you can perform Hondaman's clipped spring procedure. Only do it if it's an issue, you want full advance coming in at the proper RPM.