Topic: Can you provide me with part #

[88BuckMeister]

Part number for spark advance springs. Mine are EXTREMELY weak and appear stretched, and my IPC doesn't show them, just the entire assembly

[M 750K6]

By design, they are at full advance very quickly, by 2500rpm I think. So not especially stiff. Have you checked it with a timing light (strobe gun), to see if it's advancing too quickly?

I can't see just the springs at CSMNL or David Silver, only very pricey complete units. There is a tweak to stiffen old advancer springs, which I've not explored yet, involving snipping off the end and using the last coil to attach to the advancer plate. Others can explain it better. But I'd check with a strobe light first.

[madmtnmotors]

https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_21_250_55&products_id=2168

[88BuckMeister]

I'm referring to the coil springs that attach to the pawls behind the contact plate. I mean they are so old and stretched one of them fell off by itself when I turned the advanced over

[88BuckMeister]

By design, they are at full advance very quickly, by 2500rpm I think. So not especially stiff. Have you checked it with a timing light (strobe gun), to see if it's advancing too quickly?

I can't see just the springs at CSMNL or David Silver, only very pricey complete units. There is a tweak to stiffen old advancer springs, which I've not explored yet, involving snipping off the end and using the last coil to attach to the advancer plate. Others can explain it better. But I'd check with a strobe light first.

I am aware of that trick but I don't intend to do it as stiffening the springs causes the advance to approach a higher power curve. I don't want to change any of that. I just want new springs. But true it's tricky when all the IPCs aren't showing them individually

[88BuckMeister]

Ugh I just bit the bullet and bought a whole new advancer from 4-into-1. Unless you guys think the materials are lesser quality then I'll just steal the springs off of it. Keep in mind this is pre-Dynatech ignition install. I only need new springs because I'm installing elec. Ignition in front of them

[newday777]

I'm referring to the coil springs that attach to the pawls behind the contact plate. I mean they are so old and stretched one of them fell off by itself when I turned the advanced over

Did you not look at the Yamiya link Wilbur posted? It has the springs for the advancer.

[HondaMan]

It is 100% common for the springs to now be heat-softened on these bikes. In the 750 it is such an issue that the spark advancer, which is supposed to reach full advance by 2200 RPM, often advances fully by 1500 RPM. The 500/550 is the same stuff. The 'fix' on the 750 is to cut off one full turn of one of the springs, bending the last loop out to form the attachment to the little post on the backing plate, and then test-run to see if it delays it enough. Often it takes another 1/2 turn off the other spring to slow it down adequately. It should not reach full advance before 2500 RPM on the 750: on the 500/550 it should be later than that, about 3000 RPM, to help cope with the long intake runners from the carbs.

[dave500]

ive used pilfered springs from an old bosch dissy to fix hondas and yammy 650 twins,it aint critical the curve,its all in by say 3000 anyway and if your riding the bike correctly itll be at full advance all the time once under way,dont sweat too much precision on those springs.

[Deltarider]

[...] it aint critical the curve,its all in by say 3000 anyway and if your riding the bike correctly itll be at full advance all the time once under way,dont sweat too much precision on those springs.

This ^. And if you can't live with a maybe, maybe, somewhat fluttering idle - which is the only side effect - you can simply tweak the coil that goes around the post. No big deal. For a CB500/550 I do not recommend cutting coils. Maybe the CB750 yes, the CB500/550 no. Just tweak it, if you really must. If you want new nonetheless, realise springs length differs, depending it's a TEC or a Hitachi advancer. 

[dave500]

OOPS,Ive created a monster?

[Kelly E]

OOPS,Ive created a monster?