Weak springs on Governor Assembly / Spark advance

[jharvey]

Greetings,

So, it appears that the springs on my mechanical spark advance/governor assembly have stretched with age. (1980 GSX400ET - which I got just before they switched the model to E.I.) Here are the symptoms to confirm…

Engine idle set to 1500 RPM. After 50 minutes riding with the engine good and hot, pull into a parking lot and if I throttle up to 3000, it would stay there until I let out the clutch to ‘drag’ the engine back to the 1500 RPM idle. If I run it up to 2000 or 2500, it would return to 1500 - and if I went to 4000, it would drop back as far as 3000, but it would stay there until I let out the clutch.

It’s been suggested that I convert the bike to Electronic Ignition, but checking the price for a compatible unit is not encouraging…

Dyna S Ignition System with Coils for Suzuki GS400 Twin

The Dyna S is completely housed behind the ignition cover and uses a magnetic rotor with the original spark advancer, so the factory advance curve is maintained. Dyna high tech coils are American made, top quality performance coils. Tested and proven on street, racing, and touring motorcycles...

www.dynaonline.com

(Which, with a quick look at an online currency converter, tops out at about $550 Canadian before any tariffs, taxes, or shipping. Not an attractive alternative for this ‘fixed income’ rider.)

The Dynatek page also says that the E.I. unit, “...uses a magnetic rotor with the original spark advancer,” so, if it’s using the original spark advance, would that not leave me with the same problem anyway?



So my questions for anyone with experience of knowledge are…

-Does anyone know of a cheaper but reliable unit that would work with my model (that DOESN'T need to keep the original advancer)?

-Is it possible to replace just the springs? (Anyone know of a source - I can only find listings for the complete assembly.)

-Or finally, if I don’t replace or ‘upgrade’ the unit, is this something the bike can "live with" now that I know what it is and can compensate for it (ie. making sure the idle is back below 3000RPM as I pull up to a stop before I put the bike in neutral), or is it going to get progressively worse until some eventual catastrophic failure?


Thanks

 

[chuck hahn]

Roll the loops a bit tighter with small needle nose pliers and no your not gonna do away with the advancer.

 

[rphillips]

The diagnosis seems really reasonable, but what else could it be? Hanging idle is fairly common but don't remember weak springs on advancer being the fix... Don't remember what else the fix may be...

 

[chuck hahn]

Sloppy flyweights can cause racing and erratic rpms.

 

[jharvey]

Roll the loops a bit tighter with small needle nose pliers and no your not gonna do away with the advancer.

So can i assume that the actual tension isn't that precise - that there's no risk of making them 'too tight' if I do this?

 

[chuck hahn]

Just enough the slop is gone. if theres a few thousands play that sufficient. Youre not gonna find springs and a new advancers gonna be pricey

 

[jharvey]

The diagnosis is from my mechanic who's familiar with the bike (just replaced the 46 year-old manifold boots - and they looked every day of those 46 years on the surfaces that mated with the rest of the bike), and suggested the option of EI, but as I say the cost(*) has me looking for a way to stay with the points, or hoping I can just live with the current symptoms without fear that they'll lead to a failure.

(*)Turns out, the Dynatek link in my original post was for earlier Suzuki 400 twins and they don't make one for my model, and the only alternative I CAN find that's a match is even more expensive at about $792 CDN...

CDI UNIT KOKUSAN for Suzuki - order at CMSNL

✓ Good to order: CDI UNIT KOKUSAN ✓ Manufacturer Part Number: 32900-47020 ✓ OEM Suzuki part

www.cmsnl.com

...so unless I can find a much cheaper manufacturer of a compatible EI, it'll definitely be a case of trying to make the original points system work.

 

[jharvey]

Just enough the slop is gone. if theres a few thousands play that sufficient. Youre not gonna find springs and a new advancers gonna be pricey

Yeah, there's no shortage of springs for Briggs and Straton lawnmowers on the internet, but that's not doing me any good - I mean, it's a small bike but not THAT small. And so far the only place I see advancers listed is on eBay - where I would really have no idea what kind of shape they're in - or from CMS in the Netherlands, where the images appear to be showing used (or should I say 'refurbished') units for about $350 CDN.