Topic: K7 750 PD41A trottle spring

[Erny]

I'm pretty sure this topic is not new here, but did not find satisfactory answer

Simply, I'm fed up with very strong stock trottle spring on my K7... makes difficult to ride bike for longer time without wrist pain...
Cables are lubed, they really works fine, just that spring is too strong

Is there some easy way to fix it? Like replace spring by other one, no so strong? So tips?

[HondaMan]

The PD carbs' spring is real hard to change. Some have made a small link to reduce the preload, which helps reduce the force at any given position accordingly. This just lets the spring unwind a partial turn at its starting position: I saw one made from coat-hanger wire, with a tiny loop at the spring end and a hook at the anchor end, on a set of carbs I once cleaned for someone. It was only about 1/2" long, but I knew exactly why he had put it there!

A word of caution, though: make DEAD sure it can't break or come loose and jam the works when riding, so the word DEAD does not become a part of the conversation?

[Erny]

Opening this tread again, isn't there really anybody who replaced stock spring by some "softer"? I'm thinking to order manufacturing new one that will be 30-50% softer...

[flybox1]

how about getting a cramp buster....or grabbing a shake weight 

[beemerbum]

The PD carbs' spring is real hard to change. Some have made a small link to reduce the preload, which helps reduce the force at any given position accordingly. This just lets the spring unwind a partial turn at its starting position: I saw one made from coat-hanger wire, with a tiny loop at the spring end and a hook at the anchor end, on a set of carbs I once cleaned for someone. It was only about 1/2" long, but I knew exactly why he had put it there!

A word of caution, though: make DEAD sure it can't break or come loose and jam the works when riding, so the word DEAD does not become a part of the conversation?

I have not looked at for a while is I speak from ignorance. Why is the spring hard to change?

[pjlogue]

Opening this tread again, isn't there really anybody who replaced stock spring by some "softer"? I'm thinking to order manufacturing new one that will be 30-50% softer...

I have a '76K 750 and found a spring at Lowes that was very close to the same length but smaller diameter wire.  The diameter of the coiled spring was close to the original spring.  Worked great and reduced the force required to hold the throttle open by at least 1/2. 

-P.

[Erny]

This is exactly what I want... but cannot find such spring. So thinking to order its custom manufacturing

[pjlogue]

You can also stretch the OEM spring a bit but got easy and try it and if it is still tight stretch a little more.  You don't want the spring to over stretch and become too long at closed throttle.

-P.

[flybox1]

please understand the return springs for the earlier Ks are NOT the same setup as for bikes with PD carbs.
PDcarb springs are wound like watch springs, where round-top carbs springs are expansion springs.

[brewsky]

The parts diag actually shows a conventional pull spring for the K7, but the wound around type for the K8.

So various size links could be tried

I tried to slightly un-wind the attachment point on my K8 with no success.....the slides would not snap closed, so I just learned to live with it.

If long rides are the issue, you can use something like this for relief....
https://www.jpcycles.com/product/zz50408/sound-off-recreational-vista-cruise-throttle-clamp?mrkgcl=444&mrkgadid=3303098786&utm_source=bing&utm_medium=cpc&utm_term=ProductType3&utm_campaign=Bing+Shopping++Generic+-+Handlebars+%26+Controls&utm_content=pla&creative=77309468894661&device=c&matchtype=e

[Erny]

meanwhile I'm waiting for new spring to be manufactured (softer), I found in garage 2 softer (and longer) springs.
One was way too soft, 2 are on the limit (trottle still returns). Had to hang them in other place as are longer than original.

Just returned from test ride - it was great, comfortable compare to stock!