Bouncy Forks

[adespin]

I've no doubt that this has been asked many times before, so i apologize in advance for asking. My 71 K1 750 has a horrible ride on the front end, the forks follow every large or small undulations in the road, only hitting a pothole do i get any fork action.
  When moving the forks up and down on standstill they seem to work fine, it's putting me off going out for a ride.

[Johnwebley]

Check fork oil
You may have to much or to thick.try altering tyre pressure up or down a few Psi

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[Nurse Julie]

As John says, tyre pressure and also the type / make of tyre can make a huge difference. Also consider overhauling the forks if the basics don't make it any better. Maybe too little or too much oil, or knackered oil.

[Rob62]

Maybe its just a case of getting used to it... these old bikes have big heavy wheels and slighty cruder suspension than the modern stuff.... mine is also a little less smooth over rough surfaces than my more modern stuff but the forks have been stripped, serviced and have the correct amount of fresh oil and they work fine when being compressed... so I think it may be just something to get on with.

[Trigger]

Make sure no one has put washers/spacers on top of the springs 

[adespin]

Make sure no one has put washers/spacers on top of the springs 

Trigger what would be the reason for adding spacers on top of the springs ?
The previous owner supposedly gave the bike a full service including new fork seals and oil before selling it to me, so i will try changing the oil to 5w.

[Johnwebley]

Make sure no one has put washers/spacers on top of the springs 

Trigger what would be the reason for adding spacers on top of the springs ?
The previous owner supposedly gave the bike a full service including new fork seals and oil before selling it to me, so i will try changing the oil to 5w.

  try ATF oil

[adespin]

Is that what you use John ?

[hairygit]

Is that what you use John ?

It's what Honda recommend!

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[Johnwebley]

Is that what you use John ?

  my car is an auto,so I use some of that ,Dextron II ,get it from amotor factorer ,lot cheaper than garages .


 https://www.eurocarparts.com/ecp/c/Toyota_Corolla_1.3_1998/p/car-accessories/engine-oils-and-car-fluids/car-tranmission-oils/automatic-transmission-fluids/?522776082&0&cc5_869


 

[SumpMagnet]

Adding spacers to teh top of the forks is an old-school way of stiffening up the springs. You are basically preloading the spring. It has a side effect of reducing the travel leading to some interesting effects under load and bottoming out if you hit a bump on the brakes.

The bodgers way could involve stacks of 2p coins.....which gave you a regular size and was...well...cheaper than buying big washers! I found that one first when I unscrewed a top cap and got a surprise shower of small change.

[adespin]

Adding spacers to teh top of the forks is an old-school way of stiffening up the springs. You are basically preloading the spring. It has a side effect of reducing the travel leading to some interesting effects under load and bottoming out if you hit a bump on the brakes.

The bodgers way could involve stacks of 2p coins.....which gave you a regular size and was...well...cheaper than buying big washers! I found that one first when I unscrewed a top cap and got a surprise shower of small change.

The mind boggles

[Moorey]

A frequently done misconception.
All adding spacers does is limit the amount of travel in a spring. It doesn't stiffen springs at all. The spring rate is the spring rate no matter how many spacers are put in.
Do not confuse a springs, spring rate with a springs, load/design rate.

[SumpMagnet]

I think what was really going on was taking up the slack on worn out springs that had a permanent set. Put the springs under load and the bike would sit higher and appear stiffer.

Then you go for a ride and convince

[Paulreade]

Are your wheels correctly trued and balanced ?. My front wheel was not fully trued, it had a flat spot , I  have improved it but it needs another go, as does the rear wheel. Making a slight improvement on the front made a slight diffence to the bounce I was experiencing although I still need to properly true them both. I have also picked up some 5w oil which I will add to improve the damping. Like you it puts me off riding the Honda a little, but with some patience I suspect it will get sorted.