Front Forks

Hi all, I have just fitted new seals to the forks on my Maxim X and all is Ok as far as it has stopped the forks leaking oil, but....... the front end seems very hard, the forks move up and down Ok, but front seems to be jumping up and down slightly, and clocks are vibrating, dunno...... is it the road surface? our roads are shit at present, have I put the right amount of oil in? have I put the right oil in? have I got the air pressure right (12psi) does the front wheel need balancing? had a ride today and at 55mph it's hard to see clearly due to the vibration.
Can anyone shed any light? what is the correct oil? what is the correct amount?

Thanks in anticipation.
Mike.

 

First, I'd try to put less air in the forks (let's say 5 psi) and see if it makes a difference.

What grade of oil did you put in there and how much?

 

Hi, this may sound really bad, but I don't know what type of oil it was, it was in a container with a label that said, fork oil.
I put in the same amount of oil as I got out.
Good shout about the psi, I was thinking of trying that, as the first easy step.

Regards, Mike.

 

I seem to remember that the recommended air pressure for the Maxim-X forks is 7 PSI. I know it's a but tricky to adjust it due to the very low air volume in there, but it's worth a try. Anything around 5-7 PSI would be fine.

 

The manual just says not to exceed 17.1 psi.
I personally don't go over 10 psi.
Use a bicycle pump so you don't blow your fork seals.
Fork oil capacity is 389 cubic cm (13.2 US oz, or 13.7 Imp oz)
I'd drain them and put in the correct amount.
Might want to get some new oil too,
That way you know exactly what you're putting in there
15w is what most people use

 

Once again I have to say thank you all for the input.

Will sort our the air pressure as advised and also drain the oil and refill with correct grade and amount.

I had a great ride out today, apart from the front end problem, it's a fantastic bike, be even better when I sort out the forks.

Thanks again.

Mike.

 

When you drain the forks this time,
pump them up and down a few times to push out all of the fluid
You should look into getting a service manual for your bike
It's invaluable!

 

I have removed forks again, stripped down and removed all old oil by suspending parts, I have bought another set of seals and the correct fork oil.
Took care when rebuilding that everything was going back together the way it should, by the way the oil quantity (13.7 fl oz) equates to just short of 500mls, (half a litre)
Have put bike back together and will test ride today (if the rain stops) I have not put any air pressure in forks yet, I thought I would try without first.
Will keep you posted.

Happy Days........ Mike.

 

Disappointed, managed a test ride yesterday (25mls) with no air pressure in forks, still a rough ride. Raining again today, so as soon as it dries off I will put 5 to 7 psi in forks and try again.
(contemplating suicide)

Mike.

 

Are you fairly certain everything was assembled correctly? A backwards component may cause harshness.

Here is the exploded view: http://www.cmsnl.com/yamaha-xj650g-maxi ... ml#results

To be honest it's pretty damn tough to get all of the fork oil out by pumping, and is sometimes easier to take the forks apart and drain well.

15W oil is an "upgrade", and you may find 10W suits you a bit better.

I put 20W in mine and procrastinated like 4 months on going lower. I almost lost all of my teeth it was so rough. It's much easier to do it now while it's fresh in your mind, and with the practice you'll be able to do it blindfolded. 8)

 

I'd like to revisit the amount of fork oil that you are using. You stated, "...by the way the oil quantity (13.7 fl oz) equates to just short of 500mls."

Mignight Moose gave you the correct volume of fork oil to use; "Fork oil capacity is 389 cubic cm (13.2 US oz, or 13.7 Imp oz)"

If you are filling each fork leg with slightly less than 500ml, then you are overfilling the forks, and that is why the ride is harsh.

389cc = 389ml = 13.15 (rounded to 13.2) US oz = 13.69 (rounded to 13.7) Imp oz.

Just under 500cc is at least 100cc too much fork oil. Overfilling results in less headspace, and a higher compression ratio for the air spring, which in turn gives you a harsher ride.

 

Seems like I should be working under supervision, I feel like a monkey with a machine gun, fancy not reading Midnight Moose's post correctly, for some reason I went into my workshop with 16.7 Imp oz in my head, instead of 13.7.
Going to have to do the job again, unless I can try to drain 3 imp oz from each station through the drain plug.

Thanks again.

 

drain a whole lot and put it all back except the last three oz