Author Topic: Another years MOT and a sunny day  (Read 1825 times)

0 Members and 1 Guest are viewing this topic.

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« on: May 17, 2014, 21:04:27 PM »
MOT Just mentioned the forks as expected, bottoming out a bit but passed no problem. The anti dive valve seems free but maybe I need some oil or air. Do these forks have both air and oil? Need to replace the oil anyway as I've never changed the fork oil. Does anyone have a quick procedure for oil replace and set up of forks? The seals look OK to me.

Sent from my ME371MG using Tapatalk


Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #1 on: May 18, 2014, 10:45:13 AM »
Yes, the forks can use air too, although I never put any additional air in, I fill a litlle extra oil to make the air chamber a bit smaller, same effect but less stress for the seals.
You can let the oil off at the little bolt on the outside of each forkleg just above the axle, filling is from the top, don't forget to support the bike (small car jack or so) or it'll kneel before your eyes as you remove the second upper cap smilywhistle

Offline RuaphuNZ

  • Donator
  • Ultimate Member
  • *****
  • Posts: 1471
  • Cubic capacity, bigger the better eh.
    • View Profile
    • Powerco
Re: Another years MOT and a sunny day
« Reply #2 on: May 21, 2014, 13:00:28 PM »
On ya James, well done. When I had my bike I chanfged out the steel spacer at the top for slightly longer ones and added 5-10% extra oil and the forks stopped the excessive dive and firmed things up nicely. There is a thread I start here about three years back on what I done.
Laid back, cruising along listening to my wonderful 2.0L Vulcan Vee twin 'thump-thump' all day long, devouring the miles, enjoying life to the fullest, feet first.

Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #3 on: May 21, 2014, 22:02:10 PM »
How you want the forks to feel is quite personnal ofcourse, I always set them up a bit on the hard side. And your own weight plays a role too of course, with my 75 kilos (say 85 with helmet and leathers) I have seldom problems with bottoming front or rear suspensions.

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #4 on: May 21, 2014, 23:34:52 PM »
Thanks for info guys. They seemed ok when riding fast, just need to stop them bottoming out now and then. I weigh 13 stone - I don't do kg on body weights! I work away from home nowadays so I will not get chance to check it out until the weekend. I need to order some oil so I have it ready for a weekend. Just a bit firmer should do it.


Sent from my iPhone using Tapatalk - Buggy Version

Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #5 on: May 23, 2014, 11:21:49 AM »
13 stone converts to about 82 kg so not much different, your forks must be quite soft then to bottom out.
Like Andrew wrote, a bit more springload and maybe thicker oil can do wonders.

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #6 on: June 14, 2014, 19:28:15 PM »
Did the forks today finally. Problem was I put the drain screw on a wooden crate which contained towels, rags, sand, rubble and leaves. When I went to find it it was gone. Had to hand sift through all the crap for an hour and never found it. Then I just thought I'd check to see if anything was in the old oil container and it was in there! Must have dreamt putting it on the crate! Anyway with new oil and 1/2 bar air they are a lot better! One thing I noticed on the manual PDF I was looking at there were 2 different sets of capacities one looked official and the other said "Sean" next to them? As both sets were different I went with the ones that looked official. Any ideas which ones are right? I filled through the Schrader valves with a syringe and the cores removed.


Sent from my iPhone using Tapatalk - Buggy Version

Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #7 on: June 14, 2014, 21:45:46 PM »
The anti-dive is in the left fork and makes just a little bit of space, that's why the left takes more oil. The higher numbers are those from the thousand, the sc21 like I have, the lower numbers are the same as in the japanese cbr750 manual, you can't get it more official gribbin12
« Last Edit: June 14, 2014, 21:53:55 PM by robvangulik »

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #8 on: June 15, 2014, 01:02:09 AM »
That means I have 447, 432 in the wrong sides!


Sent from my iPhone using Tapatalk - Buggy Version

Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #9 on: June 15, 2014, 09:59:23 AM »
When I'm honest (and i usually try to be ) I didn't get that either, in my 1000 book the left leg is the one with the lesser oil.
I always measure the oil from the top (no spring and the leg shoved in totally) , 107 mm for the 750. Can be done with everything else in place, put the bike on a small jack under the engine and slowly lower it until the forklegs are totally shoved in and the bike is sloping forward. It should still stand firmly on the centerstand.
I use a piece of fuelhose, hang it in the leg with the right length, and blow in it while pooring oil in. When you hear it bubbling you're done.

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #10 on: June 15, 2014, 10:47:12 AM »
That sounds like a more reliable method! I avoided removing the plugs as I wasn't sure if I would be able to refit easily. I assume the caps are compressing the springs a bit. I will take another look as it was still not perfect. It was a lot better but still possible to get a slight clunk when pushing against the front brake. If I measure the oil with your method and put the 0.4bar air in and it still clunks then I will assume the forks are a bit worn. I do have another pair in the shed!


Sent from my iPhone using Tapatalk - Buggy Version

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #11 on: June 15, 2014, 11:04:25 AM »
Oh right - I just took the caps off and it was a good job I was ready to catch the beast! - nose dive and stand went up! (Don't have a jack!) I can now see what I'm doing - cheers!


Sent from my iPhone using Tapatalk - Buggy Version

Offline James Carter

  • Ultimate Member
  • *****
  • Posts: 101
    • View Profile
Another years MOT and a sunny day
« Reply #12 on: June 15, 2014, 11:41:01 AM »
All done - the only problem I faced was how the hell to re-assemble when I had no chance of getting it back up and on the centre stand again on my own. Then I had a cunning plan to put the caps back on and pump it up with air which worked a treat! One leg didn't have enough in and the other too much. No more clunk at all now - thanks for the help!


Sent from my iPhone using Tapatalk - Buggy Version

Offline robvangulik

  • Global Moderator+Donator
  • Ultimate Member
  • *****
  • Posts: 11294
  • If you brake late, you're riding fast longer
    • View Profile
Re: Another years MOT and a sunny day
« Reply #13 on: June 16, 2014, 00:06:26 AM »
So you pumped one leg to fit the spring in the other? Smart!
A small jack really is the thing to have, when you lower it slowly (instead of the clunk method winky5a ) the center stand should hold its own. Also comes in handy removing wheels etc. Could you get it on the stand again with the nose still down?  :headbang: read first, then write. Did you lean it against the wall or so?
I bought this one maybe 30 years ago for peanuts (or as we say, for an apple and an egg), and I think they're still cheap today. Go to a car breaker, they'll have them aplenty.
« Last Edit: June 16, 2014, 00:12:30 AM by robvangulik »