1961 model 31 csr

albreese · Post by **albreese** » Thu Nov 24, 2011 10:42 am

the front forks on the bike when hitting a bump compress ok but return with a hard bang as though there is no resistance to the return any clues please

bjork · Post by **bjork** » Thu Nov 24, 2011 10:55 am

Hi albreese, welcome to the forum. First I would check the fork oil. Check there is some still there and it's not just emulsified rubbish, the amount should be about 175cc,(per leg) and the grade 20w. If you put way too much oil in you can get similar problems too. Too much oil effectively gives you extra 'spring', as the air volume is less and you are compressing the air too. Too litle oil will also give a noisy bouncy ride, same as 'thin' or emulsified oil.
It could also be the damper rods have dropped off the fork top nuts, you will see when you remove them to top up the oil. Hope that helps, have you got a manual?Edited by - bjork on 24 Nov 2011 10:56:22 AM

Don Madden · Post by **Don Madden** » Thu Nov 24, 2011 4:59 pm

Also check that the rebound buffer springs are present. They should be on the stantion tubes between the bushes. Cheers, Don.

albreese · Post by **albreese** » Thu Nov 24, 2011 6:27 pm

thanks for replies on the case manual in hand.
cheers al breese

1608 · Post by **1608** » Fri Nov 25, 2011 11:44 am

If it has just started doing this then its probably covered by the above suggestions. However, I had a similar problem on my G12 ( fork action was too harsh as well ). The springs were the wrong length and gauge. I checked the manual and acquired the correct ones, big improvement. Many of the bigger bikes, especially twins may have had sidecar springs fiited in their past.