CRF250 L thread

[nwmschris]

its the yoshi RS4 full system (thumbs)

[Spadger]

its the yoshi RS4 full system (thumbs)

I may be interested in that if you could pm me some details etc been trying to send you message but keep failing , cheers , j

[P4ulie]

its the yoshi RS4 full system (thumbs)

I may be interested in that if you could pm me some details etc been trying to send you message but keep failing , cheers , j

I certainly don't want to spoil a sale, the RS4 is a thing of beauty, weighs nothing & so far on 3 longish trips inc a 2500+ miler, hasn't caused any issues with melting close proximity saddlebags (I don't have pannier rails) but it is very fruity. Great around town but can get very tiring after 4 or 5 hours....even with earplugs :S

Just something to think about if you do big trips

[nwmschris]

pm sent spadger (thumbs)

[anthony29040]

pm sent spadger (thumbs)

2015-06-2709.07.43.jpg (82.23 KiB) Viewed 1372 times

this is the exhaust.

[motorbike]

did you have an ejk unit fitted?

[motorbike]

i was told by a dealer if you fit a full system to a new bike.start her up for the first time run her for 10 mins the the bike recognises the system and fuel adjusts for same automatically ?

[Arthur Pint Motor]

and you just showed you don't know what are you talking about, progressive suspension is way batter is such situations (changing load, changing conditions, terrain etc) and more adventure bikes move toward it now but you don't know that

Progressive suspension is achieved by the linkage system with a linear spring. Linear spring rates are easier to get the damping right. It took KTM many years to get their non-linkage PDS system to work well, they started off with progressive springs but eventually went back to linear springs and used progressive damping.

Adding a progressive (rising rate) spring with a linakge system will increase the ramp up and probably make the damping even harder to get right, judging from the KTM story.

http://www.dirt-bike-secrets.com/progre ... rings.html

No good in dirt bikes!

Dirt bikes have adequate progression built into the suspension linkage systems or into the shock system such as KTM PDS shocks. These systems are designed to work best with the correct linear springs for your weight. The same holds true for dirt bike forks due to the air spring compression.

A progressive spring in this case is an overkill and makes the suspension too stiff deeper in the stroke. Dirt bikes are always ridden solo, and your weight and the weight of the bike remain constant (for some riders more than for others . This means that once you have the correct linear spring rates the bike should always work perfectly from ride to ride.

Big advantage in dual sport bikes!

Adventure bikes differ greatly from dirt bikes. One day you ride solo, the next you lift a passenger. You add bags, lots of extra gas or extra gas tanks etc. In other words there can be big weight variables from one ride to the next. Theoretically you need one set of shock and fork springs for solo riding and another for riding with a passenger or laden bike. You would have to change springs each time you load up or lift.

Obviously it helps to balance the bike in these situations by adding and removing preload but this is only a quick fix. The problem with a quick fix is that the soft springs still remain too soft for lifting or loading. You will still experience handling problems.

On long trips this is bad as it puts great strain on chassis and suspension and reduces long term reliability. Therefore the progressive version is a great help and can offer the best of both worlds.

The progressive spring functions in such a way that the beginning third of the suspension travel remains soft and offers a comfortable ride acceptable for solo riding. Thereafter some of the spring coils start to close up and become inactive. They create a substantially harder spring for the last two thirds of the suspension travel. This is very good for hard solo riding and for situations where you load the bike or carry a passenger.

It’s almost like cheating and having two springs in one on your motorbike!

Well I can certainly see the logic of that but they don't mention damping. The problem is that fitting a progressive spring on a (progressive) linkage system could well increase the spring rate to more than the damper was originally designed for. The CRF might end up like a pogo stick in the stiffer part of its travel.

Hopefully this won't be the case and Cowling will be a happy chappy.

[cowling]

Hi all, I'm looking to upgrade the rear shock on my Crf250l , on a budget!
I've put up with it for three years now, but as rider ability improves and the
Pace quickens the back end just now seems to be all over the place.

Been looking at the Hyperpro progressive Spring upgrade, looks as though
The Hyperpro Spring replaces the origional Spring and you keep the Honda
Damper unit, looking on eBay , they come in black or purple, any difference
In these,other than colour?I'm awaiting a reply on this from the supplier.

Anyone fitted one of these? at £84, might be worth a punt, I'm not wanting it
To be like a enduro bike, just better than what it is. Or is it a better idea to
replace the full shock, any recommendations on a budget shock for the crfl.

Cheers all, advice taken and the hyperpro spring in back in the post, winging it's way back to the supplier. (thumbs)

[robson]

i was told by a dealer if you fit a full system to a new bike.start her up for the first time run her for 10 mins the the bike recognises the system and fuel adjusts for same automatically ?

actually it's like 15 minutes, this is called 15 minutes idle reset after some major changes.
ECU should adjust, to a degree.