|
|
Post by davetesseyman on Mar 27, 2016 17:22:57 GMT
Bit of a mystery this.
Restored my sprint forks,put new shocker and spring on but when I break the swinging arm dips so much that it presses the spring against the fork leg and pops the speedo cable out of its hole. This is a lot of travel! I changed the spring for a 33% stronger one and then a 180mm one instead of a 155 one, nothing seems to make any difference? Cant take it for an mot because it vibrates like mad ! I completely stripped all the forks/drum etc and had it all chromed. I cant help thinking that I have built it wrong but I cant work out what it is?
Any ideas
|
|
|
|
Post by henri on Mar 27, 2016 17:30:25 GMT
sprint/rally/super forks are "headshakers" out the box ,because of the geometry of the spring an damper . ease on the back brake first an it lessens the effect when fronts used . this wont show on a mot test so you can go ahead an get it tested .the speedo cables routed wrong ,with not enough slack/curve in it if brakings popping it out the link .
oh,an hi n welcome . H
|
|
|
|
Post by davetesseyman on Mar 27, 2016 19:01:54 GMT
Hi Henri, I do realise they are a bit of a bugger but I have never seen one that dives so much that it bangs the spring against the fork, have you ? I think I can feel a pk conversion coming on because the engine is kicking out 24 bhp and I could do with it being a bit firmer at the front end! Thanks very much for your help and any more help you can give.
|
|
|
|
Post by henri on Mar 27, 2016 20:20:38 GMT
24 bhp? , what lumps that in there then . yep pk/px drum forks probably a good idea , personaly i'd look for px type ,as pk's are starting to get pricey .all us smallie nuts want em ,an you can stick px disc hubs on em . on a sprint i think the offset of px forks will be easier to work with . an so long as you get 20mm axle ones you can always upgrade to a disc set up later .
out the box thinking , but if ya want the best drum brake piaggio ever made, cruise german ebay for cosa forks .they would need converting at top to take a sprint headset ,but its not a big job . with the hydraulic slave cylinder blanked off an just on cable operation there a match for a disc anyday with loads more feel . theres adjusters at the heels of shoes on slave cylinder so when well adjusted have a much better contact patch over the whole shoe length .
an if ya later win the lottery "scooter&service" in germany do a outboard 4 pot caliper system for cosa forks ,usually for there 30bhp+ smallies . but at 24 your close to my 25bhp "time to go disc" limit/rule . H
|
|
|
|
Post by davetesseyman on Mar 27, 2016 21:20:25 GMT
210 malossi. Malossi ignition. Reed valve. Jl lhs exhaust.race crank. Strenghtened clutch. All done by chiselspeed. He was well chuffed with the bhp and openly admitted that he didnt think it would achieve that! It has the grin factor, but it doesn't stop. I am going to try and get on with the original front end for now because I have spent enough at the mo, any mote ideas on that ?
Ta
|
|
|
|
Post by davetesseyman on Mar 28, 2016 8:06:15 GMT
Also,you mentioned px forks,do they go straight in without and cutting welding etc ?
thanks
|
|
|
|
Post by henri on Mar 29, 2016 15:49:52 GMT
need to get "creative" for steering stops an a hole drilled for your steering lock if you still want it to work . apart from that its straightforward swap . if you want to go disc , cheapest options a et2/et4/lx front forks ,same amount of work to fit but a third the price to buy than px ones .but fork legs on other side ,so anoraks will keep walking up an telling you that .you can then tell em about the engine an watch there heads spin before pointing out were you'll stick the forks if they dont bugger off . hours of fun . H
|
|
|
|
Post by davetesseyman on Mar 30, 2016 15:26:06 GMT
Sorry to keep going on Henri but this is really bugging me! Is there such a thing as an internal stopper or rubber stopper on these forks that I might have forgotten to put in? The travel on the swinging arms is definitely pulling the speedo cable out (tried two different ones now) I have ordered the longest spring you can buy for the bugger now so that might change something ?
Will a sport mudguard fit straight on px forks ?
Ta very much
Dave
|
|
