taff_d Posted August 6, 2014 Report Share Posted August 6, 2014 Just finished my first trail on the Bulto tonight and all I can say if the front end is awefull Has anyone fitted a more modern set of forks to a Bult and if so what type and is the conversion easy ? Quote Link to comment Share on other sites More sharing options...
lineaway Posted August 6, 2014 Report Share Posted August 6, 2014 You could just do the steering stem mod. Quote Link to comment Share on other sites More sharing options...
taff_d Posted August 6, 2014 Author Report Share Posted August 6, 2014 Thats another option, fat bar conversion on the tope yoke and HFS inserts. http://www.suspensionhfs.com/en/content/en/bultaco-classic-trial-progressive-suspension-hfs-system Quote Link to comment Share on other sites More sharing options...
bullylover Posted August 7, 2014 Report Share Posted August 7, 2014 (edited) The standard Betor forks on a Sherpa were always considered one of the best forks around in the seventies. Pull them off and pull them apart. Then clean everything out and make sure everything looks okay. Put them back together again and add 180 to 190 ml of 10 to 15 weight fork oil in each leg. I use 15 weight and I weigh around 85 kgs. I am in Australia so it is probably a lot warmer over here. Some new fork springs also help heaps. Edited August 7, 2014 by bullylover 1 Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted August 7, 2014 Report Share Posted August 7, 2014 Not sure whether you are talking about the steering or the fork action itself. For me personally getting off my 300 gasser onto one of my Bultacos, the steering and fork action are the least of the differences I find hard to adjust to. I find the slow response of the brakes, clutch and engine and the added weight more of an issue. The overall handling I find to be very stable and predictable, with the bike less likely to be deflected 'off line' like the newer lighter bikes. Cheers Greg 4 Quote Link to comment Share on other sites More sharing options...
guys Posted August 7, 2014 Report Share Posted August 7, 2014 Not sure whether you are talking about the steering or the fork action itself. For me personally getting off my 300 gasser onto one of my Bultacos, the steering and fork action are the least of the differences I find hard to adjust to. I find the slow response of the brakes, clutch and engine and the added weight more of an issue. The overall handling I find to be very stable and predictable, with the bike less likely to be deflected 'off line' like the newer lighter bikes. Cheers Greg +1 2 Quote Link to comment Share on other sites More sharing options...
taff_d Posted August 7, 2014 Author Report Share Posted August 7, 2014 The whole bike is strange to ride to be fair but the front end steering and suspension are c&%p, forks have been stripped and cleaned and filled up with 200cc of 20w as recommended by inmotion. The forks still top out on acceleration but are not too bad on compression, the steering just wobbles and does not seem to want to hold a line. I know the bike is 37 year old so it's time for a front end upgrade as the std springs will be shot. Quote Link to comment Share on other sites More sharing options...
hencam Posted August 7, 2014 Report Share Posted August 7, 2014 can i enquire please as to what the "steering stem" mod is please, does it involve the 1.5°ish stem angle Quote Link to comment Share on other sites More sharing options...
bondy Posted August 7, 2014 Report Share Posted August 7, 2014 you shouldn't need to mod it just strip the fork and service them with new springs and oil. if it's wobbles the head stock bearings need changing or the top yoke nut needs tightening or the front wheel. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted August 7, 2014 Report Share Posted August 7, 2014 I had 325 bultos from 1977 to 1981 and could not fault the front end on any of the 3, fine in sections and fine on time trial type going and large drop offs. I suspect there is something wrong with your forks. Quote Link to comment Share on other sites More sharing options...
woody Posted August 7, 2014 Report Share Posted August 7, 2014 200cc is a lot of oil for Sherpa forks, and with 20 weight it could make them very hard with limited travel, which may be the reason you're having trouble. I'm using 180cc absolute max, generally 7.5 or 10 weight and I weigh 110+kg or around 17.5 stones in old money. Put new springs in, there's a choice of In Motion's own springs, Magicals or HFS. The latter two are a more modern, progressive action, I have Magicals, a mate has HFS, both work well (this is the HFS clubman kit which doesn't have the cartridge insert. I tried one of those and nearly threw it over the wall in frustration at trying to set the pressure. Springs are all you need) The bush at the top of the damper rod has a fibre seal around it. If this has gone hard or worn it will let oil past which reduces damping effect as instead of being forced through the damper rod holes it just flows past the bush. If they are worn, replacing them will make a difference to fork action and allow thinner oil. I doubt you can buy them new, you can make new seals from PTFE card. Sherpa forks aren't quite as good as Marzocchis and although they seem identical inside to me, not quite as good as Ossa forks either, but they are more than capable of doing the job. Looking to swap to other forks is wasting your money, it's not going to make a significant difference from properly working Sherpa forks. Other forks are also longer by about 2" so you can't fit them in the Sherpa top yoke unless you lap out the shoulder inside, otherwise you need yokes too. Also be prepared to have the new legs sticking out of the top yoke by about 2" because if you don't their longer length will give you something that looks more at home in Easy Rider. The 199a is more than capable of handling today's classic trials, there's no need to start cutting the head angle or top yoke. Yes they offer an improvement if done properly, but not really necessary, it's still down to the rider holding the bars. 6 Quote Link to comment Share on other sites More sharing options...
taff_d Posted August 8, 2014 Author Report Share Posted August 8, 2014 Thanks for the replies 180cc and 20w oil was recommended by one of the twinshock shops and also by the Bultaco workshop manual, I was advised to up the quantity by a very experienced twinshock rider to help out with the forks topping out and it helped. The head bearing are fine and nothing is loose I think I'm just struggling getting off a Factory Beta on to a 37 year old bike. I'm not trying to recreate a straight from the factory Bulto I just want a project to mess on with and in the end something that I like riding at the correct trial. I take it that no one has tried fitting different forks then as there has been no repies ??? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted August 8, 2014 Report Share Posted August 8, 2014 OK here's a reply about swapping forks There's a bloke here who fitted a TLR250 front end to his Bultaco but it was not for the forks, he wanted to improve the front brakes and it was easiest to do it that way. Another bloke here fitted and upside-down forks front end (Paoli?)off an early model Beta or late model Fantic fitted to a Bultaco, and that was mainly to make it easy to fit a front disc brake. Both of them looked ridiculous. The one with the Paoli front end got converted back to standard so he could ride in Twinshock class, and the bloke with the TLR front end stopped riding it and went back to riding a modern bike. Meanwhile, thousands of other people have not fitted different forks to their Bultacos, and continue to get great enjoyment from riding them that way. If your forks are still topping out with 200ml of 20 weight oil/leg, then there are a few possible causes: Someone has taken the anti-topping springs out, there is way too much fork spring preload, or the forks have been assembled incorrectly 1 Quote Link to comment Share on other sites More sharing options...
taff_d Posted August 8, 2014 Author Report Share Posted August 8, 2014 (edited) Beta forks with a disk now that's a good idea ride it in the twinshock class sit back and watch the old farts whinge " Meanwhile, thousands of other people have not fitted different forks to their Bultacos, and continue to get great enjoyment from riding them that way" Am I not allowed to be different ? its my bike my money and my time Edited August 8, 2014 by taff_d Quote Link to comment Share on other sites More sharing options...
lineaway Posted August 8, 2014 Report Share Posted August 8, 2014 can i enquire please as to what the "steering stem" mod is please, does it involve the 1.5°ish stem angle Change to the Alpina or Pursang style stem. Quote Link to comment Share on other sites More sharing options...
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