Bultaco

Im going to be rebuilding a 325 and wondered if anyone has an opinion on wether its worth boring to 340ccs ?? Anyone had any experience of this and was it an improvement?? What size piston do the 340s use? I guess the head will need machining to suit which is no problem - what squish clearance is prefered?? many thanks Stu

Hi all, my bike has been running for a wee while now, and I'm amazed at how capable it is. Having great fun on it and it makes a nice change from the modern bike. However, the Bulto runs well for maybe half an hour, then will stall, and is a right pig to start. After getting it running, it runs for shorter and shorter periods before bogging/stalling. On inspection, there is plenty fuel in the bowl, and the plug is a little sooty, but not too bad. I'm starting to think hillclimbs and hopping logs make it prone to stalling. Not much to go on, but any ideas? Chris

hello all im doing my other bult up and was woundering what rear shocks to get dont want to spend hunreds say about

I have a blue plastic Bultaco trials tank which I think is an original item as it is stamped 1979 underneath. However, it doesn't look very smart as it is very discoloured. Has anyone ever tried or had any luck in cleaning one of these tanks up and if so can you recommend a technique? otherwise I understand they are more or less impossible to paint as they are porous and the petrol vapour will lift the paint. I would like to fit it to the bike I am just finishing but it just looks a bit shabby.

Hi guys I have spent 2011, buying bits and pieces to finally build up a modified/competative bultaco and have been trying to find out what modifications work and dont work. My questions are what are the best hubs to use for braking performance? I have got steel linners in my 159 and they produce ok stopping power but nothing compared to some TYs, honda,fantics and certian pre 65 scotish winning bikes i know. Has any one tried a different exhaust on there bikes? the bultaco ones seem heavy take up a lot of room and get a lot of mus stuck between it and the rear tyre......i was think a yammaha ty pipe work may work better. last of all..... the clutch. my clutch work…

hi all my bultaco as been sat for a wile since restoring it the petrol as been in the tank for roughly 6 0r 7 months she starts up ok normaly takes a few gose when shes not been run for a wile i had her runing today started up 3thd kick ticking over no probs had a ride round the garden shes dosent seem to be pulling as she did know ive not done anything to her would it be possibel that the petrol as gone stale? hence loss of power

hi all ive had my frame powder coated .and he has powder coated the coil bracket will it be enough earth if i just take the paint from inside the holes were the bolts go throw? allso ive asked this before but have forgot when i put the fork tubes back in the legs .and tighten the bolt up at the botom ive been told to use a copper washer will this stop it leaking.and how many do i need for each leg? one or more?

hi all im taking my engin out off one frame to anougther frame quetion is if i leave the sump plate off can i get the motor in with out taking the headsteady off the head?

Hi, Where is the gearbox oil drain on the 199a Bult? Doesnt seem to be in the same place as my 190 - or am I cracking up... thanks in advance..

To retard the ign do i turn the stator plate anti clockwise a slight amount. All so i have a multi meter with a buzzer on and the top dead centre guage supplied by bultaco uk, how do i rig the multimeter up or a bulb to see when the points are oppening to gauge the amount before top dead. can it be done whitout removing the fly wheel or not.

I'm eager to enter my first trial on the M80 I have rebuilt but what's putting me off is the fact that it's not easy to start. I don't want to turn up and not be able to start it and end up wasting time and money, not to mention the embarassment factor. It's had new seals, gaskets etc and the timing is accurate. The plug is getting wet ( I sometimes wonder if I am flooding it too much) and there is a decent spark. Occasionally it will start first kick but more often that not it either takes many many kicks or it just won't start. Once its warm it starts easily. It's got the original Amal 627 carb and I've cleaned the pilot jet etc. I am considering buying a new Amal 626…

Hi Had the bultaco out at the weekend and managed to stall it on some rocks. When i started her back up and put her in first, she went backwards and had me bent over the bloody handlebars. Tried all gears and every one was in reverse. Has any body ever heard of this. Got her back home on a trailer and started her up last night and all is well again. How can a bike run in reverse. Cheers A very puzzled owner

hi all i have the 199A i use NGK is there an up grade that i can get?

I have a 199A and can buy some 92s for parts. Will the top ends interchange and are they significantly different? What about forks, clutch and gearbox parts? I know you guys know. Thanks

Gents I have recently inherited my fathers Sherpa T 1971 M80. It has stood at the back of his garage for probably 20 or more years without being started. So I have decided to try and get her going. First took off petrol tank and carb which were all gunked up. Cleaned all the jets with airline and ensured all residues were removed.Removed fuel tap and thoroughly cleaned ( replaced cork washer ). Replaced fuel lines as these had gone'hard' and brittle. Thoroughly swilled out the petrol tank. Checked for spark and was pleasantly surprised to see a nice 'fat' blue one. Put some nice fresh petrol in tank and flooded the carb. Moment of truth , I kicked , nothing , and k…

hi guys just a wee question --i have used silicone gasket sealer on magneto casing instead of the normal gasket is this OK kind regards Murray

Hello to all I've just purchased a bultaco 159 project, which needs a hole lot of work. It's stripped now and I'm working out what I need. I think it's a 350 can anyone tell me the piston diameter so I can work it out for sure. Thanks Ben

Ok, what am I doing wrong? I think I've been away too long from Bultos racing 4 strokes with electronic ignition. I've rigged up a lamp and buzzer to test the ignition timing on the M80 I am rebuilding. There are 3 wires from the magneto. Black, green and yellow. I assume yellow is from the lighting coil and so I've blanked it off. I've connected black to the coil and green to a good earth. To test the timing I've attached one lead from the tester to the black wire which I've disonnected from the coil, and the other lead to earth. I've set the piston at TDC and rotated backwards towards 2.9mm BTDC. Problem is the light doesn't go out when the points open, which I thou…

I was wondering has anyone used viton oil seals in a engine rebuild ? I use them every day in pumps and mixers in chemical works and they work well and out last the bearings. But the only downside is they groove stainless shafts more than nitrile ones do. Just a question to see if anyone has had a go before I do.

Apologies if this has been raised before, but what's the best thing to do with an old glassfibre petrol tank that has not been used for many years? I've swilled the tank out with petrol to get rid of any loose debris on the M80 I am rebuilding and removed the tap ready for a new one. But the inside of the tank is very sticky with a yellowy brown film that sticks to your finger when you wipe inside the tank. Is this likey to be old 2 stroke oil or something worse like the effect of ethanol? I don't know how long ethanol has been added to petrol and I don't know how long the bike has been stood. Should I fit a new tap and fill it up and hope for the best or is there someth…