sherpa325

Hi , make sure the crank is running true before the assembly and also check that you have the correct clearance main bearings, as both these things can cause overheating. Cheers Greg

It is surprising how easy it it to get the crank our of round if the cases are just pulled together using the case nuts/bolts. I have had two friends with bent cranks, the bultaco one only went for about an hour or so before it started to run lean[magneto seal leaking] the other was a rotax engine which used to lose power as it heated up after about an hours running- no other symptoms other than the power dropping off and the motor running hot. The way we have been putting the cases together is to pull the crank into the case using the crank as the puller. You need to have several lengths of a suitable diameter pipe, this is put over the crank as it is protrudes out of the case, a washer is then put on the pipe - the crank nut installed and then tightened up gradually, as the nut is tightened it pulls against the pipe and pulls the crank into the bearing squarely without any chance of 'bending' the crank. Once one side is in place you repeat the procedure on the other side. It is also important to use the correct 'clearance' main bearings as this can also cause the crank to be tight. Cheers Greg

I would guess this is just an early model49 with some later parts fitted- exhaust and tank. I would want further proof to be convinced this was a 'prototype' and one of Millers' personal bikes. All model27's were five speed and had IRZ carbies and were made from 67-68. In regards to it being a Miller bike from that period, all of the early photos I have of his bike show them to be equiped with his own front mudguard/ fork brace, he also had the valence removed from the front rim and PK screws instead of rim clamps- but you never know? Cheers Greg

Sounds like the tyre is not up on the bead and is wobbling- not the rim Put a new rim rubber/tape in, its not that difficult and they dont leak and you wont need a tube, use a water based lube [dishwashing liquid] when fitting tyre and rim tape When putting the rear wheel in- slide axle in 30mm from the right hand side- it will hold itself and the caliper in place, place a long cable tie[150-200mm] in between the pads. You can now place the wheel in position very easily and remove the cable tie as you slide the wheel in without marking the pads, hope this helps. Cheers Greg

The Pre Pro gas gas bikes were more like 77-78 kgs Cheers Greg

I have heard of some people having problems with brand new condensors, so I would replace that as it is cheap, also if you dont have a brand new needle jet [106] then I would replace that as well as both items can cause your problems, the needle jets wear just slightly and you will not be able to tune the bike at all, same with the faulty condensor. Cheers Greg

To me it would make sense to lower the limit say 2kg's every two years so the manufacturers can factor that into their development of their product. By the way any bike from any era that is ridden by a top expert rider for a whole season will feel very second hand. I can remember riding a national title winning sherco which felt like it had a hinge in the middle, compared to my brand new sherco

Hi, I just so happen to have a steel one handy and it measures 59.8mm, I would assume the cast one would be the same, the standard clearance would be quite small as every one I have put back together has been a tight squeeze with any clearance taken up by powder coating, paint etc. They always require a gentle tap with a rubber mallet to put them together. I always put the swinging arm and engine mount in before fitting the engine. Cheers Greg

Hi, have done a few of these myself, the frame will spring once the bottom tubes are cut, so it is important to put the engine back in the frame when fitting the bashplate so the frame is back to the correct dimensions as this is done. Also on the latter factory 199a/b the oil drain plug is on the side of the engine not underneath, so the plate can be mounted closer to the motor, you will have to allow clearance for the protruding plug so that is does not poke through the plate, where it can be damaged. I have seen original miller sherpas with the drain plug welded flush with the bottom of the motor to allow greater clearance, hope this helps Cheers Greg

If the bike has a Mk2 amal, the tunning problems will more than likely be related to the needle and needle jet wearing. The needle wears the needle jet oval and the bike will be impossible to tune, it will run poorly from about 1/4 throttle up, the slide also wears but does not prevent you from tunning it. As has been stated it is well worth replacing the points and condenser just to be on the safe side. The 'B' is bastidor, spanish for frame Cheers Greg

You are best to replace the needle and needle jet as these wear out and make the bike impossible to tune, as raising and lowering the needle will not cure the mid range spluttering that the worn parts cause. The slide also wears very quickly leaving a half- moon on the inlet side. Cheers Greg

The book 'Historia De La Sherpa T' which has the most detail on sherpa production numbers and dates, states that the paintwork becomes blue on the 199A, production begins 10th month 1978. All the photos I have of factory 199 bikes show them to be red tank and silver frame and most of them have the bottom frame tubes removed and replaced with the 199A style bashplate. I can remember taking home my brand new 199 in the crate and being somewhat disappointed when finally getting it out to find all the polished engine cases had been painted black and on top of that it was three different shades of red, the tank, guards and side panels were all different- ouch. Cheers Greg

I think you will find that the 199 and 199A and 199B all have the same gearbox other than the six speed in the 199B and you can use either combination of gearing to get the same result. The gear that concerns most of us is 1st Using 11/39 1st gear is 37.7:1 Using 13/46 1st gear is 37.6:1 Basically no difference other than you have a much smaller rear sprocket Earlier models before the 199 series run 11/46 which gives a 1st gear 37.8:1 So all bikes have the same 1st gear ratio with the factory gearing The 199, 199A and 199B have different internal gears to the previous models, the change was made to give the bikes a higher top speed for events like the Scottish Six Day Hope this helps Greg

Green is earthed Black goes to coil and kill switch Cheers greg

13/46 is correct if the bike is a 199 11/39 for 199A and 199B earlier motors before the internal gearing change are 11/46

PH is the model number B is spigot mount H is the larger body series [L is the smaller body] 26 is size in mm T = ??? D is right side mixture/idle [s is left side mixture/idle] Cheers Greg

Wow Greg thats exactly what I was planning to do with my 198 for the next twinshock masters, but I haven't worked out where to hide the radiator. Can you post pics please?Thanks David I was thinking of putting the radiator in the airbox along with the fuel injector and the hydraulic cylinders for the clutch and brakes, do you think this is feasible. I have an old lawn mower that that I was going to remove the fins from the motor, and carefully araldite [24hrs type] to the gasgas barrel and head.

Brian can you have a quiet word in your Mum's ear and mention that I am sick of Bacon and Eggs for breakfast, got to look after the heart you know. Anyway I thought I would give you an update on my 300 gasgas pro motor into my Bultaco 199a conversion. The kickstart doesn't foul the frame anymore as I converted it to left side.I intend running a bing carbie on it so people don't notice the conversion. Cheers Greg

Clockwise = Advance > Anti-clockwise = Retard < Cheers Greg

Yes is it common on bullys, it is a result of the timing being too far advanced and if you don't give it a decent kick when starting, as the piston is just about to reach TDC the plug ignites too soon sending it back the way it came, generally you can pick a different exhaust note as well Cheers Greg

I don't know for sure, but I don't think they are critical in terms of size as long as they are in good operational condition.

Try putting a new condenser in the bike. Faulty condensers will still give a spark when turning the motor over with the kickstart but can breakdown under load. They are relatively cheap and you an eliminate that area as a problem. I put one off a lawnmower once as a stopgap measure for a friend and it worked fine. Cheers Greg

I have been watching this thread for a few days now and I am still curious as to why? If you don't like the rear set handlebar position of the bultaco, I have seen several sherpas that have had the top triple clamp modified to move them forward, but to try and change the leading axle forks to inline forks has got me stumped. Every modern bike has leading axle forks, even Yamaha went to leading axle forks with the monoshock in 1984. A bike with inline forks will have a larger offset of the forktubes to compensate for the change in trail.My point is that you shouldn't change the legs without changing the triple clamps otherwise you are running a combination of both set-ups and I seriously doubt if it will work. Also on a bultaco there is no way that the mudguard is not going to foul on the downtube on full compression. As has been stated before most people I have seen who are having trouble on their twinshock, has been down to the bike being set-up poorly. Most commonly way too soft fork springs[very common on bullys] and too hard rear shocks. Bikes can be made to suit the rider by some very subtle tweaks in particular the handlebar height and the position for and aft has a huge effect on a twinshock. Also it cant be stressed how important time practising on the bike is. Just remember Bultaco won 5 world championships with three different riders with this fork and steering. Cheers Greg

Yes your bike is the first 325, model 92. The most obvious problem is the front hub, should be conical, top triple clamp is correct. The photo posted by TFTim is a little misleading as that bike is not strictly speaking correct for a 2nd series 92, incorrect rear muffler, and black not chromed header bike. As Tim said when set up correctly these are a really easy bike to ride with a very torquey engine, have fun. Cheers Greg

If they are the same as the Gas Gas ones which I think they are, you can buy a purpose built set of pliers to undo them and pull them back together again. The pliers will only be available from a specialist engineering supplier and will be expensive. How do I know this ,well my mate has a set courtesy of the mining industry, and I have tried to buy a reasonably priced set but basically no shop carries them, special order only. The pliers slide the two ends sideways to release them and basically pulls the outside end back over the ridge of the inside end to put them back together if you get my drift. Cheers Greg