bultacosteve

I didnt see the A at the end of the serial number when you previously posted. So yes that model was produced starting in 1980. Congrats nice bike!! Anytime you order parts from any Bultaco parts dealer always state the full serial number as this will more accurately reflect what parts the bike may or may not use. The year reference makes no differnce in what parts the bike uses only the serial number will. Steve

The M199 Sherpa T was produced from around 1978 to 1980. For this reason it would be impossible to date the bike unless it has registration papers. In any case the year isn't important. The only important numbers are the ones on the frame and engine. These denote what model the bike is. In your case it is a 325cc sherpa t. Almost all parts are available for this bike. Try Bultaco uk (www.bultacouk.com). I'm sure they will stock everything you are after for that bike. Ebay is a good source for parts too. Exhaust systems regularly come up for sale. You can fit a mikuni carb or go with the original bing. I would contact bultaco uk first, tell them what model you have and what you need and they can get you started. I highly recommend you get a parts and service manual for the bike. Steve

I disagree completely. Horsepower numbers will show that there is more power to be made using more oil. That isn't my opinion it is documented scientific fact, period. If 100:1 works for you or Helmut (I am aware of him although he is from ontario I am in BC) then thats fantastic. More oil equals more horsepower. Give A. Graham Bells 2 stroke tuning theory a read or any article written by Jennings (cant remember his first name Gordon I think). They are easily available on the net. Their research and development on 2 strokes is world renowned. However as mentioned if opti 100:1 works for you or anyone else thats great. I just prefer to use 50:1. Keep in mind my background. I have been a motorcycle mechanic working professionally in a dealership for 20 years. I have rebuilt literally thousands of 2 strokes and 2 facts I can gauruntee with great certainty, wiseco 2 stroke pistons always seize and if using ratios of 60:1 or less will equal engine failure for most people. Those of us on this forum are much more

without getting too far into the oil debate i am not of the belief that less oil is better...... necessarily. Any name brand modern 2 stroke oil mixed at the oil manufacturers spec is fine. I use torco gp-7 @ 50:1 in my trials bike. 50:1 does seem to be what most folks are using in the sherpas. In actual fact the harder a 2 stroke engine runs the more oil it needs. Lets take a bultaco astro as an example. here is a bike that is meant to run wide open and fast all the time. This engine needs more oil to help disapate heat away from the piston and into the cylinder wall. An engine that runs at lower rpm like a sherpa t doesn't generate the heat like an astro or a pursang so one can get away with using less oil. Optimol while still used widely here in canada and the u.s. is only good for trials type riding. In any motocross style bike that i have seen it used in they seize. this may likely have been caused by poor setup and maintenance but none the less if more oil had been used the repairs would have cost less. So in closing use any name brand 2 stroke oil like bel ray, yamalube, golden spectro, maxima, torco, motorex, motul etc etc pick one stick with it and mix it the way that the bottle tells you. Usually the manufacture will allow for any variance between 32 and 50 to 1. Theres no secret just pick one and stick with it Steve

Ok I went through this before a few weeks back on another post. On the Bing carb it uses an "air screw" . When turning the screw out from the carb it is adding more air to the fuel mix causing it to be leaner. Turning the screw in lessens the amount of air causing it to have more fuel or rich. 3/4 turn out is a good starting point. Basically start there and turn the screw out slowly, you may or may not notice that the engine starts to run more evenly and the idle speed will rise. This is fine just turn the idle down and adjust again until the lowest stable possible idle is achieved. Don't worry if its 1.5 turns out. if it runs good there then fine. But if it runs better all the way in then you need a larger pilot jet . If it runs better at lets say 2.5 turns out you may wanta leaner pilot jet. It is important to differentiate between a fuel mix screw and an air mix. otherwise you will be going the wrong direction with jetting changes. steve

Perfect description of how to set points on these bikes. If you can do em on the bultaco you can set timing on anything. My only suggestion is the use of a seperate flywheel to set the ignition. Only problem with that is the points cam on the inside of the flywheel can wear at different rates from flywheel to flywheel so best to use the one you are going to run with when setting up points Steve

Without being there to see what the problem is I have no way to help you. Sounds like the woodruff key might be the problem but i have no idea without being able to see it Steve

I would call Dave Renham and order the Bultaco service manual. It goes into complete detail on how to set up points and timing them. You will also need a top dead center gauge and a buzz box or timing lite or ohm meter to tell you when the points are opening. These tools with the service manual will enable you to do your timing. Steve

If you just got the new ignition then there is no better time than right now to replace the magneto side crank seal. When you remove the old flywheel and stator plate, underneath there is a plate with a seal in it that is held in with 6 screws. Remove this plate and tap out the old seal with the appropriate sized driver. Install the new seal into the plate using the same driver and reinstall onto the motor. and thats all there is to replacing crank seals. The right side or "pto" seal is a little more involved as you would have to remove the clutch assembly and final drive to gain access to the seal plate on that side. But for now just do the magneto side. New seals are dirt cheap and easy to come by at any automotive retailer that sells bearings. The seal size is 25x40x12. There is also an oring that should be replaced and its sizing is 50x2. On the clutch side the seal size is 32x47x12, it uses an o ring also and is the same size as previously mentioned. I have installed several femsatronic and motoplat electronic ignitions over the years but I haven't done any of the new stuff like those available from pvl or electrex. That aside it should be relatively straight forward so long as you have an accurate way of determining TDC. The product itself should come with complete instructions for assembly and will tell you how to set them up. The one benefit of electronic is that the ignition curve will advance and retard with engine rpm whereas a points system will only remain constant which can cause pre ignition or detonation problems. Spark plugs such as those available from NGK come pre gapped and shouldn't need adjustment. It doesn't hurt to check them but usually thgey are fine right out of the box. As far as which plug to use could be up for some debate. These days in my M199B I have been using a BP5ES NGK and it seems to work just fine. In my M159 I use a B7ES and it works fine. I don`t like using resistor style plugs although they seem to be all thats available now so we are kind of forced to use them. The only reason for their use is they cut down on radio interference. I would never use one on an original femsatronic ignition as it could cause damage to the system. I have worked as a motorcycle mechanic for the last 20 years and in that time have worked on a lot of different bikes. bultacos are no different than anything else out there when it comes to making them run correctly. As said in my previous post Spark, fuel, and Compression are what it takes to make an engine run properly. Take your time to make sure each one of those things is correct. Remember that 2 strokes have primary and secondary compression. That means that you could do a top end compression check and it would show fine but not run. It could be the primary or crankcase compression that is bad causing it not to run. Thats why I mentioned replacing crank seals and the like. Make sure that you have spark and that it is firing when it is supposed to. Fuel, make sure the carb is clean and that fuel is flowing to it from the tank. If those 3 requirements are met then your bike has no reason not to run. Poor running or hard starting or no running at all will always be from no spark, or poorly timed spark, bad compression or no fuel. Nothing else. Good luck Steve

So if the engine only fires when fuel is put in through the spark plug hole then I would suspect that fuel isn't getting from the carb to the engine!!!! But thats the simple answer. I am willing to bet after reading your other posts that you likely have several simple problems that need to be addressed. 1st you mentioned that your carb is brand new from bultaco uk. Take it apart carefully and make sure that the jets and all passageways are clear. you also said that you have to mess with the inline fuel filter to get fuel to flow to the carb. Make sure the petcock in the tank is clean and flowing fuel properly. 2nd is air leaks. air can leak from the intake manifold, crank seals, center case and base gaskets. If you have an air leak it will make it hard to start. If the engine is sucking air then there won't be enough primary compression to suck fuel from the carb into the engine. 3rd is spark. The timing of the spark is very important. 2.5 to 2.7 mm before top dead center is the spec. The femsa points ignition is a good one and when setup correctly there is no reason to get an electronic. A new ignition won't make it start easier. Spark, fuel, compression. those 3 things are critical. I would make sure 1st that the carb is clean and fuel is flowing. Next if you don't know the history of the bike replace the crank seals and as a matter of course replace the base gasket and intake manifold gasket. If you have spark then you have spark, don't worry about how fat and blue it may or may not be it doesn't matter. You have to only make sure that it is sparking at the right time. Set the point gap 1st and then check the the timing. If the timing is off then the stator plate will need to be moved. Clockwise advances the timing (fires sooner) counter clockwise retards it (fires later). Don't and I repeat don't adjust timing by adjusting points gap only adjust timing by moving the stator plate. If you aren't sure how to do it then have someone who does know do it. I'm sure bultaco uk could get you set up in an afternoon. Sometimes rather than throwing expensive parts like ignitions and such on the bike to try to maybe get it going better, your money is better spent paying an expert to do the work and get it going the way it should with the parts that are already there. less headaches in the longrun Steve

Just a quick note to let all those interested know that there is a classic trial at IOCO on Sunday April 3rd. There will be 2 lines. A line for the more experienced riders and b line for the less experienced. So bring out your classic iron and enjoy a great day of trialing and trail riding. Hope to see you there. Please note modern bikes are welcome to ride the event also Steve Coates

The small seal you are talking about is best pried out gently with a sharp pick. Make sure that the end of the shaft isn`t galled or burred. Grease the seal completely and find a socket the same OD of the seal. Gently tap the new seal into place. It just needs to be flush with sleeve gear end. Usually the spring side of a seal will go towards the inside of the engine. On this small seal that bultaco used depending on which direction the inside lip goes the spring could possibly be out. easiest way to tell is to look at which way the rubber seal lip faces. Install it so that the stretched side goes out so that when installing it it doesn`t hook on the gear and rip when being installed. If you don`t already have one I strongly recommend that you buy a parts manual for this model and also get the Bultaco service manual. Both are available from Dave Renham and are invaluable for this type of thing. I have the parts book open if front of me now and it plainly shows what order all the parts go in. The service manual also explains seal installation procedures. Hope this helps Steve

Check your parts manual because some 159's did use different conrods. Some may utilize the thrust washers some don't. I'm sure Bultaco uk could tell you what is what. It seems to me that I had this problem when I built up my 159 some years back. But yes it may be related to the rod. Steve

Actually the proper term is not mixture screw , but "air screw" on the bing carb. So when turning the screw in it is actually richening the idle mix (more fuel less air) and backing it out is leaning the mix (more air less fuel). So if its running better with more fuel (screw in fully) obviously it is needing that fuel to run correctly so try a richer jet. As the above post mentioned make sure the carb is perfectly clean. Even new carbs should be thoroughly checked. To clarify further a "fuel mixture" screw works the opposite way. When turned out its adding fuel making it richer , turned in it is making the mix leaner. The easiest way to determine what a particular carb has ( air screw or mixture screw ) is as follows. The air screw on a carb is always on the air filter side or rear of the carb usually near the bell mouth. A fuel mix screw is on the intake side of a carb usually pointing straight down but in certain cases could also be sideways . It is important to realize the difference between the two or your adjustments will be going the wrong direction. Steve

I stand corrected the late model 125's and bandido/montadero had to be in neutral to start. Bultaco always used a layshaft and a mainshaft in the transmission with a sleeve gear that drove the sprocket. Not like most other transmissions that use a mainshaft and countershaft type design. the latter being more efficient i think, because power comes in through one shaft and is directed out the other. with bultaco power comes in, is transfered to the layshaft and then again transfered back to the sleeve gear that is on the main. My guess is that they had difficulty making a gear drive primary system work correctly without having heat expansion problems that would change the clearance or backlash on the primary gears. It was easier to use a primary chain and be done with it. The result being a somewhat stiff feeling trans. I won't say they weren't any good because i have never heard of someone having gear box probs on a bultaco. they're built like a bricksh&^ house . I think in 77 when the M194 125cc pursang came out bultaco had by then rectified gear drive problems. They by then were using the all new geared primary motor in the 75cc frontera, and eventually it made its way to some of the late streakers. i'd bet some of that r&d was transfered to the 125 pursang. a high revving motor like that was another reason to go to gears as primary chains would be prone to breakage. Bultaco had for a long time been developing other engine types. its a shame they couldn't have made them work. The engine used in the montjuich road bike had been around for quite some time (pomeroy used it in competition). I'd bet there are less than 6 or 7 of that engine type left in existence. The late model 75cc frontera and streaker were also totally new for those models and eventually the very late model prototype pursangs had a different engine yet again. I guess they rested on their laurels because they had to. With not being able to import decent accessories for their bikes left them at a distinct disadvantage. Better suspension units and braking coupled with decent metals for frames and the like and they would have been a force to reckon with. That and scaling back their production from all disciplines of the sport to just motocross and trials I think could have helped. Just my opinion Steve

I've had it happen several times on my m159 sherpa. I used to think that it was because of improper ignition timing.... but my timing is spot on and occasionally the engine still starts backwards. It has more to do with the fact that it is piston port inlet, and that if the piston doesn't quite come over top dead center but combustion does occur causing the piston to reverse its direction of travel making then engine run in reverse. A word of caution when run this way the timing is severely retarded. If run for a decent length of time the ignited fuel will actually be "chased" out of the cylinder by spark propigation causing severe erosion of the exhaust side of the piston. Only a select few bultacos had primary kick (bandito and late model 125 pursangs.) I routinely start my sherpa in gear with the clutch out. steve

I have a 159 as well. You can go about it 2 ways. 1st is to convert it to a cable operated rear brake like the 199 series. You will need to buy a left side shifter and a right side brake pedal as well as the cable. you can get them from bultaco uk or hughs bultaco. you would have to have some tabs welded on the frame for the cable to mount to and something rigged to mount the brake. Or you you can get an Alpina type non conical rear wheel and use a rod operated right side brake. (later model alpina's had l/s sprocket r/s brake.) I know someone who did this conversion and it works really quite well. My 159 frame actually already has the hole drilled on the right side of the frame where the brake can mount to . I tried and tried to get used to left side braking and it just doesn't work for me. I have the bits to convert it but haven't had the time to do so. Plus I ride my 199B more frequently and its already set up right side brake Steve

I also have the same problem with my M199B. 1st loop it runs great 2nd or 3rd loop it gets really hot and knocks horribly. I have the timing and point gap spot on. The crank seals and gaskets are new. I have a flatslide mikuni on it with a 20 pilot and 185 main. I tried an extra base gasket to lower compression and it still gets way too noisy. I took the top end off yesterday for some regular maintenance and there is no indication of preignition or detonation. No seizure marks on the piston. I quite honestly am at a loss as to why it knocks so bad. I actually think I'll put the bing carb back on and see if that helps. Steve

Wiseco pistons are widely available and have been around for years no question. Bare in mind that this forum has a broad membership of enthusiasts, most with some mechanical back ground. And most are aware that engine break in is critical. But in 18 years of professional wrenching all wiseco pistons I have ever seen in 2 stroke engines have seized . Under the right break in conditions and a knowledgeable owner they do perform well. Their lightness means less reciprocating mass which in turn gives more power. But to the average person riding a 2stroke dirt bike out there they are a poor choice period. The use of a wiseco 4 stroke piston is a different matter. they actually perform well and are quite durable. As a professional mechanic I cannot stress enough the importance to all motorcycle owners on this forum or that come into the dealership that I work at that your factory service manual and owners manual should always be the last word in what is right and what is wrong!!!. Now given that Bultaco is not around any longer many theories can abound about what should or shouldn't be done but the bottom line is the Bultaco factory service manual should always be adhered to. The haynes manul or clymer manual that are widely available simply aren't good enough when it comes to the finer details of engine assembly and setup. Also it doesn't matter how many years experience the local machinist has. His or her experience won't come close to the engineers and people who designed the engine in question. Always follow manufacturers spec vintage or modern. I see more problems that are due to "my buddy said this" or "the internet said that". The last thing most people do is actually open the proper manual and follow its instructions. Read them, know them, understand them, your bike will be better off for it!!!

I have the factory Bultaco service manual and it states that for a new 326cc engine that the clearance should be .002 . With a 360cc engine the clearance should be .0035 Now one thing that has not been mentioned is when using a new Mahle piston you will find a letter and number stamped on top of the piston. It may be T2+ or T2-. Pay strict attention to this numbering system when boring and honing the cylinder to the correct size. These figures when used in conjunction with the Bultaco Manual will give you optimal piston clearance when reboring. The pistons were carefully measured when new and the clearance numbers were stamped on top of the crown for this reason. Pay attention to them. Bultaco knew what they were doing when they manufactured these bikes. Their way of proper setup should be accepted as gospel truth. Its fine that other people have bored and honed cylinders to whatever clearance they wanted and have "never had any problems". The problem with that is they weren't the ones who designed the engine and won't know what the thermal expansion rate of that engine is or why it is. Honestly Bultaco knew what they were doing. Piston, and piston ring and cylinder design were one of Bultacos' fortes that is sorely overlooked. Also ask your machinist when they take their clearance measurement. Is it directly after reboring? or do they wait..... If they do it right away I'd ask for my cylinder back and never use their services again. Proper clearance can only be done when the cylinder is at room temp!!!. There are many things to consider when reboring and fitment. I strongly suggest getting the proper manual and adhering to it. And make sure your machinist adheres to it too. The above only applies to original Mahle parts. When using seizco pistons I'd run the clearance at .004 thou cold to make sure a seizure doesn't occur. In 18 years of being a professional motorcycle mechanic every Wiseco 2 stroke piston that I have ever seen in an engine has seized. They're total junk. Stick with Mahle if you can .

Actually they do help hold the wrist pin bearing in place. But the real purpose for them is to centralize the connecting rod on the crank shaft. Some Bultaco cranks (not all) when pressed together allow the con rod to slide side to side. Sometimes they are able to slide a 1/16th of an inch or more. This sliding is prevented by using the aluminum thrust washers at the wrist pin. They are crucial so make sure they are installed!!!. Steve

I have a photocopy of the Bultaco factory production list. It says that 1275 Model 10 Sherpa t's were made with production beginning in December 1964 and ending in April 67. This list cannot be considered gospel truth but none the less it is on offical company letter head and was published by Cemoto. I can't verify for certain that their record keeping was perfect but according to Cemoto that is when production began and ended. I have provided a list of total production numbers for all model Sherpa T's. Don't consider this the correct amount built. I personally own 2 models that are well above the serial number range as printed. I know that the Spanish government kept track of what it was exporting under Franco's rule . If your bike has a serial number higher than what I have listed then you can be sure that that many bikes were built. here are the rest of the sherpa production numbers. I left out the 74. 125 and 175 cc sherpa's I do have numbers for them too. If someone wants to know just contact me. Please note that in some cases the production dates overlap. This isn't surprising as Bultaco would have built bikes until all parts for that model were exhausted even though production had already started on the next model. This was common practice for them. After posting this I found that it wasn't as I had typed it out. so it goes model number then the total production for that model and then the years or year it started and ended production Model production total Years produced M10 1275 Dec 64 Apr 67 M27 700 July 67 May 68 M49 4706 Nov 68 Apr 71 M80 2932 Apr 71 Apr 72 M91 1796 Sept 72 ???? M92 4578 Feb 72 Sept 73 M124 740 Feb 74 ???? M125 2108 Jan 75 ???? M133 13 (factory bikes rathmell likely rode one of these) Apr 74 M150 599 Oct 74 M151 580 (this is wrong as I have serial 850) Oct 74 Feb 75 M158 1641 July 75 ??? M159 500 (again this is wrong as mine is in the 4000 range) Apr 75 July 76 M182 500 May 76 ???? M183 790 Apr 76 M190 1300 Oct 76 feb 77 M191 1451 oct 76 ?????? M198 1770 July 77 M198A 2050 Nov 78 M198B 270 Sept 81 M199 5960 May 77 M199A 6915 Oct 78 M199B 1778 May 81 To clarify the M199 series. When Bultaco started production of the M199A they didn't give it a new model number rather they just continued with the serial number but added an A after the number on the bike. So the very 1st M199A had serial number 5961. The very 1st M199B had serial number 12876 or within 1 or 2 numbers of that. Total production of all M199 series bikes was 14653. Steve

As far as I am aware the M80 and M85 frame are identical. The M49 was different from the M80 but only in its mount points for tank seat etc Steve

Yes I am refering to crankcsae vs cylinder compression. Bultaco crank seals can go bad as well as cylinder base gaskets. Both are very easy to change and should be done on any recently purchased bike that hasn't run in a few years. I have found that the carb manifold can also leak. Air leaks even slight can cause major running issues on these bikes. Steve

As already posted it is the first of the slimline sherpa's. I had one for about 4 years. I liked how it handled and the engine was excellent. It has a few draw backs. The brakes on mine never worked very well. I put new shoes in, thoroughly cleaned the drums and made sure they were true but they still didn't work very well. The frame geometry is great but is on the heavy side. The later model slimline (M124, M125) was made from chromoly and is much lighter. The rear triangular muffler on these bikes is usually missing. Most people either took them off right away and promptly lost them or got thrown away. Consequently now they are very rare. They do come up for sale on ebay once and awhile but never go for less than 150 bucks. Not having one doesn't detract from how the bike runs. It actually will run better without it. A properly packed front muffler and the M80 sounds great. Having said all this I believe that this is an excellent classic bike and in classic trials it will perform very well. As with all Bultacos it is critical that they have properly timed spark, good primary and secondary compression, and a carburetor that is functioning properly. The Amal carbs on these wear out in about 4 rides. So when refurbishing the bike make sure you put at the very least a new slide, new needle, needle jet and gasket kit in the carb. I see more questions on classic bultaco forums about poor running bikes and the carb is always overlooked. Anyway good luck with your bike. Ask as many questions as you like there are lots of knowledgeable people on this forum. Steve