johnjsy

Hi Bill, I have sealed several fibreglass tanks with success using Slosh from Draganfly Motorcycles. It is a job best done in the summer when you can be sure the inside of the tank is bone dry. I use caustic soda to clean out any muck and residue of oil that may be left. I do this several times then be sure to rinse out with lots of hot water each time. Be extra careful, it is nasty stuff. Keep any youngsters and animals well away ! Done slowly and carefully sealing your tank will be fine. Hope this helps.......

Hi Malcolm, yes, the big end does have a lot of lateral play as the con rod is kept central by the 2 alloy spacers each side of the little end bearing before the gudgeon pin is fitted. I usually make new ones and aim for about 5 thou clearance, fiddly and time consuming but I like things to be “ just so” ! Use C 3 clearance bearings on the crankshaft, I use a a NJ 205 ECP/ C3. By SKF on the ignition flywheel side, it makes re-assembly so much easier plus is much longer lasting on that side. Make sure you get the correct O rings set for your motor, they often get left out, not a good idea ! Oils, everyone you ask have their pet theories, it is your motor, your choice. Fully synthetic is fine for modern motors, not for our 50 year old ones. I think I have tried most, but have settled on Lucas semi sync. At around 32 to 1, that is 187 cc to 6 litres of fuel. I may be right, or wrong, but my motors run just fine at that. Finally, get your nose into a good workshop manual, if you get stuck, put that hammer down and ask ! You will find lots of good info on here ! Over to you.......

The Astro would not have been much good as a road machine. Being made for short track racing the gearshift and rear brake are both on the right side. No front brake. The 250 had a compression of 12 to 1, not too practical for street use ! The 363 cc version was Pursang Mk 9 based, again 10 to 1 compression for that motor. Again, the chassis was short and light, designed especially for a single purpose, to race and win. However, the occasional one is for sale in France. I check Le Bonne Coin occasionally and the listing changes quite often. I think a late Matador would suit you ? I have 4 different Bultacos on the road. Each has its own characteristics, possibly my favourite being a 175 Lobito. John.

Hullo Art, the under carb filler is for the gearbox, on a dry motor it needs 600 cc of 90 grade gear oil. I use Comma mineral oil. The filler on the side casting is for the clutch, use 300cc on a dry motor. If just changing oils then reduce the amount by about 50 cc. There are many different opinions for what to use in the clutch, many folk use Auto Trans fluid. That’s car automatic transmission oil. My feeling is that it does not lubricate the chain properly, so I use a straight 30 mineral oil at 25% to 75% of auto trans fluid. Someone posted on here that it worked well, so I am giving that a try as well. At the end of the day I am sure you have your own ideas on best, or worst !! Oils, you decide. Hope this helps.....

Hi Cribbs, yes, diesel is great for soaking motors in that state. For parts Lynn Mobley in Nevada is a great source of parts. Let us know how you get on.

Hi Ciaran, Ebay.com the world wide one has over 11,000 entries at present. However, Bultaco U.K. In Motion usually has most of what I have needed over the years. Your next move is to source a couple of workshop manuals, often advertised secondhand. One is by Clymer Publications, the other by Haynes. Neither is perfect, but using both should steer you in the right direction for any issues you may have. If you put in a question here, always give a frame plus engine number, maybe also a picture or two of your problem as it helps a lot. There is loads of good help on this site, just ask ! Bultacos are great bikes. Properly looked after they will give you hours of fun. Enjoy.

I have an old Sammy Miller catalogue which says Ford sunburst red. I would think that any car paint supplier could mix this for you. For silver grey Ford silver fox is decent match as well. I have used both, quite happy with the result. Hope this helps............

Hullo Herman , I am not sure if anyone makes them specifically, but a person with good metalworking skills should be able to adapt something from another make. The left side placement of the starter pedal does limit one somewhat, but I remember my Suzuki Super Six I had way back was like that, a good place to start ? Some Italian bikes from the same era were also left side starters. I expect the splines from a Bultaco lever would need to be used. A matter of lining up the 2 levers then seeing what the options are. A few years back I made up one for an Ariel 500 single. We used a much later Suzuki lever and swivel with the Ariel splined piece, a solid pin in the middle then Mig welded to finish. Works well and is still in use today. So I say it is do-able with the right parts plus some help of a capable person to stitch it all together properly. Hope this helps, John.

Hi Watch this,( your passport must cause some amusement) ! Mid 1960’s I did a double entry with my 125 TSS 4 speed version, and a 250 Suzuki Super Six. These days I have 4 different Bultacos on the road, with a second Metralla slowly building. Thanks for your quick response, good to hear from you. Oh yes ,just to mention, I lent to a friend at an early 5 mile road sprint the Suzuki a his bike had problems. He did 92.5 mph across the line, I believe that time is still a record. We had a 1 Km sprint that year. Nice to look back, glad I saw the 1960’s , such good times for most folk. John.

Watch this, which year and which sprint are you in on the picture ? I remember seeing a picture in the local paper of a TSS being loaded in Granville I think it was, a couple of years ago, to Jersey. Then the trail went cold ! As I had a 1960’s TSS I was hoping to see it. Regards, John Parry.

Pinball, one thing often overlooked is a poor or non existent earth contact between the motor casings and the frame If a machine has been standing a long time then rust may be present on the engine mounting tabs. In just 20 minutes make up a fairly thick wire with a ring terminal each end. One end under a 6 mm nut at the rear of the engine casing, kickstart side, the other end to any handy bolt on the frame. Make sure your connections are super clean. That’s it ! Poor earths cause no end of weird effects, this bypasses a common one on older bikes. When everything is running as it should, just make a neater, tidier job of this good earth. Hope this helps........

Any more to report Speshal ? I have enjoyed your baptism of fire, should we say, of your crusade to rescue one more Bultaco that could so easily have been lost for ever. Well done for putting a lot of effort into your build. Don Paco would have been proud of you ! John, down in Jsy.

Hi, there is a thin shim like thrust washer that goes on after the 28 tooth gear is assembled. It is often missing on the motors I have worked on. The noise you can hear could be the starter shaft moving sideways a bit. Just to mention, these days I make my own shim, usually out of a piece of stainless. I have quite a stock of various thicknesses of stainless from for example, an old butter dish, flat part of a sink top etc: Each build needs enough clearance for expansion, but not too tight as well. Was the bronze bush badly worn ? If so the gear could be kicking sideways a bit. One other thing to consider. Oil. Avoid at all costs GL5 gear oil. It contains additatives that will eat yellow metals, that is bronze or copper based. GL4 mineral oil such as Comma 80-90 should be o.k. Mostly I use Millers Green gearbox oil which is fine. Hope this helps, John.

Hi Scbond, apologies, I am a bit behind with things, only just read about your problem. Here’s what I do— I find 2 spanner’s that are a tight but easy fit in the crankwheels opposite the crankpin if it is necessary to give a bit of a tap on the crankshaft with a copper hammer to nudge it over a bit. This stops all of the pressure being put on the big end a bit sideways. Just to mention, I now assemble my motors always using a SKF NJ 205 ECP /C3. On the ignition side. It makes assembling the lower end so much easier, also a lot easier to undo if something is not quite right. When the mains do go it is usually this side. The roller bearing is much more sturdy than the usual ball bearing of the same size. Hope this helps one —- or more of you guys out there ! John.

Hi Okie, I needed to look at the problem of the chain just kissing the swing arm on my Alpina, but not knowing that a correct item was available I made a rubbing pad from a strip of nylon like kitchen cutting board. It needed to be bent down a bit to fit, a little heat from a hot air gun set to low soon did this. Held in place with some instant grab adhesive it has worked well. It also worked well in a chain tensioner that was getting well worn. I hope this is of help, John.

Hi Rootsman,let's see if I can help a little.First off,if you are quite heavy,a recognised mod is to use Pursang springs in the forks as they are a bit longer than the usual Sherpa ones. I use aftermarket Magicals in my Alpina. Next,I have not tried this,but have seen mention to use a Yamaha brake cable on the front as they are made much heavier than others,resulting in the outer not compressing when braking hard.Look for 77-84 YZ or DT 125 MX. The brakes are known to be feeble,another piece of info I came across is to use brake lining used on fork lift trucks. I did this on a road bike,it now brakes really well.Engine. All trials models used a 60 mm stroke. The M92 & Alpina M99 are unique. The crankshaft is slightly bigger in diameter than the 250's , but I think the cases are basically the same. If you put a 250 centre gasket on a M92 case it overlaps inwards a little towards the crankshaft,needing a little careful trimming. This I did when building my M92. Important!!! Use C3 clearance bearings when building the crankshaft. Also a good idea to use a roller bearing on the flywheel mag side. It is a NJ 205 ECP/C3. That's a SKF number. These 326cc motors give loads of torque when set up nicely,a delight to ride.i hope the above is of help,and wish you well.

Hi Brian,back again.First off,before I forget,check out----Bultaco build notes by snarlyjohn. oldjohnno.id.au>b lots of very sound info there. The roller bearing. There is a lot of "fling" from such a heavy rotating mass & a roller race will handle this loading much better than a ball race,especially in a two stroke not having the benefit of a forced oil supply. The fact that it makes closing the two crankcases together on assembly so easy is an extra bonus. Getting the crankshaft central. The piston is descending on a power stroke,right ? The new charge is being compressed to escape up the transfers,so let's imagine the crankshaft is very close at 10 thou on one side but 30 thou on the other to the cases. The quantity of mixture is now having an easier path to move on one side than the other. There is also wind age to consider,drag caused my a moving object very close to a stationery object,the crankcase. Really,apart from the satisfaction of having a nice job with it fitting centrally,is minimalising those losses. To get a reading I hold the crankshaft tight to the left with one hand,then try a selection of feeler gauges on the right to get a reasonably tight fitting. Let's say it is 90 thou,half that will be 45 each side. I have a good selection of shims,some stainless,some brass,some old hacksaw blades which I use with a digital caliper to get 45 thou. With the new bearings on the crankshaft,heated R/H case on two wooden blocks,the shims sitting on the case with enough sticking out to recover with a pair of pliers( keep your fingers away from that hot case) !! --- drop the crankshaft in. Copper hammer ready,you may have to tap a little to get things just right as the heat drops away. I hope this explains it nicely. You may get into a muddle at first-- nerves-- ! But it is easier with practice. Do you have a workshop manual ? Just to mention,the two crankshaft nuts & the clutch centre plus sprocket one need 75 FT/LBS of torque. Now that IS tight! These are fine engines & will reward you with good service if done properly. Nearly bed time,regards,John.

Hi Brian,let's see if I can help. I have assembled quite a number of Bultos from 125 up over the years,I may be right,I may be wrong,but this is my way these days ! The 4 gearbox bearings,use ordinary standard ones. On the crankshaft I use C3 clearance because 2 stroke lower ends can run really hot. On the timing side I use a NJ 205 ECP/ C3 roller bearing--yes they are rather pricey but make closing the cases so much easier. The later motors towards the end of production used these as well. I also do a dummy run of putting the crankshaft in the cases with no bearings,new gasket & a couple or nuts tightened up to measure the cases to crankshaft gap with feeler gauges. On assembly I try to get the gap equal on each side. A bit of extra care now & you will get a nice sweet running motor. Oil? Now there's a minefield ! That's down to you,but these 50 year old motors don't really like fully synthetic. Most of the time I use Millers CM2T at 33 or 40 to one. No lubrication issues to date, but that decision is down to you. Over to you.......

Hi ukmatador,I use 428 chain on all my bikes,& have a 15 T sprocket on a Lobito plus on 2 Alpinas with no problems. The chain does get a bit close to the kickstart shaft,but does not touch. I use ordinary standard chain,not O ring. I do have a 16 T to put on a bit of a special 326 cc motor,it will fit, but there are other jobs to do first. I have just had a look at my Metralla parts list,& interesting to note the standard fitting is a 17 T. The rear sprocket was a 42 T giving a 2.47 ratio. Those bikes would do about 92 m.p.h. Fast enough for you ? The Matador mk 3,pretty much the same motor,had std: gearing of 15--50 which is a 3.33 ratio,so I think a 46 T rear sprocket would be worth a try. Hope this helps,over to you.......

Very often engine to frame mountings become corroded,giving a poor earth return. Bypass this possibility with a heavy section of wire with a soldered on terminal each end, from an engine bolt then to the coil mounting bracket. Easy to do,but easy to overlook. Hope this helps,John.

Hi Scot Taco,I have had a look at my listings for you. The Matador Mk 2, model M 16 gear ratios -0287...0482....0683..& 1 to 1 for top gear. The first Sherpa T,model M10, is-0350...0454...0831..& 1 to 1 for top gear. A fair bit of difference. If you had an idea to use the Matador for trials I would suggest just to find a M 10 motor in good order then swap over. The later Mk 3 Matador had a 5 speed box. Hope this helps,John.

Piston size on what did you do to your Bultaco today. Hi bultacorock,Mahle Pistons are all made to a nominal size,such as .50 oversize for instance. When finally machined they may be fractionally under or over size. The minus sign on yours indicates it is just a little under size. Each piston is carefully checked then marked before being boxed for sale.That is the marking you see. When a cylinder is sent out for re-boring the replacement piston needs to go as well so as the machinist can hone to a specified clearance. What you have discovered by accident is Bultaco quality ! Hope this helps,John.

Piston size on what did you do to your Bultaco today

Hullo Guys,apologies for being a nuisance,but have a look at Kevin Breedon Racing. All the following in stock,all at £143.86. Pencil ready ? 83.4---83.6---84.00---84.50---85.00---85.25---85.50---86.00 . O.K. Mate ? That should help you along a bit. The factory only made 500 of the 159, so relatively rare. I have a bottom end in very good shape,but no barrel or head. The parts can sit there for now,more important is a Metralla to be completely re-built. Regards,John.

Thanks Guys,yes,most Pistons have the pin offset a little to quieten the motor on the down stroke. In the 1960's I spent a lot of time at our Kart track,learning about engines. We had a lot of Villiers engines for the 200 cc class,& I used to fit the Pistons backwards so as to get a few more revs. We did crazy things to those motors that if the original designers knew of they would of had a fit ! A good time to look back on. Patrik, I would be happy to purchase your old piston from you. Is it in order to put my email address on here & make the arrangements to buy? Please advise,somebody. Thanks,John,Island of Jersey.