Jump to content

section swept

Members
  • Content Count

    1,542
  • Joined

  • Last visited

About section swept

  • Rank
    Advanced Member

Previous Fields

  • Bike
    Many overtime.

Profile Information

  • Location
    UK
  • Gender
    Not Telling

Recent Profile Visitors

8,252 profile views
  1. Your hubs may split or crack even at the correct interference fit due to the aluminium becoming age degraded...more brittle. Presumably the hub will be heated to expand the housing and the liner shoved in a freezer to shrink slightly. Using this method the liner should just slide into the housing and be allowed to cool naturally. Some people have used a resin bonding agent whilst others have employed locking screws or locking pins, although these methods may increase the fragility of the hub(s). There is info on this web site if you do a search you should find it. More importantly is that you know the inside diameter of what the brake drum should be, I would have thought. Your engineer is obviously being wary and quite rightly so. As to interference clearances and taking into consideration heat build up when braking...you would need to brake for a very long time to build up significant heat in a Bultaco brake shoe assembly front or back. Here are some details for you. The housing is bored out to accept the sleeve, read that as cleaned up. When the sleeve is installed into the aluminium housing, the interference fit is .004. When the sleeve is being installed into a cast iron housing, the interference fit is .002 to .003. The interference fit is determined by measuring the outside diameter of the sleeve, then boring the cylinder diameter smaller than the sleeve. In this case you do not want to remove much if any material from the hub. The lining needs to be in effect .004 oversize to the hub. Any areas of corrosion in the hub could be treated with a resin adhesive suitable for metal. The interference fit is a critical aspect of sleeve installation because this step ensures that the sleeve does not move when in the hub. Now you have this info I do not accept any liability for the process if you decide to employ any of the suggested methods and it all ends in damage.
  2. Looks like a collection of BSA parts put together to form a bike. Well worth restoring once you have decided on the bikes designation eg road bike proper, trials or trail. I believe Triumph used the BSA 250 bike as a sort of pseudo trail bike model. Research carefully and maybe have a look at the Otter website. You may well have a 250 Star which would have been near the end of the production life of the smaller engined bikes. That full width front hub suggests road together with the 18/19 inch rim. What ever you have the basis of a potential good and interesting restoration project...wish I had it! Good luck with what ever path you decide to follow.
  3. When you look at the arc that the kickstart travels through (say from 12 o’clock) by the time the kick start lever has met the footrest any further rotation would be lost effort it just feels as though you are achieving greater leverage by ‘kicking through’ so to speak. You can compare this action to tightening a nut or bolt, once you reach 90 degrees thats the maximum effective leverage unless you are superman. As Woody states, with the bike set up correctly (engine wise) it should burst into life at the second or third prod if not the first. All of my Bultacos kicked into life with relative ease thats 325, 350, 250 all on contact breakers, all had kick starts that met the footrest. Yes you get issues when you drop the bike but all things being equal they restart once you calm down and ensure everything is as it should be.
  4. Just had a quick look at Google, typing in BSA C15 Trials gearing. You should find plenty of helpful info and probably sort a good starting compromise to fine tune the overall rear wheel sprocket and gearbox sprocket size (no of teeth). A lot will depend on the internal ratios of the gearbox, you might find that with lower overall gearing the engine will work fine in first and second, but third and fourth might be a bit too low for any road work or distance between sections. Something else to bear in mind is the torque effect of a drive chain being pulled around the smaller output gearbox sprocket which can have/cause adverse wear issues. Then you may also have chain to frame/ swing arm clearance problems. Some negatives but not un solvable! You might consider going the whole hog and fitting C15 T internals (if some can be sourced) from the visible effort that you are putting in it will be worth it. Waiting to see the finished article...good luck with your bike?
  5. ?The Bultaco engine ignition timing if set too close to tdc there could be an instance of reverse running. This can happen if the kickstart is lazily prodded. For contact breaker systems initial setting at 3.00mm would be a good starting point, listen out for detonation on accelerating in say third gear up a slight incline. You may end up with a final setting at 2.75mm, this is measured piston travel coming up to tdc best measured with either a dti (dial test indicator) or vernier caliper, either can be positioned through the spark plug hole but turn the engine over very slowly so you don’t catch the measuring device with piston. Hope you are successful?
  6. section swept

    Montesa 349

    You can of course use Auto-trans fluid in the clutch as this is produced to work in all metal and high heat clutch packs. Less tendency for sticking too!
  7. Your frame appears to be different in that the area next to the steering head looks to be opened out as does the frame near the footrests...optical effect of photo or painted in black...does look like it has the stampings removed.
  8. section swept

    Montesa 349

    Hi Dave, recently sold my 348 MRR. There aren’t many if any good workshop manuals about but plenty of info available on this site. Most 348 (305cc) and the 349 (actual size) would be run on 50:1 fully or semi synthetic. Main thing to remember is that on long downhill sections and when slowing down from highish speeds don't close fully the throttle or you may seize the piston/ring. I gave all my info away with the sale so sorry otherwise you could have had the file. You can download a Montesa owners manual if only I could remember the blessed address.?‍♂️Type in Montesa Cota Manual that will get you started.?
  9. Don’t forget you will still need to indicate (hand signal) your intention to slow down or stop!?
  10. Well the bike starts more easily after standing for a week or two with the fuel left in the tank. Throttle response seems to be crisper than when run on pump gas. There are many who will say there’s no difference, however the main thing is at least the Aspen fuel is not attacking all that it comes into contact with. It is more stable and takes ages to go off i.e. more than a year. Try it!
  11. From your description about riding experience my advice would be to weigh the cost of buying a new 300 as against this alternative.....Buy new and you still have to spend to make the 300 more controllable for your tastes. With a new bike you will suffer a large loss in value the minute its yours. That loss in value could buy a useful trail bike or trials bike depending on which you want to do the most of riding wise. Now you still have a reserve of cash to either buy another bike...something like a good used Beta 250 for trialing or a Yamaha WR 250 for some serious trail riding..(the WR 450 is not as threatening as the engine size would have you believe...in fact its a peach for getting you out of the clag!) I am assuming that you are cash rich and not going the finance/hp or other version of deposit and rental payments...not advisable for off-road machinery. Cooler with bikes that serve a role and not dual role...with one bike, break it and you are out of action. With two at least you can console yourself if one fails.
  12. That large frame lug on the side was a give away that the frame was married to a sidecar at some stage of the bikes life. Could be that 51 H #### is a moto cross engine...just guessing not looked on the Montesa ident site. Just looked on Sheldons site and AMS Racing both do not show 51H so my suggestion is wrong, but your engine needs a good clean off in the number area. Some one on this site may be able to give some more detail as to the H .
  13. Here are a few hints, tips and suggestions to help keep your machine in good order..... AFTER EACH TRIAL : Block exhaust rear pipe ( bung or clingfilm). Block air entry to air filter ( gaffer tape or clingfilm wrap). Wash machine with garden hose or pressure washer. DO NOT AIM JET DIRECTLY AT WHEEL BEARING SEALS OR BRAKE HUBS, STEERING HEAD OR GEARBOX OUTPUT SHAFT AREA. Clean these areas with a softish bristle brush and soapy water. Dry machine off with low pressure air or absorbent cloth. Before leaving bike in store area, check or maintain the following items: Air filter housing water drain, remove bung located underside of air box usually. Allow any fluid/water to fully drain out. Remove air filter/cassette clean and re-apply Foam Filter Oil if used (important as insufficient may affect air fuel mix). Check spark plug HT lead cap and lead for security. Check around exhaust down-pipe to cylinder barrel for exhaust gas leakage ( usually due to seal settling). Check security of remainder of exhaust system. Check all controls for ease of operation, visually inspect cable runs and inner cables for damage or fraying. Pay particular attention to the throttle operation which must be smooth and precise. Check chain tensioner block and operation, confirm chain correctly tensioned with machine weighted (rider seated). Look carefully at all potential oil leak areas such as clutch cover, gearbox output shaft seal. Contact with hard objects may cause a case e.g. clutch cover to distort or move creating a leak. Spin each wheel and look for signs of out of round or buckling of the wheel rims. Check wheel spoke tension (tap with a small spanner, listen to each spokes ‘ring’ sound....dull means it is loose) Tighten loose spokes to achieve a similar ‘ring’. It is always a good maintenance plan to remove each wheel and inspect, clean and thoroughly dry the brake housings and shoes, if the bike has been ‘wading’ streams, rivers etc. Excessive rainy weather can cause moisture to get into the smallest of places! Check suspension operation front and back, operation should be smooth and progressive. Check visually for wheel alignment. Use Schrader valves to release captured air from front forks if fitted. Always a good idea to release any built up air pressure to prevent oil seal weepage When dry it is a good idea to spray water repellant aerosol liquid at the spokes, wheel rims and hud centres, avoiding brake areas. The engine would benefit from similar attention. Suggested sprays are: Silicone or WD40 or AC10 etc Now the machine is clean and dry remove the exhaust bung/ wrapping and unblock the air filter air entry.....reassemble the air filter if previously dismantled. TURN OFF THE FUEL TAP if not already performed. Start the engine and run until fuel in the carb float chamber is used up OR drain the carb float bowl. Drain the fuel tank. While the carb float bowl drain plug is out spray some silicon or similar into the float bowl and down through the carb fuel inlet to lube temporarily the needle valve and float. Allow for this when firing up the bike next time....i.e. a few more kicks might be needed but in my experience it causes little problem...unless you have been over exuberant with spraying into the carb, a quick shot is all thats needed.....and now for some... WORDS OF WISDOM: Todays modern petrol has been dosed with so many additives and chemicals to improve the environment that it now rapidly deteriorates and goes ‘stale’ very quickly. Petrol left in the fuel tank for sometime can cause issues with the fuel attacking the resins and materials used to construct the fuel tank. Even plastic tanks are not free of this problem. Unfortunately this Ethanol rich fuel also causes problems in steel fuel tanks, lines and flexible hoses. Whilst not wishing to advertise I have used Aspen Fuel which is ethanol free and has less harmful chemicals in it unlike pump petroleum, it also remains stable for quite some time without going “stale”! Ignore any maintenance regime and eventually faults will develop and stop you enjoying riding any machine. An hour or two carrying out the above should help to ensure reliability and a successful ride for the next ride.?
×
×
  • Create New...