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section swept

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Everything posted by section swept

  1. 4rt repsol. Dropping engine speed

    You really need to confirm these settings before goining any further: Valve clearances set to specification. Throttle body, air filter hose clamp not ovetightened causing distortion to TB housing. Honda put the various breathers into the design for a reason put these all back to standard, ditch any extra contrivances as unnecessary. Ensure all breathers and entry and exits are actually clear. Engine oil as specified and quantity correct. Fuel is fresh and fuel filters good. Fuel pressure to specification. Engine idle speed to Honda specification. No air leaks in inlet system or exhaust. No restrictions in air filter, system. Throttle cable adjusted as per Honda specs. Coolant temperature within Honda parameters. Cooling fan operates to Honda specs. Compression test to specifications, not guessed to be ok. Observations: too tight on the inlet and/or exhaust valve operating clearances will cause unsustainable idle speed. Coolant temperature above specification will cause erratic idle behaviour. Excess crankcase pressure will cause engine stalling and erratic idle behaviour. Poor compression will cause erratic behaviour at idle. Also poor performance in the mid range. In general it will probably come down to being something trivial being missed so be extra vigilant when making any investigations. Hope this is helpful and you get sorted.🙂
  2. bultaco model ?

    The aluminium fuel tank and seat base combined was a lovely thing when new, but after a while they used to crack around the weld area of seat and tank...not good! The first one I ordered from Mr. Miller arrived with a whacking great dent in the side of the tank. After a quick phone call a new tank was despatched and the damaged item returned...no quibble! They cracked because they were not as strong as the original fibre glass items.
  3. bultaco model ?

    That steering lock just stopped the willy nilly stamp marks being put on by anyone to totally confuse us all!!
  4. bultaco model ?

    Well we don’t have access to the amount of kangaroo skin that you Aussies have😜
  5. bultaco model ?

    5/10 for the welding
  6. engine oil

    So the oil companies invest millions in developing different oils, the bike/car/ lorry manufacturers invest millions in development to arrive at a suitable oil to suit their needs and then you want to ‘try’ a different oil....well good luck with that one. The oil specifications aren’t like shirt sizes they are arrived at by exacting scientific trials...ahem sorry about that....if you know better then you should be in the oil industry. Use what the bike makers states otherwise you will be wasting your time and money.🙂👍
  7. TLM rings

    There you go then!
  8. Suspension

    By tweaks do you mean purely adjustments or replacing the rear suspension unit with something else and changing the front forks damping characteristics? If it’s just adjustments then can I suggest that you make single adjustments to one end then the other after you have tried the bike after each ‘tweak’. On this website you will find many references to suspension set up and the best adjustments tend to be the ones coming from the people that designed the bike in the first place....the manufacturer. If you are set on going it alone then first weigh your self in your normal riding kit. Should you happen to be on the er ( politically correct description...fat b’stard) larger size then that opens up an entirely different approach. We are all different and cope with life in our own ways, but the suspension of a competition machine has been chosen to suit the Mr. Average size....bear this in mind if your bikes bottoming out with little action needed. Static sag, set this first, then get on the bike with normal riding gear and note changes front and rear, you may need a helper here to take measurements...unless of course you have really (politically correct description...arms like an orangutan) long arms. You are looking to pre load the suspension so that your combined weight together with the static settings allows full suspension movement without bottoming out...reaching full compression and banging into the end of travel. If you’ve been riding for a whole year without taking advantage of adjusting the suspension then you have been missing out on transforming both the machine and your abilities. Hope you have some good results from ‘playing’ with the suspension, it can be really rewarding once you get your head around the process.🙂👍🙋🏼‍♂️
  9. 2 Stroke oil

    Never took it off!🤪🙋🏼‍♂️
  10. 2 Stroke oil

    Two strokes and it’s gone!!!!!
  11. Piston slap confirmation

    Your cranks big end might have ‘felt’ alright on the bench but there are a few ways that the bearings can wear from barrelling to tapering depending on main bearings wear to! There was no detectable play in my crank but when taken apart there were some appreciable wear signs on the big end pin. Just replacing the piston will not solve the issue of piston slap, well it might but I doubt and it will be a costly mistake not to have a rebore and correct piston and rings. 🙂
  12. TLM rings

    So you need oversize piston to...if the cost is prohibitive to you then why not consider looking for a complete engine...or with a bit of research you may be able to cross reference the parts to another. You may be surprised to learn that not many bike manufacturers make their own pistons etc but state design needs to a piston manufacturer who then either makes or has a stock item that matches the design brief. This is how a lot of after market stuff gets into the market place. If you can make contact with a engineering company that does rebore work and engine overhauls, they might try to match up your original parts from information they have. If you are making the TLM into a 260 from 220 I think that was the original capacity you may well have to use a piston from another bike. The small/little end bearings are also mass produced and not just made for one specific type of piston, hope you are following this information as it can open up more choices to you, you might even find that costs to you are significantly less than those being bandied about by internet and other sellers. Obviously the aforementioned info applies to the piston rings as well, if not more so.🙂👍
  13. 74 ty250 seat base brackets

    You won’t find a new genuine seat, they are like rocking horse poo rare! They are not that complicated and to fabricate some out of metal would not be st all difficult. I got a very good replica (grp) with the right type of cover all complete for about £70 from Yambits they may have the brackets but don’t hold your breath. I took this route as all of the seat/saddle refurb companies that I cantacted either offered indifferent replies or were extremely expensive. Hope you have succcess. By the way the original Yamaha TY seat bases were not well thought out, if the seat cover leaked water into the seat foam there was no escape so it sat on the metal base eventually rotting the metal. Also the metal seat base is very close to the air filter cover inlet, any flexing in the seat base causes the seat base to touch the filter inlet which then bends and retsticts the air flow going into the filter housing; something to watch out for. This seat base flexing also causes cracks to appear if you are a bit heavy so ensure your replacement seat is correctly supported underneath. I’d be wary of any internet offered seats as they will invariably be rusted and welded up increasing weight and hiding nasty filler etc. You can find TY seat covers on the net and offered by some retailers but again be careful in making your choice.🙂👍
  14. 2 Stroke oil

    Shell ...out more💷 BP ....organic waste product made by small flying nectar eater🐝 Repsol....representative sold out....repair solutions needed🤷🏻‍♂️🤔 Putoline.....put a line on for a tow home🎣🤳 Castrol....Fidels casual stroll🚶‍♂️ Yamaha....aha another use for yam juice🍠 Motorex....motor is no more🛠🥢 Theres more to this oil malarkey than Inthought🤔😜🤪
  15. 2 Stroke oil

    Yogurt maybe
  16. Speedies gone to a new home, thanks for your help guys

    🙋🏼‍♂️👋🙋🏼‍♂️👋👍
  17. evo main bearings

    What no cribbing then either! 👨🏻‍🎓👨‍💻👨‍🏫🤓
  18. Bultaco M80

    From having had in my possession an ex ISDT Triumph a long time ago now, I can say that from a conversation that I had with Roy Peplow I learned this. There were 5 bikes specially built, frame number one was EXP 01 and this was the jig original. This stayed by the jig for assembly and fittings to be added or modified, the design buck in other words, it was not for use as a finished machine. EXP 02 was the build frame from which 3 more bikes were produced, EXP 03, 04 and 05. Roy was able to also inform me who had which bike, that they were all 500cc or there abouts and had Police spec exhaust cams. On the road they would all manage 100mph ( brave). He then told me he could remember all of this easily as he had all the details in a little black pocket book. At the time I was more interested in selling the bike having just put the bike through the workshop ( I took it in p/x as a non runner in bits against a new bike) as I was a bike dealer then, even the man himself Sammy Miller had a ride on said EXP 05 the bike in my possession. Having travelled a fair distance with the bike in my pick up all the way to Mr. Millers place in Hants, he confixrmed it as a factory bike but wouldn’t pay the price I was looking for so I returned to my shop and sold it the next week for £1200 (1979 prices). If only I knew where it was now🙁 I add this factual story as an indication as to how a manufacturer might number their ‘specials’ .
  19. Bultaco M80

    My M80 frame number is about 30 numbers before your’s and the reg document states 1972 so we can accept that year as true🙂
  20. Bultaco M80

    My M80 frame has 4mm thick gusset plates and the frame tube walls are 2 mm thickness. But it’s not gas pipe or water pipe or conduit tubing either. How do I know, because one of the previous owners must have used the bike in a rock breaking trial and flattened the bottom frame tubes, so I cut them off and made replacements using 1.5 mm seamless tube. It’s still a heavy frame though! 😳🙂
  21. mikuni carb set up on tiger cub

    I’d have said ‘developed rather than devolved because you now can appreciate the finer character in the older bikes. Some one who has and runs a Cub will probably be along to help you. Maybe you could ask the same question in the bike specific section of this website.🙂
  22. evo main bearings

    Nearly all bearings and seals carry identification serial numbers eg 6203-56 etc. and possibly you already know this. Although there are many bearing and seal suppliers, Simply Bearings have been excellent in supplying me with all my needs they have an excellent website that allows you to compare and choose from top quality to lower priced components for application needs. Have you not kept the old parts to refer to? Take off the seal carriers and you may be able to identify the seals and bearings, I may be wrong here, either way I’d carry out a bit of a flush through to remove any metal particles if the bearings are seriously worn.🙂You could try Feetup Trial Sport e-bay store, they may give specs or supply if the prices meet your spending needs.
  23. Piston slap confirmation

    Well the bike looks good, some engines are quiet and eventually start to make noises. Some Bultaco engines were noisy from the start, luck of the draw on manufacturers accepted tolerances. As you identified over tolerance on the piston to cylinder bore clearance naturally it’s going to ‘rattle’. Your engine could go for some time before mechanical kindness kicks in, bear in mind that excess clearance will affect engine performance and it’ll not do the piston or rings any good in the long run. Better to remedy this sooner rather than later. If the barrel is on its original bore size then a reborn and piston to the next size or two up. Small increase in capacity will be an advantage but not by much. Try for a Mahle piston, not cheap but as original equipment OE depending on Bultaco Factory finances at the time your engine was made.
  24. bultaco model ?

    I’ve had a better look around the headstock, not just at the welds and frame number and guess what? In the same area as that G stamp I have the number 4 stamped in! Was this a way of the factory identifying which worker did what frame or was it an inspection stamp. Either way it’s intriging and now I to want to know what these extra marks are....now where’s that Mr. Miller?🤔
  25. Squeak...

    Compression leaking out, or air squealing in or out from main bearing oil seals possibly. Have you only just noticed this sound🎼Compression leaking past piston rings as piston movement just stops....could be totally normal. In the quiet, ghetto blaster off, Chris Evans muted (gone would be better) talkative by standers asked to multiply 3.789 X 754.89 in there heads, and no calls from the kitchen about things not working...and you will hear all sorts of noises emitted by your faithful steed. If it were my machine and it worked as good as before the noise noticed then ignore and ride on🤔😳🙂Your engine running will utilise the compression increase on igniting the fuel and air and this will force the piston towards the cylinder walls increasing the seal. That’s why when the rings are nipped or gummed up power loss is felt. The only other thing that comes to mind is the water pump seal may be squeaking, I’ve had no end of water pumps that make all sorts of noises straight out of the box. The lube contained in the anti freeze usually helps resolve that issue. Do you still run anti freeze in your bike? Any work done and you may have had tap water put in the cooling system. I always recommend using distilled water pre mixed with the best quality anti freeze you can obtain, less chemicals to attack the aluminium. Hope you can either eliminate this sound by finding the cause or satisfying yourself that it’s nothing wrong.🙂👍
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