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Post by fairway1987 on Jun 21, 2012 8:31:59 GMT
Hi everyone.
This is my 125cc 2 stroke Minsk, which I purchased off eBay back in October 2011.
I started a thread on the 309 owners forum & I'll just cut & paste everything from there to bring you all upto date ;D
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Post by fairway1987 on Jun 21, 2012 8:33:14 GMT
Its a 123cc 2 stroke Minsk. They are a Russian bike (also sold in the UK under the names Neval or Regent) with an eye watering top speed of around 60mph. .......and yes, it's the same type of bike as the one Richard Hammond rode in The Top Gear Vietnam special!! They wern't particularly popular when they where on sale in the UK from the mid '70s to the late '80s, mainly because they where so far behind the times compared to bikes by Honda etc which where also on sale at the time and the fact they where so basic and the Communist build quality could have been better. The exhaust smoke from these bikes is comparable to that of Del boys 3 wheel van. They where and still are extremely popular in Vietnam, Afganistan, Thailand, Iran, Russia and far Eastern Europe. They where really made for off road use, or dirt track use. They where never made for long distance or high speed in mind. They are however very comfortable and quite small. If I'm honest, those downfalls are something I've really started to like about the bike, everything is so easy to work on. You could remove the engine, strip it & rebuild it in under an hour - and I'm not a qualified mechanic! To this day parts are easy to get and are cheap (can't get parts in the UK anymore though, but parts can be easily sourced online from Europe and shipping isn't too expensive, i.e a complete new engine inc postage would be around £120). My bike was first registered by a chap in Healing, Grimsby, North Lincolnshire, in June 1987. It was used untill June 1990 having covered 2,500 miles, when he decided to remove the cylinder head to de-coke it. For some strange and unclear reason, this never got done, and the bike sat in his garage, untouched, under a tarpaulin sheet untill 2011. The owner, now retired for some years with failing eye sight decided to clear his garage out with the help of his neighbour, a chap called John. He found the old Minsk exactly where he left it 21 years ago & was going to let the next passing gypo or rag & bone man take it away. John stepped in & said the bike is far too good to scrap like that & offered to sell it on eBay for him. After having it explained to him exactly what eBay was, the elderly owner agreed. I was the second bidder and won.
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Post by fairway1987 on Jun 21, 2012 8:33:52 GMT
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Post by fairway1987 on Jun 21, 2012 8:34:26 GMT
The bike even came with original old style log book, both tax discs still in the holder from '88 and '89, original bill of sale and written recept and original owners handbook! The tyre hand pump under the seat had never been used as had the original tool kit supplied with the bike in a leather holder in one of the side storage tins.
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Post by fairway1987 on Jun 21, 2012 8:34:59 GMT
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Post by fairway1987 on Jun 21, 2012 8:35:31 GMT
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Post by fairway1987 on Jun 21, 2012 8:36:02 GMT
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Post by fairway1987 on Jun 21, 2012 8:36:34 GMT
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Post by fairway1987 on Jun 21, 2012 8:43:49 GMT
Back in November '11 I stripped the engine down (without removing it from the frame) and fitted a new piston (old one had a nasty crack up one side), new rings & new gaskets. Unfortunately, at the final stage of reassembly; screwing the cylinder head down on top of the cylinder, one of the four threaded mounting posts the head is screwed down with snapped (see pic, left bolt).
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Post by fairway1987 on Jun 21, 2012 8:44:31 GMT
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Post by fairway1987 on Jun 21, 2012 8:47:22 GMT
From late Nov '11 to May '12 progress was pretty much nil due to me working away a lot and my cars taking up my free time, but I recently decided to pull my finger out and crack on with this project. I completely removed the engine from the bike (which took all of 10min) so I could clean the frame & those hard to reach places and to work on the engine at home, which was where the spare engine was. (Spare eBay engine on the left) I removed the cylinder head (again) and replaced the snapped head bolt with one from the spare engine. After replacing the head I gave the engine casing a good clean with white spirit. I also removed the fuel tank from the bike as there was a lot of crusty, dried oil stuck to the bottom of the tank. I flushed it out as best I could first with white spirit and then with parafin. I then went on to clean the fuel tap. I read in the manual that there was a very fine metal gauze filter inside which are easily clogged up. Mine was no acception, but along with various bits of dried oil & black gunk there where some gold paint shavings - I'm guessing overspray that managed to get inside the tank from when they painted it during manufacture or perhaps paint chipped off the filler neck by metal fuel pump nozzles. The fact the paint chips where still in there tells me this filter has never been off and cleaned and I'm willing to bet this crap in the fuel tap started to affect the bikes performance and probably lead to the previous owner to take it off the road in 1990, thinking the engine needed de-coking (when it actually wasn't that bad & wasn't due to be done.)
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Post by fairway1987 on Jun 21, 2012 8:48:11 GMT
I removed the base of the carb & flushed it out with parafin. It absolutely f***ing stunk when I first opened it up, it was full of oil that had gone as thick as treacle and there was a sort of oil 'skin' growing up the sides (it reminded me of the 'skin' you'd get on a pot of gravy thats been left to cool and not stirred). I suppose I was too excited about getting the bike back together & getting it running because I perhaps wasn't as through as I should have been and didn't clean it or strip it to the extent I should have, which I found out later =p~ (will upload pics later) The rubber fuel feed pipe which runs from the fuel tank tap to the carb was cracked & weeping fuel so it was replaced with a new pipe and a pair of new jubilee clips for about £3, courtesy of Pirtek in Hull. (will upload pics later) Finally, I drained the gearbox oil (only 500ml capacity), replaced the sump, filled & swilled with neat petrol (as recommended by the owners handbook), drained again, allowed to dry then filled with some fresh gear oil. The owners manual was very vague about exactly what grade of gear oil should be used, only stating, '....replace gearbox sump and fill with appropriate oil.' so I purchased a fresh 500ml bottle of EP75w90 semi synthetic hypiod gear oil & tipped that in. As the design of this bike, especially the mechanical side of things, had hardly changed from the 1950s, I expect if I was to fill the gearbox with a tin of Tate & Lyle it would probably wouldn't harm it. Anyway, with the engine etc refitted on the bike and a few drops of petrol down the sparkplug hole for good measure I gave it a kick start. On the 3rd attempt it fired up. I was well impressed because I've never removed / stripped / rebuilt ANY engine before and it was great to hear it burst into life after 21 years layed up in a garage under a tarpaulin sheet Unfortunately the bike conked out about 40 seconds later. Cutting an allready long winded & boring story shory, the bike would refuse to start without either a few drops of pertol down the spark plug hole or a squirt of carb & choke cleaner in the air intake. When it did start after doing either of these things it would quite happily rev and tick over for about 40secs before dying again.
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Post by fairway1987 on Jun 21, 2012 8:48:39 GMT
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Post by fairway1987 on Jun 21, 2012 8:49:14 GMT
Carb from spare engine now on the bike
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Post by fairway1987 on Jun 21, 2012 8:49:53 GMT
I still plan on throughly stripping the old carb down and cleaning it out meticulously this time and fitting it back on the bike as I prefer things to be original where possible, and theres still lots of jobs to do i.e the brakes need adjusting & maybe new shoes fitting, rear tyre has a slow puncture, chain needs tightening etc but my next main jobs are; 1) I've misplaced a gasket or a large metal washer or something that should go in where the exhaust screws into the cylinder block to make it airtight. Without the gasket it spits out a very small, fine mist of unburned oil and smoke. 2) I have no idea what this completely odourless black stuff is thats leaking from the bike and I can't tell where its coming from. It's either just unburned oil thats dribbling out of where the exhaust screws into the cylinder block where that gasket is missing (see above), or its coming from the gearbox, which I doubt because I put fresh oil in there.... 3) Disappointingly, none of the electrics seem to work apart from the horn (intermittently). Probably just a loose connection or plug somewhere & nothing serious.
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