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prom8n

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    Michigan, USA

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  • My Bike(s)
    1974 Dnepr MT-16

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  1. Thanks Sunstroke. Been doing some research on why this would happen, generally it's pre-ignition caused by poor / low octane fuel, or by fuel mixture being way off. Been having trouble with the carbs (Pekar K-68's) ever since I put this thing back together, and I'm gonna pull the right side head today and see what that looks like. Note that almost all of the damage is on the exhaust-valve side of the piston. Don't know what that means, but that's the hotter side. More info coming. Thanks. Paul R.
  2. More bad luck with Baba Yaga; pulled the head to find out what the clattering noise was, found a blown piston. Oh. Well, that explains the exhaust being full of oil. Dnepr MT 16, 650 engine. Had the old witch running actually pretty good a week ago, tinkering with the carb settings and timing. Would start fairly easy and run strong for a few miles, then start making a metallic clattering noise when hot. Started bogging down and blowing smoke out the left muffler, but once cool it would start again, no unusual noise. I was thinking it was getting waaay too much fuel and coming close to hydro-locking, hence the clatter and smoke, but when it was cool, it would take off like a rocket. Hmmm.... Started running like crap all the time, then quit all together.So, pulled the exhaust pipe, oil runs out. Huh? Pulled the spark plug, it's dripping with oil. Uh-oh. Rings are gone, oil's leaking by, right? Pulled the head. Oh my. Ok, now I know what the problem is, but not why. Note the edge of the piston is gone along the exhaust side. Rings were reasonably intact, cylinder is quite good (surprisingly), but the valves have lots of extra chunks on them. Valve seats are fair. Pulled off the oil pan and found lots of little metal pieces in there. I suspect the missing side piece of the piston came loose and was wedged in somewhere until things got hot, then started bouncing around and making the clatter, and eventually busting a hole in the piston. Maybe. Possibly. I have extra pistons and rings, I'll hone the cylinder to break up the glaze, and try to regrind the valves. I'll put it back together aaaaaannnnd…..see what the hell happens I guess. Feedback and opinions welcome. Yobanaya Suka... Paul R. in Michigan, USA
  3. Thanks guys, I've since read that this was a KMZ design and factory-installed during the last few years of Dnepr production. I like it, and am glad to have the extra filtration. The only problem is it sits right where I wanted to install the right leg guard / shield, so a modified mounting bracket was called for. Not a big problem. Paul R.
  4. My Dnepr MT-16 has the 650 engine with a spin-on oil filter, never seen another one with this. Curious about when they started using them. It had an (original?) Russian filter on it when I bought it, since matched up and replaced with a Wix filter. Mounted on the right side of the block just to the rear of the front cover, almost touching the forward sidecar brace. Threaded side of filter is down. Looks original. I wonder if the oil drains out back into the crankcase every time it shuts off? I guess it doesn't matter as the 20 or 30 times I need to kick-start this @#%*$ before it runs would certainly pump oil thru everything. Hey....maybe that's it. The engine won't start until oil pressure builds up! Ha! Many thanks. Paul R. in Michigan, USA
  5. Thanks N-Duck, the problem was the float in the carb was stuck and kept the needle closed. Rebuild / adjusted, working now. Been messing with the brakes, trying to get them to actually work, and the front cable snapped. At this point, I consider this ordinary. Adapted an old cable from the Yamaha out in the back shed and got that working again, brakes work rather well now. Another revelation. Lately the old witch has been starting on the 2nd kick, amazing. I'm tempted to get it licensed and make it legal to ride on the street. I was puttering down my long driveway when an older Biker Dude cruised past on his Harley, his head snapped around in a genuine double-take when he saw the Dnepr. That felt good. One small victory at a time. Paul R.
  6. Quick update for those of you kind enough to follow this thread: Last weekend I had the Dnepr starting semi-reliably, sometimes on the 3rd kick. Quite a feeling really. Rode it around the yard and took it out on the road (I live out in the country, side road with little traffic) and actually managed to get it up into 4th gear and 45 mph. I had shorts on and a bee or wasp struck my knee and stung me rather sharply, causing an interesting wobble in my steering technique. Ah well, life is pain. This weekend, it has reverted to its baser instincts and is refusing to start. It dribbles fuel all over the workshop floor, yet the fuel isn't getting into the engine. One of the tickler buttons popped out in my hand and fuel started running out of the empty hole. How do you housebreak this thing? Left fuel line is showing no fuel (clear lines) while the right is full but won't flow. I did get it running once using the enrichers but it died 100 yards away from the shop and wouldn't restart, so I had to push it (uphill) back inside. Pulled the carbs (Pekar K-68's) and started cleaning them out. Found fuel puddled up inside the slide cylinder among other places. How the #*%$ does fuel get up into the top of the SLIDE?? It goes everywhere EXCEPT into the engine. This is when I usually go sit down and have a cold beer, but I'm going thru a lot of beer..... Antics will ensue. The curse of Baba Yaga lives on. Paul R.
  7. Thanks for the feedback guys, I do appreciate it. Went out today after work and tickled carbs, the one button on the left would not shut off, so it dribbled gas all over the floor. Typical. Pulled enrichers and kicked it over 4 times to pre-load the cylinders, switched on ignition and it started on the 4th kick. Not bad at all, really. Enrichers off, good throttle response, so I backed it out and rode around the yard for awhile. Runs good, but I think I hear a rod-knock on the right. Could be exhaust leak, we'll see, but it sounds metalic. Gonna pull the thing apart and rebuild the engine this winter anyway. I'll see about some spacers for the carbs, but for the moment I'm just feeling everything out. Still haven't gotten it out of second gear. Racepres, I did have the points plate in, never worked. No, I have no idea why this Hall-effect unit is working (for now), so it's still on standby. Yes, I do have inline fuel filters, clear ones with clear fuel line, so I can see the fuel running down to the carbs. Ain't no trouble there. Inside the carb could be a very different story, but something finally seems to be working. Any thoughts on what goes on the fuel vents? Thanks again gentlemen. Good for now, but I know Baba Yaga is just resting for a bit. Paul R.
  8. OK. So.... Sitting there glaring at it, trying to think of any combination of wiring / ground / power / switches I haven't tried yet, put the ignition back together, plugs out sitting on top of the heads and tried kicking it over as hard as I could. Thought I saw a spark. Installed plugs, tickled carbs, pulled enrichers, and wailed on it for all I was worth. Fired 3 pops. Kept going. Now, I'm a big guy (6"4", 250 lbs) so I could snap off the kick start if not careful. Lost count of the kicks but after about 20 if fired and ran without any fuss, very smoothly and nicely, as if there wasn't any problem at all..... Ran it for 15 minutes in the shop, responded to the throttle well. Took video with my phone to prove I wasn't hallucinating. Timing seems too advanced, but that's an easy fix. Backed it out to test drive it and the front brake cable broke, but so what. Didn't care. (BTW, I put a little air back in the flat tires, no leak. I can almost hear this thing laughing at me). Motored around the barn for another 15 minutes and finally pulled back in and (very reluctantly) shut if off. Waited a few, and tried it again. It was a workout, but it started! Again!!. Un-Be-Freakin'-leavable. Repaired the front brake cable, came inside and I'm drinking my second beer as I type this. Oy. What a long strange trip it's been...... So, questions: 1: I used semi clear Tygon fuel line so I can see gas running to the carbs. Is it normal to see fuel boiling back up the line when the cylinders are hot? 2: It wouldn't start when hot, seemed like it wasn't getting fuel. Tickled the carbs until fuel ran out the vent, finally started. Normal? Carbs too hot? 3: Where or what exactly should hook up to the vent tubes on the sides of the carbs? I'm running Pekar K-68's. Going back out to the workshop later to try again. Baba Yaga will not be ignored. Paul R.
  9. Racepres, I was pretty happy the day my mechanic called and said the heads needed new gaskets, thinking finally, a solvable problem. When the new gaskets were installed and it failed to fire, I was so disgusted I shoved the #$%*@! out back and ignored it for two weeks. Finally hauled it back into the workshop and started this latest bout of frustration. Yesterday, while sitting there trying to figure it out, I added air to all 4 tires because they looked low and I wanted to do something productive. Two of them promptly blew the tubes and went flat. If you're really serious about helping, I will trailer the thing up to you one day soon for a look. I'm near Jackson, so a ride to Mt. Pleasant isn't too far, but be warned: I'm beginning to believe there's a Russian curse on this machine. I think I'll start calling it Baba Yaga.
  10. Well guys, it's mid July, time for an update on the Dnepr MT-16. This will be frustrating. Found a local gearhead and hauled it over to him. After 2 weeks he called and said the heads were loose and gaskets were probably blown. That diagnosis cost me $100, but I was glad to pay just to get somewhere, as I was completely stuck. It popped and spit, but he said he'd adjusted the carbs did have it running. Started it myself at home, and drove it slowly around the barn for about 10 minutes, then it really began popping and quit running. Ok, ordered new head gaskets (3 sets) from Arbalet-Ukraine. While waiting, I pulled the sidecar off to make it easier to work on the right side of the engine. Pulled the heads and found the original aluminum gaskets were in poor shape, and the small 8mm head nuts were partially stripped. So yes, the heads were loose. New parts arrived in about 2 weeks, installed new copper gaskets. Tried to torque the head nuts but couldn't get much past 20 ft-lbs before they stripped out. Also couldn't find a torque spec anywhere. Tightened new nuts as much as I dared and then double-nutted them to try and keep the heads tight. Also I was very careful not to fool with the carbs in any way, because they had been working. Put everything back together and guess what? Nothing. Went thru the usual checks, found no spark at the plugs. Again. Now, this was the same plugs (NGK's), wires, and electronic ignition (Hall effect) that was in the bike when it did run. Pulled the entire system and bench tested it with a fresh battery, got spark. Ok, so the ignition system works. Checked power to the module, consistent 12 volts. Used an actual meter, not just a test light. Re-installed everything, still no spark at the plugs. Tried different plugs, sanded all contact surfaces and used dielectric grease, installed new plug wires (copper core), tried extra jumper wires to insure ground, tried the external car battery hooked in parallel to the bike battery, then hooked that up separate from the bike. Adjusted clearance on the Hall sensor. Nothing, nothing, nothing...… Noticed once when I turned on the key, it popped. Checked the spark at the plug, and every time I turn the key, or the kill-switch, or even the ground switch under the seat, I get one spark at the plug. Breaking the circuit triggers the hall effect and fires the coil, just once. Kick-starting it gives no spark. Also note that this module has an LED that blinks whenever it's triggered, and it blinks when kick starting, but there is no spark at the plug. AaaaaahhhrrrRRRRGGGG!!!!! So: It did run, mechanically there is no issue. Carbs worked, so no fuel problem. Consistent 12v and good ground to the ignition. Ignition works on the bench. Module and coil are good. Ignition fires in the bike when switched on/off, just once. Kick starting it produces no spark at plugs. And that's where I am today. Many thanks to all of you who took the time to reply. Paul R.
  11. Thanks again for all the feedback gentlemen. Fuel tank was cleaned and dried before installing. Clear fuel line with a separate filter for each cylinder, no dirt, good visible fuel flow to each carb. Carbs have been completely dis-assembled twice and rebuilt with new parts, but I do not know what size jet came with the kit, perhaps it is too small. Also didn't touch the needle setting, could need to be changed. I'll try some lock-tite on the main jet, the aluminum was corroded and maybe I have a leak, we'll see. I'll pick up some alternate sparkplugs and try those, Autolite, Champion and Denso are easy to find here, but Sinterom, Brisk and Enker could be a problem. Sorry Luca. And I do have the points plate in place, just rigged up to an external coil. Updated to follow. Thanks again. Paul R.
  12. Racepres, I understand your reservations on in-line filters, that's why I used clear fuel line; I can see the fuel running down into the carbs. I can tickle them until fuel dribbles out, so I know the float chambers are full. Even if the filters restricted flow, it should start and run until those are dry. Luca, I was using Bosch plugs before without success. Switching to the NGK's made no difference. So: I have compression, and spark at the plugs. I static-timed it, so it's firing just past TDC. I have gas in the carbs, but it isn't getting into the cylinders. The one time it did start, I used the enrichers and it started on the 2nd kick, but won't do it again. I pulled one plug, squirted gas into the hole, replaced it and cranked. Nothing. On a whim, I pulled both mufflers to see if there was any restriction, but no difference. What the heck can stop gas from going from full carbs into the engine? Ah well, I've got 40 or 50 other projects to keep me busy for awhile. I'll come back to the Dnepr later on. Thanks for the help guys.
  13. Thanks for the responses. Yes, compression is good. I repaired one exhaust valve guide and lapped all valves, takes a real good kick to crank it over. Valve lash set to spec. I agree it's something simple, because it did run once, rather well actually. Smooth, no strange noises, but it cut out as if I'd switched it off. Using the "enrichers" yes. Cleaned everything out and blew out all passages with compressed air when I rebuilt the carbs. Twice. Idle and throttle are set to factory specs. 1.5 turns on the idle mixture, increasing this doesn't help. Tried opening the throttle by hand thru entire range, nothing. Plugs are new NGK BP7HS, as recommended elsewhere on this forum. They come out dry but sooty, indicating rich mixture. No resistors, copper-core wires. Original carb gaskets leaked, made new larger ones that seal correctly. Set a piece of thin paper over the intakes while cranking, good suction. Spark is strong and blue with the Bosch coil, fires every cycle. (Kinda like it, may end up keeping it.) Point gap set to .5mm, timing set per the manual. Sorry, should have mentioned my location: Lower central Michigan, USA. I believe it's a fuel problem. I have compression and spark (at least today), but the blasted thing won't even pop with starter fluid. Even my 70 year-old antique Ford tractor will fire on that. Been trying for over a week with this, getting fed up. Thanks again for any input. "There's absolutely nothing wrong with it, it just doesn't work." Paul R.
  14. 198? Dnepr MT-16 650, nothing but trouble. Bought it in pieces, put it back together these last 3 months. Got good compression, but... Installed new russian electronic ignition, poor spark. Suspect bad hall sensor. Replaced it with original points/condenser/coil, got good spark at new NGK plugs, still won't start. Rebuilt Pekar K-68's, found nothing wrong, no start. Occasional pop or backfire. Tried starter fluid, squirting gas right into the intakes, nothing. Adjusted the points and timing to every possible setting. It's 65 degrees here, but I tried the chokes anyway. Voila!! Started and actually ran... ...for 10 minutes! Died, would not restart. Checked spark at plugs just to be sure, gone again. Tested old coil, it's bad. Jury-rigged a Bosch 12v coil, strapped it to the sidecar strut, wired it in, got good spark (again) at the plugs. But it will not freakin' start. Gas to the carbs is good, I used Tygon clear fuel line and clear filters, I can see the fuel flowing down. Tickle the carbs until gas dribbles out, pull the chokes, crank until my leg is sore, it'll pop once in a while but no start. Checked points and timing, still good. Tried starter fluid and gas squirted again, nothing. Pull the plugs, they're bone dry, so it's not flooded. I'm beyond fed up. Unless someone out there has ANY good idea, I'm going to shove this P.O.S. off behind the barn and forget about it for awhile before I lose what little is left of my patience. Sorry for the long rant, had to vent. Thanks guys. Paul R.
  15. Thanks Luca, that makes sense. I'll get a new one and try it. Paul R.
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