My Dnepr MT-11 Story

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Orangecicle
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Re: My Dnepr MT-11 Story

Post by Orangecicle » Fri Nov 22, 2019 9:34 pm

OK, I ordered in Walbro Viton float needles and tried them in the K-68 carbs with no luck. So, I made a run at getting the old K-65s functioning, but I had the same results there with flooding bowls and gas dripping everywhere.

So . . . I need new carbs. I see various options out there. I see a pair of K-65s made by Weber on eBay for cheap. Any thoughts? I've read about folks having luck with Chinese alternatives, while other say they are junk. I know Makunis can be adapted, but I've also read someone who said they were not impressed with the results. I'm a bit at a loss. No major rush on my end. It's 23°F outside (-5°C). But . . . I could use some help.
Last edited by Orangecicle on Mon Nov 25, 2019 9:04 pm, edited 1 time in total.

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Re: My Denpr MT-11 Story

Post by dneprlover » Sat Nov 23, 2019 4:22 pm

The Walbro needles need tweaking a bit to get them right. They will work in both K68 and K65 play again and set them up so that when the carbs are upside down, the seam on the float is parallel to the float bowl joint face on the carb at shut off. bit fiddly and may take several tries to get it right. Once set, many people run like this with no problems and it has been a recognised fix for Pekar carbs for years.

They are not simply plug and play (neither are OE , they can be a PITA and when the little washers disintegrate, it all has to be done again a few weeks later) Once set, Walbro needles can be forgotten about unlike OE
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Re: My Dnepr MT-11 Story

Post by Orangecicle » Sun Nov 24, 2019 8:47 am

dneprlover wrote:
Sat Nov 23, 2019 4:22 pm
The Walbro needles need tweaking a bit to get them right. They will work in both K68 and K65 play again and set them up so that when the carbs are upside down, the seam on the float is parallel to the float bowl joint face on the carb at shut off. bit fiddly and may take several tries to get it right. Once set, many people run like this with no problems and it has been a recognised fix for Pekar carbs for years.

They are not simply plug and play (neither are OE , they can be a PITA and when the little washers disintegrate, it all has to be done again a few weeks later) Once set, Walbro needles can be forgotten about unlike OE
Well, I think I was able to get the needles to seat. It looks like the carbs are holding well enough that the bike should run. The bowl gaskets really are misshapen enough that I think I need to eventually make my own.

My new problem is electrical. The bike is on a trickle charger, so the battery is fully charged at about 12.5 volts. But, when I turn on the key, the voltage at the headlight is 11.5 volts. It is weak enough that the bike won't turn on the LED headlight I bought. {I installed the headlight on my Jeep to make sure it worked, and the wife says she's embarrassed to ride with me with one normal headlight and one funky blue one.}

I think this lack of voltage is contributing to a lack of spark. I kick started for a large portion of yesterday. I could get the bike to stumble just a little, but it would not start. When I pulled a plug and grounded it to a cylinder head, I saw only faint and random spark. The points and condenser look new, and the points look to have good gap, so I'm thinking that it's lack of power to the coil or the coil itself. So, I'm chasing electrical gremlins. My favorite thing to do. :sarcasm:

Are the newer coils that come with the electronic ignition any good? Example: https://www.ebay.com/itm/NEW-Electronic ... %7Ciid%3A1

Image
Last edited by Orangecicle on Mon Nov 25, 2019 9:05 pm, edited 1 time in total.

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Re: My Denpr MT-11 Story

Post by Roundoz » Sun Nov 24, 2019 12:34 pm

That seems like a lot of voltage drop. Either something is putting some load on the battery, there is a bad connection or bad wire or the battery is bad.
Not knowing what uses power when you turn on the switch (my guess would be the coil/s, headlight, taillight and low oil pressure light) you could check a few other things first:
What is the voltage at the battery when the switch is on?
Voltage at headlight wires with headlight disconnected?
Check the same again with the trickle charger or bigger charger connected (preferably an old style analog one that won’t turn itself off automatically. I bought one of these from a farm store - they can sometimes be handy for resurrecting “dead” batteries).
Check your spark and headlight with the charger connected.
It could be that that amount of voltage drop is normal with old style coils. I suspect they are nothing more complex than a primary winding (connected to the battery through the points that open and close the circuit to time the spark) of a few turns and a secondary winding (a few hundred turns) connected to the spark plugs. The ratio of turns gives you the increase in voltage. Shorted or open circuits can give you a weak spark and possibly more current drain (more voltage drop). You should be able to read the resistance of the windings with an ohmeter and compare them to see if one has a problem. The secondary will read much higher than the primary because it has more wire with more turns. If you read all the way through the plug lead you can see if bad leads are causing poor spark.
Note, this is all coming from general knowledge of simple ignition circuits rather than anything specific about Russian stuff. There are many ways to create spark for two cylinders.
Maybe someone with more specific knowledge of Dnepr electrics can add specific things to check or readings you should get, or possibly contradict completely what I have just written.
One thing that would be good to know - it used to be said that you don’t want to leave the ignition on without the engine running for any great length of time. If the points are closed it can overheat them and cause the open or short circuit condition. Again, I have no specific knowledge if this is the case with Dneprs.

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Re: My Dnepr MT-11 Story

Post by dneprlover » Sun Nov 24, 2019 2:34 pm

Put a voltmeter across the battery terminals with ignition turned off, take reading . Turn ignition on and take readings again. Now turn switch fully clockwise(3rd position) and take another reading. What are the 3 readings please?
Do thjis after you have cleaned all grounds and connections you can get at.

Normally with your symptoms, I would suspect the ignition switch. Dirty contacts, loose connecting tab or dirty contacts. These switches are simple to repair even though they look like a sealed unit.
Remove switch after labelling all the wires
Gently prize the 3 staking positions open keeping pressure on the connection plate
put the switch in an upright position and release pressure on the connection plate.
Clean connections and gently re rivet the connection tabs.
Coat the switch contacts with dielectric grease or vaseline
Reassemble and press the staked metal back in place
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Re: My Denpr MT-11 Story

Post by khd2 » Sun Nov 24, 2019 2:42 pm

Orangecicle wrote:
Tue Nov 19, 2019 9:18 pm
As expected the only hard part of putting the front cover back on was that odd, loose bit that was hanging off of the front of the cam shaft. Apparently, that bit is keyed to the gear on the cam by a little round pin, but keeping the bit on the pin while also trying to slip on the front cover was a B-atch. :brickwall: :rant:
For next time; if you rotate the gears so key is exactly at top, then the breather just hangs in the correct position and you can just push the front cover in place (wiggle it too much and you will have to start over though)

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Re: My Dnepr MT-11 Story

Post by Orangecicle » Sun Nov 24, 2019 6:37 pm

khd2 wrote:
Sun Nov 24, 2019 2:42 pm
Orangecicle wrote:
Tue Nov 19, 2019 9:18 pm
As expected the only hard part of putting the front cover back on was that odd, loose bit that was hanging off of the front of the cam shaft. Apparently, that bit is keyed to the gear on the cam by a little round pin, but keeping the bit on the pin while also trying to slip on the front cover was a B-atch. :brickwall: :rant:
For next time; if you rotate the gears so key is exactly at top, then the breather just hangs in the correct position and you can just push the front cover in place (wiggle it too much and you will have to start over though)
:bow: :bow: :bow:
Last edited by Orangecicle on Mon Nov 25, 2019 9:08 pm, edited 1 time in total.

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Re: My Dnepr MT-11 Story

Post by Orangecicle » Mon Nov 25, 2019 9:02 pm

I'm just posting to document some voltage findings (battery tender disconnected before reading voltage)

-- Voltage at battery, key off & kill switch in off position: 13.00v (across terminals)
-- Key off and kill switch on (run position): 12.99v (across terminals)
-- Key in "park" mode, kill switch on: 12.50v on positive terminal grounded to frame.
-- Key in run position: 12.25v on positive terminal grounded to frame.
-- Key in run, headlight on high: 10.62v on high wire
-- Key in run, headlight on low: 10.72v on low wire
-- Recheck of battery with key off: 12.60v

-- voltage drop across kill switch: zero

Fuze box under light (key on):

Image

-- Brown wire (far right): 11.26v
-- Red wire leading to 3 green wire: 11.27v on both wires.
-- Orange wire leading to yellow wires: 10.52 on orange, 10.35 on yellow
-- Grey wire: 11.15v.

Switch wiring (key on):

Image

-- Grey: 11.36v
-- Blue: 11.36v
-- Yellow: 10.34v
-- Orange: 10.33v

So . . . the switch needs cleaning as suggested by dneprlover? Me thinks he's right.

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Re: My Dnepr MT-11 Story

Post by Orangecicle » Mon Nov 25, 2019 9:09 pm

Also, one of the admins must have fixed my misspelling of the thread title. Thank you, admins, wherever you are! :cheers:

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Re: My Dnepr MT-11 Story

Post by dneprlover » Wed Nov 27, 2019 9:57 am

Nice set of readings. Things are much clearer to me now. forgive me if I'm not always lucid but I have a benign brain tumour and sometimes it plays havoc with my thinking. have to get daughter to do typing for me sometimes. I have been told off on here for being 'patronising' but I like things done in simple, methodical stages. If you don't like the style, tell me.

Take the blue wire off the ignition switch position 3 and take a voltage read to earth from that wire please. record that reading. Then disconnect the 2 wires connected to the middle position ( + ) on the G424 generator, clean the terminal and wire ends, then reassemble and take another voltage read at the blue wire to switch 3, Finally, disconnect the blue wire (+) on the battery and do a resistance test between the ends of those wires (Blue sw.3 and blue batt. (+). You can now connect both blue wires to their respective connections.
Let me know all those readings please before I finally decide in my own mind whether the switch needs cleaning. These tests will mean something to you as you are obviously ok with electrics.
Last edited by dneprlover on Wed Nov 27, 2019 4:41 pm, edited 2 times in total.
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Re: My Dnepr MT-11 Story

Post by Claus » Wed Nov 27, 2019 12:01 pm

I reckon, dneprlover will be right with the ignition switch. I don´t want to talk in between his diagnosis, because he knows his $#!+.


What confuses me:
If you read like 10,3V directly on battery poles plus and minus with a "fully charged" battery, it´s dead. To test that (beside possible problems with ignition switch /regulator/alternator excessive current draw), you could charge the battery until full and let it sit for an hour or two without the charger.
Now prior to switch ignition on, put your voltmeter directly to battery poles, switch on headlight HI, hit the brake and then switch ignition on.
If your battery drops more than 0,7V within the first 10 seconds, it´s defective. If it drops 2V or more, one cell is shot at minimum.
Even if it reads like 13V after charging. Voltage means nothing when the capacity is low.
If your battery doesn´t drop below 12,3V while doing all the readings you describe above, forget about what I wrote.The battery is ok then
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Re: My Dnepr MT-11 Story

Post by Orangecicle » Thu Nov 28, 2019 11:07 am

Claus wrote:
Wed Nov 27, 2019 12:01 pm
I reckon, dneprlover will be right with the ignition switch. I don´t want to talk in between his diagnosis, because he knows his $#!+.


What confuses me:
If you read like 10,3V directly on battery poles plus and minus with a "fully charged" battery, it´s dead. To test that (beside possible problems with ignition switch /regulator/alternator excessive current draw), you could charge the battery until full and let it sit for an hour or two without the charger.
Now prior to switch ignition on, put your voltmeter directly to battery poles, switch on headlight HI, hit the brake and then switch ignition on.
If your battery drops more than 0,7V within the first 10 seconds, it´s defective. If it drops 2V or more, one cell is shot at minimum.
Even if it reads like 13V after charging. Voltage means nothing when the capacity is low.
If your battery doesn´t drop below 12,3V while doing all the readings you describe above, forget about what I wrote.The battery is ok then
I hear ya. The battery is a basic lead/acid, but it is brand new. I don't have a stress tester, but I'm guessing that the battery is good.

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Re: My Dnepr MT-11 Story

Post by Orangecicle » Thu Nov 28, 2019 1:36 pm

dneprlover wrote:
Wed Nov 27, 2019 9:57 am
Nice set of readings. Things are much clearer to me now. forgive me if I'm not always lucid but I have a benign brain tumour and sometimes it plays havoc with my thinking. have to get daughter to do typing for me sometimes. I have been told off on here for being 'patronising' but I like things done in simple, methodical stages. If you don't like the style, tell me.

Take the blue wire off the ignition switch position 3 and take a voltage read to earth from that wire please. record that reading. Then disconnect the 2 wires connected to the middle position ( + ) on the G424 generator, clean the terminal and wire ends, then reassemble and take another voltage read at the blue wire to switch 3, Finally, disconnect the blue wire (+) on the battery and do a resistance test between the ends of those wires (Blue sw.3 and blue batt. (+). You can now connect both blue wires to their respective connections.
Let me know all those readings please before I finally decide in my own mind whether the switch needs cleaning. These tests will mean something to you as you are obviously ok with electrics.
OK, blue ignition wire off its terminal under the switch. The voltage initially was 13.06 in all positions.

Reading on the middle wire on the generator both connected and disconnected: 14.48v

I disconnected the middle gen. wires, which look like hell, and cleaned the terminal before reinstalling (it looked pretty clean).

Reading on the switch blue wire disconnected after cleaning: 14.49v in all positions.

Disconnected positive battery cable and tested resistance to the blue switch wire: 0.01v

The wiring on this thing looks like it's from Chernobyl.

Image

I was shocked to see that this little blue wire is all that the bike needs to run. I suppose since you never have a significant load on it, such as a starter, a small wire is adequate. It sure looks odd, though. And mine is most definitely old as sin.

Image

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Re: My Dnepr MT-11 Story

Post by dneprlover » Thu Nov 28, 2019 2:26 pm

Thankyou for carrying out those tests.
My recommendations:
optional)
Replace that blue wire from battery/generator/switch with one of a very slightly heavier grade using new terminals and some dielectric grease ( we normally use petroleum jelly type substances.) I would prefer you did this due to extra lighting loads you have/may add.
Replace the old Soviet cloth bound coil with a newer type such as the one you show in the photo of an EI system

Compulsory)
Strip and clean the switch as previously outlined and carry out your voltage tests across it again to gauge any improvement

Hope my advice has been of some use .
Cheers
Fred
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Re: My Dnepr MT-11 Story

Post by Orangecicle » Thu Nov 28, 2019 2:37 pm

dneprlover wrote:
Thu Nov 28, 2019 2:26 pm
Thankyou for carrying out those tests.
My recommendations:
optional)
Replace that blue wire from battery/generator/switch with one of a very slightly heavier grade using new terminals and some dielectric grease ( we normally use petroleum jelly type substances.) I would prefer you did this due to extra lighting loads you have/may add.
Replace the old Soviet cloth bound coil with a newer type such as the one you show in the photo of an EI system

Compulsory)
Strip and clean the switch as previously outlined and carry out your voltage tests across it again to gauge any improvement

Hope my advice has been of some use .
Cheers
Fred
Absolutely! Thanks so much for chiming in.

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