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Post Info TOPIC: Solenoid fixes and lessons learned


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Solenoid fixes and lessons learned
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My bike developed a problem when trying to start the engine. Pressing the start button would occasionally just produce a click from the solenoid, but the starter would not turn. Repeatedly pressing the button would eventually trigger the starter motor and turn over the engine. The problem was getting worse so I had to find a fix.

I opened and cleaned the handlebar switch with the start button, no improvement. I opened the starter motor, cleaned it and found that the brushes were getting on the wear limit. I have another starter motor so I used the best parts from both to assemble a good one. Tested OK with a battery off the engine, but still no improvement when starting the engine.

Last thing to check was the solenoid itself. I took it off the bike and checked the resistance between the threaded copper poles both "ON" and "OFF" using a 12V battery. Infinite when "OFF" (no power supplied), but when I fed 12 volts to the smaller wires the resistance only dropped to a few megaohms rather than zero. Several test made showed some variation, but always a high resistance. Problem found, but what about the solution?

 

 

 

 



-- Edited by PurpleWheels on Sunday 18th of October 2020 01:32:48 PM

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New solenoid.


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I found a thread here about the solenoidsand reading it it seemed that these are not made to be repaired. At least not very easily.

https://ttr250.activeboard.com/t44548337/starter-relay-aka-solenoid/

I can't find new ones here, so the second option was to look for something adaptable. The article above warns against pattern solenoids due to low quality and bad experiences, but I didn't have any alternatives really. I found two almost identical solenoids sold here for the Chinese brand bikes, so I got the more expensive one that the seller recommended as I have a "big bike" (=250 cc...). He explained that the cheaper version was known to have issues and not last very long. The more expensive one cost me the equivalent of 7 Euros, I guess I could afford that.

Here's the beauty. The box mentions "High quality" and even "People oriented", whatever that may mean in the context of solenoids..?

IMG_0644B.JPG



-- Edited by PurpleWheels on Sunday 18th of October 2020 01:31:44 PM

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I had to cut the the wires as they had small bullet connectors that don't fit the TTR wiring, and replaced them with two spade connectors. This was meant as a temporary fix so I didn't use the connector from the failed solenoid, which would be a nicer way to do this. The insulated spade connectors fit nicely into the connector on the original wiring.

Everything installed and connected on the bike I tested and the bike started at first attempt. Problem solved... no

A few days later I wanted to go for a ride, and turning on ignition nothing lit up, not even the smallest light bulb. Completely dead. I measured the voltage and found 2.36 volts on the battery! That's the lowest I've ever measured on a 12 V battery.

Obviously I was suspecting the new solenoid, so I took it off the bike and measured 42 kOhms across the poles when it was supposed to be infinite, i.e. it was passing a low current across when it was supposed to completely off. That must have drained my battery over a few days of not riding, and actually killed it. Even after charging it would not turn the engine over. I didn't open the solenoid yet, but I will as I'm curious to find what causes this fault. confuse

 

 



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Meanwhile I had opened my old faulty solenoid to check the inside. Very similar to the pictures in the article in the link above. I used a Dremel to cut the sides carefully so I could separate the two halves. The connectors were burned and oxidised.

IMG_0659.JPGIMG_0661.JPGIMG_0690.JPGIMG_0692.JPG



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I cleaned up the connectors with a small file to get clean and flat copper surfaces where they touch.

IMG_0701.JPG

However, I wasn't happy with the small part in the center as the surface was still pitted and I didn't want to remove more material. I realised that I could pull it off the plastic pin in the center and turn it over. The other side was oxidised but flat, so after careful sanding I got it nice and shiny, and pushed it back on the plastic pin.

IMG_0704.JPG

IMG_0705.JPG

IMG_0707.JPG

Following that I assembled everything with all the seals, used epoxy around the rim to glue it all back together after cleaning the rim. I finally put a cable strap around the solenoid to ensure that it stays in one piece should the epoxy not hold.

I had already cut the wires to re-use the connector on my new solenoid at a later stage, so now I had to reconnect the wires which explains the pink connectors. I found using these easier than soldering.

IMG_0710.JPG

IMG_0746.JPG

IMG_0772.JPG

I tested the solenoid off the bike with a battery and it works perfectly. Tomorrow I'll get a new battery and I'll be able to put the solenoid through proper testing. I'll let you know if my fix holds up or if it is just a little less temporary than the Apsonic solenoid. evileye

A new solenoid is obviously the proper fix for this problem, but maybe this can help someone who is in a situation where replacement solenoids are just not available and needs a temporary solution that doesn't involve push starting the bike.



-- Edited by PurpleWheels on Sunday 18th of October 2020 01:37:32 PM

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just get a solenoid off a recognised bike honda suzuki kawasaki yamahe thats what i did on another bike i think they all work in the same way but test it to make sure its the same and work the same

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Great repair!

There is something incredibly satisfying of fixing something like the solenoid where the manufacturer clearly never envisaged anyone trying wink

I see Steve has a genuine used solenoid in stock here if anyone is looking for a good OEM one.



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I opened the new solenoid and it's clear that it is not sealed against water. It was on the bike for 5 days with occasional rains, and I found water inside. See the picture. Corrosion has already started. In addition the dimensions of the copper parts are inferior to the original Yamaha part. Just confirms that it's better to get an original part, even if it's second hand. And yes, these are pretty standard so a solenoid from another bike may fit just as well.

The picture shows that there is no seal on the rim of the metal cover, it's just tightened against the plastic part on three sides. I only needed to twist a screwdriver in the slot to open this. Opening it also means that it will no longer work as the two coil wires on the left are pulled apart, so while it's easy to open it cannot be repaired. disbelief The box it came in did mention "Easy to maintain", I guess they mean it's easy to pull apart. 

Maybe this type of solenoid could work if it's installed in a dry location on a scooter, but on the TTR these are exposed in a rain even when the bike is stationary. 

IMG_0781B.JPG



-- Edited by PurpleWheels on Sunday 18th of October 2020 05:24:12 PM

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