A forum for owners of Yamaha TTR250 trail and enduro bikes!

PurpleWheels · Veteran Member

Solenoid fixes and lessons learned

TbirdX · Veteran Member

New solenoid.

PurpleWheels · Veteran Member

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..?

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

PurpleWheels · Veteran Member

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...

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

PurpleWheels · Veteran Member

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.

PurpleWheels · Veteran Member

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

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.

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.

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

JOHNYBOY · Super Guru

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

TTRfan · Super Guru

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.

PurpleWheels · Veteran Member

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.

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

PurpleWheels · Veteran Member

Update on my solenoid fix, as promised: No luck, didn't work for long...

I went for a ride last week and when trying to start the engine after stopping for a while the solenoid would not disengage, i.e. the starter kept turning after the engine started and I released the button. I pressed the started button a few times and tapped on the solenoid and luckily it released.

I am now looking around for a used replacement solenoid with my mechanic friends here.

In conclusion, it was a good try to fix it, and done partly out of necessity and partly out of curiosity. Result was only partial success.

twoscoops · Member

For TTR owners in Canada I purchased this starter solenoid from www.fortnine.ca. Direct replacement, same plug, no modifications needed.

Highly recommend shoptotallyttrs.com, my experience with them was great!

But for those in Canada this may be an alternative to the genuine Yamaha part. I have no affiliation with fortnine, but have purchased many parts and products from them over the past few years.