# Honda 1986 TRX 125



## 1gr8bldr (Mar 24, 2013)

Was building something for a man who ran an auction. He had a near perfect 1986 Honda TRX125. It was to be auctioned Saturday night. But it would not start. As good a shape as it was in, I figured if that if fixed it would be fun for my son. Only one other bid against me. Got it for $220. Got it home. This thing looks like it broke in 87 and been garaged ever since. Anyway, I checked for a spark first. No spark. So I went on the internet and seems that lots of owners have this same issue. Frustrating that after reading over 40 threads about this issue, not even one was complete, actually telling what fixed it. As many as has this problem, someone should post the fix. I promise I will, if I figure it out. But I need some help. Gonna download a manual for it today.


----------



## rjcruiser (Mar 24, 2013)

Sounds like a problem that a lot of the 3 wheelers had.  Think it was the stator or the excitor coil on a lot of them.  Might check some of the 3 wheeler forums and go from there.

Might even be a bad CDI box.

Good luck and post some pics.  I think you got a bargain.


----------



## 1gr8bldr (Mar 24, 2013)

Based on what I have read, probably the CDI. I did not realize that this thing is considered vintage. Only CDI I can find for it is Ebay and seller says it does not work?????? Selling it for a paper weight?


----------



## rjcruiser (Mar 24, 2013)

Lol  no reason to buy one that doesn't work.  Check the 3 wheeler forums....lots of things out there.  Worst case, buy a Lifan motor and do a swap.


----------



## 1gr8bldr (Mar 24, 2013)

I have been trying to cross reference the CDI part number to see what other machines used the same CDI but so far, have found none. If I could find others using the same, it would increase my chances at a ATV junk yard. It will be a shame to give up cause this thing is like a new one. The joint line of the tire molding, the thin paper like rubber between the treads, is still there on the factory tires.


----------



## rjcruiser (Mar 24, 2013)

Dont give up.  Google is your friend.  Did you see this thread?

http://forums.atvconnection.com/honda/288526-resolving-trx125-no-spark-issue.html

Shows how to test to see if it is the cdi unit.  Also, there's a member onhere who has restored quite a few Honda ATCs...do a search and send him a pm....betcha he'd know a bunch more.


----------



## rjcruiser (Mar 24, 2013)

Just found this site for cdi units

http://www.regulatorrectifier.com/catalog/Honda-193?page=1


----------



## Backlasher82 (Mar 24, 2013)

Check the neutral switch, they get corroded. The switch is on the LH side of the motor, above the sprocket. It'll have 1 wire going to it and you can check it real quick with an ohm meter, it should show continuity to ground when in neutral. 

If that checks OK get a manual or find the specs for testing the stator online. Plug caps go bad too so take it off the plug wire to eliminate it. Should be able to find specs on the ignition coil and check it too. 

Eliminate everything else, including wiring before buying a cdi unit.


----------



## 1gr8bldr (Mar 27, 2013)

In too good a shape to give up looking for the cdi


----------



## rjcruiser (Mar 28, 2013)

that is beautiful.  If you give up...I'll give you $200 for it


----------



## Backlasher82 (Mar 28, 2013)

Have you checked the other ignition components and eliminated the neutral , kill and ignition switch? CDI units can go bad but it is very rare, hate to see you spend the money and not fix the problem.


----------



## 1gr8bldr (Mar 28, 2013)

Backlasher82 said:


> Have you checked the other ignition components and eliminated the neutral , kill and ignition switch? CDI units can go bad but it is very rare, hate to see you spend the money and not fix the problem.


Been wanting a new, better multitester, so I am waiting on the UPS truck. Gonna throw my old one away. So as soon as it gets here I will troubleshoot it per the manual. I am suspecting that it is the CDI. The internet is full of people hunting for this part


----------



## 1gr8bldr (Mar 28, 2013)

rjcruiser said:


> that is beautiful.  If you give up...I'll give you $200 for it


In good shape, did you notice the tread on the back tires. They are 5/8 deep


----------



## rjcruiser (Mar 29, 2013)

1gr8bldr said:


> In good shape, did you notice the tread on the back tires. They are 5/8 deep



The tires are great....the rims are super clean...no dents on the lip...but I think the thing that sets that trx apart is the plastics.

Not only is the red plastics perfect, but the black mud flap pieces as well as the tool kit cover is all there.

Very very difficult to find one that has all those plastics in that good of shape.


----------



## 1gr8bldr (Apr 7, 2013)

Update; started on this thing today. No spark. Removed the plastic, tank and air box so I could get to everything. Got out my multimeter. About all I know how to do is voltage check and continuity. I can figure out mechanics but electrical stuff on a motor, well I need to learn. But I noticed that I could get no continuity between each end of the spark plug cap. So I bypassed it, took it off and stuffed the male plug end into the the center of the rubber plug wire. Got spark now So, since it would spark through the plug, I figured I would see if it would hit once. So I sprayed starter fluid into the plug hole, quickly screwed the plug in and hit the start button. Did not hit or begin to. Tried this several times cause I was surprised it would not hit. Spark/fuel, why not? This makes me wonder if the timing is off.????


Update on Fat Cat rebuild, got it tore down, only thing lacking  to put it back together is deglazing the cylinder.


Update on XR100, after rebuilding it 1 month ago, the crank bearing/seal has gone bad. Splitting the case will be a learning experience. Maybe the next rain day


----------



## 1gr8bldr (Apr 7, 2013)

I wanted to understand the cap, so I busted it open. It has a resistor in it and a spring that keeps it making connection. There was a 1/4 inch gap with no connection. That should be the problem????? except that in the air box, I found another cap. Seems someone was chasing this rabbit before me. So, it could be something else and this  having happened while they were working on it


----------



## 1gr8bldr (Apr 7, 2013)

Tried the starting fluid again, got spark, got fuel, it should bust off, AND IT DID THIS TIME! Just got to put it back together, hook up the gas and ride


----------



## rjcruiser (Apr 8, 2013)

Awesome!!!!

Glad to hear it was something as simple as the plug wire!


----------



## 1gr8bldr (Apr 8, 2013)

It fired with starter fluid so I know I can get it going. While putting it back together, I figured I would clean the carb. As I expected, it was pretty clean. Gas back then did not cause the problems of todays gas. But the jet was barely open so I tried to clean it out but since I have nothing smaller than a needle, I managed to push something into the hole so now it is blocked. Went to the Honda shop and ordered a jet for it. The off brand they had in stock would not fit. Rather than wait for the jet to arrive, anybody got a trick to clean them out???? Dang thing was clean as a fork but I decided to run my smallest jet cleaner thru but it would not fit, being a couple sizes to big. It is smaller than the smallest pins or needles


----------



## rjcruiser (Apr 9, 2013)

carb dip over night?  compressed air?

I usually take a wire brush bristle and use that to push through the jets.  Would that work?


----------



## 1gr8bldr (Apr 9, 2013)

rjcruiser said:


> carb dip over night?  compressed air?
> 
> I usually take a wire brush bristle and use that to push through the jets.  Would that work?


I tried carb cleaner, soaking and compressed air. I will check and see if I have a wire brush that small. My jet cleaning multipack, having probably 30+ wires does not go this small


----------



## 1gr8bldr (Apr 9, 2013)

rjcruiser said:


> carb dip over night?  compressed air?
> 
> I usually take a wire brush bristle and use that to push through the jets.  Would that work?


You are the man Wire brush worked. Had to look through several till I found one small enough, but it worked. Purs like a kitten.


----------



## 1gr8bldr (Apr 9, 2013)

Everything works, head lights, brake lights. The front tires still have 1 inch rubber mold hairs


----------



## southgaoriginal (Apr 9, 2013)

wow, that picture brings back memories Had one just like that got in 1989 paid 800 for it then and sold it for 600 in 2005.  God only know how many miles we put on that thing


----------



## rjcruiser (Apr 10, 2013)

1gr8bldr said:


> You are the man Wire brush worked. Had to look through several till I found one small enough, but it worked. Purs like a kitten.





Nice.....Glad it worked out for ya.  I tell you what...that thing is sooo cool.  Love the vintage look and congrats again on the find!


----------



## hiawassee1 (Apr 10, 2013)

Always loved those Fat Cats, my best friend had one growing up.  i came across one on craigslist up here a couple weeks ago, in fairly good shape, but the guy didnt have a # on the ad, and has never gotten back to me, bummed, was thinking about rebuilding for my 10 yr old son.


----------

