PDA

View Full Version : Has anyone ever put TRX300 Starter Gears in a Big Red?



newby200x
08-29-2014, 09:57 AM
I found some reasonably priced starter gears from a TRX300 on ebay. It has the same tooth count, but a different part # from the 86 ATC250ES. Just wondering if anyone has ever replaced their gears from a TRX300 before, seems like it would be a direct replacement.

ps2fixer
08-29-2014, 12:16 PM
Interesting idea, I did a little digging, and it appears that the TRX250 is a direct swap, so if the teeth count matches, I would think it should work from a TRX300 as well. What year TRX300 were you looking at?

newby200x
08-29-2014, 12:57 PM
it doesn't say... I just looked up the part # from a 96 and it showed the same teeth count.

ps2fixer
08-29-2014, 01:12 PM
Looked into it a bit further, The reduction gear, and the gear that slides on the shaft are interchangeable to a 1987 250es, and I would think that would mean they fit for 85-86 as well (guessing here). The gear that goes in and catches the flywheel gear and is attached to the shaft is a different part number, and interchangeable machines are all trx300's, so either it is a different length, or they made it a separate part number for that model.


I'd say if you need one of the gears that fit the 87 250es, go and buy the trx300 ones and give it a shot (and let us know :D). To go the opposite way, I have an 86 trx250 that I'm going to be parting out, so I could offer up the starter gears out of that for a fair price as well.

bkm
08-30-2014, 01:03 AM
I have a set of TRX300 gears if you are looking for a set. They came off a 99. I know for a fact the starter from a TRX300 will only work on a 87 250es/sx because of the extended starter gear nose that rides within a bearing on the gear plate. Now the gears???????

SUPERBEAST
08-30-2014, 01:38 AM
are you trying to avoid buying a new starter? you can get a new one on ebay for about 40 bucks

newby200x
08-30-2014, 07:33 AM
Splines on my starter are toast. Just saw a good deal on 300 gears and figured it would be the same..ps2fixer has some gears for me already though. .thanks guys

atc007
08-30-2014, 08:29 AM
You're gonna need a new one way bearing if it ate the starter gears..

newby200x
08-30-2014, 10:27 AM
The flywheel one way locks one way and spins freely the other....the kick start doesnt slip nor does it make the winding noise after shutting down so im hesistant to change either side right now. Im going to just keep a close eye on everything and see how it goes

honda4h
08-30-2014, 10:56 PM
the trx 300 gear. well the one that has direct contact with the starter that always goes are not interchangeable on 1985-86 big red/sx. only if it were that easy this would have been discovered years ago.

ps2fixer
08-31-2014, 12:15 AM
the trx 300 gear. well the one that has direct contact with the starter that always goes are not interchangeable on 1985-86 big red/sx. only if it were that easy this would have been discovered years ago.

Do you know what the differences are between the two gears?

I just tested a 1985 TRX250 starter gears in a 250ES big red, and it worked fine. The direct contact gear with the starter IS DIFFERENT, but it is with the smaller section of the gear going to the other gear which is also different. If changed as a pair, it works. I also swapped the starter, it is 10 tooth, I didn't count a 250es starter gear to verify if there is a difference or not.

Overall the TRX250 gear set is about 18% lower geared, meaning the starter has to spin faster for the same rpm of the engine. Should be easier on the starter, but I don't know if there were any design differences in the starter for the different target RPM speeds.

honda4h
08-31-2014, 12:37 PM
pics i'm not sure whats going on with pic's199981?199981 the 300 gear is much thicker and there are 2-199980199981199981199981199981250es different gears 199980199980199980199980199980199980 what the funk pics keep down loading

honda4h
08-31-2014, 12:45 PM
pic199982 the too big red gears are totally different thickness and the smaller part is a different tooth count i found them on the early production 1985

Tecate250
05-04-2017, 12:38 PM
So could you just ground down the gear to make it fir. I just tried to put a set of gear in a big red that were missing. It all fits well but can get cover back one.

Dirtcrasher
05-04-2017, 04:46 PM
Send me the gears, I'll turn them thinner on the lathe. If you can draw it with specs, I can do it/make it.....

TheRealFatShady
05-05-2017, 12:35 AM
the 300 guys with big motors switch out the the 250 gears and whole assemblies.