TRX250R Rebuild

nick20555

Living life 2 strokes at a time
Jun 23, 2014
690
149
107
32
Just outside Evansville, IN
So I picked up this 1986 TRX250R yesterday. I've always wanted one since I was younger so I couldn't pass up a decent deal on one so I could eventually put in the work to make it the best looking and driving 250R I can build. So here are the pictures of how I got it.
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The plastics are really rough and its got some goofy paint scheme going on. The guy said the person he got it from listed a bunch of engine mods but he doesn't remember. I'll eventually dive in the motor and find out. He did say it has to run 93 octane or it runs like sh*t so I'm thinking head mod at least. Not quite sure what I want to do with it first but eventually I'm gonna replace the plastics, gusset the frame and powder it red, paint the motor black again. put the thumb throttle back on, weld the crack in the exhaust (has a Curtis sparks mx exhaust), rebuild the carb (leaks if the gas isn't shut off so I'm thinking needle and seat or bad float height), and maybe more in the future including motor mods.
 
Looks nice man the black and white looks awesome. I've always wanted one of those
 
Awesome! Looks like a good place to start.

The carb should be a Keihin PJ if its still original. Parts are readily available for them still.
Awesome! I read that they are 34mm but couldn't find out what kind of keihin. If I needed to double check the size to make sure it is stock, where would I measure? I was just looking to get one of those moose rebuild kits for it and use that for my replacement. I wouldn't use the Jets or anything but would that be OK to replace it with?
 
Save your money on the kit, unless it's cheaper that way. All you need is float needle and seat, bowl gasket. Unless the kit has parts for the choke.

Have you ridden it much yet?
The quad who's handling all others are measured against will be harder to make noticeable improvement. Maybe front shocks.

Probably second only to Banshee as to parts availability.
 
From what I could see, the needle valve or whatever it's called cost more to buy alone than in the rebuild kit. Not sure if the bowl gasket comes with though. Its been a while since I had a carb apart. Is the seat a separate piece from the carb or is it just an o-ring that the needle sits on?
 
Here is the link to jetsrus. They have 2 listed for 86's. Id give them a call, and see what you actually need. Ive had good luck with buying stuff from them.
http://www.jetsrus.com/carb_rebuild_kit/carb_rebuild_repair_kit_honda_ATV.html
photo_keihin_PJ_exploded_view.JPG


As far as front shocks go, the stock 250r shocks are probably some of the best stock ones ever made. I actually ran a set of them on my 400ex. We have works tripple rate's on ours, and its a nice setup, but if I had to, I'd still run the stock set. Nothing wrong with them in my opinion.
 
Thanks for going as far as finding the links for me dirty.

I think I might be too fat for the stock setup cuz it compresses a lot just me sitting on it and it's really soft. They could have leaked too cuz it is 30 years old but I know if I hit a jump or a bump at speed in the trails then it would bottom out real easy. On that note, I probably need to gusset the frame soon.

And don't get too excited blaster crazy cuz it will probably a slow process. I have a perfectly running blaster so I'm in no rush.
 
Here are some pictures of the pipe. The first is of the crack that needs welded. It walks around a previous weld that looks like was for putting the mount back on. This probably explains why it has a little bracket that it mounts to rather than directly to the frame. I'm going to see if I can grind it down so it isn't so raised and probably the reason for the crack.
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The second is of the previous weld right at the main bend in the pipe. You can see how poor of a weld it is.
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Third is just a picture that shows the dings in the pipe.
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This just shows the condition that my pipe is in and the reason why I'm not too worried about it if the attempt to patch the crack in it isn't successful and destroys it. I probably need to get a new one at some point anyway.
 
Nice R...Looks like a nice start . Here's some links for the needle seat and the bowl gasket . I would only use the Honda..Keihin part needle seat . Not one from those cheap rebuild kits . They are great bikes with tons of aftermarket . You're going to love it . I had one back in the late 80's to 95 before I blew my back out . I should have kept it anyway . Looked for over a year for another R before I settled on the blaster I picked up last winter . R's are way too rare and expensive in my area . $2000-$3000 for a beater when one actually shows up or $6000-$7000 for a nice one :eek:

http://www.ebay.com/itm/Honda-OEM-ATC-TRX-250-Float-Valve-Set-16011-HA2-671-/381330742069

http://www.ebay.com/itm/HONDA-KAWAS...85-/371375360382?_trksid=p2141725.m3641.l6368
 
Thank God I rescued this poor R. I got the pipe welded and ready to go. New Uni filter came in (old k&n was filthy), got a swing arm nut (was missing), throttle cable for thumb throttle (had twist throttle), new grips (was missing throttle side one), and parking brake block off (didn't have one on). In the process, I noticed that it had no chain rollers (bottom or top). I also took the carb out to put on the throttle and did a little inspection to find the needle clip was bent (no idea what clip position it was aiming for), the carb bowl was cracked where one of the screws to hold the bowl is, most likely is was because they tried to put on two bowl gasket on top of each other, and it appeared to still have stock jetting despite the pipe and air filter that I know was added.

Looks like I got a lot of work ahead of me. I'll probably just be better off buying a bigger carb since I will most likely be building the motor eventually. I also need to get those chain rollers on and that probably means a new chain and sprockets because it will have to be significantly longer to go around the rollers.
 
After a year since I last messed with it, I finally started working on the R again. Not too much physical progress yet but a lot of thinking and planning got done recently.

After finding problem after problem with the quad and the condition it is in, the previous owner(s) must not have cared too much to keep it reliable and in good shape. Because of this, I decided its best to just tear it all down and have the motor rebuilt even though it technically runs just not the greatest.

I took the motor out and here is how it sits now in my messy garage:

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The motor has been shipped out to have work done. When the motor arrived, the builder convinced me to go big with a 350 cylinder and +4 crank for a 363 motor. He said that is his go-to standard big bore he puts in there. It wasn't much more money than just a rebuild and the work I wanted and he said he sees time and time again, people sending motors back cuz they want a bigger build. Since I know I will probably be one of those guys too, I decided why not spend a little more money now and save more in the long run by having him go ahead and build the big bore now. He's also going to powder the cases and covers black and leave the cylinder and head glass beaded so it looks bare aluminum. This was the color scheme the 89/89 Rs had and I like that idea better than the all aluminum looking motors the 86/87 Rs had and it will look better in my opinion with the color scheme I'm going for. So that's whats in the works now. I'll try to keep you guys posted when it comes back in about 4-6 weeks.

Now I'm just planning on what else I want to do with it until the motor gets done. I've already purchased the big bore pipe for it and working on getting a 38mm air stryker for it. Also, I went ahead and pulled the trigger on a great deal on a +1/+4 axle. I got my electrical components on the way to hopefully fix the kickback issue the quad had before I tore it down.

I've already talked to my suspension guy to figure out what to do with the shocks. He said he can build me whatever to match the arms I buy so I just need to figure out what arms I want and he will build the shocks for them. So I'm currently doing some research so I can decide on what long travels I want. ASR builds some long travels at a decent price just like for the blasters. Alba makes some long travels at an even lower price for the 400ex which apparently fit 250Rs too as long as you put spacers in where it bolts to the frame. But everyone I've talked to really recommend the JD performance arms but they are a good $300 more than the ASRs and even more than the Albas. It's a tough decision and one I'm still debating.

This weekend I plan on trying to make more progress toward stripping the rest down to bare frame so I can get going on having the frame gusseted and then powder coat afterwards. I'm going to powder coat the frame a deep red like my 04 blaster frame. I really like that color and the powder comes out REALLY good and super glossy. I'll probably do just the frame red and the swing arm, axle, and arms black. I have black wheels to go with it. I'm also thinking about the black carbon fiber looking race cut fenders for it. I really think the black/silver looking plastics matched with a red frame and black arms and stuff will really look good. It's a way to keep the silver/black theme but still have a subtle but eye catching red frame.

Anyways, that's what has been going on the past couple weeks with my R. This next month can't go by fast enough! I really want my motor back so I can ride this thing!
 
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A guy I was out riding with last weekend had a TRX250.
They are a long quad, like a Banshee, better at hills and roads than the rough stuff. A lot more stable than a Blaster at (+60mph!) speed. Motor was strong, lots of top end power, but at least this one was a bit thin on bottom power. I think you are doing the right thing with the big bore kit. The TRX plants its power better than a Banshee so it should use the extra displacement well.

I had my 240 Blaster, which is a stock Vitos BBK cylinder, but I do have a tight squish torroidal head on it now. This set-up favours low and mid-range but gives up some peak rpm power. I usually had the jump on the TRX at low speeds and in the rough stuff, but when the trail smoothed out, he was gone!

They are an epic machine. Much simpler (and cheaper to work on!) than the Banshee,much more sophisticated than the Blaster. Good rig. Get'er going!
 
A guy I was out riding with last weekend had a TRX250.
They are a long quad, like a Banshee, better at hills and roads than the rough stuff. A lot more stable than a Blaster at (+60mph!) speed. Motor was strong, lots of top end power, but at least this one was a bit thin on bottom power. I think you are doing the right thing with the big bore kit. The TRX plants its power better than a Banshee so it should use the extra displacement well.

I had my 240 Blaster, which is a stock Vitos BBK cylinder, but I do have a tight squish torroidal head on it now. This set-up favours low and mid-range but gives up some peak rpm power. I usually had the jump on the TRX at low speeds and in the rough stuff, but when the trail smoothed out, he was gone!

They are an epic machine. Much simpler (and cheaper to work on!) than the Banshee,much more sophisticated than the Blaster. Good rig. Get'er going!

Everyone keeps telling me these 363 builds are amazing. The say a well built 250R can run with the best but like you said, lack some down low power so you really gotta know how to ride it to hang with the best of the modern quads. But with the big displacement, they say you can really ride it like a 4 stroke and bog it down and still grunt through it. All while still having that amazing up top 2 stroke power.

The engine builder has already filled my head and told me that this 363 hes building for me is without a doubt strong enough to wipe the floor with any 450, even built ones, at least in a straight line. He says the only thing that will ever beat that kind of a build is a full blown $10,000+ professionally built 450 race motor.

Now I don't need that kind of power but he convinced me of the big bore because is much easier to ride if your not as skilled or lazier with your riding. Obviously this is not a build for a beginner and with that kind of power, it will wear you out quick but when I say not as skilled or lazy, I mean more like my riding style. I'm knowledgeable on a 2 stroke (riding them for 15+ years) and I've had the power of a 450 (even raced one for fun about 6 times). But by no means am I a great rider though and I get lazy after a short time and just start dogging it. The low end grunt with a strong top end like this big bore build should be perfect for what I want.

Also the biggest thing I'm looking forward to is taking this thing when its done to my local county fair. We have what I like to call "redneck drag races". No professional or even semi-serious drag builds ever show up. Its just people like me with their quads of all kinds with zero mods to some fairly built 450s. To put it in perspective, the quad that won the unlimited class last year was a guy I knew who has an 09 YFZ with pipe, port, and cam. Somewhat built but not serious builds. I wanna take this beast of an R and throw it in the unlimited class and laugh my ass off when these 16 year old kids with brand new 450s that their dads bought for them get left in the dust with their jaws on the floor while my 30+ year old 2 stroke stomps their "powerhouse" 450s. lol. I know, real mature, right.
 
So here is the look I'm somewhat going for. Love the color scheme!

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That's very close to what I'm looking for as a result but I'm going to but my own touch on it.

The red will be a little darker of a red and SUPER glossy. Also I wont have as much polished/chrome on it. The nerfs will be black, the arms with be black, the bumpers black, and the wheels all black. But the red frame and carbon fiber looking plastics look awesome. He's even got the same motor color I'm going with. Can't wait!
 
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Just a little more progress on the R tear down. The spare blaster I'm rebuilding so I can sell is taking up most of my time but still put in about an hour on the R. Down to pretty much just the brake lines, arms, and swing arm until the frame is ready. I'll work on the swing arm and the axle while the frame is getting done.
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I got the rest of the tear down done the other day except the swingarm bolt. It was SEIZED.

So to save time and a big headache, yesterday we just decided to cut the bolt out. After we cut it, it came off the swing arm with a few blows from a big ol hammer. Looked like it hadn't seen grease since 1986 lol.

Now its just waiting for our powder coating prep guy to find a day after work he doesn't mind staying after another hour to hit it with the blaster and then it will be on its way to our welders to find a day they don't mind staying over an hour. Gonna have to buy a few lunches for these guys calling in this many favors lol.

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The axle I bought is sitting next to it so I can blast and powder that as well. It fits in our blasting cabinet so I can do that myself. I know some people say don't powder axles because it cracks and some say it does great but I figured, since I can powder it for free I'll give it a shot. Worst case, it cracks and then I'll just strip it down again and paint it real good.
 
Just thought I'd give a quick update on my build.

Our powder coating oven's fan went out literally as they were about to do my black parts. That held up the process a bit. Late last week, work was able to get install a replacement fan in the powder coating oven and get my parts powder coated. They look AMAZING! Pictures can't do it justice. Its got an outstanding gloss to it and a slight metallic flake that my camera can't pick up. Its a darker shade than most reds but matches by Blaster's frame perfectly but with more gloss and that's the shade I wanted.

Unfortunately, work around the house kept me busier than I wanted to be this weekend so only a small amount of time was able to be put in on the R. What I was able to do was install the bearings and seals into the newly powder coated swingarm and get it mounted on the frame. I'll probably try to get the rest of the rear end assembled this week because my arms will be in later this week most likely.

Here's a pic for you guys. I know, my garage is a mess. Its only temporary though.

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