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1988 trx300fw

19K views 143 replies 19 participants last post by  shadetree 
#1 ·
Well outlaws, the tear down has started !. removed the topend while the motor was still in the frame, as you can see, the piston died !..lol. cylinder was in pretty bad shape. i'd almost be willing to bet, by looking at the piston, that i've got a bent exhaust valve ?. have not tore the head down yet, just wanted to get the motor out, and torn down a bit to get the cam chain out, clutches out. called it a night. enjoy the tear down pics :).
 

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#4 ·
lol, I think your right !. it was pretty gooey and sticky to say the least !!. rod seemed to be ok from what little time I had my hand on it, everything looks to be in good shape so far. although...the clutch one-way bearing is bad, won't catch when kicking it over. this is the trx300fw that jeep gave me for rebuilding his '97 trx300fw.
 
#5 · (Edited)
That was the first 300 I picked up. I picked it up about 5 years ago. Later on I picked up a couple of 2nd gens because I really wanted to run 424's and the only way to get a 424 for a first gen is the custom $500+ ones. Figured I would fix this one up and flip it, but Shade has more time and expertise than I do, and I'm sure his end result will be much nicer than any attempt I would have made.

I already had some parts I sent with it that I knew it would need. Freshly bored cylinder and new piston, timing chain, battery, front knuckles with new bearings and ball joints, new tie rod ends, gasket kit and oil seals, air filter, spark plug, and a stock 300 rear end with a rebuild kit. I was hoping that would be all Shade would need.

Hopefully the rest of what is needed won't set him back much.

When I bought it, by all appearances it had been sitting in the guys yard for years without moving. Had about 4 inches of tree sap on it.

That said, it was mostly there (missing rear end) and black engine oil is better than milk (water)!
 
#7 ·
update: just as I said, with the piston destroyed like it was ?, sure enough, exhaust valve was bent, exhaust guide was damaged. was able to order new intake and exhaust valves, both guides, and a one-way clutch bearing. my first glance at the head seemed like it would not work with the ex valve seat ?, but i'm pretty sure it will be ok.
 
#10 ·
Yep, but same batch that my daughter's 300 cylinder was in, and it seems to be good to go.

That 350 cylinder actually doesn't smoke anymore since I put a new crank in it. As I understand it, Dick's was subcontracting out the cylinder work. Think it was to Ted Thomas IF (big if) I understood things correctly.
 
#12 ·
just came in from the shop, started In on the carb, well...lets just say...its not gonna work !!..lol. jets were busted off down inside, corroded big time !. now i've got to come up with a carb..( sigh ). I can see right now, this build is gonna get pricy !..lol.
 
#14 ·
well crap !!. it doesn't look like I am going to make any headway on this build ??. decided to start rebuilding the rear diff with new parts that jeep supplied, only to find out that when he stuck the diff together...HE DID NOT GIVE ME THE SHIM WASHERS FOR THE RING GEAR !..ROFL !!. at this rate, I might have this done around x-mas ?!..lol.
 
#15 ·
anyone got some rear diff shim washers for a '88 trx300fw ??. oh...and maybe toss in a '88 trx300fw carb ?..rofl.
 
#17 ·
yeah fish, this is what I hate about starting from scratch..we have no idea what thickness its suppose to be ?. i'm missing the pinion gear washer as well !..lol. I guess you might be able to round up as many as you can, including the pinion gear washer, I can '' test fit '' the new ring gear and pinion gear together, and '' feel '' for a good mesh ?, and which ever ones I don't need, I could send them back to ya, other than this ?, I have no idea what to do here seeing how i'm putting this together from scratch...lol. its a new ring and pinion gear set, all new bearings and seals, I just dont have these damn shims and washer ?. i'm gonna have to have a longgggggggggg chat with jeep over this crap !!..rofl.
 
#20 ·
hi ya @Manny, I took care of the carb problem, as well as the rear diff, thank you very kindly for the offer ! :). I do still need to locate a front bumper and front rack, this one is just trashed. got my eye out for these parts...lol. this is deff gonna be a long time to build this puppy !..lol.
 
#22 ·
update: well outlaws, after giving this crank some very close inspection, it seems the rod is not gonna work. after speaking to retro, he recommended going to mr. crank shaft, I looked up his prices, and I just can't see spending that much cash on it. sooooo, I bit the bullet, and ordered a used crank from power sports nation, about $ 34.00 bucks, ad said good usable condition, what the heck, right ?. and before you ask !, yes, I just placed an order for brand new crank bearings from rocky mountain atv, another 100 bucks, but worth it !. as for the carb ?, I was able to hit my bud up who i've known for over 25 years ( great guy by the way ! ), he had a trx300 carb that he gave me !. I did order a brand new choke cable, starter valve part set from partzilla ( pricey little bugger !..lol ), so thats on its way. still waiting on my intake valve, exhaust valve, valve guides, and one-way clutch bearing from rocky mountain atv. was able to work a little on the front bumper, for the most part, I '' think '' ?, I can rescue it !, so far i've got it pretty much back in shape, still got some '' fixing '' to do to it ?, but i'm sure I can make it work :).
 
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#23 ·
here is the front bumper, as you can see, it had a hitch welded to it. I cut it off with my angle grinder with a cut-off wheel, its gone !. with some whacking with my dead blow hammer, and my shop press, I was able to get it straight ( for the most part anyway ), i've got an idea on how to fix it better, will update that later with some before and after pics :). i've got to fix the front rack, as the PO cut the rail off it , no clue why they did this ?, but I will fix it !.
 

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#24 ·
update: got a little done on the front bumper, everything is just in the ruff for right now. got the front rack's rail welded back on, I think its looking pretty good so far ?. not done yet on the front rack, I want to cut the very front down tubes off, and put some new , and longer tubes on there with some better metal clamps to attach it to the very bottom front bumper. little things like this make my day, I enjoy doing stuff like this :).
 

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#26 ·
update: got some more work done on front bumper. after looking at old '88 trx300fw's, I see there is no protection around the headlights ?, hmmm. well..i've got a plan !!!. well, an idea anyway..lol. have not started on it yet, needed to take a break for now. but i'm sure I will be the only person ( maybe ? )..that has done, or will do what I got in store ?. lets just say..it will be all custom work ?!..lol.
 

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#28 ·
ty retro !. yeah..anything I do now has to be an improvement !..lol. it was in pretty bad shape, but its coming back together :). power sports nation had a few trx300 cranks, and out of all that I looked at, the one I bought was higher priced !..lol. most were like 24 bucks.
 
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#31 ·
update: well heck, where to begin today's story ?..lol. I started out this morning wanting to finish up putting the head back together, ok..out I go to my shop, press in the brand new valve guides I bought from rocky mountain atv, go to slide the new valve in..wait...what ?..it wont fit ??..wth ??. my first thought was I got the wrong parts ?, came inside, checked my order, nope, all part numbers matched the packages !. hmm. went back out to shop, tried new valves in old guides..they fit !, but not in the new guides I just pressed in ?!. wth ??!!. called rmatv, told them what the deal was, they got back to me later, said no guides are out there for any trx300's, and they spoke to honda corp, told them all these guides they are selling/sent to all dealers...ARE WORTHLESS !!!..LOL. got my money back. soooooooooo..word of caution !!!!, DO NOT BUY ANY VALVE GUIDES FROM PARTZILLA, BIKE BANDIT, RMATV, OR ANY ONE FOR A TRX300 !!!!!, THEY WILL NOT FIT ANY VALVES YOU MAY OR MAY NOT BUY ?!. take my word on this..it will not work..period !!!.

so, now I had to call my bud up, and ask him if he has a spare trx300 head ?, he says come out an look, but he doubts it ?. well..see..i got a back up plan !!!. low and behold, the trx300 uses the exact same valve guides as the trx250 fourtrax, atc350x, and a few other atcs and atvs, what was odd though ?, is the valve guides from a trx350 old school are not listed in the parts break down on all years and makes the trx300 uses ?. anywayyyyyy, I did find a trx300 head, came back home with that, got it all cleaned up the '' second '' go around with easy off oven cleaner, set that aside. cleaned my buds trx350 wrecker carb up seeing how it had rust in it instead of clean fuel ?!!..lol. done for tonight, i'm tired, been fighting this trx300 head all damn day, and it has turned into one long nightmare for me , but I got it all together !!.
 

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#32 ·
called rmatv, told them what the deal was, they got back to me later, said no guides are out there for any trx300's, and they spoke to honda corp, told them all these guides they are selling/sent to all dealers...ARE WORTHLESS !!!..LOL. got my money back. soooooooooo..word of caution !!!!, DO NOT BUY ANY VALVE GUIDES FROM PARTZILLA, BIKE BANDIT, RMATV, OR ANY ONE FOR A TRX300 !!!!!, THEY WILL NOT FIT ANY VALVES YOU MAY OR MAY NOT BUY ?!. take my word on this..it will not work..period !!!.
!!.
That's screwed up. Wonder how many of those have been purchased that ended up getting tossed in a box because they didn't fit?

This what you got? https://www.partzilla.com/product/honda/12232-HA0-305?ref=1440682e002cc6d5d2f7ee5ce595e5944c56f869

Does the (O.S.) mean anything?
 
#35 ·
Yep, ^^^ oldmx, ya nailed it! ^^^^ "OS" denotes an oversize valve guide.

Back in the good old days when things were repaired to perform better than new, rather than replaced, most shop owners maintained their own valve grinding & guides reconditioning equipment. In that repair environment oversize guides were always in very high demand. Nowadays shops don't fix or recondition stuff to perform better than the original though, they throw good parts away once they become worn. There's not many of those craftsman shops left anymore, just several generations of indistinguishable robot parts replacers. Each labeling and selling themselves to be repair techs. LOL!!! :)

You can use those OS guides, they're darn good and useful parts. But you must heat the head up in an oven (300 - 350 F) before pressing the old & new guides else risk breaking the casting or buggering up the hole and guide, leaving them crooked or off center. Then ya gotta run reamers into them to bring the bores out to clearance fit the reconditioned (or new) valve stems. Then ya recond the valve seats and valves and you're done. Valve seats used to be replaced in the same step too, while the head was hot, fresh out of the oven. Some of the old-timers (and a few younger ones, my favorite old-school machinist is in his early 40s) still fix stuff right. But most shops don't.
 
#42 ·
thanks fish, I might try them later ?, right now i've got a replacement head, I just put my new valves in it. this head is in decent shape that came with the bike, I even had trx350 rancher valve guides in it, gas tested the valves for leak test, and it passed !..lol. only down side is the guides inside were not long enough to support the valve stems ?. and this concerned me when running. I will just give it to my bud, if and when he needs or want to use it ?, we both know we can use valves out of some old models , like trx250 fourtrax, atc 350x. he's got a lot of old trx250 fourtrax's in his bone yard..lol.
 
#43 ·
@fishfiles , i'd be willing to bet, they are using OS guides when they recondition heads for folks ?, they got the machines to ream them out, press them in, no one would know the difference unless they were like me ?, and tried doing this themselves ?!..lol.
 
#44 · (Edited)
update: some good news finally !!..lol. was talking to my mail man the other day ( same guy I sold that '05 trx500fm too ), he said his brother had some tires and rims off a trx450es that was just laying around, I told him I could use them on this trx300fw, seeing how I plan on putting front disk brakes on it. they are 25x8x12 fronts, 25x10x12 rears, I think this will work out just fine for this ?!. he sent me a text yesterday, told me he dropped them off, put them on the side of my carport ?, I never seen or knew they were there ?!. sure enough, went outside, there they were..rims were like new !, center caps there, tires with decent tread !..just wow !!!. I was stoked he did that, another reason I felt good about selling him that atv dirt cheap..KARMA WILL ALWAYS DO YOU RIGHT !! :).
 
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