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Kibblesnbits

87 fourtrax 350, got lucky I think when the timing chain slipped, amazing it ever got so loose

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Goober suggested I check this site out. Got this bike¬†no run and no roll, dragged in reverse a bit and broke the seized rear drum, added a battery and cleaned the carb which was the worst I've ever seen, ever, blasted some starter fluid and was doing doughnuts in the front lawn in seconds ūüôā smoked a bit though at high rpm but sent it for 2 weeks anyways, thing had zero lack of power unreal for its age. Had it on the lift for new brakes all around which btw 00-03 rancher brakes for the front are compatible, I went to start and nuthing but a weird crunchy noise (timing chain slipping) so I tear her apart and all valves are bent pretty bad, so new valves (seated with grind paste) new chain, new oil filter and sparkplug, even swapped out the front and rear diff oil that was beat. Thing runs like a champ now except it still smokes a bit at high rpms, when I took it apart I thought the sleeve looked clean with no scratching but the rings seemed a bit loose(measuring tool battery was dead) so maybe the rubber/plastic boots around the valvestems might be letting oil past idk¬†

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Edited by Kibblesnbits
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The chain must have been really loose and beating around wildly to cause that damage ----------    I think the 350 engine  is built the same way as the  300s ,  the crankshaft timing gear / sprocket  is machined on the crank and not replaceable , I had an engine with a bad timing chain gear and it ate a couple of timing chains up before I figured  out what was causing it , 100 hours or less and the timing chain was gone , took another  crank to fix that  -----  you can take a new chain and wrap it around the gear to check how the chain fits to the teeth , it will look something like ,  the first 2-3 teeth fit ok  and the 4 will not line up properly , cause the teeth get worn out of timing

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3 minutes ago, Fishfiles said:

The chain must have been really loose and beating around wildly to cause that damage ----------    I think the 350 engine  is built the same way as the  300s ,  the crankshaft timing gear / sprocket  is machined on the crank and not replaceable , I had an engine with a bad timing chain gear and it ate a couple of timing chains up before I figured  out what was causing it , 100 hours or less and the timing chain was gone , took another  crank to fix that  -----  you can take a new chain and wrap it around the gear to check how the chain fits to the teeth , it will look something like ,  the first 2-3 teeth fit ok  and the 4 will not line up properly , cause the teeth get worn out of timing

It mad no noise or indication that there was an issue till I went to start it after pulling it up on the lift and redoing all the brakes (minus lines, pretty sure I need those to) it coughed and lost all compression while also amking an odd grinding noise(Chain slipping) so it  happened under power from the starter not the engine so I got lucky. So If I have this problem again in the next year I guess I need a new crank, thank you. Any chance you've done the brake mod that gives you sudo locking diffs by chance?

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2 hours ago, jeepwm69 said:

Welcome aboard.  We have a few "tank" aficionados here.

 

@shadetree, @Goober, and @DuckOfDeath

Second person to call it a tank lol and I like hearing that but other than being a honda whats the redeeming qualities? The solid axles? Cause looking around and I feel it's the only quad out their ive seen that has them.

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3 hours ago, Kibblesnbits said:

It mad no noise or indication that there was an issue till I went to start it after pulling it up on the lift and redoing all the brakes (minus lines, pretty sure I need those to) it coughed and lost all compression while also amking an odd grinding noise(Chain slipping) so it  happened under power from the starter not the engine so I got lucky. So If I have this problem again in the next year I guess I need a new crank, thank you. Any chance you've done the brake mod that gives you sudo locking diffs by chance?

Nope , never heard of sudo lock , but have added shims to 300 and 450 front diffs 

 

The best thing of the 350A and D is the rear end , it is one of the best designs for a straight axle 

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48 minutes ago, Fishfiles said:

Nope , never heard of sudo lock , but have added shims to 300 and 450 front diffs 

 

The best thing of the 350A and D is the rear end , it is one of the best designs for a straight axle 

Awesome. I'll have to take a closer look at it. The sudden lock is basically you install a second brake lever/master cylinder on the left and and run a strait line from each lever to its respective front brake and when ever only one tire spins you grab a bit of brake for that tire so the diff transfers the power to the other tire and both will spin, watched someone online crawl around a swamp pretty effectively with it. What did the shims do for you?

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1 hour ago, Kibblesnbits said:

Awesome. I'll have to take a closer look at it. The sudden lock is basically you install a second brake lever/master cylinder on the left and and run a strait line from each lever to its respective front brake and when ever only one tire spins you grab a bit of brake for that tire so the diff transfers the power to the other tire and both will spin, watched someone online crawl around a swamp pretty effectively with it. What did the shims do for you?

 

Washers lock the spider gears together.  Both front wheels pull.  Horrible if you’re not going in a straight line though. Makes steering really tough. 

 

It’s like adding a spool to a truck/jeep

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I like them because they are simple and tough‚ÄĒexcept for the fuel system‚ÄĒbut I appreciate how designers were try to keep the CG low in the frame. And they‚Äôre heavy.

no fuel gauge, speedo, gear indicator. The only rig that’s simpler is the TRX300.  


Those solid axles will wear you out on a rocky stretch though‚ÄĒthat machine¬†will make you pay‚ÄĒbut I‚Äôve always had good times on it. I don‚Äôt hot rod it though because new parts are hard to get.

 

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12 minutes ago, Goober said:

I like them because they are simple and tough‚ÄĒexcept for the fuel system‚ÄĒbut I appreciate how designers were try to keep the CG low in the frame. And they‚Äôre heavy.

no fuel gauge, speedo, gear indicator. The only rig that’s simpler is the TRX300.  


Those solid axles will wear you out on a rocky stretch though‚ÄĒthat machine¬†will make you pay‚ÄĒbut I‚Äôve always had good times on it. I don‚Äôt hot rod it though because new parts are hard to get.

 

Thanks for sending me here goober, I crawl around in mud around cornfields, never had it above 3rd lol, I love simplicity, less things to break) and yes it IS a workout but ill probably never upgrade. Infact I'll be keeping an eye for another one cause my brother is dissapointed by his polaris 400 4x4 2stroke, I might just keep buying them and build a whole fleet since fixing small engines has really developed into a hobby for me and after getting 5-6 different models running the hondas are where its at.

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On 12/11/2021 at 10:41 AM, Kibblesnbits said:

Thanks for sending me here goober, I crawl around in mud around cornfields, never had it above 3rd lol, I love simplicity, less things to break) and yes it IS a workout but ill probably never upgrade. Infact I'll be keeping an eye for another one cause my brother is dissapointed by his polaris 400 4x4 2stroke, I might just keep buying them and build a whole fleet since fixing small engines has really developed into a hobby for me and after getting 5-6 different models running the hondas are where its at.

welcome. my first 1989 trx350D foreman 4x4 ( that is still in my yard ! ) will never be sold !. this is where it all started with my hobby ( 30 yrs ago ! ). i've had my hands on a lot of these models...and i'm here to tell ya..they are tanks !. with that said, they also require parts..and new parts are being harder and harder to locate !. and when you do find new parts ?, YOU BETTER HAVE DEEP POCKETS !..LOL. do yourself a huge favor..don't go messing with a good design, by this..i mean keep it simple on upgrades. leave the front end alone..it was designed the way it is for a reason, its called limited slip..and this will make it alot easier to ride in tough spots. DON'T GO LIFTING IT..AT ALL !. the front  swing arm can only swing so much, after the point of no return, you run the risk of tearing up the fenders from to large of tires ?, or tearing up the drive line ?, trust me..drive lines for these are getting VERY hard to find these days !. you can put 25x8x12 tires on the front, and 25x10x12 tires/rims on the rear..WITHOUT A LIFT KIT !. my '89 trx350D foreman 4x4 has this on it right now, no issues at all !. you will have to move the foot guards from rear fender up further to clear the tires ?, but its not much. i have a thread in the brake section ?, or the custom section ?, where i put a high lifter disk brake kit on the front. you can also use atv super brake disk kit as well ( seems high lifter is putting china parts in their kits now ! ), you will need some 1/4 steel plate for spacers for the mounting brackets, you will also need a trx420 front brake master cylinder, the factory master cylinder will NOT work with disk brake kits.

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15 hours ago, shadetree said:

welcome. my first 1989 trx350D foreman 4x4 ( that is still in my yard ! ) will never be sold !. this is where it all started with my hobby ( 30 yrs ago ! ). i've had my hands on a lot of these models...and i'm here to tell ya..they are tanks !. with that said, they also require parts..and new parts are being harder and harder to locate !. and when you do find new parts ?, YOU BETTER HAVE DEEP POCKETS !..LOL. do yourself a huge favor..don't go messing with a good design, by this..i mean keep it simple on upgrades. leave the front end alone..it was designed the way it is for a reason, its called limited slip..and this will make it alot easier to ride in tough spots. DON'T GO LIFTING IT..AT ALL !. the front  swing arm can only swing so much, after the point of no return, you run the risk of tearing up the fenders from to large of tires ?, or tearing up the drive line ?, trust me..drive lines for these are getting VERY hard to find these days !. you can put 25x8x12 tires on the front, and 25x10x12 tires/rims on the rear..WITHOUT A LIFT KIT !. my '89 trx350D foreman 4x4 has this on it right now, no issues at all !. you will have to move the foot guards from rear fender up further to clear the tires ?, but its not much. i have a thread in the brake section ?, or the custom section ?, where i put a high lifter disk brake kit on the front. you can also use atv super brake disk kit as well ( seems high lifter is putting china parts in their kits now ! ), you will need some 1/4 steel plate for spacers for the mounting brackets, you will also need a trx420 front brake master cylinder, the factory master cylinder will NOT work with disk brake kits.

Well you just saved me alot of time and effort thanks, I welded a plate inside the frame on the front for a winch but that's it for modding as I'd like to keep her as is since she performs so well except that I'm adding a heated thumb lever cover and maybe some heated handgrip, also adding a second brake lever on the left so I can control the brakes in front individually to sudo lock diffs when one is spinning and the other aint. After getting it all back together I found that finding TDC was easier to do it manually by sliding something down inside the sparkplug hole and noticed that non of the lines marking TDC lined up when piston was at max height, lines were off by a half inch or so weird right? I'm looking at tires the last couple of days because I'm pretty sure it still has its original tires, turning in the snow is nonexistent lol, im looking at the k9 kingsville 24x9x11 or Cordova mudcats 25x9x11. I saw that post about adding disc brakes to the front, absolutely amazing write up and will do the swap when these new brakes are done. Just found an 86 fourtrax that's looks like he'll but owner says it runs and needs nothing (believable but doubt) 800 bucks might snatch it up if it's still around after the holidays, thanks again goober

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Glad you’re here. members here really know these machines. You have stockers, modders and mudders. 

 

If you’re interested in powering accessories there’s a weatherproof 12vdc plug below the handlebar cover, right side. Picture of one from a later model.
 

TDC is easy to find without sticking anything into the plug hole. Pull plug and valve covers, rotate engine counterclockwise (manual incorrectly says CW), watch intake valves open and, as soon as they close look for timing mark. 
 

Tires. I prefer ITP Mud Lite AT and Carlisle AT489

 

 


 

09F6543B-C795-4680-9DA3-DEA158EE1F1A.jpeg

30FD74BB-E107-45E4-80B7-A4707C2A1FEB.jpeg

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9 minutes ago, Goober said:

Glad you’re here. members here really know these machines. You have stockers, modders and mudders. 

 

If you’re interested in powering accessories there’s a weatherproof 12vdc plug below the handlebar cover, right side. Picture of one from a later model.
 

TDC is easy to find without sticking anything into the plug hole. Pull plug and valve covers, rotate engine counterclockwise (manual incorrectly says CW), watch intake valves open and, as soon as they close look for timing mark. 
 

Tires. I prefer ITP Mud Lite AT and Carlisle AT489

 

 


 

09F6543B-C795-4680-9DA3-DEA158EE1F1A.jpeg

30FD74BB-E107-45E4-80B7-A4707C2A1FEB.jpeg

I'll have to try that thanks. I was wondering what the ! that thing was, awesome. The plastics on the red one is mint wth, a new set of plastics cost more than I paid for my whole rig lol and those mudlights look pretty sweet, I just want a bit more tread myself. I would like to illuminate my yellow lights but both my bulbs are missing and the manual had it labeled number 3 but I couldn't find the reference chart, any chance you can point me in the right direction

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Use the oem parts finder at Rocky Mountain atv and Partzilla. Get part numbers.

 Used harnesses available from power sports nation.

oh yeah you have 87 model. Most likely same part number but check it out 

88D095BD-7E7A-4FB9-8E04-A17F635FC22F.jpeg

Edited by Goober

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4 minutes ago, Goober said:

Use the oem parts finder at Rocky Mountain atv and Partzilla. Get part numbers.

 Used harnesses available from power sports nation.

oh yeah you have 87 model. Most likely same part number but check it out 

88D095BD-7E7A-4FB9-8E04-A17F635FC22F.jpeg

My hero, ill be bookmarking that site now.

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Thanks yw. everything I know about atvs I learned from the members here. ūüėé

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13 hours ago, Kibblesnbits said:

I'll have to try that thanks. I was wondering what the ! that thing was, awesome. The plastics on the red one is mint wth, a new set of plastics cost more than I paid for my whole rig lol and those mudlights look pretty sweet, I just want a bit more tread myself. I would like to illuminate my yellow lights but both my bulbs are missing and the manual had it labeled number 3 but I couldn't find the reference chart, any chance you can point me in the right direction

 

They make a Maxxis Mudbug in 25x10x11.  My favorite tire.  Have them on 5 different ATV's.

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6 minutes ago, jeepwm69 said:

 

They make a Maxxis Mudbug in 25x10x11.  My favorite tire.  Have them on 5 different ATV's.

Oh snap those are awesome, now I'm torn, wonder how those will look on my 11x7 rims lol

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6 minutes ago, Kibblesnbits said:

Oh snap those are awesome, now I'm torn, wonder how those will look on my 11x7 rims lol

 

I have 26x10x12's on my 12x6 wheels, and 26x12x12's on my 12x7 wheels.  They'll work fine on your wheels.

 

Also have 27x10x12's on 12x6, and 27x12x12 on 12x7's

 

and 28x10x12 on 12x6 and 28x12x12 on 12x7 wheels.

 

I have a couple of 350's like yours and have been torn on keeping the 11" wheels and running 25" Mudbugs, or swapping a disc conversion on the front, and running 26's on 12" wheels.

 

Keep in mind if you do the disc brake conversion you'll have to run 12" wheels up front, so if you're planning the disc conversion you'll need to buy 12" wheels and tires to fit them (you don't want to buy new tires for 11" wheels that won't work with disc brakes if you're planning on a disc swap)

 

 

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17 hours ago, jeepwm69 said:

 

They make a Maxxis Mudbug in 25x10x11.  My favorite tire.  Have them on 5 different ATV's.

he can't ( or shall i say , shouldn't ? ) run anything larger than 25's on this atv, least not without rubbing fenders without a lift kit ?, and lift kits on these do not work well over time. i had to mod the rear fender on my '89 trx350d, 25's were to big, would rub the inner rear fender, had to move the foot guard forward..remember ?.

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2 hours ago, shadetree said:

he can't ( or shall i say , shouldn't ? ) run anything larger than 25's on this atv, least not without rubbing fenders without a lift kit ?, and lift kits on these do not work well over time. i had to mod the rear fender on my '89 trx350d, 25's were to big, would rub the inner rear fender, had to move the foot guard forward..remember ?.

How did you go about moving the rear foot guards forward? Those mud bugs look right up my alley.

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