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kevin_c

trx350 mystery

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1 hour ago, kevin_c said:

Is there also a way to check when the top end is disassembled?

 

Not reliably no... you can look at the teeth on the cam sprocket to see if there is a lot of wear on the tips of the teeth, but you'd be making a judgement call about the condition of the chain without proof. The only way to be sure is reinstall it and check the extension of the chain tensioner. Since you have the motor apart it might be a good idea to replace that chain anyway right now to insure that ya don't have to go back inside later on to replace it.

 

The best manufacturer for new TRX350 cam chains is D.I.D. You can find DID chains for sale on eBay and elsewhere on the 'net. You'll need a new right side cover gasket if you decide to swap in a new chain. Let us know if you decide to swap the chain, we can give ya a couple pointers on R&R-ing that side cover that might save ya some time.

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2 minutes ago, retro said:

 

Not reliably no... you can look at the teeth on the cam sprocket to see if there is a lot of wear on the tips of the teeth, but you'd be making a judgement call about the condition of the chain without proof. The only way to be sure is reinstall it and check the extension of the chain tensioner. Since you have the motor apart it might be a good idea to replace that chain anyway right now to insure that ya don't have to go back inside later on to replace it.

 

The best manufacturer for new TRX350 cam chains is D.I.D. You can find DID chains for sale on eBay and elsewhere on the 'net. You'll need a new right side cover gasket if you decide to swap in a new chain. Let us know if you decide to swap the chain, we can give ya a couple pointers on R&R-ing that side cover that might save ya some time.

 

  To my untrained eyes the cam sprocket looks good. I was hoping to avoid taking the covers off but since I don't have a good understanding of what went wrong it is probably a good idea. 

 

 

 

 

image.png

 

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That sprocket looks like it is in excellent condition to my old eyes. You can reassemble the topend except for the rocker box cover and check the chain length to be sure, before you rush out to buy a new chain. It's no more work to replace the chain with the cylinder head on the motor, than it is with the head off.

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5 hours ago, kevin_c said:

 

Thanks shadetree good point. I've read in other parts of the forum how to check for stretch in the chain while the top end is still on the motor. Is there also a way to check when the top end is disassembled? Right now my chain is just hanging there above the crank case while I work on the top end.

nope, chain was suppose to be checked while top end was still together.

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Hey Folks. Its been a fun yet perilous journey. Using advice from other threads and here I ended up doing a top end overhaul - valves, rings, seals, cylinder care, etc. Once back together it fired right up using the kickstarter! No smoke and it sounded great. I made the decision to address the electric start issue later (mainly because I wanted to use the bike in a dog trial this past weekend). When I got it to our club grounds, it ran great for about 5 minutes and seized up again. I heard a grinding sound as the engine quit sounded like it was coming from the left side of the crank case. Well I pulled the left cover off and discovered a chewed up starter reduction gear...and worse. One of the teeth ended up in the stator which chewed up the flywheel - horrible. So, I'm beginning to think that the "seizing up" I reported in the beginning had nothing to do with the top end and all to do with the starter reduction gear. 

 

I haven't pulled the flywheel yet (waiting for the puller) but the one-way bearing seems to be okay (when I turn the main drive gear it doesn't have any play and catches immediately if turned in the opposite direction.)

 

At the minimum I need a new flywheel, stator, and starter reduction gear :(. 

 

IF the one-way clutch is in good shape, any ideas why the reduction gear would get all chewed up? 

 

Side notes and sad stories from the top end rebuild:

 

1. I stripped out one of the 7x145 mm flange bolts that bolts on the valve cover. Had to call 13 places to find it off a junker (now I've got 2 extra if anyone else needs one 90052-HA5-67). 

 

2. My brother was clearing the crank case side cylinder gasket with a razor and he dropped it into the right cover side hole. He then took a magnet on a piece of fishing string and ended up dropping that in there as well. We took off the right cover, found the razor and magnet. During reassembly we didn't notice that the reverse stopper level spring pin had popped out before we torqued the cover down. Ended up with a 1.5 mm diameter hole in the seam between the cover and crank case - horrible. Used a product called alum bond to repair, seems to hold oil well. I learned to hold the reverse stopper lever spindle in with a screwdriver while I put the cover on. Hard lesson. 

 

 

161300437_3763456917104430_6082566037589939416_n.jpg

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What a mess , I seem to remember reading about different year  350s having different starter gears --------    did the electric start ever work for you since you got it , did you ever swop out  any of the starter gears ????  

 

So now that you got the tooth out the flywheel and the start gears freed up , does it turn over now ? 

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57 minutes ago, Fishfiles said:

What a mess , I seem to remember reading about different year  350s having different starter gears --------    did the electric start ever work for you since you got it , did you ever swop out  any of the starter gears ????  

 

So now that you got the tooth out the flywheel and the start gears freed up , does it turn over now ? 

 

Indeed a mess. I didn't try the electric start but I did verify that the starter worked when it was pulled off. I didn't touch any gears. The previous owner said the e-start stopped working a long time ago and he just used the kickstarter. I assumed it was a bad starter or a wire or something - poor assumption on my part. 

 

It turns over fine with the stator out, both by rotating the flywheel bolt and with the kickstarter. 

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I am no 350 Guru , but I think the 86 was a stand alone year for the starter gear , maybe the problem is the PO never could get the starter to work cause it is the wrong gears , I just looked at Partzilla's break down , it tells you the number of teeth of each gear , maybe count the teeth and look at the break down and be sure you have the right gear set in there ---- could also think if the bearing was bad the gear could cock and damage the gears ----seems it must happen often the gears get messed up as I have read about it before , and I think one gear set is very hard to come by and think it might be the 86 as it was the first year and a stand alone --- I am going to see if the special man will stop by and give some in put on the situation -------   @shadetree

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I did talk to the 350 Guru and he said a 86 is a stand alone year for the stater gears , I asked him to stop by when he gets freed up ----   What I am saying is what you need is very rare 

 

I just thought of something else I forgot to ask him about , the stator -------   I know my 300 had two options for the stator , they were interchangeable as long as you changed it as a set , flywheel matching the stator ------    I just looked at the 350 stator and they do show two different ones by years  , but  what might be happening with the 350 is , it is not a different amperage stator like the 300 , but the 86 350A was a/c  , then the next gen 350 D was  d/c ---- so don't jump into ordering parts to quick as you might get the wrong stuff , e-bay and other sellers will either lie or don't know and will tell you stuff fits and it don't ----- 

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Bummer!

yeah early 86 TRX350A starter gear sets had the oval cover cavity; 87 TRX350A and maybe later 86s had teardrop shaped cavity. The oval shaped cavity had a machined surface for the gearset shaft
The teardrops I believe have a bearing  in the cover, which could help you source parts and build better. Definitely a longer starter shaft on the 87.

if you could find an 87 TRX350A it would be an upgrade to use the cover, stator, starter and starter gear set. Maybe flywheel too.

TRX350A had a stator with an exciter coil: 3 yellow wires, a green ground wire, Bu/Y pulse generator wire and Bl/R exciter coil wire. 
 

I personally own 86s but i have 87 TRX350A for work machines. Be happy to take pix for you

822B331E-BDCC-4B34-9CBE-A595C9307297.png

1C95EE92-8147-43DC-9224-2F06CB82C54F.png

Edited by Goober
U
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If your on FB in the group Honda Hoarders there was a guy that just posted some 350 parts for sale, yesterday I think. He had 2 motors that looked to be complete and was either 86 or 87, I didn't look close enough but they had the lower left crankcase breather and tank. He might part them out or if by chance your close enough it would be a bunch of parts.

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14 hours ago, toodeep said:

If your on FB in the group Honda Hoarders there was a guy that just posted some 350 parts for sale, yesterday I think. He had 2 motors that looked to be complete and was either 86 or 87, I didn't look close enough but they had the lower left crankcase breather and tank. He might part them out or if by chance your close enough it would be a bunch of parts.

On it  - thank you!

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19 hours ago, Fishfiles said:

I did talk to the 350 Guru and he said a 86 is a stand alone year for the stater gears , I asked him to stop by when he gets freed up ----   What I am saying is what you need is very rare 

 

I just thought of something else I forgot to ask him about , the stator -------   I know my 300 had two options for the stator , they were interchangeable as long as you changed it as a set , flywheel matching the stator ------    I just looked at the 350 stator and they do show two different ones by years  , but  what might be happening with the 350 is , it is not a different amperage stator like the 300 , but the 86 350A was a/c  , then the next gen 350 D was  d/c ---- so don't jump into ordering parts to quick as you might get the wrong stuff , e-bay and other sellers will either lie or don't know and will tell you stuff fits and it don't ----- 

Thank you. I was reluctant to hop right into buying parts for the reasons you mentioned. It looks like my first reduction gear is 43 / 18. Funny enough, only the out 43 side is damaged. The inner 18 look fine, along with the other gears on the spindle all the way down to the main drive gear. 

159975666_194654695370779_3538297266592235462_n.jpg

160869437_2971293949753060_6248041498286596897_n.jpg

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Looks like 43/18 are the correct numbers for a 1986  and the other two gears are 25 and 21 ----  also I do believe the starter is different on the  1986 , what's different is the length of the shaft that sticks out of the starter , it  is longer on one (1986 )  or all the others ( 87-up ) , I am not sure which one is longer , my main stay on 350s is taking the rear ends out of them and selling what ever is left 

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7 minutes ago, Fishfiles said:

Looks like 43/18 are the correct numbers for a 1986  and the other two gears are 25 and 21 ----  also I do believe the starter is different on the  1986 , what's different is the length of the shaft that sticks out of the starter , it  is longer on one (1986 )  or all the others ( 87-up ) , I am not sure which one is longer , my main stay on 350s is taking the rear ends out of them and selling what ever is left 

 

 

I see. I will need a new starter also the teeth on that are damaged. The 43/18 reduction gear is still available, and I found a junker for the flywheel and stator. Still not sure why all this happened, or why the one-way clutch seems intact. Maybe I'll know more when I pull the flywheel. 

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@Goober brought up about the starter gear covers being different on the 86   -----    I see the 86 also has a different side cover to accept the different cover , wonder if someone piece  together that engine from different years ---------   could just be the gear broke 

 

 

Which one of these two starter gear covers does your have  

image.png

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So my 86' has the cover in the upper picture (circled in yellow) without the bearing (#32). I'm curious if it would accept the setup from 87' with the bearing all the other parts look the same. Good suggestion @Goober

 

 

 

 

 

image.png.68ab3a459ec24206a929f157202e440e.png

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Good question.

yup you have the same setup i do. The starter shaft is very short. the starter gear likely failed and broke the reduction gear. 
 

According to the Rocky Mountain atv OEM parts finder, only the gear that engages the flywheel is common between the early 86 and late 86-87 TRX350A.all other components from that point to and including the starter are different.

 

you def need a new starter and reduction gear set. Idler gears B and C look ok?

flywheels and 70 tooth gears appear same. 
 

You’d be scaring down fewer parts if you stayed with original config.

Edited by Goober

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Carefully consider parts mixing. For instance. this number flywheel has limited application. Well you’re tossing it anyway but make sure the newer flywheels backward compatible.C3787DD2-0B54-4E03-B693-349389E27F27.png

 

 

22883988-DA65-4148-AEDE-103A66F2B436.png

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Thanks @Goober I'm keeping it original. I should have the holder and puller this evening and I'll take a closer look. The idler gears look great, along with the 18T side of the reduction gear and the 70T drive gear. Maybe someone was giving it lots of throttle while cranking the electric start? I'd hate to put all these good parts in and have it happen again. 

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My guess the starter gear was worn and slightly stripped 
all 86ers including me ought to inspect their starters and probably replace them if the gear shows moderate wear or is skipping

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you are staring down a scary road here bro !. don't go buying and mixing stators, alt's , and all else unless you know for a fact you are buying parts for a 1986 trx350 fourtrax !!, REASON : this year MUST have a stator, flywheel, and matching gears to make it run. this model is a stand alone model for the electronics when it comes to firing the spark plug. why you ask ?..THIS IS A DC CURRENT MODEL !, all other models after are AC current models.

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5 hours ago, shadetree said:

you are staring down a scary road here bro !. don't go buying and mixing stators, alt's , and all else unless you know for a fact you are buying parts for a 1986 trx350 fourtrax !!, REASON : this year MUST have a stator, flywheel, and matching gears to make it run. this model is a stand alone model for the electronics when it comes to firing the spark plug. why you ask ?..THIS IS A DC CURRENT MODEL !, all other models after are AC current models.

 Uh oh. Thanks @shadetree. I bought the used flywheel and stator based off part # 

stator: 31120HA7-671

flywheel: 31110-HA7-751

 

Not sure I understand what a DC current model means. AC is produced from the motion of the stator which gets rectified and regulated. Is that correct for the 86’ also? 

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yup
A/C CDI for TRX350A 

D/C CDI for TRX350D 

 

the service manager explains pretty well. Most importantly know your engine number and try to get parts for your model. Lotsa sellers don’t really know but knowing what to look for such as numbers of teeth in a gear set really helps.


@shadetree is super smart, esp on these quads 

 

fortunately your quad ran before this happened 

Edited by Goober
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