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First post, I think?

2K views 23 replies 6 participants last post by  1idejim 
#1 ·
Began to post recently and was directed here, my original may not have made the grade.

Anyhow, I have just acquired a 93' trx300fw in pretty great cosmetic condition. Oils looked clean without burn signs or smells.

Turned the key on and no dash lights so I figured the battery dead, .01 VDC, it's toast.

Flipped the compression release lever (csl) for kick starting and the kick lever went down effortlessly. Noted the csl did not return to the down position so I flipped it down and again the kick start lever went down effortlessly.

I put the transmission in gear and the machine jumped forward with some kick start lever resistance.

My brother in law took it on trade and basically gave me the machine so I figure it's worth fooling with, I need 2 quads for work anyhow.

Here's what I've done and observed so far.

1) I removed the valve covers and checked both the operation of the compression release lever (works properly, opens exhaust valve) and timing chain movement. The timing chain moved when I turned the reduction wheel counter clockwise but not when I kicked it.

2) I removed the head cover and inspected the valves for any issues with springs or apparent broken/missing parts. Visually looks good.

3) Next I loosened the tensioner bolts without retracting the tensioner mechanism. Reason was I wanted to see if there was much pressure on the timing chain as there was a wee bit of slack but not much when I inspected the chain. A new chain may or may not be warranted but contingent on what's next.

4) Next step was removing the sprocket, the cam and suspending the chain from wire.

5) I then removed the head and inspected the valves visually. No burned seats, bends, there's some carbon build up but nothing excessive.

6) If I place tension on the timing chain the piston works normally.

My next step is cleaning all of the parts and measuring the barrel, piston, cam, valves etc.

I guess my question is, if everything measures out good, what's your opine on the low compression issue?

I may decide to put in new gaskets and reassemble the engine. (That's contingent on the measurements.) Buy a new battery and do a compression test, see if it starts and call it good for a bit.

Or

I may decide to do a real rebuild now rather than later.

Thanks :)
 
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#2 ·
First off welcome to the forums! And take this for what its worth as i know nothing about utility quads. Expecially ones that have electric start and kicker back up. But here are the things that jump out at me from reading your post. First i wonder if you actually had zero compression because to me it sounds like the kick start wasnt turning the motor over at all. Which would also explain why the decomp lever didnt reset. And also why you said turning the reduction gear moved the cam and timing chain but the kick start didnt. I would think it should. The part that has me scratching my head is the fact you put it in gear and moved the kick start and it moved the quad forward. That would tell me its making a connection to something for sure. I wonder if there is a type or starter clutch or one way bearing that turns the crank when you kick it over and that is going bad? Or the reduction gears that connect the crank to the kick start are missing teeth or broken in some way? I may have completely miss understood what you were saying and if i did just ignore my input lol. Wouldnt offend me in any way. Im a sport quad guy. Just my .02
 
#3 · (Edited)
Hello, welcome to the forums!

I'm interested in your previous posting issue... were you instructed by software to try posting again? Was it an automated moderation notice, or was it something else? If we have something going on preventing new members from posting we'd like to know, so it can be fixed. Thanks.

Now for your TRX300FW questions... which I'm not sure that I understand your issues completely. Are you saying the kick starter does not crank the motor over when kicked?

EDIT: oops... didn't see your reply SlammedRanger
 
#6 ·
I was directed here by the mods and don't know if my thread was allowed untill I followed prodical.

I live a ways from town and wasn't prepared with a new battery, the quad was delivered on a weekend and I still haven't gone to town for a battery.

I don't go to town very often so....

When I unloaded the quad I don't know if the compression release was engaged or not but I pushed it off in gear without a lot of force, I could engage the transmission and move it with or without the plug in it before I tore into the motor.

I first thought the compression release was broken but discovered that not to be the case.

Second thought was the one way bearing in the kick start or flywheel was bad. After a little tinkering and testing I have doubt this is the case.

Since the piston looks good and there's no scratches or evidence of damage to the sleeve I'm wondering why my compression would seem to be so low.

Granted, I jumped the gun and dove in prior to getting a battery and doing a compression test so I'm asking questions of more knowledgeable persons. That be you guys!

I am a troubleshooter in an unrelated field so I'm used to performing tests and know better, I'll be more patient next time.

I haven't done anything that can't be undone for minimal cost, new gaskets and reassemble. New battery and start with a compression test or I can ask of you to play devil's advocate and play 20 questions.

1) what's the possibility my valves were out of adjustment which caused a lack of compression?
2) could this be caused by excess slack in the timing chain?
3) out of spec piston, rings, sleeve?
4) bad one way bearings in either the kick start or flywheel?

Just asking for the odds are or direction to move in.

As of right now I'm inclined to clean it up and reassemble the engine and start with a battery.

Thanks :)
 
#7 · (Edited)
Hi and welcome!
I am thinking perhaps you didn’t do the compression test as described in the service manual. If you mentioned that you did, I missed it.
Quad in unknown condition can be confounding—no stuck valve? at this point may as well rebuild it?
BTW you shouldn’t be able to move it easily while in gear
 
#8 ·
1) what's the possibility my valves were out of adjustment which caused a lack of compression?
2) could this be caused by excess slack in the timing chain?
3) out of spec piston, rings, sleeve?
4) bad one way bearings in either the kick start or flywheel?
1) An overly tight valve adjustment that holds a valve open, a burned/worn out valve/seat/guide or a stuck or bent valve can lead to low or no compression.

2) Excess slack in the timing chain can lead to the chain jumping teeth on the sprockets, which results in the valvetrain being out of time. So yes, if the chain jumped over one or more teeth you'd lose compression... and possibly bend a valve head if one of them is open and contacts the rising piston.

3) Certainly, if cylinder/piston/rings wear (or damage) becomes serious enough you can have a loss of compression so great that the motor will not run.

4) A bad one way bearing can "slip" when using the kickstarter, which results in the kickstarter will not crank over the motor. Is your motor cranking over when you use the kickstarter? Or no..?

A blown head gasket, a warped or cracked head, a broken rocker arm, broken chain, broken cam, broken crankshaft/connecting rod, plugged intake or exhaust port etc... can also cause a loss of compression.

I still don't know the answer to this question so please excuse my ignorance... Does your motor crank over using the kickstarter, or no?
 
#13 ·
I'm starting to get the hang of this forums format for posting. First time I've been able to quote.

Originally I suspected either the compression release or the one way bearing.

Eliminating the CRL as it did open the exhaust valve I am focusing on the one way bearing on either the flywheel or the kick starter.

Holding the timing chain in place and actuating the kick start lever it was going pretty smooth. Then it quit. Then it was smooth again. Then it quit.

Pretty sure installing a new kick start one way bearing wouldn't hurt a bit.

I also scraped some of the carbon build-up from the piston which revealed contact marks from both intake and exhaust valves. This is getting more complicated but will be a good experience for me.

As I said earlier I am a troubleshooter in the irrigation field. I work with both water which can be seen, felt and tasted as well as measured and electricity which cannot be seen, felt or tasted but it can be measured.

I'm not a fan of throwing parts at a problem as a means of diagnosing said problem and I want to know what I'm looking at and why it's not working correctly.

With a bit of guidance from you more seasoned mechanics I'm sure I'll get this bike running in no time at all.

Thanks :)
 
#11 ·
I belong to other forums but find the navigation of this forum different enough to be somewhat confusing.

I'll take a few pics and attempt to post them later today.

In scraping the carbon from the piston I did discover dings from both intake and exhaust valves.

I'm pressure washing the backhoe tomorrow and will clean some parts up.

I've done some small engine work before but this quad will be my first engine in a long-long time.
 
#14 ·
I use the classic version of this site , at the bottom left on the page there is a drop down box , try switching to classic and see if it is easier for you

the dents in the piston may be ok ------------- I don't get what your saying about holding the timing chain in place , I am thinking you have the head off and holding the chain with your finger where the sprocket would normally be ------------ it is fairly easy to take off the right side cover , the both clutches , the one way bearing is inside the clutch and you can check the one way bearing with your finger
 
#17 ·
Yes, I believe I posted this 93' fourtrax 300fw earlier, won't hurt to post it again if I have.

Beginning Monday I'll be watching my son's house where there will be no cell or internet reception. Once in a blue moon but mostly nothing. 10 - 14 days of zip so I'm taking my time opening this bike up.

All of my parts are bagged, labeled and boxed so there won't be confusion or lost parts, life sometimes gets in the way and memories do fade. Trying to keep things straight from the get go.
 
#18 ·
I'm having some difficulty posting pics using the drag and drop AND I'll be out of service for both my phone and internet for about 2 weeks.

One of my grandsons has qualified for the IMRA/IFR tour finals rodeo in Oklahoma City the 18th - 21st and I'll be taking care of their animals and place while they're traveling there and possibly to a college in Colorado which has invited him for a campus tour.

I'll check in as often as possible but I expect to be staying out of service for up to 2 weeks. You guys don't give up on me.

I'll get the parts all cleaned up, the cam, sleeve and piston mic'd, but wait to inspect the gears and bearings.

I'm looking forwards to doing this project (especially with your guidance) and would really like to get this bike in tip top shape this year.

To tell you the truth, when I shoved this bike off the truck it was in better shape than any of the bikes I ride at different ranches I work at and has better brakes than ALL of the bikes put together at one ranch in particular. :)

You all have a great couple weeks, I'll get my act together and return by February fool's day.
 
#20 ·
Hope you all are well, I'm ready to proceed.

Everything mic'ed good and is clean.

I removed the right crankcase cover without removing the kickstart mechanism.

The clutch spins in one direction only while the flywheel will spin both ways.

I'm thinking (and asking) the one way bearing is bad. To the best of my knowledge there are 3 one way bearings. Starter - flywheel - clutch.

I've ordered a one way clutch bearing and complete gasket kit so far. I'm wondering about just purchasing a flywheel complete with bearing as it's about the same as a bearing off eBay.

Same with a starter one way bearing/starter kit.

Thanks again
 
#21 ·
Another thing I was curious about is if anyone had any suggestions on specialty tools I need to tackle this venture.

I ordered a shop manual (I have one on my phone too) and valve compression tool, flywheel puller and I used a hose clamp for a ring compressor.

It nice having the correct tool for the job for sure.
 
#22 ·
An air or electric Impact gun (with a 27mm socket) will be needed to get the nuts off from the clutches. Along with a flywheel puller, a good set of metric 6-point sockets and other common hand tools are needed. You'll need a feeler gauge to readjust the valves, some red loctite threadlocker for the cam bolts, hondabond 4 gasket sealer for the head cover, cleaning solvent, clean rags, gasket scrapper, motor oil & oil filter etc.

Don't use a hose clamp for a piston ring compressor... very, very, bad idea. You will score the rings and piston and possibly break a ring. If you can't borrow a ring compressor at a local auto parts store, learn how to compress them one at a time using your fingers while supporting the jug with your free hand. The manual shows you preferred locations around the piston for each ring end gap. Take your time and ask questions... and have fun!
 
#24 ·
Hello again, been a bit busy while awaiting parts. My shop manual showed up today, I now have a pistol ring compression kit and valve spring compression kit. My gaskets are in the roll away drawer and I've acquired a flywheel complete with one way bearing. Hondabond showed up the other day so now I'm waiting on thread lock and a bit of time.
I'll spend some time reading my manual and cleaning up everything as well as I can and hope to get this project going.

I really appreciate all of your input.?
 
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