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Riverside21

A timing issue with 1996 TRX300FW

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A little back story:
Last winter I picked up a 1996 trx300fw in what I thought was good condition. Turned out I ended up doing a major overhaul to get it going, including piston, rings, cam chain, etc.... At the time of reassembly I set the "T" and got the two dash lines on the cam sprocket close to level on the head and went with it. This machine always seemed somewhat low on power to me for a 300. Fast forward to a few weeks ago: My buddy wanted to get one of these and we found him a nice 1991 model. I was blown away at how much more power his has (all stock) and feels like a 500 compared to mine. At the time of purchase I mentioned how much more power this one had over mine and the guy selling it mentioned to check my timing (he has bought/repaired and sold many 300's he told us).

I decided to first check everything with a timing light and tach as it states in the manual, and compare to my buddy's machine. at the 1450rpm idle I was slightly off of the "F" and at 4500rpm my two vertical "advance" lines were not even close, just barely starting to come into the inspection hole! As I figured...I checked all the same parameters on the 1991 and everything was spot on, lining up with the pointer. I then decided to pull my valve cover and investigate the possibility of being off a tooth, and noticed that when I'm on "T" my lines on the cam sprocket are not level on the head; one side is high and one is low. After fooling with this thing for a while and moving the sprocket a tooth each way, the lines still will not level on the head. I'm wondering if the sprocket on the crank got moved out of place?? I thought they were pressed on (I did one on an xr200 crank), but I have no idea what the previous owner of my 1996 did because the engine was jacked up when I got it.

Any ideas on this one?? Thanks in advance!

Edited by Riverside21
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Have you tried finding TDC using the piston and then see where the T was lining up at? What brand of cam chain did you use when rebuilding it? 

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I was just thinking about tdc and a possible stripped key.  I will check it tonight for tdc.

 

It is a d.i.d. chain.

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Welcome to ATV Honda! Those timing marks on the cam sprocket are slightly off sometimes, depending on the length of the chain due to chain and sprockets wear. But you may have a partially sheared woodruff key where the flywheel locates to the crankshaft. Also make sure that your CDI is a genuine OEM Honda (or Ricks Motorsport Electric) part. China knockoff parts are garbage on ATVs.

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Thanks!  I will check for tdc tonight and report back.  I am actually on my 3rd cdi box.  When I got the machine the stock Honda one that was on it (Shingarden I believe) had a bad starter circuit and would not fire a spark while pressing the start button. It would only fire just as the button was released, but the bike would start and run from there.  I replaced it with a Rick's to fix the starting problem, which it did....then 3 months later the Rick's completely blew out and bike wouldn't run.  I am now on the 2nd Rick's.  Engine never made any better power with any of the other cdi's, but I never checked the timing with those ones.  

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@Riverside21 Honda Parts Nation or Partzilla. Go OEM and you won't have to worry. This probably won't apply but storytime. Several months ago watching Nick's Garage on YouTube, had a mustang, timed it up wouldn't fire, hook a timing light and it flashed on the end of cranking so coil was shot. If you haven't get your money ney back and go OEM CDI and coil. Like I said I doubt this will apply but good info to know.

 

Also use a NGK DPR8EIX9 iridium plug greater spark. DON'T get those E3 garbage. I been running the iridium plug for years now. Great spark fires with very little effort.

https://www.amazon.com/NGK-Iridium-Spark-Plugs-DPR8EIX-9/dp/B00MRAV2U8 

 

Or get one for $ 9.59

https://www.amazon.com/NGK-DPR8EIX-9-Iridium-Spark-2202/dp/B0032YRU3G

 

 

Edited by F250 guy

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I had my son check for tdc while I'm at work....He says it's good, piston is at tdc and the "T" mark is lining up.  

 

Now I'm confused as to why my cam sprocket lines are off and I'm not hitting the marks with the timing gun.  

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The cam chain sprocket of the crankshaft is made onto the crank , I have had one that was worn bad and was eating chains up quick , till I replaced the crank  ---- did you at the least replace the cam sprocket when you did the chain 

 

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Rick's make a good cdi , I have many of 300s running Rick's CDIs  with many hours and never had one good out yet , but there are fake Rick's  out there , where did you buy your Rick's from , if off e-bay , then good chance it is a fake , cause Rick's don't sell on e-bay , now it is possible , someone is selling a real Rick's on e-bay , but I would chance it and buy directly from Rick's on the phone 

 

Philips , I do believe was the manufacturer of the  OEM CDI for a 96 , and the problem you described with no spark while the starter button is held in , and spark when the button is let go  is very common on the 96  

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I did not change the cam sprocket, it basically looked new with no detectable wear.  Crank sprocket end also was in good shape from my remembrance when I worked on it.  

 

My original cdi was a Philips HM5.

 

This bike just doesn't want to make good power like that 91 does.  The 91 pulls strong up hills to the point you back off the throttle, the 96 falls flat and requires more throttle and a downshift.  My carb is good/clean/rebuilt and no other obstructions in airbox thru muffler.  My 96 also has more compression (about 15 psi) more than the 91.  I'm stifled and am still wondering why my bike is not advancing the timing to the two dash marks.  

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I will say this. I've had many 300's over the years. Most ran good, some ran great and some just never had it no matter what mod was done to it as far as power/performance. I never investigated the poor running ones, just got rid of them. They ran good enough for most but for me it was a dud machine.

 

With the timing light your checking the electronic side of it (pulse, cdi, coil, etc). Even if the cam chain timing is off it would have no effect on that reading. I was hoping for a sheared key and the flywheel slipped as that would explain the cause.

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Riverside , I had a problem with my 300 one time , it ran like I thought  it was out of time , it turns out being the diaphragm in the carb had a crack in it , ran ok up  to 1/2 throttle ,  then no power  after 1/2 way and that was making me think it was a timing issue 

 

the  sprocket will get worn where the chain will fit nice for about 6 teeth then the 7th link will not align just right in the center  , the pitch of the chain is off ,  you can see this with no tension on the chain and the chain wrapped around the sprocket , after 6-7 links the chain starts rising up 

 

I know what you mean about one running better than the other , I can say I see it , my wife's 300 is a 96 frame with a 90 engine and wiring harness , it is a strong  running bike , I mostly ride my 92 , it has some mods to it   and it is the best running one of my bunch , I also have a 95 , 2 - 96s , and a 2000 ---- the older ones ran better , 88-91 had a hotter cam , 88 had a hotter exhaust pipe , the early ones had no limit cdis and bigger jets in the carbs ---- maybe that other guy has something going on with his 300 

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Well, after doing some more fooling around and checking things I'm confident that the mechanical timing is good, albeit the sprocket lines aren't totally flat with the head.  

 

I think the reason the 91 has more bark is because of the gen1 cdi, the airbox intake system and the exhaust.  The 91 draws air thru the frame tube, which has a larger opening than the plastic tube my 96 uses and the exhaust diameter coming out of the head is 32mm compared to my 29mm. 

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