Timing the gears in the motor - Honda TRX Forums: Honda TRX 450R Forum
 2Likes
  • 1 Post By gboezio
  • 1 Post By Steelesrt4
 
LinkBack Thread Tools
post #1 of 13 (permalink) Old 07-23-2019, 06:13 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
Timing the gears in the motor

I bought a 07 trx 450er that didn't run. Guy said it ran great before. Obviously wasn't taken care of but had Elka shocks and was the right price. I wanted a project. What was I thinking???

Ended up they replaced the starter clutch but didn't put it together right and the motor was essentially locked up. I, not knowing how any of this worked but being mechanically inclined decided to tear it down to make sure the Piston wasn't ruined. Found out there were no shims on the intake valves. Wtf? Piston and cylinder looked good. In my mind it must be the transmission. Trans forks and gears were fine. Only after pulling it all apart did I read about the starter clutch.

I put the whole motor back together and had a pro shim the valves and time the motor. Try to start it and it backfires out the exhaust. Read and search and find something that says there's a rotor/gear that swings by the flywheel and if that's not right the the spark will be off.

Is that correct? I pulled the side cases and did my best to match all the marks up on the gears on the crank and flywheel. Checked timing and that was all perfect.

Can anyone tell me how this stupid rotor is supposed to sit when the flywheel is set to top dead center? Picture include.

Any other advice would be great. Really want to get it running. I think if j can just confirm where this thing should sit in relation to the flywheel I'll be golden.

Then it will be is the carb working like it should. FYI, I have already pulled the cases and moved this rotor/gear after checking pictures and videos online and now it's backfiring out the intake, so it definitely seems to have changed something. Won't start off the starter but will run if I pull start it with another ATV and dump the clutch. Right now it will not idle, but it had good power when i gave it gas.

Thanks for helping. Be kind, it's my first Honda and it hasn't been fun haha
Attached Images
File Type: jpg IMG_20190710_195923553_1563919886154.jpg (138.2 KB, 15 views)
Steelesrt4 is offline  
Sponsored Links
Advertisement
 
post #2 of 13 (permalink) Old 07-24-2019, 07:06 AM
250EX Rider
 
Ryan94Wright's Avatar
 
Join Date: Sep 2015
Location: Tucson Arizona
Posts: 298
First thing I wanna point out there is no gears that are going to change the Ignition Timing...These engines are not like old V8's and old Inline 4 Cylinder engines where you adjust the Ignition Timing by twisting the Cap and Rotor lol... These bikes use a Trigger/Exciter Coil that sends a Signal to the ECU when the engine it right before TDC and then the Throttle Position Sensor on the left side of the Carburetor tells the CDI to adjust the timing accordingly to the RPM range it uses 3D Mapping.


When you installed the new shims... did you even measure the Clearance after installing the shims? Because you have to use a Feeler Gauge to measure the new clearances between the Cam/Intake Lifters and the Exhaust Lifter/Exhaust Valves.

I would have treated this job as if it were a "Fresh Build" or a "New Valve Install" by blind Installing a shim size that looks like it would fit. From experience this is easy for me to tackle and know what I am doing. But that is what makes this situation kind of hard is that I have no clue if your valves are relatively new, brand new or just plain worn out. Also not to mention the fact that it's a 2007 it probably has the OEM intake valves in it still which are Titanium valves... and what I'm thinking is the intake valves could very well be so worn out that may be why the previous owner had no shims in it, to their lack of knowledge they probably thought that it would get their .006" Spec Clearance back by removing the shims completely and while doing so it did not work. I never ecoment running an engine with no shims because you can knock a valve keeper out and drop a valve into the piston... Anyways so they sold it to the lucky guy like you lol.




If I were you. This is what I would do. Put your Engine at TDC, Measure the intake Valves (They should be .006" for the intake) and (.011" for the Exhaust's) then (.022" for the Decompressor Lifter).


If all fails these observations then take the cam tower back out and blind install a couple shims into the intake. I would say like a couple of 1.20 Shims in each intake valve, remember this is just for a blind install for now to figure out a good starting measurement. Now Re assemble the Cam Tower and making sure to torque the four 10mm Cam Tower bolts down to 10ft-lbs. Now put your cam shaft to T.D.C. (you can do this with out hooking the timing Chain up just so you can take your measurements) Now how to put your cam in the TDC position with the Cam sprocket and Chain being disconnected is simple as making sure that the intake Lobes are pointing to the back of the quad while the screw holes for the cam gear are pointing at 6 O-Clock and 12 O-Clock position.


Now firmly holding the cam shaft from spinning and using a Feeler Gauge see what size fits in between the Intake Lifters and the Cam. Should be .006" or close to... And the exhaust's and Exhaust Lifter should be close to that spec. Expect the gap to be way to big right now. If you can't even fit the smallest feeler gauge in it then your intake valves need to be replaced.



I say the intake Valves because if it pull starts fine then it's a common way to know.

Build Break Rebuild Better
Ryan94Wright is offline  
post #3 of 13 (permalink) Old 07-24-2019, 07:13 AM
450R Rider
 
gboezio's Avatar
 
Join Date: Jun 2011
Location: Victoriaville, Qc
Posts: 2,086
Welcome to the forum, the way I understand it, you have a loose flywheel, it's supposed to be a no brainer since there is supoosed to be a key on the crankshaft that sits in the slot of the flywheel.
With the piston at TDC, the T of the flywheel should align with the case arrow below the cylinder (stator case off) or the timing hole (stator case installed), the dot on the main gear on the transmission side should also align with the case arrow. Don't run the engine without the crank key or you may end up with too much timing and ping the thing to death.

Edit, : I think I misunderstood, you are talking about the balancer, no it does not affect the timing at all, it cancels vibration, both arrows on the gear behind the starter clutch and the balancer gear need to be aligned otherwise the engine will rips mounts and take a hike on it's own lol
Ryan94Wright likes this.

2008 TRX 450ER XC racing
FMSQ # 281

Last edited by gboezio; 07-24-2019 at 07:18 AM.
gboezio is offline  
post #4 of 13 (permalink) Old 07-24-2019, 06:27 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
Thanks for the feedback guys.

The timing and valve shims were set by a pro so I have no doubt those are good to go. And we got lucky that the intake valves weren't too tight. They did need shims to be at the right adjustment.

If the "rotor" is just a counter balancer then I'm at a loss for the backfiring out the exhaust/intake.

The flywheel is fine. The key is in there and hasn't sheared off or anything. The Piston is at TDC when the flywheel timing marks lines up with the case.
Ryan94Wright likes this.
Steelesrt4 is offline  
post #5 of 13 (permalink) Old 07-25-2019, 12:55 AM
250EX Rider
 
Ryan94Wright's Avatar
 
Join Date: Sep 2015
Location: Tucson Arizona
Posts: 298
Oh I gotcha, I thought when you said pro that is was typo is all.

I would still double check the cam timing and the Exhaust Decompression Lever to make sure it's got the proper clearance.


Also another thing to look for - Did you check to see if the engine has spark while cranking it? See if it has spark with the spark plug removed while grounded to something bare metal.. If you don't ave spark then hold the throttle in a about 1/4 throttle and see if it gets spark. Sometimes the cable get get out of adjust meant and then the Throttle switch and the carb switch will go out of sync and will loose spark. It's a Safety mechanism.


Are you running an Aftermarket CDI unit?


Did you Ohm the stator with a Multimeter?

Build Break Rebuild Better
Ryan94Wright is offline  
post #6 of 13 (permalink) Old 07-25-2019, 02:37 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
How would I test the stator. I have a multi meter.

The quad is burning fuel when I try to start it off the starter so the spark is there at idle. I'll pull the plug and check.

How would I adjust the idle or fuel mixture in the carb. Is it a needle in the side or do I need to open it up. I already pulled the carb apart and cleaned everything and put all new seals/gaskets. I bought a jet kit but didn't know enough to mess with that.

I tried to search Google and search on this forum for a how to guide on setting up the carb with photos but haven't had much luck yet. I did find a few posts but need some pics
As far as I know the cdi box is stock.
Steelesrt4 is offline  
post #7 of 13 (permalink) Old 08-05-2019, 09:38 AM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
Pulled the quad with another quad and it will run but only at mid throttle or more. I pulled the carb apart and cleaned it again. The Jets in the bowl seem strange. Are there right? Top right says 75. Middle says 72. Bottom middle and bottom are identical and both say 42. The washer and o ring are gone on the bottom so I ordered new OEM. Should the bottom middle also have a spring and washer and o-ring?

Are these the right jet sizes? Pics below.

Also, how should the side look? The arm that turns the throttle plate didn't touch the button on the idle screw until I had the idle adjuster turned in the whole way to the stop.
Attached Images
File Type: jpg IMG_20190801_221758698_1565012241191.jpg (85.3 KB, 7 views)
Steelesrt4 is offline  
post #8 of 13 (permalink) Old 08-05-2019, 10:23 AM
450R Rider
 
gboezio's Avatar
 
Join Date: Jun 2011
Location: Victoriaville, Qc
Posts: 2,086
Sooo, what I understand from this is that the idle screw has been replaced by a pilot jet ??? The one with an O ring, washer and spring is the idle mixture scew

This an aftermarket version but the tip is the same, there should be no 42 on it.
Other than that stock main is 120, no lid and piped uses 162 main (the one under the needle), maybe it was a 172, double check

If there is a jet in the mixture screw channel, it will not idle and start and if there is a 72 in the main jet channel, it will just work at part throttle

2008 TRX 450ER XC racing
FMSQ # 281
gboezio is offline  
post #9 of 13 (permalink) Old 08-06-2019, 10:03 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
Thanks!!!! I found a 120 jet for the main and put that on. The 165 main jet I have doesn't fit the needle for the main. Turns out the 165 jet was from a kit for a 400, not the 450, so I'll have to order one.

The carb rebuild kit I got had the same idle adjuster that you have pictured so I put the o-ring, washer, spring on it, and set it two full turns out from all the way in.

Does it matter if the o-ring is at the bottom or the top of the adjuster? The video I watched on cleaning the carb showed the o-ring at the bottom, but the image you posted shows the wrong at the top of the spring. Think it makes a difference?

It still won't start off the starter. Pulled it with my Jeep and it will start when I pop the clutch. still doesn't want to idle once running but does seem to run much better as long as I give it a little throttle with my thumb.

I don't think the main jet would have anything to do with the idle. Should I give it another turn out on the idle screw?

Last edited by Steelesrt4; 08-06-2019 at 10:19 PM.
Steelesrt4 is offline  
post #10 of 13 (permalink) Old 08-07-2019, 09:59 AM
450R Rider
 
gboezio's Avatar
 
Join Date: Jun 2011
Location: Victoriaville, Qc
Posts: 2,086
Some carburetors are bricked because of alchool or excess carb cleaner, if you know someone that has a good one you can try swapping.

I would do a compression test on this thing.

If you haven't check for spark

2008 TRX 450ER XC racing
FMSQ # 281
gboezio is offline  
post #11 of 13 (permalink) Old 08-07-2019, 08:48 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
I turned the idle screw to 2.5 and 2.75 turns out. When I pull the choke out it has started a couple times very briefly, but mainly it wants to backfire out the intake or the exhaust.

It definitely has compression and spark. I pull started it with my Jeep again and even going super slow it will bump start but doesn't want to stay idling. If I give it a little bit of throttle it will run but it stumbles and pops a lot. I drove it around the block and it ran but not well.

I wish I had another carb to test it with. I don't know anyone who has a trx450. I'll keep reading and see if I can find anything else
Steelesrt4 is offline  
post #12 of 13 (permalink) Old 08-09-2019, 01:24 PM Thread Starter
TRX90 Rider
 
Join Date: Jul 2019
Posts: 7
I sent the carb out to someone to have it professionally rebuilt. I should have it back in a couple weeks
Steelesrt4 is offline  
post #13 of 13 (permalink) Old 08-09-2019, 11:42 PM
TRX90 Rider
 
Join Date: Apr 2018
Posts: 3
something I discovered the other day, a weak battery will not spin the starter fast enough to start and it will backfire. bike would backfire when trying to start, messed around trying to get it to run and killed the battery, hooked it up to the charger and left it for a few hours. came back to the charger saying the battery was bad. got my friends battery tester and it said the battery was bad. hooked up the jumper cables to my other bike and she fired up, only issue was the battery
muisejt is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda TRX Forums: Honda TRX 450R Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome