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Need help with starting issue

907 views 6 replies 3 participants last post by  Thrown Stones 
#1 ·
I picked up 2005 trx450r the other week. Mods are as follows: Has a 06+ FCR carb and air box. Has a webcam grind # 961-962 CRF/ignition/stator/flywheel. CPcarillo 13.5:1 piston, Hinson clutch system and yosh full exhaust.
I have been having a starting issue with it. If the motor is cold it will take quite a few kicks to start and if it’s hot I can’t it to start at all.

First place I started with was the carb. I pulled the float bowl and it was pretty nasty. Ordered a rebuild kit and cleaned the entire carb. Also replaced the diaphragm as well. The needle is a ncvq needle. It is on the 4th notch from the top. The main jet is a 160 and the pilot is 45. The carb rebuild did not fix the start issue but it def was needed.

Next I went on to the valves and decompression mechanism. The exhaust valves were at .010 and the intakes were at .009. The decompression arm was at .024. Correct me if I am wrong but you get the decompression amount by adding the exhaust clearance to the clearance amount between the rocker arm and decompression mechanism. I believe for 04-05 it’s to be .017.

However I was reading on the forum how people say that you should set the decompression by hooking up a compression gauge. So I pulled the plug and did the compression test. It was only building up to about 60 psi. I then backed the screw out on the decompression mechanism, kicked it over a few more times and it got up to 90 psi. I did leave the compression gauge on for a little while and the pressure didn’t drop so I think I am good there. But that is where I stopped at for the evening until I can get some other peoples thoughts. I read on the forums that an electric start you set the compression at 90 but I could not find what you set a kicker model at.

Also I took some photos of the spark plug. It looks pretty dark to me. Also looks like it has some detonation on it. Can anybody give me some guidance? Is it running to lean? Do I need to bump up my jets?

Thank you for any help you can provide. Sorry for the lengthy post, just wanted to give you as much information as possible.
 

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#4 ·
Brandon79, yup I am going to put the intakes into spec.

Thrown Stones, I am having issues getting it started cold and hot, but I have had more luck with getting it to start cold versus hot. Yes, if you get it started and ride it, it rips and seems to have no issues. A few years ago when I had my previous 05 450r it had an issue that seemed like it was sputtering when you rode it and that was loose wire on the coil.
I did take a look at the cam as well and timing looks good. I attached a photo.

Thank you for your responses and help. Have plans to go to the track this weekend but hoping to get this sorted out.
 

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#5 ·
Update - I shimmed the valves and put them into spec. Set the decompression mechanism to 100 psi and put a new spark plug in it.
Tried starting it and Now I can’t get it to start at all. I checked and it does have spark. After kicking it over and over again I pulled the new plug out and it was still as dry as a bone. I’m assuming this means it’s not getting enough fuel so bumped the pilot jet back up to 52.
Still could not get it to start. Even tried getting it to bump start and it wouldn’t.
One thing that I did want to note, when I was setting it to top dead center I could not find any markings on the flywheel. I know that you are suppose to go off of the gear on the right side which is what I did do but I don’t know why the flywheel would not have any markings on it.
Anybody else have any suggestions as to what to check or do next? I am beyond stumped at this point.
 
#6 ·
Ok, finally think I got it figured out. I think it was a combination of the the idle not being adjusted properly with the fuel screw and also the decompression mechanism. After I set the decompression I found out that you are to do this with the throttle held wide open. So I did the decompression again the correct way and I was able to get it to start after a good 15 kicks. Let it warm up, drove it around to get the motor up to operating temp and then I did the idle on it. I shut it off and then when about a minute or two later I started it again and it fired up in one kick.
Thank you all for your help.
 
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