Problem :(

[trx400Rider]

Well I just got through installing the crf450r timing chain. But there seems to be a serious issue. It will turn over fine, it gets gas and I'm pretty sure it gets spark to. B/c it'll fire every so often. Is it possible for when I set the time that it wasnt on the compression stroke? I lined the marks up on the flywheel with the flywheel cover.
Could it be that? Or something else? I need help, BAD! I havent rode my EX in almost 3 months now. I finally got around to getting the timing chain.
I hope I figure this out soon. And I know this great place has the folks with the knowledge!!!

Thanks guys

[hocman123]

the compression stroke dosen't matter when u install it for the first time b/c when u install the cam (with the loobs faceing down) u are setting the stroke when u set the timeing. as long as he loobs was down.

if it has been sitting for 3 months i would get new gas expecially if u use regular gas. i had a friend that used regular and after about 3 months he had the same issue we got new gas mixed the new and old gas by rocking the atv. and we added a little bit of sea foam cleanner in the gas. it fired right up after that. maybe clean the carb out if that dosen't work.

[trailrider894]

If you put the cam in lobes down with the engine at TDC, it is fine. Clean you float bowl on your carb and get new gas. Also check your spark plug.

[trx400Rider]

What lines do I have to line up on the flywheel? the marks with the T. Right?

[trailrider894]

Originally posted by trx400Rider
What lines do I have to line up on the flywheel? the marks with the T. Right? Yes, you want the T to line up. This really sounds like a fuel problem.

[trx400Rider]

Its getting gas though. But you may be right about the gas being stale. When It dropped the timing chain I took it all apart that day, Including draining the carb. So I dont know. =(
This is deffinetly difficult.

[CJM]

Best thing to do is try fresh gas.

If you have some carb cleaner around I would take off the airbox and spray a few shots and see if it runs, it runs its your fuel, if not you got more issues.

Did you make sure the cam gear lined up with the head (2 marks should be parallel to the head) and did you make sure the valves were correctly adjusted?

[trx400Rider]

I'll try the carb cleaner. And yes, I did make sure the 2 lines on the cam gear was parallel with the head.
How many different marks are on the flywheel. If its not the fuel, I'll re-check the the timing. It wouldnt be hard anyhow since I only have the gas tank on.

What kind of plugs do you all use?
Im running an NGK, not sure what one.
Which one would you recommend? I read somewhere that some certain plug lowers the head temperature 5 degrees! I'd like to try that one out.

[CJM]

I just run the stock NGK plug, no issues with it.

[trx400Rider]

Alright. I've replaced my plug once, not b/c It needed a new one. Just b/c the engine is a few years old.
Before the timing chain jumped off the bottom gear, the engine always made a odd ticking sound. It was getting much louder, then the timing chain finally gave out.
When I removed the chain, it was worn out. Considerably worse on one side of the chain than the other.
Do they normally do that, or is there something else wrong?

[AtvKid4Eva]

i would say your timing is off. Check again, line up the "T" and make sure the two lines on the cam sprocket are level with the head and the lobes are facing down. Ive had them act like they were gonna start like your describing and the timing was off a bit. If it ran before you replaced the chain then that's all it could be.

[tri5ron]

you have bent valves

[AtvKid4Eva]

why would he have bent valves?? did the bike run prior to the cam chain falling off?

[crownandmonster]

If the bike was running when the cam chain slipped/broke, there is a very good chance the valves got bent.

[hocman123]

Originally posted by crownandmonster
If the bike was running when the cam chain broke its almost guarantee that the valves are bent.

not totally true i had my tensioner break 2 times and it slowlly went out of time u could kind of hear it. untill it shut down and never bent any valves. If the chain breaks when riding i wouild think that the valves would just stop opening b/c the cam will not be turning anymore. so if they can't open they wont hit the piston

[crownandmonster]

Originally posted by hocman123
not totally true i had my tensioner break 2 times and it slowlly went out of time u could kind of hear it. untill it shut down and never bent any valves. If the chain breaks when riding i wouild think that the valves would just stop opening b/c the cam will not be turning anymore. so if they can't open they wont hit the piston


That is true, however if a valve is open when the chain breaks and the piston is moving fast enough if can contact the valve before spring pressure closes the valve

[hocman123]

true i guess it all depends on how unlucky u are b/c that would i guess to be kind of a rare think to happen

[trx400Rider]

Update:
-I rechecked the timing, it was right on.
-Its getting fuel, the fuel is not stale.
-Very good spark
-No compression. I tested it with a guage, it wouldnt read anything!
It blows air out the plug hole, and out the breather on the valve cover.
-The valves seem fine, I can compress them by hand and they return fine.


The machine was running fine before the chain jumped off the bottom gear. The machine completly died.
This is soo coonfusing!!! I refuse to give my money to any dealer for labor. lol. No offense to dealers, but I'd rather do it myself! haha

[426kidz]

have you checked your valves too see if they are dialed in right? I may have had this happen before when that little fuse on the side went out...check that too,lol check all little things you could have over looked!so hard to help when cant actualy see or hear anything going on.

[hocman123]

Originally posted by trx400Rider
Update:
-No compression. I tested it with a guage, it wouldnt read anything!
It blows air out the plug hole, and out the breather on the valve cover.
-The valves seem fine, I can compress them by hand and they return fine. haha

why is there air blowing out ur plug hole idk how u do compresson tests but if u got the tester in and there is air leaking past then then it is not on enough and thats why u have no compression.

or one of the valves is bent open and u would never get comprssion with out then sealling good. just pushing then down by hand will only tell u if the springs are working good. b/c it could be bent down low before the guides. in order to really check it u need to take the head back off and look at the bottom of the valves and see if they look unevean in the seat

[trx400Rider]

Im going to adjust the valves and see what happens.
If that doesnt solve it, Im guna have to take the head off.
The valves did feel all fine when I compressed them by hand.
But I guess you cant be a 100% sure they are ok without removal of the head. =(
This sucks, its been soo nice here and I cant ride!!!

[426kidz]

all you have to do is remove the valve covers....

[trx400Rider]

Update: I just got done adjusting the valves, they were way off. I got them adjusted to specs. But it still doesn't want to start.
It doesn't seem like it has much compression. My pressure gauge doesn't pick anything up.
And the timing is right on.


426kidz I'm talking about to see if the valves are bent or not seating right. I wouldn't be sure unless I remove the head.
The valves will compress and return fine.
But I guess the valve face can be cocked a little bit and not seat right at all.

I guess my last resort is to remove the head. Unless someone has any other ideas on what my problem is.
This sucks.

[crownandmonster]

how are your performing the compression test?

[trx400Rider]

Update: Just got done taking the head off and come to find out that it bent the two intake valves! Whoo hoo!
My 416 piston is still in perfect condition thank god.

What else should I do besides replace the 2 intake valves while I have the head off?
How much is an intake valve? I'd like to buy them from my local dealer b/c the parts are normally in within a day. But if there is an online place that has a much lower price, I'll do that.

[hocman123]

well honda is cheapper on valves then the after market stuff. but when u do it i would also order new seals to do all 4 valves and i would cheak the springs on the head and make sure they are still in spec and order new ones of them if u need them.

and u can order the stuff from bikebandit.com, mrcycles.com, of rockymountain now has oem stuff. bike bandit is the best for speed b/c they keep a large amount of parts at there warehouse unlike other places that need to order the stuff from honda to them, then they repackage it and send it to u which can sometimes take 2 weeks.

[trx400Rider]

Well I think the valve seals are fine, I replaced them when I did the 416 kit over the end of the summer. Havent ran it but about 50 hours since.

But I think I'm going to replace the guides for the timing chain.
How much would it cost to do +1 valves and port&polish job? I'd love to do that.

[hocman123]

+1 would be a lot of money u would need all new valves all after market and have to get a good machine shop to cut the seats bigger i would maybe check out ebay for them. but i looked them up a long time ago and i know i wouldn't do it for the price

[trx400Rider]

Yeah I guess I'll just let it be a fantasy for now. I just want to get it running again. It has been way to long. I'm going through withdrawls haha.

Atleast I finally found out what it was. It took awhile. My dad kept on telling me to take the head off from the beginning hah. Kinda stubborn I guess lol.

I supose instead of doing a P&P job and +1 valves, I'll add an Ironcross bumper, Renthal chain&sprockets, a Spal fan and maybe some ASV levers.

Get it ready for this southern summer :)