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2005 crf 150f help with timing setting/valves

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Well my son had the bright idea of adjusting valves while i was gone yesterday because it started on 3rd kick!!! Well now it wont even start??? Come to find out he pulled the head and turned the upper cam gear also?? I got the valves back right i think??( 0.004 )intake & exhaust??? But now the timing issue thats another thing. All i remember to do is find tdc on piston but thats pretty much it!! The upper cam gear has two marks on it ( one across from each other,one on one side of gear and one on other side) but i dont see any marks on head/cylinder to line them up with?? Also do i need to get to lower gear now and line those marks up also?? Or does putting piston tdc do that??? I read somthing in a blog about "f" mark and "t" mark but i dont know what that means either??? I orderd a manual today but wont be here for a week. So if anyone has delt with this issue before please give me heads-up with any help or advise....thanks,yz-maniac...

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I tried that,but still nothing? Also son said he might of turned cam sprocket around alot?? But when i put piston tdc and marks side to side im getting nothing?? Could i be out 180 degrees or somthing??? Also spins like i have plug out (no resistance) but plugs in

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It sounds as though you have a good grasp on how to set the cam timing. It is easier with the left side stator cover removed. There is a pointer cast into the centercase that makes it easy to position at TDC. Plus, the magneto doesn't continually pull the engine "away" from TDC like it will when the side cover is in place.

If the valve timing is correct and it feels as though the plug is out when kicking it over, it is likely that one or both of the valves is bent. This happens if the engine is kicked through with incorrect cam timing and interference between the piston and valves slightly bends them. Once bent, there will never be any compression. I hope this ISN'T the case as you will need to pull the engine, remove the head and install new valves at a minimum.

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:banghead:MAN I REALLY DIDNT WANT TO HERE THAT,BUT I THINK YOUR RIGHT!! BECAUSE I PULLED THE MAG COVER AND MARKS ARE LINED UP ON "T" MARK WITH PISTON TDC AND CAM MARKS VERTICAL OF EACH OTHER( LINED UP WHERE HEAD/CYLINDER MEET) WITH ALL THIS LINED UP SHOULD CAM LOBES BE IN CONTACT WITH TAPPETS OR STRAIGHT UP IN AIR ?????( WITH ALL MARKS LINED UP MY CAM LOBES ARE NOT IN CONTACT WITH VALVE TAPPETS,LOBES ARE POINTING UP TOWARD HEAD!!!) WHICH I THINK IS RIGHT BECAUSE IF CAM LOBES WHERE IN CONTACT WITH TAPPETS WITH PISTON TDC THAT WOULD MEAN THE VALVE AND PISTON WOULD BE IN CONTACT WITH EACH OTHER AND HENCEFORTH BENT VALVES RIGHT?????THANKS FOR YOUR REPLY....

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:banana:well guys here is the latest and greatist. i went back thru all the steps(timing) and readjusted the valves and lo and behold we have compresion again( ye,ha.)and she fired up on first kick...But she dont sound right ( tickity-tack) and the exhaust pipe gets hot very fast and shes pretty gutluss(boggy)..do yall think i need to still fine tune valve adjustment????? or could i still possibly have bent valves???? at first i adjusted valves at TDC but that wasnt working very well,so i turned over and when there was no pressure on valve(stoped moving) thats when i adjusted it 0.004-0.005 do yall think i should go 0.003 to eliminate some of the free play between valve and rocker arm?????? thanks in advance for any help!!!!!!!!

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How long has gas sat in there? If your gas has ethanol in it (I think MOST all pump gas has 10% ethanol) then the ethanol breaks down in as little as 2 months! And a few more months and the gas itself is bad, as well as clogging up your jets as it drys...

The bikes are already lean from the factory, so any clog in the jets will make it more lean.

Also btw, if your timing is 180 out, it wont affect anything.. Since the spark fires EVERY rotation, and 180 out on the cam is still in time with the piston, it doesn't affect anything..

Every 360 on the piston = 180 on the cam.. So 180 out it's still in time... It just means when you adjust hte valve, you gotta have the cam 180 out! If you have it lining up, and 180 out, then it'll be on the intake stroke which you can't adjust the valves at!

You must adjust the valves with the CAM on the compression stroke... So the cam isn't opening the valves at all.

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Also I personally run my valves so .002 will go and .004 wont..

I make it so .002 has some drag, and .004 wont fit in at all..

It's not 100% to spec, but works for me, and both my honda trail bikes are close to that from the factory.

The tighter the valve to spec, the more power you will produce. The more air will be able to enter the cylinder, and more exhaust will be able to exit. But if you go too tight, when the motor heats up, the valves will be held open, and you'll lose power and run the risk of burning a valve.

Leaving the valves loose will make them louder, but have less chance of going out of spec and burning a valve.

I personally always run my valves towards the tight side, and I check them every 6 months max. I know SOME engines people recommend running the valves EXTRA tight. I'm not sure if the 230/150 is that type of engine. I do know my friends s2000 is that way as I just read up on it and adjusted his valves past the tight end of his spec by .002 for more power 👍

Of course, if his valves tighten up more and we don't check them often, then he'll run the risk of crashing a valve into his pistons or burning one up

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thanks towlieee makes scence,im going to try 0.002 and see how she does! and let you know latter today,thanks again man

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well i did that, and no change! so im starting to think that either the valves bent or burned,it quit making the tikity-tac noise but pipe still getting way to hot,and back firing(popping) on throtle down,also will not idle unless choke is on??

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sounds like your pilot jet is just clogged up

Have you ever done the 'power up mod' on the bike? If not, I'd at least go up 1 size on the pilot jet, it will make the bike start way easier, and get rid of that low end pop.

Since the bikes are lean from the factory, it helps to rejet them richer so they run better and cooler 👍

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YZ-Maniac,

Your cam timing may still be one or more teeth off from correct. If the exhaust gets hot like you claim and it idles poorly, it may be that the cam timing is still off. Make certain you release the tension on the timing chain when adjusting the cam timing and that the chain is tensioned when checking the cam timing. Of course, if your carb is not working correctly, that could be a problem of its own.

Make certain that you are adjusting the valves at the proper stroke as well. Remember, the cam turns 1/2 the speed of the crank. You can watch the cam turn when you rotate the crank. You will see that when you rotate the crank 1 full revolution, the cam will have only turned 1/2 revolution. As you have learned, when the piston is at TDC, the valves can be fully closed OR at overlap. If you adjust at overlap the valves will rattle like crazy. The engine would NOT run if the valves were bent, so you got lucky there.

Its easy to tell when the engine is at overlap or "true" TDC. With the valve caps removed, simply watch the rocker arms when the crank approaches TDC. When approaching TDC overlap, the exhaust valve will be closing and the intake valve will be opening at the same time with both valves slightly open at TDC. When approaching "true" TDC, both valves will be fully seated. You want to adjust when fully seated.

If any of this work is too difficult, it may be best to take the bike to your local shop to have it checked out. Could be money saved in the long run!

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thanks coeshow,I dont think carb is a factor because it never was.i know its timing or valve adjustment because thats what my son messed with! and bike ran perfect before he did. thanks to your and towlieees help i got valves right now so it makes scence that its still in the timing. thanks for your advise sir. and i would take to shop but its personal now and i have to lick this thing on my own.(ha,ha)but again thanks alot for all the advise and i will keep everyone posted on the outcome.thanks,yz-maniac...

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YZ maniac,

I can aid you in setting the cam timing correctly. If you want any advise I will gladly help you with step by step instruction.

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If you dont mind that would be cool,the service manual i ordered has not even shipped from shop yet!!! So it will be another week before i get it.i was going to wait on manual but if you can walk me thru it?? My son said he never moved chain any noches on cam( said he took head off and turned cam and chain together???

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YZ-maniac,

It appears that kkim has provided a link to download the CRF150 service manual. You should be able to use it and the pictures to your advantage. If you find that you are still having difficulty, please contact me and I'll try to assist you further.

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ok well here is the latest and greatist guys( coeshow),i finally had time to tear into the engine on the crf 150 and take the head off and the problem was what coeshow originaly thought the whole time!!!! i hade a bent intake valve!!!!!! the exhaust valve was fine,but for the money im replacing both the intake & exhaust valves and the valve seats, parts are ordered and on there way,and i already picked up some permatex valve grinding compound for lapping( seating ) new valves in....i will keep everyone posted on the outcome when she goes back together..and wow talk about schooling 101 of hard knocks man, i showed the son how to properly adjust a valve on a 4-stroke engine so this would not ever happen again.......i want to thank COESHOW for all his help!!!!! Danny

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That's great! You found it!

Coeshow needs some gas. He's very helpful.

While you have the head off make sure the valve guides are still tight in the head. A bent valve can loosen them up sometimes. This can cause it to smoke.

Remove thespring base washers so you can see where they go into the casting and give them a pull and push hard in all directions. You shouldn't see or feel any movement. Oil near the base can help detect movement if theres's any.

Ya replacing ALL 2 valves isn't too hard on the wallet. 🙂

Good luck!

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ok well here is the latest and greatist guys( coeshow),i finally had time to tear into the engine on the crf 150 and take the head off and the problem was what coeshow originaly thought the whole time!!!! i hade a bent intake valve!!!!!! the exhaust valve was fine,but for the money im replacing both the intake & exhaust valves and the valve seats, parts are ordered and on there way,and i already picked up some permatex valve grinding compound for lapping( seating ) new valves in....i will keep everyone posted on the outcome when she goes back together..and wow talk about schooling 101 of hard knocks man, i showed the son how to properly adjust a valve on a 4-stroke engine so this would not ever happen again.......i want to thank COESHOW for all his help!!!!! Danny

Read the service manual before lapping the valves, some of the Hondas have stellite coated valves and all work must be done on the seat, not also on the valve like on cars. Check progress with Prussian Blue. Final lap with a fine compound about 1/2 turn. If you lap too much or grind the valves you will wear/cut thru the stellite coating. Valves are the same size as Honda Civics so those tools can be used to prep the seats.

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