37 replies to this topic

[GoBollzD33P TT Bronze Member]

Hey guys before i get into it here is the back story of my situation. I have an 08 crf490r. the head on my motor apparently has titanium pro circuit valves and springs. the valves are worn out and need to be replaced so what I am currently in the middle of doing is swapping the head with my stock head with stock valves and springs from my factory motor. i removed the "pro circuit" head and currently have the top end and now i have a few questions that i would like answered before i continue any farther on my dirt bike..

1. The right exhaust valve bent and kissed my piston.. before i jump the gun and remove the motor to tear my bottom end apart i was wondering if you guys can give me some insight if my piston appears ok from the looks of it.. the vortex piston was installed at the end of august and has maybe 12-14 hours on it at most. in this pic you can kind of see how bent the valve is


here you can see where the valve kissed the piston.. am i ok? am i safe or do i need to clean the top up or worse, change the piston?


2. How can i confirm that the "pro circuit" springs are titanium from the head that i am changing? and if they are titanium and are in good shape... should i run those on my stock head with my stock valves or should i just leave it as is and install my stock head?

i'm sure i will have more questions tomorrow but i want to get these 2 questions out of the way first so i can get everything sorted out and make sure that this job goes as planned.. so what do you guys think?

[CamP Get Help Now]

Titanium is non-magnetic. If a magnet doesn't stick to the springs, the are Ti.

I doubt that the springs are Ti as it is a poor material for that application.

Edited by CamP, 30 January 2012 - 09:48 PM.

[chooken Get Help Now]

why did the piston contact the valve ?

[GoBollzD33P TT Bronze Member]

ok good to know i will stick to my stock head and get this now back up head rebuilt and ported out.

how does my piston look? anything i should be worried about?

chooken, on 30 January 2012 - 10:34 PM, said:

why did the piston contact the valve ?

umm i think what holds the valve in came out?.. i don't really know what i'm talking about lol.. anyways that's all the damage that was done and i am now swapping valves so do i have anything to worry about with the piston?

Edited by GoBollzD33P, 30 January 2012 - 10:40 PM.

[Shawn_Mc]

chooken, on 30 January 2012 - 10:34 PM, said:

why did the piston contact the valve ?

great question. It doesnt look like it got dropped completely so Id say one of those trick springs are dead and it let the valve float. Or the spring broke?. The guide probably has some damage too after having that bent valve shoved up in it.

The two little cresent pieces that hold the valve into the top of the spring retainer are called keepers. If one of those popped out and the valve dropped in and got smacked, bent, then stuck...thats actually a best case scenario. But Youve GOTTA find that keeper.

If thats as bad as the valve got bent, the piston is probably ok. Just make sure the top ring spins in the piston freely. The combustion chamber is awful carboned up for 12-14 hours. Its either way too rich, burning oil or both.

[GoBollzD33P TT Bronze Member]

regardless of what happened to the valve (i'm assuming it simply wore out).. i will be running my factory head with valves and springs

i'm more concerned about the piston because i am really doing this on a budget and do not want to touch the bottom end if i do not need to... so by the looks of it is the piston ok or do i havr to take more detailed photo's for you guys tomorrow?

sorry shawn i didn't see the bottom of your post so i didn't the rest of your comment... actually now that you mention it i do think that the keep wore off and the valve fell and that's why it bent.. buuuuut, i really don't think i seen the keep anywhere.. i will look but idk. why do i need it??

i will check the ring tomorrow and see if it free spins, what can i use to clean the carbon off or should i leave it be?? to be completely honest at least 7-9 of those hours were riding hard in a small dune like sand pit so needless the say the bike was pushed a few times

Edited by GoBollzD33P, 30 January 2012 - 10:59 PM.

[oakhillbiker TT Silver Member]

no way would I use that piston you could have cracks you cant see and find that keeper you dont want it showing up at the wrong place and wrong time it's probley down by the flywheel

[nesc103y TT Bronze Member]

Consider the force with which the piston hits the valve.
That force gets directly transmitted throught the piston, down the rod, to the big end and bearing cage. Which is already a weak link, even in the best of conditions.
You can "probably" just freshen up the head and put it back together and be ok with it. Then keep a very close eye on the engine oil for foreign matter.
I wouldn't reccomend that.
If it were ours, I'd rebuild or replace the crank, and replace the piston, at the very least.
It's not pretty when the various parts in these things start comming appart, or come in contact with other parts they were never designed to meet.

I see this sort of thing all the time. A guy will have some engine failure and replace the failed parts with no thought about the snowball effects of that failure.
Then further down the road a chain reaction of failures start to occure. It's not pretty

[jjy130 TT Member]

agreed, my buddy had a valve crack and jammed the piston. He replaced the valve and kept riding...ended up cracking the connecting rod and putting it through the case so the motor isn't even worth fixing now

[mrmoto35 TT Rusty Steel Member]

jjy130, on 31 January 2012 - 09:19 AM, said:

agreed, my buddy had a valve crack and jammed the piston. He replaced the valve and kept riding...ended up cracking the connecting rod and putting it through the case so the motor isn't even worth fixing now

Ouch!! I would heed this post if it were me. Even though damage my appear to be minor, the damage that can't be seen can lead to far greater cost in the end. It is kinds like flying planes. If the prop kisses the ground you are looking at basically replacing the entire motor. That kiss sent a shock through the entire motor and going through it is an FAA mandate if I remember right.

Edited by mrmoto35, 31 January 2012 - 09:48 AM.

[GoBollzD33P TT Bronze Member]

Well Damn none of this sounds good at all. I really can't afford to buy parts and spend money I don't have and the piston is still fairly new so I can't just swap my head and be fine with it this bike can either sit here and rot or I'm selling it.

It's nothing but problem after problem.

[GoBollzD33P TT Bronze Member]

alright guys here's an update. me and my buddy decided to get serious with this bike and we are tearing it completely apart. we moved it down in to his basement and we have a room set-up specifically to work on it. some good news is that i actually had the keeper still intact with the valve so there is no longer a threat of a keeper lost in to the motor... here are some pics of the progress so far lemme know what you guys think and any pointers and things i should look out for at this point.. also i took some more pics of the piston top but i will get better close ups when the motor is out.










one thing i do want to ask you guys.. in the picture above the frame is stained and unnattractive.. what can i do and steps involved to clean and shine my frame up?

Edited by GoBollzD33P, 31 January 2012 - 03:36 PM.

[94cr rider TT Bronze Member]

steel whool

[GoBollzD33P TT Bronze Member]

will steel wool also shine it up or do i need to wet sand for that?

update guys.. my buddy is a mechanic for ford so he pretty well knows engines and what not and he's having fun with my bike so we decided to tear my motor right apart and inspect everything to make sure what is in tip top shape and what can be replaced

the motor is on the bench and appears to be in good condition but i will update this thread with pics tomorrow and show you guys where i am at.. my plans are to clean and buff the frame right up and replace what needs to be replaced.. i am so glad i tore the bike down to where it's at because i am already noticing some minor things that need to be replaced

[brucegregory TT Member]

get a mouse electric sander with 320 paper then move to 400 then mothers or never dull my bike looks like a mirror it does not take much time and it cleans up in a few mins after riding

[CamP Get Help Now]

GoBollzD33P, on 31 January 2012 - 10:02 AM, said:

It's nothing but problem after problem.

That's why after 40 years of riding bikes, I only run bone stock engines. Modifications often turn into headaches.

[CamP Get Help Now]

GoBollzD33P, on 31 January 2012 - 05:43 PM, said:

update guys.. my buddy is a mechanic for ford so he pretty well knows engines and what not and he's having fun with my bike so we decided to tear my motor right apart and inspect everything to make sure what is in tip top shape and what can be replaced

Please tell us that you guys have a real honda shop manual.

[mrmoto35 TT Rusty Steel Member]

CamP, on 31 January 2012 - 08:23 PM, said:

Please tell us that you guys have a real honda shop manual.

It's the Ford F150 manual. Close enough! HAHAHAHAH gotta have some humor when it's all going bad!


And I am glad to see them going down the righ path. Wasn't long ago I watched a buddy take a short cut on his yacht and the next time out we broke down in Long Beach harbor with the starboard engine grenaded. Next thing I know TV's and Microwaves were being thrown overboard LMAO!

[GoBollzD33P TT Bronze Member]

CamP, on 31 January 2012 - 08:23 PM, said:

Please tell us that you guys have a real honda shop manual.

Lmao yeah I have a manual saved to my laptop we are doing it all by the book.. and I know what you mean with the modifications but what can I say It's Impossible for me to leave something stock!!! Lol, that and I'm addicted to going fast!

mrmoto35, on 31 January 2012 - 08:33 PM, said:

It's the Ford F150 manual. Close enough! HAHAHAHAH gotta have some humor when it's all going bad!


And I am glad to see them going down the righ path. Wasn't long ago I watched a buddy take a short cut on his yacht and the next time out we broke down in Long Beach harbor with the starboard engine grenaded. Next thing I know TV's and Microwaves were being thrown overboard LMAO!

I know what you mean man lol. I was going to go the cheap route but screw It.. its still winter so I have loads of time to replace what needs to be replaced. I will update pics tomorrow on the progress

[chooken Get Help Now]

CamP, on 31 January 2012 - 08:22 PM, said:

That's why after 40 years of riding bikes, I only run bone stock engines. Modifications often turn into headaches.

make the motors flow or breathe real good is a safe option