Anyone have an intake valve stretch?

[ride_red]

Rechecked the valve clearances today after 650 miles of Dual Sporting. A good while back I reshimed to the loose side of the limit. Stock the bike had two that were too tight. Well.....all were fine except for one intake valve---NO CLEARANCE. I couldn't spin the bucket over the valve and when shot with alot of WD-40, it was evident it was not closing----ran past the seat into the cylinder. I pulled the cam retainer and put a ruller across the two intake valve retainers. The suspect one is about 20 thou or so higher than the one next to it. Pulling the head as we speak (got oil on the keys here). I guess there is a posibility that the seat is recessing into the head but I really think the valve is streching. I guess Ti streches (and breaks).

Anyway thanks and I appreciate hearing any idea/experience with this. RR

[Red_450]

Ride Red...Do a search for 450F Tight valves,April 29 from MXTECH member # 9292 I just read it over and it may apply to your problem.

[ride_red]

Hey Red 450, thanks alot. That is exactly what I found out after pulling the valves from the head. The sealing surface on the valve is wearing down. Ti =soft? Nice. I have about 40 or so hours on the bike, I don't over rev it and always use premium unleaded. I just hope the $50 a piece valves are available.

My best advice is to check the valve clearance on a regular basis. This happened rather fast. Like the other thread said, a warning sign is if the bike has a hard time staying running at idle. Coincidently this is how my bike acted when new. Like I already said, tight valves were at fault then too. RR.

[Red_450]

Ride Red, Keep us informed on what happens and what the total costs are. At 30 hrs. my intakes were tight and the exhaust were within tolerances. Sure hope I'm not looking at valves at 40 hrs.

[ride_red]

Red 450, no doubt I'll keep everyone up to date on this. Also thanks to you and others who posted info on this and other things. Like I said the valves are at least $50 a pop (replacing both to be sure). Gaskets ain't cheap either. Doing the work myself---can't imagine labor charge on this.

Interesting little post script to all of this. As I was pulling the keepers out of the retainers, my dad walked in with the mail. I got a 4 page questionare from Honda asking for my impression of long term satisfaction of ownership experience with my new CRF 450. I'm afraid I got an oily finger print or two on the document. But I feel that will be the least of their concerns when they get that letter back. RR

[SFO]

Check out these guys...

http://www.blackdiamondvalves.com/

They made the os ss valves for the woody kile built 63rwhp500cc crf that Kevin Atherton

won on.

A stainless one piece valve is currently in the design stage for production for the cr-f.

Until then they will custom make your valves for around 40$ each and they will be serviceable ie refaceable unlike the oem honda part.

[SFO]

Thanks for the +1 comp ticket on the soul train RR.

How much does a oem intake valve go for list, BTW?

After some research I have discovered Honda has designed many of their components to be unserviceable. R&R, puts the green back in hondas pocket instead of the rebuilders.

I would cut my wrists before I cut a head with stones.

A serdi is not to be confused with other cutter style machines using a cutter.

The secret is the floating spindle that locks rigid after locating on the carbide pilot that is inserted into the valve guide.

Unlike the other machines utilizing a fixed spindle and a ball driver that relies on the pilot at all times to create concentricity along with springs and stuff.

BTW, the set up shown in dirt bike this month was not a 30k$ like they said. It was aball driver set-up.

Serdi is the s***, but I am borderline spamming now.

Honda sells a bare head for under 200$ for the crf I believe. A savvy ripper could put one on the shelf.

[ride_red]

OK, here's the latest. First off I'd like to thank Bill (SFO) for that great info. Only here at TT will you get that type of information so fast.

Being though the new Honda valves came in I thought I'd give them another chance. Had dealer call Honda for any info on the problem. Of course their response was "Duh, huh. Taint never heared of that happin out in the there field yet". I might be taking some liberty in the transcription of that. And also don't use anything but genuine Honda replacement parts. Thanks guys (Honda). Guess I'm left out in the cold holding my manhood again. Nuf said.

So at any rate, upon inspection with a magnifying glass the seat had circular grooves where the valve contacts. These were transfered to the worn valve. I am assuming when the valve seat was first machined these grooves were left in. Should have been a mirror finish. In time these grooves ate the Ti valve.

So what to do now. OK, you can use a stone type grinder to refinish the seats. (I know the CRF shop manual even showes stones). But this leaves a rough surface which is smoothed out by the final process which is lapping in the valve with compound. You can't do this with Ti valves because of the protective surface on the valve. So the next and only thing to do is to find a machine shop which has a $30,000 Serdi valve cutter. This machine actually uses a cutter instead of a stone. The cutter leaves an almost perfect surface. Anyway I did this and now the head is going back on.

I'll keep everyone posted on anything else. Also if I'm all wet about any of this info please throw in a word or two. RR ?

[ludicrous_larry]

RideRed,

How much did the "Cutting" put you out? And who did it? I'm just kind of curious and thought that the info may be kind of useful to any TT'ers who find they have the same woes as you sometime in the future. I don't have your problem right now, but will take a gander at my valves next month when I get back into port.

[ride_red]

I think the valves are $63 a pop list. Also had a local machine shop do the seats. Close friend---no charge type thing, but I think it wouldn't be much. He just "kissed" the seat to straighten everything out.

I must have missed the Dirt Bike article. Was it CRF specific? Thanks guys. RR.

[SFO]

Originally posted by ride red:

I think the valves are $63 a pop list. Also had a local machine shop do the seats. Close friend---no charge type thing, but I think it wouldn't be much. He just "kissed" the seat to straighten everything out.

I must have missed the Dirt Bike article. Was it CRF specific? Thanks guys. RR.

It was adressing RFS's and not with the timeliness or intellegence of TT I would humbly say.

[ June 06, 2002: Message edited by: SFO ]

[no_wing_no_prayer]

i think i have found out what is really going on with the valve wear on the crf's. the valves are actually spinning on the seat. if you look closely at the wear mark on the valve it is pollished. or at least mine are. when the spring is compressing it is actually spinning the valve across the valve seat. im going to try and secure the spring so that they wont spin. i will get back to you on this as soon as i get new valves. and by the way anyone who is from canada wont be able to get them because honda canada has no stock at all in the country at this point. ?

[ride_red]

Yeah, like I say I did notice circular grooves on the old valve and seat too. Just thought these were in the seat from the factory and got transfered to the softer valve. But I could see how a spinning valve would cause this also. Just don't know if a valve could spin while seated though. Some small block Chevys use rotators on the EX valves. Think it turns when lifted off the seat.

Hey that's a real grind that Honda doesn't have the valves in stock for you guys. I've been doing some soul searching the past few days and man I just don't know. I---um---I think I might just jump ship on this old gal. It would be one thing if Honda was in our corner (in words and in actions) on some of these issues. I'm not asking for much, maybe just some constructive advice every once and a while.

Oh well, enough of that talk. Like Smokey the Bear, I don't want to start any fires here. RR.

[mxaddict]

Originally posted by ride red:

Oh well, enough of that talk. Like Smokey the Bear, I don't want to start any fires here. RR.

Man, and I had the blowtorch all fired up and ready too.. ?

(Easy now, I'm just kidding, if I had a bunch of problems it would already be gone.)

[ June 06, 2002: Message edited by: mxaddict ]

[ride_red]

Lol, thanks man.

The main symptom that started me looking into the valve clearance in the first place was stalling at idle. If some of you old timers here remember, that was my main let down when I first bought the bike (that thread got a little hot---whew!). Although the stalling was more pronounced then. Well I just got the bike back together and it acts like it did right before I checked the valves. Guess I have a day of tinkering tomorrow. Think I'll screw with the jetting again. Sort of a let down today.

But you know, I'm not feeling blue. Actually the last few days I've been feeling orange-------real orange. RR

[Red_450]

Ride Red....Don't jump to the orange side. After all who else could I get to post photos for me. Never have figured out how to do that yet.It's pretty bad when I can convert a frame to a fuel tank faster than I can post a photo.

[mxaddict]

Originally posted by ride red:

Actually the last few days I've been feeling orange-------real orange. RR

Well, the hardest step is admitting you have a problem. You ought to join a 'fruit fondler's' support group to get therapy, and quick. I've seen it a thousand times, first wax fruit, then real produce and finally gay men. It's an aweful downward spiral. Quick now, grab a beer, burn some meat and call that UPS delivery 'person' back to your house, that should help. ?

[ride_red]

Ha, Ha, Ha. ? You guys are too much.

And by the way, what's up with those front fenders. Did they call in Leonard Nemoy to design those? Now that I've brought him up, he is rather handsome don't you think? OH MY GOD, I've already started the downward spiral! RR.

[SFO]

With the advent of the ti valve I believe the manufacturers have reduced the seat pressure on the spring so they can fully take advantage of the the lightness of the ti valve.

This reduced seat pressure has a side effect of less accurate valve control if the springs are not up to snuf, there is less margin for error or wear as the springs get time on them they will not control the valve as well.

The erroded ring on the valve face is considered by some to be caused by float or inaccurate valve control. The harmonics that set up on the valve face/seat junction when the valve is not being controlled are very destructive. The other thing is that the valve face gets rid of 75% of its heat throught the face/seat junction and when it is not in contact with the seat when it should be it will quickly overheat and become unable to defend itself against the corrosive nature of the combustion process at this elevated temperature.

I would highly suggest replacing the springs with the valves even if they are "in spec".

Sorry for rambling...

Bill

[mxaddict]

Originally posted by ride red:

Ha, Ha, Ha. ? You guys are too much.

And by the way, what's up with those front fenders. Did they call in Leonard Nemoy to design those? Now that I've brought him up, he is rather handsome don't you think? OH MY GOD, I've already started the downward spiral! RR.

lol!! that was good...