used 05 crf450 needs a good once over

[mxcrazed]

Hey guys, I just traded my F4i that I put down for an 05 crf 450
the bike wont Kick Start in its current condition but it will pop start with a whole bunch of throttle and it will idle with the idle screw almost all the way in. I took off the carb today and cleaned the heck out of it and everything appeared to be pretty clean except some garbage in the accelerator pump. With everything clean I installed a 175 main jet and a 55 pilot jet put the needle on 5 and turned the idol air screw to 1.75 turns out. The stock settings were 42 168 and 4 with 1.5 turns out, theese were the smallest jets I had to replace them with. The reason for the carb adjustments is because I was told that it may have a 480 kit installed. It has the stock pipe and silencer with a Profilter air filter which I cleaned. The cylinder has an La sleeve sticker on it and a casting mark from 09 so I know that the top end is no more than two years old. my compression tester showed 45 psi with the decompression arm enabled and I checked the timing it appeared to be off by less than one tooth so I assume it is correct.


The questions that I have are pretty specific because I've done a good amount of reading.

Unfortunately I couldn't find my feeler gauge today so I did not get the specs on my valve clearance but I'm not sure I understand the recommendation. I will buy a new feeler tomorrow though.

int: .006 +- .001 in (.16+-.03 mm)
ex: .011 +- .001 in (.28+- .03 mm)

most say to run it closer like .004 in .008 ex

I assume this means at TDC I should be able to fit a .004" feeler between my cam and the top of the valve on the intake (snugly). To adjust I must subtract the difference between my reading and the spec from the installed shim and that will be the measurement of my new shim. Then recheck after installing new shims.

Should I buy a whole shim kit or just the correct ones?
How do I know if the valves themselves are garbage?
What has to be replaced along with the valves if they have to be done?


I found these videos very helpful.
valve adjustment
timing check


Thanks for reading!!!

 

[Ol'89r]

You have to disable the Decomp to get an accurate compression reading.

You should never bump start your bike if it won't kick start. (Referring to the current crop of fourstrokes). If the bike won't kick start, it is usually an indication that the valves are tight. If you bump start it and run it anyway, you could do damage to your valves and head.

Your valves have a Titanium coating on the seat face area. Once that coating burns off, your valves are junk. If the bike is operated without the necessary valve clearance, it will burn the valves and possibly damage the seats.

I would stick with the recommended valve clearance rather than take the chance of running them too tight.

Your assumptions of how to check the valve clearance is correct.

You can buy the whole shim kit or just the ones that you need. It is very convenient to have the whole shim kit available. They cost around 80-90 bucks.

You can check the condition of your valves by disabling the decomp and doing a compression test. If you compression is low, you will have to remove the head and physically check the valves. Pour gasoline into the intake port and then into the exhaust port. If gas leaks past the valves, you should remove them from the head and inspect them. If they are burnt, it will be obvious to the eye.

IMO, if you are unsure of the history of the bike, you should go ahead and replace the valves, valve springs and guide seals. If the valves have too much time on them, they can break and lose their heads. If that happens, it will cause a lot of damage to your engine. The piston and rings should also be replaced. Find someone with experience and the proper tools to do your valve job. It is critical that it be done right. Check your cam chain and guides also.

A good way to go is the Kibblewhite stainless steel valve kit. They will outlast the standard valves and can be ground and re-seated like a normal valve. Be sure to use the Kibblewhite spring kit with the SS valves.

A factory service manual will be a big help. ;)

 

[mxcrazed]

Thanks 89'r I appreciate the thorough reply. My other bike is also an 89 check my sig.
I'll definitely try the gas trick asap that one sounds easy.
Do the valve seats have to be replaced typically? I also like the KW valve kit but there are no valve guides or seats included.

Would you happen to know how to disengage the decomp? Is 75 psi what I should expect with the decomp off?

Thanks again, -Dean-

 

[Chili]

89 for ol'89r refers to the fact he was born in 1889 not that he rides an 1989 ;)

 

[Uchytil]

he was born in 1889

:laugh:

 

[Ol'89r]

89 for ol'89r refers to the fact he was born in 1889 not that he rides an 1989 ;)

Silly Canucks. :moon: :nener:

I have motorcycles that are older than that. :whoa:

mxcrazed. Normally the seats don't have to be replaced. They can be re-cut or ground. You will have to check the guides for wear. They usually don't need replacement unless the engine has a lot of time on it. Off the top of my head I can't remember the Decomp setup on the '05. If you take a look at it you should be able to figure out how it works and just lock it in the open position. You should have at least 130-40 psi compression with the throttle held wide open while kicking the bike. All of the wear specs are in the service manual. If you don't have one of those, you should.

Look real close at my avatar picture. You will see where the 89 came from. ;)

 

[mxcrazed]

Well I tested the valve lash and both intake valves were less than .002", I think my buddy has a shim kit so for now I'll loosen up the cam and check the valve seats with gas. After I reshim it I'll do a comp trst

 

[Rich Rohrich]

If the intakes are less than .002" then you don't have to waste anymore of your time. With that little clearance the surface coating is worn off and the valve face has receded. In other words the valves are cooked, so pull the head get a proper valve job done and replace all the valves and springs.

 

[mxcrazed]

That's what I was afraid of. I still want to shim it and do a comp test without oil then with oil to see how the rings are. That way I'll also have a gratifying before and after. I'm definitely going with kibblewhite valves this new breed of four strokes is garbage my cbr600 spins to 14,200 rpm and has 16k mile valve inspection intervals. I really want to do all I can to make this thing reliable I remember my first xr I rode that thing for years without doing a thing, that's how it should be.
That being said who do you guys suggest for the valve job.

 

[Rich Rohrich]

Ol89r's shop would be an excellent choice. You know it will be done right that way.

 

[Patman]

If you wanted a low/no maintenance bike like your old XR you should have bought an XR, most everything else might be a 4 stroke but they will need a lot more love (aka $$$).

Lucky you that '89(geez)er and Rich have responded, you pretty much have the answer to your problems from two of the best. Don't waste your time looking for other (cheaper) "fixes" because they ain't out there.

 

[helio lucas]

this new breed of four strokes is garbage my cbr600 spins to 14,200 rpm and has 16k mile valve inspection intervals.

try to race it on dirt and the 16k miles should go down to, say, every other ride?!?! :cool:

 

[Matt90GT]

FYI go back to stock jetting. Just cause you install a larger bore or cam or other part does not mean the engine needs more fuel. Many times it becomes more volumetric efficent and thus the jetting stays the same. Start at stock, run it and go from there.

All other info is correct. This is not an XR. And they have very short service intervals. Pistons are at 15hours per the service manual.

 

[mxcrazed]

Well then does somebody want to buy this piece of garbage. Or maybe I'll get my f4i back my cr is a monster I don't need to deal with valve garbage.

 

[mxcrazed]

Quote: Originally Posted by mxcrazed this new breed of four strokes is garbage my cbr600 spins to 14,200 rpm and has 16k mile valve inspection intervals. try to race it on dirt and the 16k miles should go down to, say, every other ride?!?!

I highly doubt you are remotely accurate although there is ground behind your argument. I suppose we could learn from someone with a similar engine in their quad. But I'll let you know that this bike has been down about five times. The worst was the most recent which was at about 75 mph where it flipped right side wrong then slid about 300' and impacted a guard rail bending the entire front fork and wheel. This accident nor any other managed to knock the valves out of adjustment even with over 14k on the clock.

 

[Rich Rohrich]

You bought a worn out 5 year old high rpm RACE engine that sounds like it was never maintained, and now you come out here bitching because you have a worn out 5 year old race engine. Get a grip.

 

[Ol'89r]

This accident nor any other managed to knock the valves out of adjustment even with over 14k on the clock.

How does crashing your motorcycle knock the valves out of adjustment??? I'm a little confused. :coocoo:

 

[mxcrazed]

So your telling me that my cbr600 f4i isn't a high revving race engine it's .6 L that produces 109 hp in production trim and probably more like 120 with the intake full exhaust and power programer installed. It revs higher has more moving parts and lasts longer. Something is wrong here when the same manufacturer produces two ohv engines and one has one tenth the service interval. Sounds like you need ss valves and stiffer springs to fix a valve float issue. On top of the fact that people have seen longer service intervals by running the valve lash tighter than hondas "recommended" specification. Sounds like Honda triple f$@*#d up crappy valves, crappy springs and a bad specification because they probably cheeped out on R&D.

This is my fourth Honda motorcycle so don't act like I'm ripping Honda because most of the stuff they produce is great. This head clearly isn't their best work.

 

[mxcrazed]

I haven't seen valves come out of adjustment personally on these bikes. But on the cbr forum I've seen a couple guys that ended up with valve ticks from accidents. I also have a close friend that rearended somebody and only had cosmetic dammage on his truck besides the fact that he had several valves out of adjustment immediately afterwards. His radiator wasn't even busted.

I didn't crash five times in my defense it had been down on both sides after already having been repainted when I bought it.

 

[IndyMX]

I'm no engineer, or even that great of a mechanic, however, logic would suggest to me that an engine turning 11,000 rpms with one cylinder is doing 4 times the work and wearing 4 times faster than an engine with 4 cylinders turning 11,000 rpms.

But this is a forum on the web, not logic.

 

[Rich Rohrich]

. On top of the fact that people have seen longer service intervals by running the valve lash tighter than hondas "recommended" specification. Sounds like Honda triple f$@*#d up crappy valves, crappy springs and a bad specification because they probably cheeped out on R&D.

Tightening up the lash to extend valve train life has no basis in fact, regardless of what some know nothing wanks on the internet might want to tell you.

If you can't see the difference in stress, material requirements, valve mass to rpm ratio, and service requirements between a 67.0 x 42.5 mm engine with tiny steel valves that is run on the street and a 96.0 x 62.1 mm single compresssion ring piston, titanium valve race engine that has to survive in a harsh environment, then you probably should stick to two-strokes. Race bikes require RACE MAINTENANCE schedules. Two strokes just don't bite as hard when you ignore them.


BTW, try seriously road racing or drag racing a CBR600 and you'll find that that your precious 16K mile service interval no longer applies. ;) Treat it like a race bike and you have to maintain it like a race bike. No getting around that.

 

[mxcrazed]

Every cylinder moves it's valves once for every rotation. And every piston has four strokes pr combustion cycle. The f4i produces 245% of the power with 25% more displacement even 75% of that 245 gives you roughly 185% of the power or 21% more power pr cc/cylinder. So basically it is doing more with less.

 

[Rich Rohrich]

Every cylinder moves it's valves once for every rotation. And every piston has four strokes pr combustion cycle. The f4i produces 245% of the power with 25% more displacement even 75% of that 245 gives you roughly 185% of the power or 21% more power pr cc/cylinder. So basically it is doing more with less.

A wise man once told me to never argue with an idiot. It's proven to be good advice over the years, but I haven't always been smart enough to know when to heed it.

 

[dirt bike dave]

Actually, it's doing more with more. More valves and more cylinders, that is.

16 smaller valves in a street bike = less maintenance than 4 big valves in a race bike.

As for the 245% of the 125% x 75% = 185% or 21% more per cc/cylinder, I have no idea what that means. If the point is that the f4i is a marvel and the CRF450 is an embarrassment, well, I'll just have to take your word for it. Seems to me they both work pretty well for their intended purpose.

 

[mxcrazed]

okay well i was writing a long witty response but firefox crashed so i lost all the text.

I'm sorry i offended the four stroke gods but hopefully we can all be mature enough to get back to the point.

basically all i have to say is that if your done patronizing me and you would like to help me build this thing for longevity it would be appreciated.