Tell Me Your Horror Stories of MX 4 Stroke Engines

[Birken Vogt]

This weekend we went for a desert ride, well one of the "old timers" who has an XR400 is now itching for a CRF450. I told him I thought they were too maintenance intensive for a play rider, well another know-it-all who was standing there (but not on the ride I might add) :blah: said "remember so-and-so, he's had one for 3 years, never rebuilt it, it's just fine...." Anyway I am a heavy truck mechanic by trade so I am big into service invervals, etc. So I was wondering if any of the dire predictions about these 4 strokes being an expensive PITA are coming to fruition, or if you can really expect them to survive 3 or more years of long, though non-competitive riding.

Myself if I had to buy new bikes it would be just updated versions of what I have now, an XR650 and a CR500AF, if I could get a big enough tank and a soft seat, otherwise I would just buy a steel frame CR500

Birken

 

[robwbright]

There aren't any, are there? Those are just spook stories made up by 2 stroke guys who don't want to enter the 21st Century. ;)

 

[Rich Rohrich]

Rob - Give it a rest.

Birken - With regular maintenance the CRF 450 has proven to be a great engine, but probably not the best choice for consistent desert riding. It's oil capacity and maintenance intervals are clearly designed around MX usage. The XR650R or the CR500AF would be much better choices for the application.

 

[robwbright]

Rob - Give it a rest.

Well case closed, Rich. I guess there really aren't any of the 4 stroke horror stories he asked for. I notice no one has posted any by 12:30 today.

I know that many of those alleged horror stories I've seen and heard about were caused by insufficient maintenance and were not the fault of the bike.

I know I have a reputation as a "2 stroke guy" - and rightly so. However, maybe you didn't see it, but I believe I posted yesterday in another thread that I agreed that any bike, 4 stroke or 2, properly maintained, will likely last a long time. That's not the issue with me. The fact that 4 strokes are more maintenance intensive makes them less appealing to me because of the extra time and money issues - and I don't have enough of either.

It appeared from the post that Birken is having some of the same concerns. And yes, from my friend's experience and from what I see on here, I'd agree that the CRF450 is pretty reliable when it's maintained properly.

And yes, one of my buddies has a 250f horror story, and he's trading it (oddly enough, for another 250f) less than a month after buying it. Others were trying to persuade him to get a CRF450 instead.

 

[Rich Rohrich]

maybe you didn't see it, but I believe I posted yesterday in another thread .

Rob - You are correct, I didn't see it. I usually ignore your posts, mainly because like so many others you provide nothing to this type of thread other than simple parroting of third person " my friend's cousin's brother knew a guy" horror stories with no details, or the standard two-stroke zealot knee jerk response like you posted above.

Just like in your profession, having real facts with real details, about specific failures is far more useful when someone has specific questions. Your insistance on constantly piping in with nothing useful is getting really OLD.

If you would bother to look you'd see I'm one of the few who has bothered to document some very specific issues with specific current four-strokes. Unlike you, I'm actually QUALIFIED to answer Birken's questions.

We get it Rob you like two-strokes. When you can do something other than RIDE a bike and pay someone else to modify it get back to me. ;)

 

[XRpredator]

Richard, don't hide from your feelings!

 

[Masterphil]

Here's yet another "unqualified" post, at least compared to Rich anyway.
The only failure I've had with a "modern" 4T motor was a bad left side main bearing. The bike was a 2002 yz426f. I feel that this part failed prematurely, but this is only my opinion. Fortunitely, I cought the problem before it could mess up anything else and only had to replace the main bearings. This could have just as likely happened on a 2-stroke as a 4-stroke. This was something I was a little pissed about at the time, who likes to split the cases on any motor. But, it will not keep me from buying another yzf if that is what I want in the future. Other than the main bearing problem, my '02 yzf has been bullet proof, not even needing the valves shimmed.

I do agree that for desert riding, a XR650, CR500, or 525exc to be your best options.

 

[robwbright]

you provide nothing to this type of thread other than simple parroting of third person " my friend's cousin's brother knew a guy" horror stories with no details, or the standard two-stroke zealot knee jerk response like you posted above.

Your insistance on constantly piping in with nothing useful is getting really OLD.

If you would bother to look you'd see I'm one of the few who has bothered to document some very specific issues with specific current four-strokes. Unlike you, I'm actually QUALIFIED to answer Birken's questions.

Rich:

First, did I represent myself as knowing as much as you in another life?

Second, I have received several complements on the usefulness of my posts, but you are entitled to your opinion. Apparently some here think I "pipe in" with useful things on occasion. And BTW, the other day I actually recommended a 4 stroke to a fellow on here - and I did not try to discourage my friend from getting the new 250f - he's got the money, knowledge, time and discipline to keep it going for years. If that's the way he wants to go, there's a 99% chance he'll have a fine bike for quite some time.

The point I was trying to make with the initial, sarcastic post is that most 4 stroke guys (and I do not deny that 2 stroke guys like myself are/have been biased as well) go on and on about how great the 4 strokes are, but when someone asks what the problems with them are, in many cases the response is a lot of crickets chirping - unless a 2 stroke guy posts something critical, then the 2 stroke guy will get flamed.

To prove my point, Birken asked for stories about 4 stroke problems at about 10:15 - and still 6 hours later the only two stories are from 2 stroke guys - one experiential and one anecdotal.

I don't recall EVER seeing a 4 stroke MX guy admit that if there were no double displacement advantage rule in MX, he'd be on a 2 stroke. I suppose those posts exist, but I haven't seen them. The refusal by many to acknowledge that gets "really OLD" as well.

And Rich, till YOU basically told me to shut up, I made no reference to YOU. I highly respect your knowledge of motorcycles, as you may have noted in the past, when I have sought your information and advice - and I would do so again should the need arise - you were VERY helpful on the fuel issues.

I have bothered to look at your posts on numerous occasions, and I am well aware of the specific problems you have documented re: the 4 strokes and especially your fuel articles. I've read quite a bit of it, and I have used them to discuss the problems with others - to the point of printing them so others can read them.

Yeah Rich, I get it - I know nothing about motorcycle engines compared to you - and as noted, I have never represented that I do. You are the all-knowing god of motorcycle knowledge compared to me (and I am not being sarcastic here - that's a compliment). With the exception of Eric, I don't know of anyone else I would sooner ask a difficult engine question.

In fact, in the initial version of my first response to your telling me to shut up, I had a whole paragraph basically bowing down to you precisely because I know I don't know much at all about motors experientially. I took it out for brevity and because I thought you'd get the point. You get the equivalent in this paragraph.

And BTW, I provided details of my friend's RMZ250 in another post last week and saw no need to repeat it in this thread. Suffice it to say the bike is, in his words, "the biggest piece of junk I've ever seen."

 

[Okiewan]

but when someone asks what the problems with them are, in many cases the response is a lot of crickets chirping - unless a 2 stroke guy posts something critical, then the 2 stroke guy will get flamed.

unless of course the failures, etc aren't happening nearly as much to us 4-strokers as the 2-strokers like to think :p

I think Rich's problem is that you are passing a lot of bad mojo towards 4-strokes with no personal experience. A lot of he said / she said / I read on the internet, stuff. If your opinion was somewhat balanced (yeah, I've seen the 1-2 4t posts of yours) and didn't come across as so biased... ? The "what bike do I get" replies seem canned; "not reliable, expensive maint, get a 2-stroke".

Fact is, 4-T's aren't as bad and 2-T's aren't as good as a lot of the stuff you read on the web would indicate.

"the biggest piece of junk I've ever seen."

Odd.. the biggest pile of rolling crap I ever owned was a 2-stroke (seriously). How is that useful for anything?

I'm sure everyone appreciates the input, but honestly, seem to be way too biased towards one bike type.

 

[muddy226]

Hey Rob, I like your posts, please don't be discouraged, sometimes there are situations where there is a lack of soundly researched and replicated data, and anecdotal evidence is all thats available, often coloured with personal opinion. If everyone only posted known and referenced facts, there would'nt be very much to read on here! Also, I think that some of the more outrageous posts ( I don't mean yours ) are an excellent method of stirring up Rich to step in with his specialist knowledge and outstanding pictorial and written communication skills.
For the type of riding mentioned I would think the CR500 would last nearly forever, but might it be a bit of a handfull ? I would have thought a pukka enduro bike of largish capacity ( either 4t or 2t ) would fit the bill, although I don't have personal experience.

 

[Okiewan]

Well said muddy ...

It helps also when someone posts an opinion... and qualifies it as such.

Seriously Rob, don't take it personally. It's all good.

 

[XRpredator]

Opinions are like cowboy hats. And I like my women like I like my tractors.

I can't get any more specific than that. Please don't ask me to explain

 

[ellandoh]

green and smell like diesel fuel?? me too

as far as 2t vs 4t, after all things are considered , ride whatever gives you the biggest smile.......

i wish my bike took more maintenance, putzing in the garage with my cycle, jeep, truck, sled, etc. with DRN on the laptop(wireless) is what gives me smiles. when riding is not an option.

 

[Patman]

I think it not important if it's 2T or 4T but what type of oil you use :p

 

[oldfrt613]

Uh, what was this thread about ?

 

[ellandoh]

Ginger or Marianne

 

[oldfrt613]

Ohhhh !

 

[fizzle]

Birken,
I can't say that I have a lot of experience with single-cylinder thumpers (or dirt bikes in general). I have had Yamaha YZF street bikes for quite a few years. They redline at 13,500 rpm. Never had any real issues with them, except for keeping all 4 carburators in sync.

I've owned a 2-T YZ for 2 months and a 4-T YZ(acutally the Mrs. owns this one) for 1 month. I've had no issues with the 2-T and one minor issue with the 4-T, which is most likely due to my own ignorance of fuel additives (or just plain bad fuel). This summer I ought to have a very good opportunity to ride two very similar bikes with very different engines and get the pro's and con's of each for the same riding condition (woods and recreational MX). If you are interested is seeing how it goes, keep tabs on my blog

(Note: the following paragraph is an opinion, the opinion of a noob who nearly fell for Okie's "April Fool's name hack")
I will say, though the linear, consistent power band of a 4-T feels "right" to me, and the speed racer turbo boost powerband of my 2-T scares me, I feel very comfortable tearing into my 2-T engine (even though it's my first one), yet I am very intimidated by even thinking about doing anything to the top end of the thumper. Perhaps that is why it is easier to hate the thumpers and gossip about their high maintenence....because we are intimidated by their high-tech, high-tolerance engines, so instead of diving in and figuring them out, we take them to shops to get regular preventative maintenence done then complain about the costly maintenence to cover up our own inconfidence (I know that's what I did this week). That's my take on this controversey.

 

[VintageDirt]

I got me a 33 year old two-stroke and it's never had the oil changed, in fact I'm not sure it even has oil in it.

 

[oldfrt613]

I have both and work on both. The thumper does take longer to do most any maintenance than the 2 stroke ( except mix gas, that's faster on the thumper ). The thumper really isn't that much more complicated than the 2 stroke when you throw in the power valves on the 2 strokes. There is less working room on the thumper. I can't even change a carb jet on it without taking the subframe off. I run an hour meter on the thumper and am religious about watching the valve train. I have had no real issues with the thumpers. Some of my buddies have had major failures, but these are the same guys who seem to guage when to change the air filter by the thickness of the dirt accumilated. They basically ride until it quits. My take is that the thumpers are less tolerant of poor maintenance than the 2 srokes. And as a mechanic, you know what kind of things happen with valve train failures.

 

[Birken Vogt]

I should have known what the thread would disintegrate into and I should have posted at a better time when I could jump back in to head off some of the crap. But too late I guess. Anway I would like to elaborate on the question if it's not too late. Apparently they need frequent top ends and valve train adjustments. Has anybody tatered one by going too long on these. Like I said I am a professional mechanic, actually more of a fleet manager but that is with diesel engines. I tend to do things on schedule but at the same time I will stretch intervals as far as I can based on evidence to save time and money. Unrealistically frequent specified intervals chap my hide

Anyway I am curious to know if anybody has gone too long on a piston and have it get sideways and take out a cylinder plating for instance or maybe neglected valve adjustment and had something happen. I am familiar with the story of the RMZ camshaft I think it was. Any more like that would be good. Also do these motors just get "plumb wore out" when you ride the heck out of them. My idea of a good day is 2 or 3, 100 mile long rides. Which I have a hard time doing any more due to my ancient machinery it seems :p But that's all right because I also get tired more easily than I used to. It seems like most of the "kids these days" want to just ride their CRFs over some jumps for a half hour, then sit around camp talking about their new gear. They don't really put the hours on that they claim. Basically I am asking if anybody rides serious desert/long distance with these things. I realize they are MX bikes. But as often as I can keep it running I ride my CR500 on these types of rides and it is a MX bike too. If these things do just as well I might get one some day if I get sick of fixing the CR. It breaks stupid things like gaskets and hoses more than anything internal.

Birken

 

[Okiewan]

Why mess around? Here's your desert bike:

 

[Birken Vogt]

I'd love to, does anybody make a real gas tank for it?

Birken

 

[Papakeith]

That looks like our Dirtrider test bike. If it is, methinks you might want to take a closer look at the tank :)
How many gallons = "real"?
The test bike had a Clark Oversized tank on it.

 

[oldfrt613]

IMHO either a fresh XR650 or CR500AF will fill the bill better than a 450 MXer