Well it finally happened to me...

[fandl450r]

I have owned my 450R since I took it off the showroom floor, and have never had a problem with it. Until now, as of yesterday, after a good day of riding, I locked up the motor. :mad: As of now I havent opened it up yet, but I hope to god this doesn't cost me an arm and a leg. Sorry just had to vent.

[Pappy]

My brothers 04 YFZ finally went saturday.


Shawns 04 450R went 3 weeks ago.


We have grown to expect it since noone seems to want to tear them down and fix them before they grenade:p

[quadwanter]

dang that sucks..hope you get it back running soon...


what all can you do to prevent this from happening?

[fandl450r]

Originally posted by Pappy
My brothers 04 YFZ finally went saturday.


Shawns 04 450R went 3 weeks ago.


We have grown to expect it since noone seems to want to tear them down and fix them before they grenade:p

What gets me is that the piston was replace, all gaskets about 15 hours ago, along with new valves etc. New cam chain was put in as well. But its locked up tighter than the hubs of hell. We'll see what she looks like when I tear it down, and of course pictures will be taken. :D

Oil gets changed every ride, as well as a clean air filter.

[crazedape]

I feel for you. If you can't fix it, I am sure Norris can.

[fandl450r]

Yea it sucks, I'll be able to fix it, just not sure as to the extent of the damage, and how much I'm going to have to shell out. Pappy, were they stock motors?

[Pappy]

Yep stock.

My brothers has been maintained like it was the space shuttle:huh he had commented a week or so ago that if the bottom end did not go he would rebuild it all this winter including the wr crank etc. He was about 7 weekends to early:p (Murphys Law lives near me:mad: )

Shawns had an estimated 1500 miles on it, all GNCC and local XC racing. My brother takes care of his quad so I know it had the oil changed after every race. (BK Performance is quietly winning a few National and local classes:devil: )


I also know that there may be an issue with the 07's, but I am watching instead of being a pesimist on these damn engines

[fandl450r]

Yea I hear ya. It just seems odd that this would happen after so few hours on the new top end. Granted, 14.1 compression may not have helped, but I may be second guessing this CP piston now, if it's the culprit, we shall see this next weekend.

I'm just hoping its not the rod or that it dropped a valve.

[Jersey450R]

CP pistons are junk! f & l, my buddy rebuilt his motor with a 14:1 CP with Rage porting and polish. Rode it around...tons of power! Packed it up, we all went down to florida for a race, the motor didnt even make it 2 full days of riding.
leave the 14:1 CP's for the pros that have a new rebuild every race. were now running a weisco 2-ringer 12:1 in his bike with rage porting and a tapered carb and runs great. the 14 is just too much without a falicon wrapped up into the bottom.

good luck in the rebuild, i know my day is coming too. I have never opened my motor in 2 years, runs strong like the day i got it. pulls polished motors all day! I'm just waiting for the boom. :rolleyes:

[fandl450r]

Yea I'm definitely planning on going back down in compression, possibly even to a three ringer. Like Pappy said about murphys law, I've had a hellacious week, and it just keeps getting worse.

I had a 13.5 for the longest time and had countless hours on it. But this CP piston imo should have lasted a lot longer than the time it had on it. But as you said, it requires more maintenace, which it got, but we will see what happens when the motor comes apart.

I mean it has a bunch done to the motor, oversized valves, ported/polished head, dual rate valve springs, titanium retainers etc. So I'm sure that didn't help the reliability, but oh well back to the drawing board for somehting new. :devil:

[DieselBoy]

dude, what exactly gave out? the rod/crank? the piston? the cam chain, the valves hitting the piston??? the crank bearings??

this is exactly why i want a raptor instead of a race bred quad such as the YFZ, 450R, LTR, etc.

does anyone know what causes these engines to "give out"?
Is it the fact that it's revinng so high, or that everything is under so much stress? i want to know. lets assume in a perfect world they were maintained religiously, and then give some explanations.

[trick450r]

dont feel bad my 14.5:1 JE, dasa head motor made it 5 laps out of the box before the big boom..its goin on about 2 hours now after i rebuilt it and its runnin great.

[DieselBoy]

Originally posted by trick450r
dont feel bad my 14.5:1 JE, dasa head motor made it 5 laps out of the box before the big boom..its goin on about 2 hours now after i rebuilt it and its runnin great.

did you figure out what happened with the previous motor setup?

[Jonesy]

Originally posted by DieselBoy
dude, what exactly gave out? the rod/crank? the piston? the cam chain, the valves hitting the piston??? the crank bearings??

this is exactly why i want a raptor instead of a race bred quad such as the YFZ, 450R, LTR, etc.

does anyone know what causes these engines to "give out"?
Is it the fact that it's revinng so high, or that everything is under so much stress? i want to know. lets assume in a perfect world they were maintained religiously, and then give some explanations.

There are many different theories about why they give out relatively early. Partly to the higher rpms that they are turning, partly to the "pancake" style pistons, partly to the rider and conditions they are rode in, partly to mr. murphy.

I know that we have rebuilt quads only for them to lock up 4 weeks down the road, then others will run for years on end. One banshee we did (port and polish, super light pistons, carbs, milled head, pipes, and a few other bolt ons) ran for 4 years w/o any problems, being ran atleast 1 weekend a month, but usually 2 or 3 weekends. It all just boils down to dumb luck, and a roll of the dice.

[Jersey450R]

does anyone get that these high strung ported motors need a good bottom too?

[underpowered]

Originally posted by DieselBoy
does anyone know what causes these engines to "give out"?
Is it the fact that it's revinng so high, or that everything is under so much stress? i want to know. lets assume in a perfect world they were maintained religiously, and then give some explanations.

lots of factors go into this. Hi revving, reving so fast , the pancake style piston are usually the most blamed culprits. But the 14:1 was putting a lot of stress ont eh bottome end.

A lot of it is luck as jonesy said. My 426 was together for 3 years, tore it down for a rebuild and the cylider only had .5 degree of taper in it, almost like new and the piston did not have a single scor or scratch on it. needless to say, it is still on that bore with only a new piston. Now my buddies 440 was together for about 2 weeks before it went boom, destroyed top and bottom ends. on teh same quad we rebuilt it with a 460 stroker motor and it has been one of the most reliable quads i have ever seen. he has not had a single problem out of the engine, and it is a 13:1 piston, running no base gasket, decked head and a think head gasket so he is actually close to 14:1 with no problems. It is just the luck of the draw is some cases.

[DieselBoy]

i see. everytime i see 450 quads & bikes the riders are always hammering the crap out of the throttle so I don't know. Ontop of that they're always saying how "yeah, I just did new valves, camchain, bottom end, etc. and Its gonna need another one this winter". I don't think I really desire a 450 over a nice 660. Correct me if I'm wrong, but the 450's seem to need alot more internal motor attention than that of a utility/raptor non-race engine...I've talked to guys with 'em at gopher dunes and they all seem to be real happy with theirs as far as reliability/durability, except for the one way bearing which is fixed with an L&A kit. I've got no quads right now so I'm looking for a nice 2003 or so raptor 660. As it sits now I could buy a 700R But im not sure if im ready for the whole fuel injection thing, and besides it would be borderline too much in my budget. I want a good priced, good condition 660 so I'm not empty pocketed after I buy it. I'm sure you can understand. The 2 quads I had was pinching me for money, and I'm glad that's over with.

some people just get lucky.

[Jersey450R]

Originally posted by DieselBoy
i see. everytime i see 450 quads & bikes the riders are always hammering the crap out of the throttle so I don't know. Ontop of that they're always saying how "yeah, I just did new valves, camchain, bottom end, etc. and Its gonna need another one this winter". I don't think I really desire a 450 over a nice 660. Correct me if I'm wrong, but the 450's seem to need alot more internal motor attention than that of a utility/raptor non-race engine...I've talked to guys with 'em at gopher dunes and they all seem to be real happy with theirs as far as reliability/durability, except for the one way bearing which is fixed with an L&A kit. I've got no quads right now so I'm looking for a nice 2003 or so raptor 660. As it sits now I could buy a 700R But im not sure if im ready for the whole fuel injection thing, and besides it would be borderline too much in my budget. I want a good priced, good condition 660 so I'm not empty pocketed after I buy it. I'm sure you can understand. The 2 quads I had was pinching me for money, and I'm glad that's over with.

some people just get lucky.

go as fast on a rapterd, and see how long the chassis will last you :cool:

[Pappy]

Originally posted by Jersey450R
go as fast on a rapterd, and see how long the chassis will last you :cool:

Ummm, I havent seen a 450r or YFZ chassis that has not had cracks, even from riders that professed they were just chump riders and did not race.

The new engines have a life span much less then previous models. That is the trade off for higher performance...or so I am told.


I reckon that is why there is a 400ex in my garage and no more 450's

:chinese:

[DieselBoy]

listen i know you guys don't fancy the raptor but it's what i'm looking at for a quad... i can't race, nor ride extremely hard because my back is basically destroyed. i suffer day in and day out from backpain and i just ride trails, and light track riding. it's the only thing i can do without excrutiating back pain.

sorry. didnt mean to hijack your thread...

[underpowered]

well if you look at ti this way, a stock 450 has more power than a stock craptor 660. a motor with 200cc's less with the same power. the motors are jsut in such a high state of tune from the factory they do not last. and the vavle problem is because of the high revving. the vavles are slmming open and shut so much they jsut wear down and actually i have seen z400 pull them completly through the head. Kibblewhite valves are a good fix for this, they last much longer than stock vavles. camchains are a problem that is usually fixed by a HD cam chain.

[DieselBoy]

the fact that the raptor is such a bigger engine is a definite advantage in my eyes. the engine is not under continous stress, and they still rip your arms off when they accelerate. a 450 having more power is meaningless to me.

the motor never really "works" hard, like a 450 where its always getting every ounce of power...

but your theory on the 450s makes sense.

and its also the crankshafts that seem to bugger up on these.

[quadwanter]

this thread scares me....im freaking out and wondering how long until my "new to me" R will blow up :mad: :ermm:

[KiethShwiggy300]

Originally posted by quadwanter
this thread scares me....im freaking out and wondering how long until my "new to me" R will blow up :mad: :ermm:

Tomorrow













Jp

[MAaudioX10]

Originally posted by DieselBoy
the fact that the raptor is such a bigger engine is a definite advantage in my eyes. the engine is not under continous stress, and they still rip your arms off when they accelerate. a 450 having more power is meaningless to me.

the motor never really "works" hard, like a 450 where its always getting every ounce of power...

but your theory on the 450s makes sense.

and its also the crankshafts that seem to bugger up on these.

You know what, there is nothing wrong with wanting a 660. Typically, displacement doesn't equal horsepower. What it does equal is TORQUE. Unrivaled torque. None of which, ANY of the 450's can brag about. 660's are torque monsters and will do MORE than enough for your intentions.

Just keep your hands out of the motor and, learn from everyone of these guys mistakes. NOT to buy a 450. That is, unless you like going into the motor and dumping hundreds of dollars every time the bottom end gives out.

Evidentally, your not looking for the fastest thing out there. 660's are comfortable and reliable. Just toss a wider axle on it for stability and go ride, have fun.....and, stop listening to the kids around here.

[250rAL]

That's the problem with trying to make a four stroke run like a two stroke.:devil:

[Toadz400]

Originally posted by MAaudioX10
You know what, there is nothing wrong with wanting a 660. Typically, displacement doesn't equal horsepower. What it does equal is TORQUE. Unrivaled torque. None of which, ANY of the 450's can brag about. 660's are torque monsters and will do MORE than enough for your intentions.

Just keep your hands out of the motor and, learn from everyone of these guys mistakes. NOT to buy a 450. That is, unless you like going into the motor and dumping hundreds of dollars every time the bottom end gives out.

Evidentally, your not looking for the fastest thing out there. 660's are comfortable and reliable. Just toss a wider axle on it for stability and go ride, have fun.....and, stop listening to the kids around here.

Bingo. I don't agree with what you said about the 450's, but I do think people give the Raptor less credit than it deserves. I love Raptor's, they are indeed torque monsters and very comfortable quads. I've also never had a problem with the quad being tippy, I think it's just people's excuse for not knowing how to ride properly ;) .

DieselBoy - If your back is that bad have you thought about trying to find an Outlaw? Or possibly waiting a few years until you can afford a new one? That way you can have the speed/power of a sport quad with the nice ride of a utility. Trust me, your back is nothing to be messing with as I'm in the same boat as you. I absolutely destroyed my lower back last winter and it hasn't gotten any better. Doctor's won't let me get surgery so I'm stuck with this problem for the rest of my life, feeling like I'm 80 at the age of 18...it's great. I'm currently trying to get rid of my YFZ450 as I can't even ride it anymore because of the pain it causes me and I have college coming up in a few months. The thought of buying an Outlaw has definately crossed my mind but I was thinking about waiting until I'm done with college to pursue a new quad.

[crazedape]

I have a 250r, a 450r, and a crf450r. I had a raptor until somebody stole it. I loved to ride that raptor, it was smooth and worked flawlessly, I never had one problem out of it. I am not a racer I just like to ride. I have rode a lot of quads and the raptor and the 250r are my favorites to ride. The 450 is fun but it isn't the same as the other 2.

[fandl450r]

Finally got it torn apart, looks like it was the rod bearing.

[fandl450r]

Another

[fandl450r]

Cylinder

[fandl450r]

Not something I enjoyed pulling out and seeing, brand new filter, soaked in metal shavings.

[Mxjunkie]

God dayum :eek2:

you weren't kidding when you told me there was a chitload of metal shaving's!

[knighttime]

Originally posted by Pappy



I reckon that is why there is a 400ex in my garage and no more 450's

:chinese:


:bandit:

[firefighterjosh]

Yer filter looks like a christmas tree :p

[Architects]

Originally posted by Pappy
Ummm, I havent seen a 450r or YFZ chassis that has not had cracks, even from riders that professed they were just chump riders and did not race.




I had 3 full days at an Mx track and manged to crack my frame and im not pro by any means.

yeah i agree that i think it is a combination of things to make these motor have a less life span then the "typical" 4 stroke motor...But what kills a 4 stroke the most is RPM's....4 strokes are not really made to be producing 13 thousand RPM's ....like the statement be4, thats what you get when you try and make a 4 stroke run liek a 2 stroke....i think its funny when people say their 450 will last forever and make fun of us 2 stroke guys cuz we CHOOSE to rebuild our bikes or quad every winter...i think alot of people will be going to a 2 stroke, or going to a 400ex, Z's or raptors...

as for dieselman you should look into a 400ex since your not that worried about power and they have good relieabilty... the EX is a quality quad (not saying the raptor isnt) but i would much rathe rhave a nice EX with suspension mods for your back

Originally posted by 250rAL
That's the problem with trying to make a four stroke run like a two stroke.:devil:

Werd.

:cool:

[R450HQ]

Should have got a yamaha...

[fandl450r]

Yea and then have it blow up 2-3 times previously? No thanks.

[chad502ex]

sorry for your luck. I've seen this countless times when the cranksaaft journel flex under load- especially on the first generation engine where the OEM piston is a anchor compared to aftermarket 'drop-in' lightweights.....
-----------------------------
think about it for a second or two....

pistons that are significantly lighter than OEM which rev to 11,000 rpm over time will put huge 'twisting' loads on the crankshaft journels causing them to twist. The twist is from an imbalance of the assembly (crank and piston) [harmonics caused from the piston and crankshaft no longer being true] the lighter the piston from OEM the more this situation is amplified. So, why are stock OEM never been touch setups failing? IMO; i've seen where many many flywheels were within 'tolerances' and not condsidered 'true' at 11,000 rpm. Two seperate situations in my opinion, but when rod base disintegrates, its usually from crank journel flex under load. compression has nothing to do with harmonics being generated...

JMO.

[punker69q]

Originally posted by chad502ex
compression has nothing to do with harmonics being generated...

JMO.


well, the amplitude of those harmonics is affected by the compression, not the frequencies.

[chad502ex]

Originally posted by punker69q
well, the amplitude of those harmonics is affected by the compression, not the frequencies.

I never mentioned the frequencies. compression does not cause a harmonic condition to occur, its the imbalance of the recipicating weight. When harmonics occur because the crank is not balanced to the piston pack weight, then compression will affect the amplitude of the 'pounding'.

[chad502ex]

By the way, I forgot to mention that when harmonics occur that under load the journel will twist and flex. The twisting and flexing of the crank journels is what destroys the rod base. Welding the rod base pin to the journel half reduces the 'twist'

[Ghost-Rider]

Man that sucks.

[R450HQ]

Originally posted by fandl450r
Yea and then have it blow up 2-3 times previously? No thanks.
Should have got a yamaha...

[DieselBoy]

Originally posted by fandl450r
Yea and then have it blow up 2-3 times previously? No thanks.

NO! So you can RIDE instead of TURNING WRENCHES ALL DAY!

[fandl450r]

Originally posted by DieselBoy
NO! So you can RIDE instead of TURNING WRENCHES ALL DAY!

Haha yea right! I've owned this bike from day one and this is the ONLY problem I have EVER had with it.

[quadmxracer]

I say we don't care who rides what quad and let Justin fix his bike. I know how he rides and two years on the same bottom end is pretty good. Hope you get it rockin soon. Let me know if you want any help there chief.

-Clayton

[czrider263]

Originally posted by chad502ex
By the way, I forgot to mention that when harmonics occur that under load the journel will twist and flex. The twisting and flexing of the crank journels is what destroys the rod base. Welding the rod base pin to the journel half reduces the 'twist'

is that why the falcon cranks are welded?

[96lapis coupe]

Originally posted by R450HQ
Should have got a yamaha... Could someone please ban this troll?

[chad502ex]

Originally posted by czrider263
is that why the falcon cranks are welded?

yes. they weld the pin to keep it from seperating or twisting under load.

[Toadz400]

Originally posted by 96lapis coupe
Could someone please ban this troll?

Why? None of you guys have a problem when someone says "Should've gotten a Honda" or "Ride red or don't ride at all" or stupid crap like that. They're all the same. But I do not encourage people to suggest another brand of quads as the solution to a problem such as this, unless he were riding a Polaris ;) .

So chad502ex, should I thank the meth-heads when they welded the wrist pin to the piston and the crankshaft to the rod when they blew up my brand new Banshee engine? :blah: :(

[chad502ex]

Originally posted by Toadz400
So chad502ex, should I thank the meth-heads when they welded the wrist pin to the piston and the crankshaft to the rod when they blew up my brand new Banshee engine? :blah: :(

who and why would anyone do that?

[86 Quad R]

curious....

what is the rod length/stroke ratio on the pancake piston engines?

also are you guys running rev limiters? if so, what is it set at and do you constantly exceed it?

[Toadz400]

Originally posted by chad502ex
who and why would anyone do that?

I guess when you're on meth and you're riding stolen quads, you really don't care what happens to the engine. My guesses are they ran straight gas in my Banshee and they beat the crap out of it.

[400exrules]

my 99 400ex runs strong, and im almost 100% sure it was never rebuilt. And yes, ive rode it hard. its been kept up with, maintenance wise, and it still runs great.

i will be tearing it apart soon to put in a 416, but it could still run the way it is now for who knows how long.

a friend of mine has a z400 with a 13.5:1 440 piston in it with stock studs, stock crank, etc....and he runs the hell out of it and its never had a problem.
guess part of it is luck

[DieselBoy]

I was just pulling his chain. Honda guy's are overly brand loyal, and it's amusing to push their buttons. On another note, these 450s are getting worse (longetivity/mechanical) every year they make them. But, if all you give a crap about is revving a fourstroke to the moon and rebuilding it all the time then I guess that's the bike for you, but it still baffles me WHY you would want to waste time taking it apart when you could be riding, additionally the cost

[firefighterjosh]

Originally posted by DieselBoy
I was just pulling his chain. Honda guy's are overly brand loyal, and it's amusing to push their buttons. On another note, these 450s are getting worse (longetivity/mechanical) every year they make them. But, if all you give a crap about is revving a fourstroke to the moon and rebuilding it all the time then I guess that's the bike for you, but it still baffles me WHY you would want to waste time taking it apart when you could be riding, additionally the cost

I own both Yamaha and Honda. I love the Yamaha, But Love the Reliability of the 400ex:p

[fandl450r]

Well now it's decision time. Do I take the time rebuild it all, from bottom end up, have everything new, and spend a lot more. Or do I salvage and sell what I can, and buy a motor.

Decisions decisions. This is the time when a streetbike looks better and better.

[1fst400]

I would build it back up again with better parts so hopefully it will last just as long or longer.

how many hours do you think you have had on the motor? Do you ride every day or just once and a while? and do you beat the piss out of it. just curious..

[crazedape]

well Fandl if you ride a streetbike like you ride a quad you will be a stain on the pavement. You are an awesome rider but those streetbikes are a different breed and pavement is not as forgiving as dirt.

[Toadz400]

Originally posted by firefighterjosh
I own both Yamaha and Honda. I love the Yamaha, But Love the Reliability of the 400ex:p

I've had more problems with my Honda than my Yamaha. The only problem I have with my YFZ is that Yamaha uses very cheap bolts.

[fandl450r]

Originally posted by Toadz400
I've had more problems with my Honda than my Yamaha. The only problem I have with my YFZ is that Yamaha uses very cheap bolts.

I had nothing but bad luck with the Yamaha I did own, this is the only problem I've ever had out of the 3 Honda's.

[DieselBoy]

ive also had great luck with my yamahas and not so much with my hondas... I dont hate either manufacturer, I just like the yamahas... good machines.

[N300exJ]

Count me in as another one. Just discoverd today that my rod bearings have takin a crap. Didnt take it apart yet but the oil filter was so clogged with metal shavings the filter actually imploded. I did take off the head cover and my cam isnt fried. I guess i caught this thing early before it locked up on me and did a ton of damage. Only internals are an HRC cam. time to build this thing up good. Not bad for 13 months(ridng at least 10 to 20 hours a week) of hard abuse and racing around in the woods. And yes i changed my oil all the time.

[honda350r]

Anyone who owns a 04/05 450R will experiance this problem if they keep it long enough!

The problem is the left case ,there is no bearing retainer and the bearing walks in the housing.. I have two new left cases on order right now..

I can't keep up with all the honda motors going down.. These new four stroke will be junk when the are 5 years old !! Resale value will be very low on old 450rs for sure ..

[awsomeaussies]

Maybe I'll just keep the ol' 400ex for a while:o 6 years old and zero problems:cool:

[K-Dub]

This thread is making me want to sell my 450R and go back to a 250R. I figured out my gas milage to be 19mpg on an average and have enough gas receits to have over 6000 miles on my 450R. I have done nothing to the engine but change the oil and filter. It had the HRC kit in when I bought it. This thread is making me worry that my engine is ready to go any min. I was thinking about putting a new piston in it this winter. But should I go ahead and change the crank also if I keep it. I bought my 250R 3rd handed in 1993 and raced and rode it for 4 years with the original stock crank and crank bearings and never had a problem, the guy that has it now didnt have to put a crank in it till 01. I put a new piston and rings in it once a year (or when I started losing compression). I can rebuild a 250R top end for under $100 and 35min of my time in the pits at a race, theres no way I can do this to the 450R. Ive never been sold on this high out put 4 strokes (even though I like my 450R) and if there not going to last atleast 4 times longer than a 2 stroke I think Ill go back to the 2 stroke. The reason I bought a 450R over a 250R in the first place was not having 17 year old parts on a quad (frame, brakes etc).

[N300exJ]

You could always just put a 250r engine in your 450r.

[Castor-426ex]

man this sucks im supposed to pick up an 07 r today lol i want sumthin with the reliability of my old 400 bc all i do is woods ride...just curious though and dont mean to sound ignorant did the crf version of this motor have the same problems? im aware of the lousy top end time on the dirtbike version ...i just want to know what kinda crap im gettin into...bc if its gon be the same thing you guys are dealing with...ill just go find a used 05 for a decent price and when i get it ill jerk the motor and go from the crank up...thats better than spending over 6 grand on a quad that will cost me more than that in the longrun....god i hope that made sense lol

[yellow400ex05]

castor i think thew older models are the bad ones the newer ones are more reliable and don't have the issue anymore i belive, but dont quote me on that because i'm about 70% sure.

[Castor-426ex]

i dunno know pappy said sumthin bout the 07s im havin 2nd thoughts:confused: :confused: :confused:

[honda350r]

[QUOTE]Originally posted by K-Dub
[B] I was thinking about putting a new piston in it this winter. But should I go ahead and change the crank also if I keep it.

Yes,and while you are at it replace the left crank case..

[44oEX]

you guys talk about how the engines rev to high and that one of the reasons they blow up...did you ever think that a street bike rev's in the 16000 ( 600cc ) and most don't have any problems?

[Toadz400]

Originally posted by 44oEX
you guys talk about how the engines rev to high and that one of the reasons they blow up...did you ever think that a street bike rev's in the 16000 ( 600cc ) and most don't have any problems?

The pistons are also a lot smaller than a 450 piston. Those engines have a lot more R&D and technology put into them to allow them to rev up to 16k RPM.

honda350r - You keep metioning the left case. How will ordering a new case fix the problem?

[Castor-426ex]

pappy tell me what you know bout the 07's besides the electric start problem

[woodsracer420]

I just pulled my engine out of my 450r today, motor is locked, pretty sure its bad crank bearings. btw its an 05 that had oil changed every 2 rides or every race.

[woodsracer420]

also right before it locked it started make a "whining Noise" from the bottom end

[xrxmxcx]

same thing happened to my friends..

oil squirter for the crank bearing gets clogged, it can happen randomly, and then the bearing goes, it welded the bearing to the rod and seized her up, even cracked the cases

damn honda's

[fandl450r]

Well back on topic. My motor will be getting sent down to Quinn Motorsports for a COMPLETE rebuild. All bearings, seals, tranny gears, everything will be replaced. Stay tuned. :)

[woodsracer420]

just found out it wasnt a crank bearing but its the rod that seized