Any guesses on the problem.... TRX520R

[416exmx]

Well the motor on my 520R let loose today. Im getting ready to go tear her down and see what happened. Any guesses as to what happened? It is an 05 bottom end and the complete top had 6-7hrs MAX. Ill post back with what happened. n-Motion themselfs built the motor.

nMotion 520cc Kit
Oversized Valves
Cam
Adjustable Cam Gear
Head Porting
Heavy Duty Valve Springs
41mm FCR Carb
DynaFS Ignition

[GPracer2500]

I'll guess rod bearing failure.

Did it grind to a halt, go BANG, suddenly loose power, or...?

[kazpr]

Originally posted by 416exmx
[B]N-Motion themselfs built the motor.
Ya I live not to far from Nmotion and the 2 poeple that had racing for them kept blowing the 450r motors up then they switched them to yamaha. Please post what you find I am very curious about this!

[416exmx]

It made a "thud" and locked tight.
Trashed all the valves, head, piston and cylinder. I figured it was the rod but it was ok. The crank seems to be ok but may feel a little rough(bearings). I dont think it jumped time either so I am still a little stumped on what caused it. I had just shifted from 2nd to 3rd and got on it (not hard really) and that was it. I let it warm up good and everything also. Here are a few pics.

[416exmx]

head

[416exmx]

....

[exrider008]

HOLY CHIT that head look really bad...did u call Nmotion?:eek2:

[ThumPIN_450R]

Are the oversize valves Nmotion installed titanium and what type of fuel were you using? Leaded fuel and titanium valves aren't a good combonation.

[450RRyder]

what type of gas werew you running because me buddy had the same thing happen to him.

[416exmx]

VP fuel

[GPracer2500]

Yikes. That's ugly.

Boy, it's hard to imagine how that could have happened without it jumping time [shrug]. I mean, how else could the ALL the valves come into contact with the piston? I suppose a serious case of valve float or broken valve keepers would do it...but all the valves at once?

Keep us posted.

[TURBO-530R]

What Cam?

[kazpr]

Guess it was the nmotion cam a custom grind they use.

[DieselBoy]

Holy @#$%.

[R3Concepts]

Thats NMotion for ya.

Some more details would get us closer to telling you why it did it.

Got any pictures of the thrust side of the jug? Are there any forced oilers for the wrist pin on the piston? If not, that will lock up and brake the thrust side of the jug, and ultimately do excatly what that did to your head.

It also looks like it may have dropped a valve, and thats a train reaction.

[chad502ex]

Thats NMotion for ya.

It seems that a clay check for P-V clearances was not performed to verify proper clearances.

From the photos, it appears that the first to snap was the intake valve head causing the remaining to break when the intake head was flopping around the cylinder. From the intake rub on the piston it looked to me that there was to much advance in the cam, or a cam with a lot of overlap. A few degrees retarded on the cam may have prevented the intake from contacting the piston while the piston moves to TDC.


One other observation is that there was serious removal of material in the combustion chamber to unshroud the valves. IMO; way too much.


Sorry for your luck. I'll upload a few of your pictures again to illustrate my meanings.

[chad502ex]

ONE OTHER POINT:

DO NOT TRUST THAT YOUR BOTTOM END ROD AND CRANK ARE SAFE AND UNHARMED. at least send it out to be balanced and verifiied before building again.

[chad502ex]

clue3.

sorry for my spelling errors today ppl.

[GPracer2500]

Boy, with only 6 or 7 hours on it it's hard to imagine how the engine builder could do anything but pony-up for repairs. Now, if the engine had 100 hours on it that might muddy the waters a little [shrug].

What is the expectation on hopped-up engine builds anyway? I mean, if I have a builder put together a 60+ hp YFZ/TRX/LTR, what's the expectation? Where does the builder's responsibilty begin and end? Certainly at some point (well after 7 hours, I've got to believe) the customer is on there own dime.

Is it normal to have a conversation witht the builder during the planning phase about "what if" failure scenarios? Seems like without that the customer is only left with the builder's unspoken stand-behindedness of their work.

If there is any silver lining, maybe it's that this builder will learn from the failure and improve their product. Maybe it's a stretch to call that a silver lining, but it might keep the same thing from happening to some other unsuspecting customer.

ETA: I picked a 60+ hp build randomly. If anyone has any comments feel free to modify that example to whatever suits you.

[chad502ex]

Originally posted by GPracer2500
Boy, with only 6 or 7 hours on it it's hard to imagine how the engine builder could do anything but pony-up for repairs. Now, if the engine had 100 hours on it that might muddy the waters a little [shrug].

What is the expectation on hopped-up engine builds anyway? I mean, if I have a builder put together a 60+ hp YFZ/TRX/LTR, what's the expectation? Where does the builder's responsibilty begin and end? Certainly at some point (well after 7 hours, I've got to believe) the customer is on there own dime.

Is it normal to have a conversation witht the builder during the planning phase about "what if" failure scenarios? Seems like without that the customer is only left with the builder's unspoken stand-behindedness of their work.

If there is any silver lining, maybe it's that this builder will learn from the failure and improve their product. Maybe it's a stretch to call that a silver lining, but it might keep the same thing from happening to some other unsuspecting customer.

ETA: I picked a 60+ hp build randomly. If anyone has any comments feel free to modify that example to whatever suits you.

are you suggesting an engine builder should warranty a 60hp setup and all its parts after it leaves the shop? name one that does!

[GPracer2500]

Originally posted by chad502ex
are you suggesting an engine builder should warranty a 60hp setup and all its parts after it leaves the shop? name one that does!

No. I'm certainly not suggesting that! lol

I guess I'm just wondering if it's reasonable to expect the builder of 416exmx's engine to be responsible. Your analysis of the damage seemed to suggest that a mistake may have been made during the build. Did I misinterpret that?

[kazpr]

From what I have heard they were building alot of trx motors for the TQRA and they were all trashed.

[chad502ex]

Originally posted by GPracer2500
No. I'm certainly not suggesting that! lol

I guess I'm just wondering if it's reasonable to expect the builder of 416exmx's engine to be responsible. Your analysis of the damage seemed to suggest that a mistake may have been made during the build. Did I misinterpret that?

416's are poballyone of the most relible bulds for 400 (is the 416), as the 520 should have been too.

Personally I think the NMotion cylinder casting is awesome. I'm not saying that I'm fond of their porting or pistons though. I think this failure was due to cam timing, agressive can profile, and incorrect fly cutout depth on the piston. One thing most forget is that a bigger bore piston has more wobble than a smaller bore setup; so, P-V needs to be a tad bigger than what most think or BOOM!

[R3Concepts]

Id be willing to go out on a limb and say that bike did not make 60 before it blew up. NMotion even on there own dyno falls short of there "HP claims to fame"

[416exmx]

I myself never touched this motor. It was built by brit mansell and atv scene as a project quad and n-Motion did all their work in their shop and helped tune it a few times at the races. brit put probably 5 hrs on the bike and i had put maybe 2hrs (most of which was just playin around). The cam gear was tight so it didnt move. The chain was tight so i shouldnt have jumped. I however have not taken the side cover and flywheel off yet to inspect any further. Here is the kicker though. My buddys 06 YFZ was settin the same shop this one was and they had been settin together for the last 2 weeks. I rode mine probably 3-4minutes yesterday before this happened. My buddy got on his YFZ tonight and after 3-4mins of riding, his locked tighter hell. HMMMMM. We just put a piston in his and he had about 2hrs on it before this happened. I will tear mine down further and take more pics of the parts. I've been busy partyin so maybe tomorrow i'll get to it.

[NmotionBeanCntr]

Originally posted by 416exmx
I myself never touched this motor. It was built by brit mansell and atv scene as a project quad and n-Motion did all their work in their shop and helped tune it a few times at the races. brit put probably 5 hrs on the bike and i had put maybe 2hrs (most of which was just playin around). The cam gear was tight so it didnt move. The chain was tight so i shouldnt have jumped. I however have not taken the side cover and flywheel off yet to inspect any further. Here is the kicker though. My buddys 06 YFZ was settin the same shop this one was and they had been settin together for the last 2 weeks. I rode mine probably 3-4minutes yesterday before this happened. My buddy got on his YFZ tonight and after 3-4mins of riding, his locked tighter hell. HMMMMM. We just put a piston in his and he had about 2hrs on it before this happened. I will tear mine down further and take more pics of the parts. I've been busy partyin so maybe tomorrow i'll get to it.

I was reading through this post to see what should be passed along to the guys. Kevin here told me to pass on the fact that this engine was built by Brit Mansell, et al and NOT by NMotion. We did jet it for him, but that's all we did.

Edit: We did adjust the valves, but that was over a year ago at Loretta Lynn's, and at that time, the valve clearance was checked and passed muster. As we understand it, the motor has been rebuilt since then by someone else. Also, we do not have a custom cam grind.

[chad502ex]

Originally posted by NmotionBeanCntr
I was reading through this post to see what should be passed along to the guys. Kevin here told me to pass on the fact that this engine was built by Brit Mansell, et al and NOT by NMotion. We did jet it for him, but that's all we did.

Edit: We did adjust the valves, but that was over a year ago at Loretta Lynn's, and at that time, the valve clearance was checked and passed muster. As we understand it, the motor has been rebuilt since then by someone else. Also, we do not have a custom cam grind.

what is your first name, just wondering? Is john still there?

[NmotionBeanCntr]

Originally posted by chad502ex
what is your first name, just wondering? Is john still there?

I'm Frank, and yes, John is still here. As the bookkeeper here, (since we have so few beans to actually count), I get a few minutes every now and again to check on the forums.

[Prey]

chad, great info as always


just thought i would add the picks of my nmotion motor here (not trying to suggest they are at fault), i bought this bike from a member of this board who bought it from one of the nmotion sponsored riders, i had just replaced the piston, and was running the 208/921 can. there we some lessons learned here for me, unfortunately after the dropped valve, one of the big lessons being interaval the springs needed to be changed :(.





http://i27.photobucket.com/albums/c156/kstanka/DSC00907.jpg


http://i27.photobucket.com/albums/c156/kstanka/DSC00906.jpg


http://i27.photobucket.com/albums/c156/kstanka/DSC00908.jpg

[chad502ex]

Originally posted by Prey
chad, great info as always


just thought i would add the picks of my nmotion motor here (not trying to suggest they are at fault), i bought this bike from a member of this board who bought it from one of the nmotion sponsored riders, i had just replaced the piston, and was running the 208/921 can. there we some lessons learned here for me, unfortunately after the dropped valve, one of the big lessons being interaval the springs needed to be changed :(.



sorry for this unfortunate event.

get her back running soon :(

208/921 was installed on new springs? was the intake followers oversized? how long do you estimate the use of that cam on those springs?

[Prey]

Originally posted by chad502ex
sorry for this unfortunate event.

get her back running soon :(

208/921 was installed on new springs? was the intake followers oversized? how long do you estimate the use of that cam on those springs?

nope, the springs were old (that is where i am accepting blame for it, when i replaced the piston, i should have checked the valves and replaced the springs) the intake were oversized.

as far as time on it, it was bryce simons 04 race bike, i bought and put another 30 motos on it (i am adding some to include practice time) so i dont really have a good estimate of how much time was on it (one of the reasons i mentioned above that i was not trying to lay the blame on nmotion)

weekend after next i am taking it to PA to have a P&P sparks head (with KW springs and valves, i may ask him to put stock springs in it) 06 crf cam, 12:1 piston and new cylinder. hopefully it will be the mx power i am looking for but with the durability i am looking for as well.


this winter if you have the time, i was hoping to send my 06 head to you with emphasis on really smooth upper 40's type power for XC racing if that is something you would be interested in

[416exmx]

Originally posted by NmotionBeanCntr
I was reading through this post to see what should be passed along to the guys. Kevin here told me to pass on the fact that this engine was built by Brit Mansell, et al and NOT by NMotion. We did jet it for him, but that's all we did.

Edit: We did adjust the valves, but that was over a year ago at Loretta Lynn's, and at that time, the valve clearance was checked and passed muster. As we understand it, the motor has been rebuilt since then by someone else. Also, we do not have a custom cam grind.



After talking to one of you guys I got the story straight. I have not posted back since really, but yes I now know that you guys didnt build it. I was just going by what I was told when I bought the quad from Brit. It appears that he was the one with misleading information. He claimed the quad only had 5hrs on it also. I however do really appreciate the nMotion guys taking the time to talk with me(dont remember who I spoke with on the phone).

It just goes to show what buying off the internet gets ya. I myself have NEVER sold a quad and mislead the buyer, and the buyer has ALWAYS said "wow this looks way better than I ever thought it would". When I buy quads off the internet I am always sayin "wow not quite what I was expecting".

[Prey]

just to specify, when i bought the bike it had the valve train and cam, i never changed anything, just the piston. when i was putting it back together i did check clearances IAW with the manual which were fine.

[chad502ex]

Originally posted by Prey
nope, the springs were old (that is where i am accepting blame for it, when i replaced the piston, i should have checked the valves and replaced the springs) the intake were oversized.

as far as time on it, it was bryce simons 04 race bike, i bought and put another 30 motos on it (i am adding some to include practice time) so i dont really have a good estimate of how much time was on it (one of the reasons i mentioned above that i was not trying to lay the blame on nmotion)

weekend after next i am taking it to PA to have a P&P sparks head (with KW springs and valves, i may ask him to put stock springs in it) 06 crf cam, 12:1 piston and new cylinder. hopefully it will be the mx power i am looking for but with the durability i am looking for as well.


this winter if you have the time, i was hoping to send my 06 head to you with emphasis on really smooth upper 40's type power for XC racing if that is something you would be interested in

just give me a shout when your ready.