Raptor 125 massive engine failure

[ccdhowell]

My girls had a race yesterday. This would be the second race on the Raptor 125 since I put a new piston and cam in it and I was looking forward to seeing how my daughter adapts to the new power. Got to the track and it wouldn't start. Messed with a little, put a new plug in and it fired up, it's running a little rich with the new Kehein carb.

Anyway, she went out to practice on the track, made a lap and came in to tell me about the track, she was very excited with the new power. When she suited up to go out again I told her to run it hard to see how hard she could push the engine. (Engine had about 5 hours on the new topend so I figured it would be good). Engine locked up about half way through the lap, she walked back and I rode out to recover it. When I got it back to the pits I took the plug out and it had been smashed by something.
http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3193.jpg

I withdrew her from the race and she helped me take pictures while her sisters had the fun.

This morning I took the engine apart and found that exhaust valve head had been broken off, danced around in the chamber punching holes in the piston. The pieces of the piston rained down on the crank and locked it up.
http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3197.jpg

http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3196.jpg

http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3198.jpg

http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3201.jpg

http://i698.photobucket.com/albums/vv342/ccdhowell/Raptor%20125%20engine%20failure%20Aug%2010%202011/IMG_3202.jpg

The head seems fairly dry to me, maybe the oil pump failed to start all this, don't know yet. I fished all the debris from around the crank and it now rolls around just fine. Don't know if I'm gonna split the cases or not, don't want to.

Anybody know how to check the oil pump on these engines? The plastic gear on the oil pump isn't broken & has no missing teeth.

So our next race in in six weeks, hopefully I can have this engine rebuilt with maybe some more power by then.

On more thing for those using the Procom rev box, I had turned it up to setting #9, which is max timing advance and no rpm limit...that may have been the real culprit here.

[Logan #34's Dad]

WOW! That hurts. I'm not a 4 stroke guy yet but, I'd say the unlimited rpm thing could be the issue. I'd bet those valves are not able to handle that type of abuse. Does anyone make them out of Titanium yet?
I'd never run a fourstroke without a rev limit.....

[jweidner]

Wow CCDhowell !

That doesn't look good, I am working on an xc raptor 125 right now that looks to of over heated and has crank damage, but this needs to run this weekend.

You mentioned setting nine with no rev limiter.... thinking exhaust valve hit the piston. There isn't much installed spring pressure on these quads. I am running setting 5.

I do have a spare head and valves if you can't find them. May have a cylinder... Let me know.

Being the connecting rod doesn't look to be purple from heat, I would say oil pump is fine. The cases should be split just to be sure everything is clean.. hate to see failure once motor is together.

Let me know,
Thanks,
Jason

[ccdhowell]

Thanks Jason, I'm working under the premise that TTR125 heads will work just fine, I think they're identical for all practical purposes, and the cylinder too. Heads can be found for the TTR easily and for not too much. The bore has a couple nice scores in it, I may go with a Kitaco 150cc kit. A little reluctant since it would mean that I'm a rule breaker in our two race series, but seriously I don't think we'd still be able to catch the fast Apexes and nobodies gonna protest and put up the money in a kids class. I am torn as to what to do tho.

Good call on the color of the rod, it didn't get hot, but the head is drier than it should be I think. I've only had it off the one time to put the piston and cam in it and I think I remember the cam area having a good little bit of oil being there.

You know the lack of valve spring pressure is kinda scary and I should have known better than to run on the unlimited rpm setting. It was actually tricky setting the valve lash, I kept compressing the valve spring. Looking to upgrade those for sure when I go back together.

[jweidner]

No Problem..

[jweidner]

Thinking... TTR 125 Top end is the same, however the crankshaft assembly is a little different.

My series does not allow me to run anything above 125CC, however with the right combo they can keep up with the apex.

Be sure when putting back together that oil passage going to top eng is clear of restrictions, works like the trx 90.

First week of October I will have 12:1 comp pistons with skirt coating available in 54mm and 54.5mm. Check out R&D spring..they have TTR retainers and springs.

[ccdhowell]

I'd be interested in a 12:1 piston if you can bore the cylinder also.

I know you were developing the 125, can you port heads and install bigger, better valves too?

[Ryko racing]

I think the problem is in the lack of a rev limiter. When things start floating around bad things happen.

[chunky0071]

Originally posted by Ryko racing
I think the problem is in the lack of a rev limiter. When things start floating around bad things happen.

With stock compression and cam these motors have a hard time over revving but with piston and cam they will over rev ans go down hard. You can have that cylinder plated and repaired witch would also help with heat.

[Coley'sdad#8]

what you have there is a classic textbook ole fashioned valvetrain float just like Ryco said, motor overreved (probably in the air) spring hat floated, keepers flew away, the valve made a run for the border but was intercepted by the warden aka El piston and within about the time it takes a gnat to blink you have a wonderful , expensive collection of conversation pieces you will keep for years and show to your friends. These pieces are also going to be referred to as a "smartnin lesson":rolleyes:

lightweight / stock valvetrain components will NOT handle the option to go unlimited rev that's why it came with a rev limiter from the factory (and be sure to put the stock rev limiter in with the conversation pieces box) lol, get good rev springs, hats, retainers, guides and timing chain.
oil flow / I am not for sure on these engine's but find out how to increase passage sizes to moving components like on other engines i.e. hondies.
If you don't like the looks of this kind of failure there are other options like building an engine with a lower rpm power curve which is much easier on them and your wallet, there are just way too many moving parts in a 4 smoke to be winging up glass breaking rpm's with. A 4 stroke with a nice bottom , hard hitting mid range to middle upper range is much easier for your pilot to ride when they might come out of a corner in a wrong gear so they don't have to feather clutch and heat it up cause thats where you will be next.:D

[T@AFP]

Man, I hate to see this.
I am at the begining of building 2 raptor 125 for the GNCC and the engine is at the top of my list. (Actually 2nd, but the suspension is finished)
I have spoken with several motor builders and haven't pulled the trigger on who to send them to. Due to lack of experience with the Raptor 125's. However, they have all built 250's.

Do you suggest heavier springs to reduce the possibilities of floating the valves?

Keep us posted on this please.

Thanks,
Tom

[Ride1Rob]

Originally posted by Logan #34's Dad
WOW! That hurts. I'm not a 4 stroke guy yet but, I'd say the unlimited rpm thing could be the issue. I'd bet those valves are not able to handle that type of abuse. Does anyone make them out of Titanium yet?
I'd never run a fourstroke without a rev limit.....

What he said! You can't run the fourstroke motors with no rev limiter on them like you can the 2strokes. They'll catapult which is exactly what happened here. Definitely going to be a costly repair. OUCH!

[Ride1Rob]

Originally posted by T@AFP
Man, I hate to see this.
I am at the begining of building 2 raptor 125 for the GNCC and the engine is at the top of my list. (Actually 2nd, but the suspension is finished)
I have spoken with several motor builders and haven't pulled the trigger on who to send them to. Due to lack of experience with the Raptor 125's. However, they have all built 250's.

Do you suggest heavier springs to reduce the possibilities of floating the valves?

Keep us posted on this please.

Thanks,
Tom


Tom, from what I can gather these motors are pretty much untested in terms of building them into firebreathers. The stiffer springs will definitely help with valve float but it could also be an issue with too much tension if there's not a common ground found somewhere in between. Hopefully there are a few options in springs.

[jweidner]

Hi CCDHowell,

I offer a wide rage of motor combinations for the Raptor 125. I'm currently building 125cc Raptor engines for my nephew who runs XC racing in PA.

I am able to do everything ranging from standard case split, check clearence on everything and assemble to complete blue print and balance.

Head work varys depending on what type of racing your doing. MX style head will tend to have a different port profile than cross country.

I race what I build so I know what works! PM me

Don't worry about the rev limiter, I NEVER ran a rev limiter on a trx 90 and NEVER broke anything, If this is the biggest problem you'll have.... your doing good.

ALthough the motor looks bad in the pictures, parts are reasonable in price... atleast it wasn't a kitaco 125CC honda engine.

Thanks,

[Ride1Rob]

Yeah, but that Honda engine is way more advanced in terms of a racing blue print. Not so much on these Raptors. It's trial and error until someone figures out how big/bad they can be built and what their tolerance levels are. Even on the Kitaco heads they have to be setup properly to withstand high output rev limiters. And you're speaking thousands of dollars in parts differences between the two :ermm:

[ccdhowell]

After some careful conversation with my daughter it became obvious how she grenaded the engine. She was in third gear pinned on a short straight and kicked it down into second to slow for the corner. It overrevved...end of story.

There were 19 Raptor 125s at the John Penton when I went there in July. Seems to me it is the XC quad of the future and that the aftermarket will catch the drift and develop parts for them. Heck on an XC track they're very competitive with mildy built engines and good suspensions anyway. It's the way to go and this is just a small setback for us at the moment.

[ccdhowell]

Originally posted by T@AFP
Man, I hate to see this.
I am at the begining of building 2 raptor 125 for the GNCC and the engine is at the top of my list. (Actually 2nd, but the suspension is finished)
I have spoken with several motor builders and haven't pulled the trigger on who to send them to. Due to lack of experience with the Raptor 125's. However, they have all built 250's.

Do you suggest heavier springs to reduce the possibilities of floating the valves?

Keep us posted on this please.

Thanks,
Tom

Tom, I think jweidner is out front of most on these engines. Seems to me that he's done some work with them with good results. He's be the one to ask those questions and maybe do your engines. I'm working with him to help get mine back together.

[jweidner]

Hi Ride1rob,

I will have to disagree with the trx 90 motor being more advance than the Raptor.

1.Both motors bore,stroke and rod length the same.

2.Both use a typical over head cam rocker arm assembly.

3.Both use a hemi style combustion chamber (old school, no high tech design here)

4. Both have the same lubrication design

...The only item in the honda head that is different than the raptor 125 is dual springs in the honda for more valve seat pressure. (This can be accomplished on the raptor for under $200)

My point is that both motors are very similar, the honda has been out for 20 or more years so of coures there will be more parts available, but please don't think that the raptor can't achieve the same results the honda has..

Thanks,

[Ride1Rob]

I was saying that the Honda engine is more advanced due to more R&D over the years. Therefore, it is a better engine performance wise than the Raptor. There are wayyy more performance parts available for the Honda where there isn't for the Yamaha. Don't think there's a $500/$600 head available for the Raptor just yet. It's going to take some time for the Raptor to catch up.

[jweidner]

I know what your saying ride1rob....If I only worked for Kitaco.
You are certainly right, the honda has been out for a long time and this is why there are so many parts available.

I hope these quads hang around for a while, can do so much more with the chassis than you can the trx.

Thanks,
Jason

[Christiansdad]

Stick with stainless steel valve's and duel springs. That looks like my crf 250 at one time. My exhaust valves are stainless and intake are titanium.(they were titanium) Titanium valves are to much money and not worth the performance. It cost me around 400 bucks including the intake valves to fix just the head..not including the top end kit:( But if you has the doe and wana show 2 strokes up call "PRO CIRCUIT" racing up. They are pretty much the best when it comes to anything...thats what seperates the boys from the men plus daddy's wallet:eek:

[T@AFP]

Jason
PM sent

[Ryko racing]

I dont run a Raptor but i have heard from a relible source that for that motor RAGE has done their homework.

[jlhughes750]

Originally posted by Ryko racing
I dont run a Raptor but i have heard from a relible source that for that motor RAGE has done their homework.

Yes.