Shop was rejetting and seized my engine!!??

[GASGAS300HP]

Hey all thank in advance for reading my post. I took my Gas Gas 300 Wild Hp ( 2 Stroke ) quad into a local shop today because I hear rejetting is very necessary with these quads running rich from the factory. They dynoed my quad once and said it was fine; the second run after supposedly only cleaning the air filter my quad siezed/locked up?
I guess I'm at a loss according to the owner but I'm not so sure thats ok with me. My quad had maybe 10-20 hours tops on it; all bone stock. Ran great before It was taken to the shop but it had a tendency to drown out plugs if the fuel or choke was on long before starting. Any suggestions for me on how to deal with the shop or I guess ultimately on ordering new parts to rebuild this? ( I didn't sign any release saying it was ok if something happened if that matters?! ) Ughh I hate this but again thanks for reading!

[MattR]

Sorry to hear your unfortunate luck. I don't have any personal experience with dynos nor the risks potentially associated with them. I do my jetting old school style by ride-and-feel.

Does the shop have any policies for this type of matter? I would think if you brought it to them for the sole purpose of jetting and they seize your engine for "poor jetting" then shame on them. I would think they should stand behind their lack of expertise and correct their mistakes. That's just me talking from an integrity standpoint.

Now if you brought it to them for "only" horsepower/torque dyno runs, then the jetting was your fault and not theirs. So it really depends on the real situation... how you approached them for their services and what the expectations were for the paid services.

As a side note, you indicated that the first run went "fine" according to them. Did they have a fuel:air ratio meter installed during the run? How did they come to this conclusion? This may give you some ground to stand on since you were relying on their expertise. In the end, it still comes down to their shop's policies and their integrity as a shop to stand behind their work.

Worst case scenario... they won't replace any parts and just claim it's your fault. In which case, I would leave and never return to their shop again... nor recommend them to my friends. Most times our lessons learned come at a price. Good luck!

[mountain thumper]

sorry to hear that!
i would definately toll them either make it right or id seek legal council.
im the kind of person that would freak first and go in and threaten the guy with bodily harm... thats why i do all my own work, because you never know when something like that will happen, and i know if anything breaks theres noone to blame but myself, plus im very poor and cant afford professional work

[GASGAS300HP]

Sorry I'm so frustrated and sick to my stomach after today. So he first dyno run was what they called a base dyno run. They did have a air fuel mixture they showed me quickly. I'll get a copy of all this tomorrow; should have today but I was almost at a loss for words. The second run was supposedly after only cleaning my air filter. One thing I learned tonight from talking with dynojet owners and shops dynoing a two stroke you have wind down off the throttle not just drop off dead from a redline hard pull. Letting go of the throttle will seize the engine by cutting off lubrication! Hence 2 stroke; I have video of these guys doing exactly this! Anyway I guess tear down will show evidence. To answer one previous question my quad was none stock sent in for rejetting. Not just for horsepower dyno runs; good point and thanks for your support in the replies.

[SpeedyManiac]

Sounds like the shop should be rebuilding your quad.

[rpduc]

I have never seen the air filter set-up on a quad but... a thought about them cleaning the air filter. Maybe they didn't get it seated properly when they reinstalled it so it was sucking air?? That would make it run lean too no?

[wence]

Surely the air filter was clean before going to the dyno???
Sounds to me as they are looking for excuses.
Make the ba--ards pay I say.
Cheers Mark

[GASGAS300HP]

If interested in helping me build a case or diagnoses here is some video that was taken at the shop; I requested this on each dyno pull and left my camera there. I Hope these links work; I've never used you tube. Funny thing is the videos on my cam corder were only about 45 seconds apart? Seems my 2nd Dyno wasn't recorded?!!

http://www.youtube.com/watch?v=yEX_euuFE_k
http://www.youtube.com/watch?v=Mi2FkJDY1aw

[RBD]

There are two things I see in the video;

1) It does not look like there is enough cooling air passing over the bike. The operators pant legs and long sleeve shirt are not flapping in the breeze (so to speak).

2) I am not real fond of the way the operator would throw power down and then back off with the throttle (looks like he closed the throttle) without pulling the clutch and a little free revving before pulling another load.

In my opinion (and I do not know if they were used or not) when putting a engine on the dyno, you definitely need a EGT, CHT and even a coolant temp monitoring. It is very hard to seize an engine when using these types of gauges. In other words, if you pay attention to these gauges, the operator can stop an engine before it blows up. Again, just my opinion.

Ron

[ferguscawley]

I run my own dyno shop her in Ireland and run a Dynojet 250i dyno. I agree with Rons comments and would like to add some more :

The air/fuel ratio is unlikely to have been the cause of your seizure. There seems to be plenty of 2 stroke smoke from that exhaust, even at full chat. That tells me that the bike was getting plenty of fuel, assuming your premix ratio was not stupidly oily. My guess is ther seizure was due to an over-heating problem. As RBD mentions, there is no sign of cooling fans active during those runs.

Another thing is that the dyno appears to have an inneffective brake. Usually after I do a power run, I hit the brake on the dyno to bring rear wheel speed down immediatley. On a 2 stroke, I pull in the clutch and apply dyno brake and then blip the throttle during the decel to keep the crank & piston cool. The electric brake on the dynojet 250i dyno will bring the 500kg dyno drum/roller from 170 mph to zero in less than 4 seconds. The drum on this particular dyno seems to run on with very little retardation.

Just my 2 cents


Fergus