Engine trashed from Glamis sand (pics)

deej: the yamaha racing 4-strokes have a 5 valve design. Their R-series street bikes and also snowmobiles use this design. Not sure if any other manufacturers use more than 4 valves.

Never had any problem running the STOCK air filter in sand. Bummer.

HOLY HELL :applause:

The breather hose would not let sand into the cylinder/exhaust.....

I cant believe how much sand is in there!!!



I agree, the oil is pretty clean, no sand. Also from looking closely at the piston today, it shows lots of small pits, like it was sandblasted. Also the rings are stuck in their grooves from sand. I'm certain it ingested the sand through the intake.

no way the bike sucked in that amount of sand , i think the sand in the exhaust pipe got there when you fell.

it defenitly sucked the sand in through the intake side .it would not take much sand to do that damage .

i would look at the airbox, air filter side off things

I think what is important now is getting your bike fixed, not how the sand got there. Knowing won't change anything. But it would still be nice to know. Maybe you could see what people think at a Glamis only message board; more people with experience with things like this :applause:

I've only been to Glamis once, but I ride in deep sand daily and I"ve never seen anything like that.

The circumstances of the, um, get-off he had etc. and what happened to the bike in the interim before they retrieved it just leave too many unanswerable questions.

Based on my own experience I think that riding your dirt bike in sand isn't more inherently damaging to your motorcycle's components than a nice dose of silty mud. In fact, I'd rate the sand as harmless in comparison.

Obviously, decidiing whether or not to ride your dirt bike at Glamis shouldn't even remotely hinge on whether you think sand is bad for your bike. Dune jumping is exhilirating but dangerous, and even if you are on your game it seems that all the bad accidents involve collisions w/ unseen traffic.

IMO anybody who would ride around on a bike or quad at night on a wknd in Glamis is asking for a helicopter ride. If you are jumping make sure there are reliable spotters on hand........

I think what is important now is getting your bike fixed, not how the sand got there. Knowing won't change anything.:applause:

On the contrary.

Priority is to know how sand can get inside like that, in order to prevent it from happening again.

its looks like there are worms on the top-right valve groove on top of the piston

How About The Fuel Tank?cracked Or Someone A Joker?do You Run A Fuel Filter?no Way The Filter And Carb Passed That Much Sand.2 Smokers Are Less Sensitive To Dirt Than A Thumper And I've Never Even Seen A 2smoke Come Near That Much Dirt Internally.

If the motor happens to make 1 revolution in reverse direct, the exhaust will act like the intake and suck air and whatnot in threw the pipe. We all know to well that 4-strokes kick back in reverse direct sometimes just by kick starting them, let alone in a crash where the RPMs may be up a bit. My guess is when you crashed, your tail pipe was in the sand just as the engine died and it kicked back sucking in the sand. Your friends trying to start it is the reason the sand in the pipe was saturated in gas, and it would only take a couple of engine fires to embed the sand into the carbon deposits. Why is it in the carb slide?, because it was pushed in there when the intake valves were acting like exhaust valves and pushed it in :applause:

Sounds like you took a pretty rough tumble. I don't know about you, but when I tumble like that I get dirt or sand every where, same for the bike. I think you could have gotten sand in the pipe as well as in the air box, and if your carb slipped at all or the boot's were loose on either side you could have gotten sand in there as well. Hope you can find the parts you need on here or ebay and you are back riding soon.

Are you sure the sand didn't blow in the exhaust pipe and then through the open exhaust valves? (or maybe sucked in when you went start it)?

On my last trip to Glamis, the wind was blowing very hard, causing a transparent but visible wall of sand 6 to 8 feet off the ground (everywhere). I was concerned about the exhaust pipe filling with sand, so I turned the exhaust end away from the wind and put a rubber plug in it.

How was the wind on that weekend?

Good point about blowing wind, yes Sunday when we picked up the bike it was pretty nasty (blowing sand). I'm stumped as to how it got so far up the exhaust, it was all in the header, almost none in the silencer. Like I said before, I'm certain it ran with sand in it, who knows when, whoever just said it may have run backwards for a moment sucking in sand and blowing it through out the intake. Interesting point, I never thought of that, I'm sure it was possible as the bike went end over end down the razorback its exhaust became plugged with sand. As far as sand in the tank, I'm running a inline fuel filter and no sand in it. Anyhow I just pulled the eng out yesterday and am preping the frame to paint it black. It's going to get the yellow Hurricane kit and I decided on ordering the 426 rod, piston and cylinder. I figure the best way out of this mess is to make my bike even better in the end. I'll be sure to post pics in a month or so and let you guys know how it goes from here. Matt

deej: the yamaha racing 4-strokes have a 5 valve design. Their R-series street bikes and also snowmobiles use this design. Not sure if any other manufacturers use more than 4 valves.

Hey thanks for the post, so is it 3 intake and 2 exhaust? What is the reason for this design?


i have ridden in glamis for 3+ years and now im migrating out to dumont... I have NEVER EVER seen a motor look like that due to sand... now you make me want to take mine apart just to be sure... there is definatley something wrong...

Also I've been kicking around the thought of boring out to 420, anyone done this with good results?


Eric Gorr did my 400.

You have two options:

go with the stock crank and con-rod and 420 kit (what I did)


426 crank assembly, cylinder and piston.

The 400 uses a smaller piston pin.

With the damage, I would really suspect bad crank bearings. IF I was to keep the bike, I'd go w/ the 426 setup.

You have to decide if the $$ is worth it for a bike this old...(???)

I'd have to say the wind filled the bike. Just like a beer bottle in the dunes. If it was on it's side with a good wind on the downside of a razorback, it wouldn't take much time to fill that much sand in the motor. We've all seen the dunes go from chewed up to pristine within one hour of a good wind.

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