question on internals

[sahlberg]

Ok, I know how to ride quads and all that but what exactly is in the interals? I know all about car/truck engines.....especially the hemi engine, but i dont know chit about atv engines.

Is it with the smaller engines, 1 piston (combustion chamber) and with the bigger quads, two? I noticed with the 400exs, they can run dual exhaust since they have to exhaust ports. Does that mean that theres 2 combustion chambers? Can you guys just help me out with the basics of it? You don't have to explain how it works, just wondering what the hell is inside these haha. thanks

[450R_lover]

well.. majority of the engines have one piston. some have 4 valves such as the 450r, some have 5 such as a yfz450. Some have DOHC (yfz) some have SOHC (450r). The reason the 400ex has 2 different head pipes coming out of the engine is because of its head design. It has 2 exhaust ports but they are just separate, whereas a 450r head has 2 exhaust ports but they are together so it only requires one header. anything else? :D

[sahlberg]

I think i get it lol. As far as the valves, like you said 4 valves. 2 for air and gas, 2 for exhaust? I'm not 100% sure if everythings the same as cars lol.

And , with the dual exhaust ports, people said running dual exhaust instead of the combined single exhaust messed up the compression. Can you run duals on the 450R safely or is that not possible since you said the exhaust ports were very close. Sorry if i ask stupid/simple questions, i just have to get used to atv engines since i've been mainly learning all about car engines.

[sahlberg]

oh, and what 'exactly' is the 'head'? My friend said he basically got a whole new head on his blaster but i'm not 100% sure whats considered the head. I know it's the top of the engine, but what in there? Sorry, I'm just trying to learn. Thanks

[Flyin-Low]

Alright, a Blaster is COMPLETELY different than a 450r (or any 450 for that matter).

Blaster = 2 stroke
450 = 4 stroke

The 4-stroke engines are the same as a car engine, just image your hemi with 1 piston.

The head is where the ports, valves, cam ect. go on a 4 stroke.

2-strokes don't have valves or a cam or any of that complicated stuff so your buddy just got a new combustion chamber basically.

I dunno, theres tons more... but pretty much the same as a car engine.

-Martin

[sahlberg]

oh, ok. Yeah, i knew his was 2 stroke but never really knew the exact difference between 2 and 4 stroke.

So, a 450R engine is basically my hemi engine, but 1 combustion chamber, 1 spark plug in there, and 2 exhaust ports? Is it possible to run dual exhaust on these?

thanks for the help! i appreciate it.!

[Flyin-Low]

Yep, completely possible.. In fact a company by the name of LTE (looney tuned exhaust) makes a set up for a lot of quads with dual headers running on each side to the back with dual silencers.


-Martin

[450R_lover]

yeah, you can run duals but not "true" duals. There is only one hole for the exhaust ports so the dual exhaust will split into two after it comes out of the head.

[sahlberg]

ohh...ok. But i heard running dual exhaust will screw up your compression. Is this true? I hope its not lol because I really want to get duals, even if it isn't true duals.

[450R_lover]

no, it wont mess with the compression of the engine.