Downshifting a 2 stroke

[Speed Wobbs]

I just recently got my first 2 stroke, a Cr250. As iv been watching youtube videos and such people always say in the comments "dont engine brake, youll blow it up." Am i downshifting wrong? I pull the clutch in, blip the throttle and downshift at the same time. What do they mean by engine braking? Just coasting? Or not bliping the throttle or what. I know its probably a dumb question but someone please tell me how to ride my dirtbike!!! lol thanks

Edited June 9, 2017 by Speed Wobbs

[TheKX500boi]

Some people are so stupid. You're downshifting perfectly fine. Some people say if you're going down a hill for example and the throttle is closed the engine wheel will spin end up spinning the engine and then it'll seize from lack of oil. Biggest load of bull I've ever heard just ride it. 

[Kompact]

21 minutes ago, Speed Wobbs said:

I pull the clutch in, blip the throttle and downshift at the same time.

?

[91kdx25088]

5 minutes ago, TheKX500boi said:

Some people are so stupid. You're downshifting perfectly fine. Some people say if you're going down a hill for example and the throttle is closed the engine wheel will spin end up spinning the engine and then it'll seize from lack of oil. Biggest load of bull I've ever heard just ride it. 

if your not jetted right it will happen. engine braking is when the clutch is released and your throttle is closed, while your moving of course. your engine is spinning faster than its being fed gas/oil, that's a very real issue. if your engine is spinning at 10,000 rpm and your throttle is closed, your only feeding the engine an idle amount of gas, your going to have issues. Its probably among the top several reasons two strokes blow up.

Edited June 9, 2017 by 91kdx25088

[TheKX500boi]

9 minutes ago, 91kdx25088 said:

if your not jetted right it will happen. engine braking is when the clutch is released and your throttle is closed, while your moving of course. your engine is spinning faster than its being fed gas/oil, that's a very real issue. if your engine is spinning at 10,000 rpm and your throttle is closed, your only feeding the engine an idle amount of gas, your going to have issues. Its probably among the top several reasons two strokes blow up.

Nah there's still oil/gas mixture left in the crankcase when you close the throttle thats plenty enough to keep everything moved. Although if you were coasting down a massive hill for example and the engine was redlining with the throttle closed you might have a problem.

[91kdx25088]

Just now, TheKX500boi said:

Nah there's still oil/gas mixture left in the crankcase when you close the throttle thats plenty enough to keep everything moved. Although if you were coasting down a massive hill for example and the engine was redlining with the throttle closed you might have a problem.

correct jetting has a huge factor on this.

[BushPig]

2 hours ago, Speed Wobbs said:

I just recently got my first 2 stroke, a Cr250. As iv been watching youtube videos and such people always say in the comments "dont engine brake, youll blow it up." Am i downshifting wrong? I pull the clutch in, blip the throttle and downshift at the same time. What do they mean by engine braking? Just coasting? Or not bliping the throttle or what. I know its probably a dumb question but someone please tell me how to ride my dirtbike!!! lol thanks

I engine brake all the time with my 2t bikes, obviously it doesnt work as well as a fourstroke and needs to be supplemented but it makes a difference. It means using the engine to slow you down.

As for coasting, you're jetted on the very edge if your bike nips up after a straight from chopping the throttle. Oil falls out of the fuel as the fuel atomises. It sits in the bottom of the crankcase like a sump (to a lesser degree obviously). Hence you are not " instantly cutting" the oil supply when you close off the main/needle.

[BushPig]

If it's lean it will sieze. Could sieze anywhere. 

[Pigsfly]

Only one way to ride ,WOT.

 

the end

[HappyAndy]

This is a non issue on a healthy well jetted 2t. You don't want to engine brake all the way down a mountain, but for ordinary situations it's no problem at all. If it were the manufacturers would be making all 2ts oil injected. 

I did once melt a piston ring after engine braking, but there were other circumstances: no one knows how old that top end was, there was a double down shift from WOT, it was an air cooled KDX and the fins were packed with mud, when I rebuilt it I found the carb float level was off by a lot. That engine was in trouble no matter how I ran it.

[motrock93b]

You don't need the clutch to downshift. Just close the throttle, use both brakes normally and press down on the gearshift lever to engage lower gears as needed. By doing it this way, you'll hear your engine speed and can have it in the right gear for acceleration. This technique will give you a bit of ABS type engine braking as well. It's a very common technique.

Have fun with that cool Smoker!

[turbo dan]

You're much more likely to seize running it with the throttle cracked at 10000 RPM in top gear.  Small bores are especially prone to this.  With stock gearing they'll run all day at top speed in top gear with the throttle just cracked open.  That'll burn 'em down every time. 

Engine braking is nothing.  Unless you somehow engine brake all the way down the back of a mountain or something, but even then the engine in generating no heat, moving almost no air and still getting lube from the pilot circuit.  I've had bikes that loaded up if you coasted down too long.

[CDNSXV]

There is no need to use the clutch on a dirtbike and unless you are running really high rpm, there is no need to blip the throttle.  

[turbo dan]

13 minutes ago, CDNSXV said:

There is no need to use the clutch on a dirtbike and unless you are running really high rpm, there is no need to blip the throttle.  

No clutch shifting will hammer grooves into your clutch hub and basket.  Its not great for the gearbox either.  Shifting under load increases the chance of mis-shifts where the dogs engage only partially and slip back out again.  That'll round off the dogs eventually and make the transmission more prone to false neutrals and popping out of gear.

You can sneak shifts in when the tire is off the ground without the clutch.  That's not a big deal.  It is best practices to shift with the clutch under power though.

[Motox367]

25 minutes ago, turbo dan said:

No clutch shifting will hammer grooves into your clutch hub and basket.  Its not great for the gearbox either.  Shifting under load increases the chance of mis-shifts where the dogs engage only partially and slip back out again.  That'll round off the dogs eventually and make the transmission more prone to false neutrals and popping out of gear.

You can sneak shifts in when the tire is off the ground without the clutch.  That's not a big deal.  It is best practices to shift with the clutch under power though.

Absolutely agree man? and personally have done all that 4 times to yz250's.  But I do slip clutch under wide open upshifts of any kind. I try not to abuse the tranny in my transition to 450s. dont ride as hard now tho helps. but unless op is going down 2 mile hill he should be ok for coasting id say 

Edited June 10, 2017 by Motox367

[BushPig]

On 6/11/2017 at 3:45 AM, turbo dan said:

No clutch shifting will hammer grooves into your clutch hub and basket.  Its not great for the gearbox either.  Shifting under load increases the chance of mis-shifts where the dogs engage only partially and slip back out again.  That'll round off the dogs eventually and make the transmission more prone to false neutrals and popping out of gear.

You can sneak shifts in when the tire is off the ground without the clutch.  That's not a big deal.  It is best practices to shift with the clutch under power though.

 

On 6/11/2017 at 4:10 AM, Motox367 said:

Absolutely agree man? and personally have done all that 4 times to yz250's.  But I do slip clutch under wide open upshifts of any kind. I try not to abuse the tranny in my transition to 450s. dont ride as hard now tho helps. but unless op is going down 2 mile hill he should be ok for coasting id say 

Agree entirely. 

I'll clutch unless its a critical section, even then I will back off, why not allow everything to unload nicely and just slide together rather than forcing it, you dont wanna dry dog your bike's box do ya?? FWIW, my bikes wont go into gear unless I back off and allow everything to unload, dunno what CDN is going on about.

 

[motrock93b]

Here's what a Pro has to say about it.

[MiWiAu]

I just took Shane Watts' Dirtwise 2-day course two weekends ago. He's an advocate of no clutch upshifting or downshifting. He does his upshifts WOT (power shift).

 

I JUST started riding dirt bikes, but have a lot of prior [paved] track day experience.

 

During the Dirtwise class, I was having a hell of a time getting my timing correct for braking, downshifting, and transitioning from standing to sitting for tight turns.

 

I reluctantly tried clutchless downshifting and couldn't believe how smooth and benign it was. I'm sold on clutchless downshifting (in the dirt).

 

During our race starts, I couldn't bring myself to powershift, so I did my traditional sportbike up shift by preloading the shifter lightly and cracking the throttle to temporarily reduce load on the driveline. Feels smooth, and I'm not competing for world titles, so I'll save the wear on the bike. [emoji4]