Jump to content

New on 2 stroke, somes questions

Recommended Posts

Hello.  Sold my yz450 and got a yz250 2 strokes. It's a 2007, in nice shape, bone stock except for a pro circuit work pipe abd a 304 shorty silencer. 

The previous owner ran Hyperteck 50:1 oil/gaz mix. When i start the bike the idle is realy fast for 2 or 3 minutes, and the bike smoke alot!!! I have remove the cab to clean it and the main jet is a 192 (178 stock) and 48 pilot. 

I have order new pipe o-ring because smoke exit between pipe and cylinder. 

Now i want to mix it with yamalube 2R at 40:1 (because yamalube is the esiest oil to get for me). Do you think that 192 main is way to big??? 

I am new to 2 strokes and i look at you tube for good jetting videos but can't find one good for me. 

Can you give me somes tricks pleasec to get started? 

Thank's

Share this post


Link to post
Share on other sites
On 9/14/2018 at 6:34 AM, David L. said:

Can you give me somes tricks pleasec to get started? 

Thank's

pro circuit has jetting guidlines on their site, don't soak the carb in carb cleaner just use some spray. Buy keihin jets, not cheaper chinese kit's or jets.

Share this post


Link to post
Share on other sites

@David L. google spanky’s jetting guide 

45 pilot is a good start 

search zook needles for yz250 in this site 

40:1 is good ratio , but don’t be afraid to go 50:1 if you trails/single track ride

Share this post


Link to post
Share on other sites

Ok. I have go down from 192 to 182 on main jet. I have put a new sparkplug and make a WOT pass, clutch and stop engine. 

I have cut the threads of the sparkplug and this is what i have obtain. 

 

15371364590215187634491996002128.jpg

20180916_183528.jpg

Edited by David L.

Share this post


Link to post
Share on other sites
18 hours ago, highmarker said:

pro circuit has jetting guidlines on their site, don't soak the carb in carb cleaner just use some spray. Buy keihin jets, not cheaper chinese kit's or jets.

I have check it, but they say to keep stock 178, or if i am right, go down to 175....🤔

Share this post


Link to post
Share on other sites

 Guessing the previous owner somehow was guessing he needed a bigger main when he changed pipe?  who knows, maybe he bought a chinabay jet kit LOL.  Yamaha is usually real close in their stock 2 stroke jetting.

Edited by highmarker

Share this post


Link to post
Share on other sites

Anywais, i think this bike have been jetted by a pro.  I have find a washer under the needle clip to fine tune it between #2 & #3 clip position.... 😁

  • Like 1

Share this post


Link to post
Share on other sites
Hello.  Sold my yz450 and got a yz250 2 strokes. It's a 2007, in nice shape, bone stock except for a pro circuit work pipe abd a 304 shorty silencer. 
The previous owner ran Hyperteck 50:1 oil/gaz mix. When i start the bike the idle is realy fast for 2 or 3 minutes, and the bike smoke alot!!! I have remove the cab to clean it and the main jet is a 192 (178 stock) and 48 pilot. 
I have order new pipe o-ring because smoke exit between pipe and cylinder. 
Now i want to mix it with yamalube 2R at 40:1 (because yamalube is the esiest oil to get for me). Do you think that 192 main is way to big??? 
I am new to 2 strokes and i look at you tube for good jetting videos but can't find one good for me. 
Can you give me somes tricks pleasec to get started? 
Thank's


why not go 32:1 on the Yamalube like the manual suggests?

Share this post


Link to post
Share on other sites
1 minute ago, Tahoe Gator said:

 


why not go 32:1 on the Yamalube like the manual suggests?

 

Finally, on the pics i have post, the test was did at 32:1.

But today my son ride the bike, and it was only is third time on a bike so he ride it realy slow and not go on the pipe really often, so he fool a plug. 

But i will stau at 32:1

Share this post


Link to post
Share on other sites

if he was using the bike for ice racing in frozen quebec temps long pulls ? could explain the big main jet. Bigger carb or bored carb too. 

Edited by highmarker

Share this post


Link to post
Share on other sites
8 hours ago, highmarker said:

if he was using the bike for ice racing in frozen quebec temps long pulls ? could explain the big main jet. Bigger carb or bored carb too. 

I have think about ice racing. 

For the carb, when i have open it, he seam to be pretty stock.  No sign of boring in it. 

Thank's

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×