Jump to content
Sign in to follow this  

Jetting input please

Recommended Posts

May get more results in here. Basically I blew up my top end by what a member here said was way lean conditions. I will post pics of piston.

I rebuilt it. 55mm wiseco. It has a hot rods crank and rod. Bills pipe and if someone could tell me what can it is that would be great. Not sure on reeds. I'll post those pics to.

I have read up on tuning and jetting just not sure what jets I should get.

Anyway. It had a 50 and 280 in it. Going to the shop tomorrow to pick up some jets, but what ones?

Share this post


Link to post
Share on other sites

If your ignition side seal is leaking the skid marks on your piston will be as large as the skid marks in your shorts when it seizes again. :jawdrop: :jawdrop: :jawdrop::cry: :cry: :cry:

 

They are easy to replace by the way.

Share this post


Link to post
Share on other sites

As stevethe has mentioned, if your ignition side crank seal is worn, there's a good chance it was the cause of your previous engine seizure.

 

A worn/damaged LH crank seal:

sucks in un-metered air / leans out the air-fuel mixture / raises the combustion temperatures and finaly seizes your engine.

 

Since you are going thru all the work and expense of rebuilding this engine, it makes no sense to run it

if the seal is in questionable condition as you may be rebuilding it once again much sooner than expected.

Edited by mlatour

Share this post


Link to post
Share on other sites

OK. I will grab some today and just do it. But any input on the jets? Were to start? 50 seems good for pilot but 280 seems way off for main? Maybe the guy I got it from was trying to go rich to compensate for crank seal? Should I go back to stock? Whatever that is?

Share this post


Link to post
Share on other sites

crank seals?    and I checked the reeds.  not replacing what isnt broke.

 

Yeah, but see you can't do that.

You must maintain the motor BEFORE things break, or when they do break, it will break catistrophically!

 

" checked the reeds".....I'm not talking about chips, I'm talking about the reeds sealing. They fatigue from all that bending and stop sealing way before they start chipping.

Pour gas into the reed block and hold the assembly reeds facing down:  and if gas come out any faster than one drip per 2 seconds, your reeds are worn out.

Share this post


Link to post
Share on other sites

There is no reason to change jetting if it ran well before with the jet you have

 

I had the bike 3 weeks and rode it maybe 5 hours before it ruined the top end.  so basically I just got it.  I am not so sure it ran "well".  obviously it was lean.  a 280 jet seems pretty extreme from a 175 stocker that comes from the factory rich.    I am thinking he was probably trying to compensate for a lean situation caused by like you said a crank seal (thanks for the input BTW).  I would have never known

Edited by Redneck-Rider

Share this post


Link to post
Share on other sites

Yeah, but see you can't do that.

You must maintain the motor BEFORE things break, or when they do break, it will break catistrophically!

 

" checked the reeds".....I'm not talking about chips, I'm talking about the reeds sealing. They fatigue from all that bending and stop sealing way before they start chipping.

Pour gas into the reed block and hold the assembly reeds facing down:  and if gas come out any faster than one drip per 2 seconds, your reeds are worn out.

 

ah...    I was unaware of reeds going weak.  I thought they were chipping or not.  

 

I am still learning all this bud.   This is my "first real" dirt bike.  and first bike I have worked on like this.  

 

turns out there is a ton wrong with it.  Had I known what I am learning I never would have bought this one I would have waited for a better bike.  but its a learning experience.

Share this post


Link to post
Share on other sites

ah...    I was unaware of reeds going weak.  I thought they were chipping or not.  

 

I am still learning all this bud.   This is my "first real" dirt bike.  and first bike I have worked on like this.  

 

turns out there is a ton wrong with it.  Had I known what I am learning I never would have bought this one I would have waited for a better bike.  but its a learning experience.

 

Great attitude about this. 

So many people give up as soon as it gets difficult...

 

Good job.

  • Like 2

Share this post


Link to post
Share on other sites

ok, I am getting really annoyed with this thing.

 

SO, again.   when I got it it had a 50 and a 3rd clip position and a 280 jet.  

 

It idled and ran descent.  turns out it needed a top end. 

 

anyway.  all that is new.  no leaks.   at the shop they told me I needed to be at a 30 pilot (seemed wrong) 2nd clip and a 190 main.   ok.  I tried it.   nope.  lean down low and rich up top (I think).

 

so I put the 50 in, and that allowed me to get my idle back to normal.   1/2 turn out was higher idle and 1/4 turn was good idle were I liked it.   seemed to foul up top.   actually stalled under relatively heavy throttle.   however at half throttle it felt about perfect.

 

SO, since I was on 1/4 turn out from all the way in I thought I needed a bigger pilot.  I was busy so I had my mom who was in jackson at the time pick me up a 55 and 60 to bump up my pilot.  well, they were wrong...   anyway. 

 

my my mom got me a 180 main.  so I dropped from a 190 to a 180 main, and now when I start it it just revs instantly and I have to kill it...   if I turn the choke on it will idle kinda normally.  

 

WTF...  does the main control the idle?   I assume the answer is to get a bigger pilot.  

 

This was on the 2nd clip position.  Since the store is closed I thought to try the 3rd clip position to add fuel.  well, that changed nothing.  still revd way high and I had to kill it...  

Share this post


Link to post
Share on other sites

I'm tellin' ya, you left crank seal is gone.... that's why you have runaway rpms.....that's why you need such a large pilot.

You need to do a LEAK DOWN TEST as you are going in circles, guessing your way to nothing....

 

As mentioned before, idle is pilot only

 

Needle is mid throttle only

 

Main is nearly full to full throttle only.

 

The 

Share this post


Link to post
Share on other sites

replaced the crank seals.   not sure that was the problem, but the left hand side one when sitting on the bike was questionable.  I did find I have a craked intake manifold (that I replaced) also found a throttle cable issue.  ordered one of those to, but was able to a temp repair to get me riding. 

 

So, I started the jetting process.   basically what I came up with is 65 pilot/3rd clip/210 main.  Seems to be damn near perfect.   I do have a little spot at mid rpms/certain throttle position that may be kind of a flat spot before the power band, but not bogging or missing really.  could be normal.  lol.  never rode one of these newer 2 stroke bikes. 

 

I was surprised how big of jets I had to go with...   but, the bike seems to be really happy the way it is.  

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

Reply with:

Sign in to follow this  

×