Jump to content

Critique my 4mm woods build


MLack

Recommended Posts

  • 8 months later...

**UPDATE**

 

Was installing a new kicker the other day and then realized i was able to push the kicker all the way down with my hand with very little resistance...HMMMM. I did a compression test and got 70 and 50psi. WTF!Pull the top end off and can feel the piston to cylinder clearance is huge, they feel really loose in the bore. Ring end gap shows .069 and .129. Needless to say it needs a top-end after about 10 rides. 

 

I talked to Kevin and a couple other builders and the consensus is......Air filter letting dirt past. There are tons of vertical scratches in the bore and some on the piston. Piston is a matte grey color and the bores are very shiny. 

 

I used a cleaned and oiled UNI filter for each ride. I used Amsoil oil mixed @ 40:1. The trails I ride are pretty much just open dirt roads used for logging back in the day. So its dusty and being as open as they are the bike sees alot of WOT. 

 

 

Any other thoughts on why I'd lose a top-end soo soon? What else can I do to prevent this from happening again? Tighter fitting K&N filter with outerwear? more oil?

Link to comment
Share on other sites

Defiantly not dirty fuel. Petcock is new.  If any leak it would have been where the filter is clamped to the airbox. Guess there was no way for me to tell if they were bored incorrect. The end gap was in spec when I installed the pistons. 

 

 

The rings look good. No noticeable wear on those and they are not sharp at all. I can only assume they were chamfered properly when he bored it. I'm from MN. 

Link to comment
Share on other sites

Stock airbox with out a lid. I had the factory white cage in there that has a rubber gasket between the white cage and the airbox housing. They are bolted together tight  Then, I used a huge half inch ziptie on the internal yellow filter and one on the outer red filter. I don't think there is any way dirt and dust got through that. 

Edited by MLack
Link to comment
Share on other sites

  • 3 weeks later...

UPDATE:

 

I noticed a few things after looking over the bottom end. Little bit of trans fluid on the clutch side of the crank and the trans fluid was very shiny when I drained it. So I split the cases to inspect everything. Looks like the crank seal on the clutch side fell victim to the dirt being inhaled as well. So new set of seals coming. The shiny trans fluid..the clutch looks toast. A few questions.

 

What clutch? Tusk HD or the Driveline?

 

Now the trans is out, a good friend of mine runs a machine shop and can modify the shift drum for the bearing and mill down every other dog on the gears. Is this worth the hassle of pulling it all apart? is the "pro-mod" trans good for a woods bike? Backload an issue? Alot of on and off the throttle going to be a problem?

 

 

Let me know what you all think. 

Edited by MLack
Link to comment
Share on other sites

MN CREW!!!! SpecialBlend: Where you from and where do you ride?

 

 

Zilla: I have everything except the bearing on the cam and the dogs cut. I'm just worried about the on throttle and off throttle in a woods bike. Ive read all day on this damn think and Im sure I'll be find. Maybe over thinking it. I think ill have him cut 2-5. I don't see the need to cut 1&6.  Correct me if I'm wrong. 

Link to comment
Share on other sites

2-5 would be murdered in the woods. You want a promod.

 

no no no. Im talking about a promod. But only cutting 3 dogs off of gears 2,3,4 and 5. Leaving gears 1 and 6 with the full 6 dogs. 

Edited by MLack
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...