[Molish]

Cylinder sleeve is hosed on my quad.

Crack that goes up the cylinder wall to about 3mm form the top, 3/4 the way around the top and back down. Total loss on the sleeve and the rings. Piston head looks ok though.


Here is my problem. I can go two ways with this to fix it.

1) Keep it a 426. There are rumors that this is more reliable with the standard 10mm head bolts (or more reliable all around). I need to buy a 400 sleeve, have it pressed in and ground down to the 88mm spec. That costs about 275 where I live (100$ for the standard 400ex sleeve, 100$ to press it in and the old one out, 75$ for the grind from 400 to 426).

(side note, the piston head "LOOKS" ok. Is it possible to be warped or damage in a fashion that I can not see?)

Est total = 275$

2) Go with a 440 kit. There is one from DTM Powersports on their ebay store. It's out of stock untill this Saturday. Link here to the 440 from DTM.

Comes with Jug, piston, rings, gaskets. No cost to press in a new sleeve, just a flat 350$ for the kit. The one thing I don't have are the 12mm bolts for the head (the HD head bolts). There are rumors that I'll blow head gaskets left and right without the HD bolts.

Est total = 350$
Extra for HD bolts = 100$ (50 for bolts, 50 for install)

I've been told if I can get the 10mm to 40lbs-ish with some good heat treated lock tight then I should be ok with the 10mm head bolts. So I might not need to spend that extra 100$.

I already have the SPAC 4inch fan mod for my oil cooler, so I'm good on the heat problems that are inherent for the 440's.





I want reliability. This is a trail machine, but will see open fields/backroads and I LOVE jumps. I'll be doing some cross country with her, so I don't wanna be screwed out in the country somewhere.

At this point, I'm at in impass. I see it being cheaper for the 426 kit, and that was already on her anyway. I hear of 440 problems with the head gaskets and the 10mm stock bolts. So I'm leaning to staying with the 426.

 

[Red-Rider]

I used to have a '99 EX, I sent the jug to Pro Fab ATV and had the 425 job done and I loved it. It was built to be a trail machine also. I was running the hotcam (I think) brand mid-range cam. I wish I never got rid of it.

There's my $0.02.

 

[shadetree]

i'm not a sport quad rider..and i never will be..lol..and i'm always looking at ways to save money...and i try to stick with stock..sooooooo..if it were me..i'd stay with stock..too many problems come from matching higher end parts with old ones..this i know from working on bikes for 12 years..thats why they say in repair manuals..( this needs to be replaced as a set )..if you put a hd or new part in with an old one..you are taking the risk of creating a chain reaction..this is my $ 0.02. worth...lol

 

[submarine 300]

^^^^Agree when you start replacing parts with higher comp. parts the old stuff will start to break, and fast!

 

[Molish]

Think I'll go with that line of thought. Stay as stock as I can (well, stock for when I bought it anyway)

I'm pricing out all the stuff I'll need and staying with the 426 is coming up on top as far as good pricing.

New sleeve - 90$ - Advanced cylinders
Install - 100$ - local shop
Grind to 88mm (426cc) - 75$ - local shop
Hone - ??? - local shop
Cylinder rings - 36.07 - local shop
Cylider gasket - 7.50 - motogrid.com
cylinder o-ring - 5.85 - motogrid.com
head gasket - 17.97 - motogrid.com
cam plunger - 10.72 - motogrid.com

Total = 343.11


440kit = 370$
HD head bolts = 115$

Total = 485$




I need the gasket and o-ring for the crankcase to jug because both were destroyed when I took it apart. The head gasket is just an extra just in case (my triple metal one might have dirt and be a HAIR bent because of rough handling in a dirty environment after I took it off. It still might be good, but why risk it?).

And I did the mistake EVERYONE does when they pull a head for the first time, I lost the Cam plunger and spring. I found the spring later on, and had no idea where the hell it came from until I started reading other peoples rebuild stories. What the hell does that thing do that can cause a rebuild to 100% NOT WORK until you get it back in there?

Can anyone see anything else I might need or might have missed? I'm trying to think through this 100% before I start ordering.

 

[Redracer]

The 440 kit is known to be extremely reliable. I would go with the HD bolts, I have heard of the regular ones causing blown gaskets... just like you said.

 

[shadetree]

Think I'll go with that line of thought. Stay as stock as I can (well, stock for when I bought it anyway)

I'm pricing out all the stuff I'll need and staying with the 426 is coming up on top as far as good pricing.

New sleeve - 90$ - Advanced cylinders
Install - 100$ - local shop
Grind to 88mm (426cc) - 75$ - local shop
Hone - ??? - local shop
Cylinder rings - 36.07 - local shop
Cylider gasket - 7.50 - motogrid.com
cylinder o-ring - 5.85 - motogrid.com
head gasket - 17.97 - motogrid.com
cam plunger - 10.72 - motogrid.com

Total = 343.11


440kit = 370$
HD head bolts = 115$

Total = 485$




I need the gasket and o-ring for the crankcase to jug because both were destroyed when I took it apart. The head gasket is just an extra just in case (my triple metal one might have dirt and be a HAIR bent because of rough handling in a dirty environment after I took it off. It still might be good, but why risk it?).

And I did the mistake EVERYONE does when they pull a head for the first time, I lost the Cam plunger and spring. I found the spring later on, and had no idea where the hell it came from until I started reading other peoples rebuild stories. What the hell does that thing do that can cause a rebuild to 100% NOT WORK until you get it back in there?

Can anyone see anything else I might need or might have missed? I'm trying to think through this 100% before I start ordering.

i'm guessing it moves the cam ??..lol..as far as what your missing...seems like you got it all covered..as long as you gather up all your old parts..make a list of them..compare them to your new list your getting..you should be ok..oh..not that you need to do this..but..when i do i top end job..i take my tap-n-die set..and run it down the lower unit head studs, just so i know i'm getting a solid hold.

 

[Molish]

Awesome idea shade. I'll mark that on my list right now.

 

[Helmut]

Personally, I would stay as close to stock as I could to keep the dependability. Stock=Dependability.

 

[tomgodd]

Agree with the stock comments.

 

[Molish]

Yup. I priced everything I think I need for the 426 rebuild with a new exhaust and a new sprocket for my rear and it still comes out less then the 440kit with the HD bolts installed. That's money I can put elsewhere in her (new bearings, etc etc).


My biggest issue is like you guys said, staying as stock with certain items as possible so I can still get parts easy for her. Gaskets and everything can be gotten easily for the stock 400. Since the 426 is a stock 400 sleeve ground to 88mm, the gaskets and everything are the same. I wasn't sure if that is the case with the 440 kits.

Plus I liked the pep the 426 had. I don't wanna lose that feeling like others have said with the 440. Even blowing smoke with dead rings and a giant crack in the sleeve, I had to hang on FOR DEAR LIFE when I pegg'd her. I can't wait to feel that when she is 100%.

Man, do I miss riding....