Author Topic: Cracked head  (Read 2332 times)

0 Members and 1 Guest are viewing this topic.

Offline FAT-TOY

  • Legend
  • *****
  • Posts: 708
    • View Profile
Cracked head
« on: May 09, 2017, 07:44:19 pm »
   A mate dropped in today with this head, it has a crack between the spark plug holes which seems to be about 6mm deep, so not through to the top of the thread.  I think it's off a 250  Elsinore motor fitted to a Honda Odyssey dune buggy thing.  He has been told that it might be ok to leave it as is and only to worry about it if it gets worse, I tend to think that if it were mine I would have it ground out and welded.  So anyone had this problem and what is the best option.  I have attached a photo so hopefully the crack is visible.
                                            Zane

Everyday I find one more name to add to the list of people who piss me off.

Offline TT5 Matt

  • Legend
  • *****
  • Posts: 1538
    • View Profile
Re: Cracked head
« Reply #1 on: May 09, 2017, 08:49:38 pm »
Find an mt250 head that's not cracked as there the same along with the barrel

Offline pokey

  • Legend
  • *****
  • Posts: 1454
  • Arse .. Elbow. Know the difference
    • View Profile
    • FB
Re: Cracked head
« Reply #2 on: May 09, 2017, 08:59:46 pm »
Well theres a hot spot just waiting to develop detonation. Any damage from wayward rings or whatever will heat differently and retain heat causing pre ignition and......
Offset plug holes suck. The flame front doesnt burn correctly using the design of the head. Check a normal mx single plug head with decent perf and it will be in the middle of the dome so it can create an even burn so all power is created not lost.
 I had. DG head on my odyssey. Went well and hePs of fun but that stiff axle makes them easy to flip but good for sidewYs stuff.
I would be drilling the crack and welding the plug holes then machining the combustion chamber and drill and tap a single plug hole. Odyssey engines get hot as the airflow is restricted behind the driver so im guessing the heat found the weak spot.

Offline MaxPower

  • C-Grade
  • **
  • Posts: 142
    • View Profile
Re: Cracked head
« Reply #3 on: May 10, 2017, 04:21:19 am »
If that was on my bike I would do what it took to make it right.
A lot of effort and money goes into getting to a race.
I want no chance of a DNF because I didn't spent the time or a few dollars to fix my bike right.
Besides to me that looks like a problem waiting to happen

Offline Momus

  • Legend
  • *****
  • Posts: 687
    • View Profile
Re: Cracked head
« Reply #4 on: May 10, 2017, 01:50:40 pm »
Cnut of a job to repair let alone convert to single plug. I had 13 Odysseys when I ran the hire business. I'd quietly reinstall it while looking for another head; they are always on UDs Ebay.
If you love it, lube it.