Author Topic: Holed piston  (Read 5099 times)

0 Members and 1 Guest are viewing this topic.

Offline husker

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 139
Holed piston
« on: February 02, 2016, 06:00:54 PM »
Hole in one of the pistons is why this GTR got parked back in 1982.  The old clutch rod is 5mm shorter than the new one, is this common to have that much wear?
« Last Edit: February 02, 2016, 08:24:19 PM by husker7519 »
1968 Bridgestone GTR350,  1971 Kawasaki A7SS, 1983 KZ750 LTD

Offline slawsonb

  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 1398
Re: Holed piston
« Reply #1 on: February 02, 2016, 07:40:32 PM »
Looks like it was running a little lean!...lol
5mm (.197in) is a lot for the clutch rod to wear. Does it look like it's been modified?
...bert

Offline husker

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 139
Re: Holed piston
« Reply #2 on: February 02, 2016, 08:37:34 PM »
Not that I can tell Bert. The short 10mm rod was missing so I will cut a piece off the old rod. The actuator was also broken so ebay supplied another.
1968 Bridgestone GTR350,  1971 Kawasaki A7SS, 1983 KZ750 LTD

Offline slawsonb

  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 1398
Re: Holed piston
« Reply #3 on: February 02, 2016, 08:49:36 PM »
I think the clutches on 350's have become a source of frustration for many. During the period when clutch plates were unavailable folks tried all kinds of things to get their bikes rolling again. Extra plates, both friction and inner, and lots of home brew fixes for the rod length. Just getting it back to stock, should give you excellent results.
...bert

Offline coxy

  • coxy
  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 1108
Re: Holed piston
« Reply #4 on: February 03, 2016, 01:10:53 PM »
That's interesting the holed piston how does that happen in a two stroke. I think it might be more than just running to advanced. Maybe oil pump wrong jets blocked oil line .anyway I have some second hand pistons though dirty I think there in good shape if you want them I can dig them out and send a picture

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 344
Re: Holed piston
« Reply #5 on: February 04, 2016, 02:39:31 AM »
A holed piston is typically ignition related. Lack of oil would lead to a seizure.

paul

Offline husker

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 139
Re: Holed piston
« Reply #6 on: February 04, 2016, 08:54:33 AM »
Thanks for the offer Coxy but I have 2 new pistons and rings. One of the first of many purchases for this rebuild. The left carb must have been too lean for some reason and I will need too check it out extra carefully. Don't want to hole a new piston! I did take the bowls off and the carbs were surprisingly clean for sitting for 30+ years.......Rod
1968 Bridgestone GTR350,  1971 Kawasaki A7SS, 1983 KZ750 LTD

Offline Jeff Bar

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 484
Re: Holed piston
« Reply #7 on: February 04, 2016, 09:04:37 AM »
I agree that hold like a too lean gas/air mixture not lack of oil.
Check that side for air leaks around gaskets and seals make sure main jet
is not too small very smart to start with new pistons and ring Jeff Bar

Jays100

  • Guest
  • Trade Count: (0)
Re: Holed piston
« Reply #8 on: April 22, 2016, 09:34:10 AM »
Hi all, this is my first post.  As of today, I don't own a Bridgestone but have ridden and worked on many.  Also have extensive 2-stroke experience racing/riding (with the associated spectacular meltdowns thereof), I'm an engineer.  I'm currently jonseing for a 350GTR...

Generally, spark plug temps need to be below 400F.  Above that and bad things happen!

On this topic, may I ask a couple of questions?
-what spark plug are you using/heat range?
-has timing been properly set? On both sides?
-which side failed (see above)
-how was it ridden when it failed? (WFO? Hot day heavy traffic?, ??)
-what fuel are you using? (octane?) (from same supplier?)

I personally like the timing question where one side is advanced and the other retarded (puns intended) for this fail but detonation could also be a factor.

Hope this helps!
J

Offline husker

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 139
Re: Holed piston
« Reply #9 on: April 23, 2016, 07:49:01 AM »
Thanks J. Except for what jets are in the carbs I don't know the answers to any of the other questions. Even the plugs were missing. The former owner is no longer with us so I will just have to be make sure I get this thing back together and set up right........Rod 
1968 Bridgestone GTR350,  1971 Kawasaki A7SS, 1983 KZ750 LTD

Offline srpackrat49

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 154
Re: Holed piston
« Reply #10 on: April 23, 2016, 10:33:33 AM »
When ya get it back togearther ;D  do a leak down test 8) that will show ya if there are any leaks in the seals and all.....  in the old days on cars we did that to find the leak... may be some one here can walk ya threw the steps.... get er done !!!

 


Gallery


Views:221
Comments (0)
By: Jon West

Views:1362
Comments (0)
By: rwgibbon

Views:1691
Comments (0)
By: Perry L Anderson

Views:1757
Comments (0)
By: Perry L Anderson

Classifieds

Gto
Date: 03/02/2024 06:49 am
Time Left:
Looking for a BS90 used or new luggage Carrier assembly

Date: 02/01/2024 04:19 pm
Time Left:
Gto
Date: 10/19/2023 01:08 pm
Time Left:
Urgent - l/end roller bearing & piston pins needed
Date: 10/08/2023 03:25 am
Time Left:

Recent Downloads added

Chibi, Chibi Deluxe, Tora Service Manual
Rating: (None)
Filesize: 20383.27KB
Date: May 01, 2023, 08:35:39 PM
Chibi_Tora_Parts_Manual
Rating: (None)
Filesize: 14301.44KB
Date: May 01, 2023, 08:25:53 PM
BS200 Mk II RS & MK II SS Exclusive Parts
Rating: (None)
Filesize: 358.29KB
Date: March 07, 2021, 07:30:10 PM
1970 sales brochure
Rating: *****
Filesize: 6753.33KB
Date: July 16, 2020, 10:01:18 PM

Powered by EzPortal