Author Topic: 175/200 Crankshaft Project  (Read 4557 times)

0 Members and 1 Guest are viewing this topic.

Offline skiri251

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 45
Re: 175/200 Crankshaft Project
« Reply #40 on: April 08, 2017, 01:06:32 PM »

Yes. Then off to Sears Point he following week. I'll be in either a garage on the front row or the one by itself when you first enter the track. #108 yellow and red paint. Still got a little ways to go. Gotta put the motor and the rest together!

paul

p.s. See you there

Great!
Hope I can make it.

Offline bert Lilley

  • Trade Count: (0)
  • Registered Bridgestone Member
  • **
  • Posts: 20
Re: 175/200 Crankshaft Project
« Reply #41 on: April 19, 2017, 06:02:32 PM »
Hi guys , just reading your posts regarding the 175/200 center pin breakage and have a question
What material are you upgrading to when you replace the stock cente pin ?

I do undestand and support what karl indicates regarding the hormonics above 10,000rpm. Yes a 4 bearing crank would elevate a lot of the issues, i also think a professional balancing done would truly help as well.
A good friend of mine purchased a factory TD3 crank from Japan he took his pistons/rings  new crank etc  iand had tested for balance and it was realy out of balance. He was not impressed.

Bert Lilley

Offline OldSwartout

  • Global Moderator
  • Trade Count: (0)
  • *******
  • Posts: 953
Re: 175/200 Crankshaft Project
« Reply #42 on: April 19, 2017, 08:49:26 PM »
i also think a professional balancing done would truly help as well.
Bert Lilley

I got a quote about 10 years ago from a reputable balancing business here in Indy, it was going to be about $200 for a balance job on my 175 crank.  It had to be assembled without rods, they substituted balance weights for  the recommended percentage weight of rod, bearings, piston & rings and balanced the crank, then the crank ends had to be disassembled and the rods and lower rod bearings installed. Unfortunately, I never got around to doing it. It probably would have been a smart thing to do.
Karl Swartout
Mooresville, IN
BS175 Roadracer
BS350 GTR

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #43 on: April 20, 2017, 11:43:08 AM »
I'm using an industrial dowel pin from Grainger that is 80 x 20mm. I originally bought them just to use for mock up and the machinist i use said they were pretty hard so why not give it a try. He shortened them and added centers. The original BS bearings fit well. The only problem I think I have so far is the way the holes were bored in the webs, not as accurate as it should be. One crank went together ok. The pin fit was a bit soft on the press gauge in my opinion. I'll see how it goes this weekend. Fired the bike up last night with that crank. The second crank had material move when the pin was installed and would not true to anything respectable.

I agree that balancing would be nice. Maybe in the future. We'll see how this one behaves this weekend. Ideally the new pin holes should be done with a Jig Bore machine. Still can't find a place that has one that isn't some big Gov contractor.

paul

p.s. I think I will try just a new center pin to 20mm on the next one and have connecting rod pins stepped to minimize variable on the alignment of so many holes. 

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #44 on: April 30, 2017, 03:27:01 AM »
Well the first crank made it thru 6 races so far. Ended up stripping the teeth off the idle gear and missed two races because I didn't pack a spare.

paul

Offline old smokey

  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 678
Re: 175/200 Crankshaft Project
« Reply #45 on: May 01, 2017, 12:13:06 AM »
That sounds like pretty good results, now you just have to pack more spare parts.... ::)
'67 350 GTR undergoing repairs with a '75 Yamaha TX500 front end

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #46 on: May 01, 2017, 01:32:16 AM »
I already pack too many. I just have to bring the right parts I need.


paul

Offline craig641

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 26
Re: 175/200 Crankshaft Project
« Reply #47 on: May 23, 2017, 12:31:09 PM »
So, are you ready to sell one yet?  I broke another one in a race yesterday.  It was my last crank.  I need to find one to have hope of getting something out of this season.

Craig

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #48 on: June 06, 2017, 01:26:35 AM »
Hey Craig,

did you come up with any donor cranks? I'm meeting with another machinist this week about the cranks.


paul

Offline craig641

  • Trade Count: (0)
  • Full Bridgestone Member
  • ***
  • Posts: 26
Re: 175/200 Crankshaft Project
« Reply #49 on: June 12, 2017, 09:59:30 PM »
Paul,

I had parts for five cranks.  I talked with my local guy and he's going to get my flywheels bored for the main crank pins but then I need to talk to you again.  If you've got the jig to press these together we should try to get them all done at once.

Let's also compare machining costs and pin costs.  My guy seemed very reasonable.

I had a race this past weekend in New Hampshire.  My stock crank survived.  The pistons didn't. 

Craig

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #50 on: June 14, 2017, 12:30:20 AM »
Hey Craig,

the connecting rod pins I used are Suzuki T20 TC250 Part# 12211-11000 or 12211-08201. 20mm x 48.8mm. I shortened these to 48mm.

The shims I used where Honda Part# 132002-GC4-600. These are 1mm thick (roughly) big end shim washers that fit CR80 or CR85.

If you got stock KT100 big end bearings they should be fine. The KT100 big end pin is probably too short.

The pin I got for the new center is from Grainger. 20mm x 80mm long metric hardened dowel pin.

The newest machinist that I went to yesterday morning charges $75 an hour. He thinks 2 hours to bore holes in the centers for the new 20mm pins (4-5 crankshafts so 8-10 holes) and remove existing pin. The pins from Grainger are hard and so is the crank (I think cranks are case hardened to around 60-62 Rockwell). I had the pins  shortened to around 72-73mm. I'd have to measure one to get the exact length. I also had centers added.

The fixture I made is only for aligning the center webs to 180 deg. Then they're checked for true. The outer webs still have to be done the old school way and trued as well. I pressed the centers together and had someone else true the outer webs.

paul

Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #51 on: June 18, 2017, 02:08:30 PM »
Hey Craig,

the part numbers for the base shims I had made out of aluminum at Cometic are

B1055SP1025A  .025"
B1055SP1032A  .032"
B1055SP1040A  .040"

These are for a 175 cylinder and they need to be trimmed to fit. I'm sure they can be used on a 200 cylinder as well. They were around $6-7 each.



Offline bsracer

  • Trade Count: (0)
  • Expert Registered Bridgestone Member
  • ****
  • Posts: 286
Re: 175/200 Crankshaft Project
« Reply #52 on: August 27, 2017, 01:58:39 PM »
I picked up the bench center that I was looking at to use as a truing stand. I was set on around $250 and the guy finally came down to $260. Long drive to get it (2hrs each way) but I think it will work well. I still want to get some machinist V-blocks. Then I can check using both the ends and on the bearing surfaces.

paul

 


Gallery


Views:9
Comments (0)
By: OldSwartout

Views:20
Comments (2)
By: AlanJohn

Views:19
Comments (0)
By: AlanJohn

Views:23
Comments (0)
By: AlanJohn

Classifieds

350 gtr parts bike
Price: $0.00
Date: 10/03/2017 09:06 am
Time Left: 76d 7h 4m
Surfrider 7 50cc Motorcycle For Sale - SOLD

Price: $175.00
Date: 09/29/2017 10:43 am
Time Left: 72d 8h 40m
****

Price: $0.00
Date: 09/14/2017 01:44 pm
Time Left: 57d 11h 41m
SUPER RARE 1965 BRIDGESTONE HUMP BACK SPORT 90.

Price: $1400.00
Date: 09/03/2017 02:02 pm
Time Left: 46d 11h 59m

Recent Downloads added

How to build a 149 mph 350GTR....
Rating: (None)
Filesize: 7154.56KB
Date: April 18, 2017, 08:25:38 AM
Bridgestone 100 Sport Brochure
Rating: *****
Filesize: 937.72KB
Date: July 08, 2015, 12:58:53 PM
BS 100 Sport Australian Brochure
Rating: *****
Filesize: 937.53KB
Date: June 29, 2015, 06:40:40 PM
Bridgestone 350 GTO - Moto L├ęgende May 2003
Rating: *****
Filesize: 9429.41KB
Date: April 22, 2015, 04:18:43 PM

Powered by EzPortal