Author Topic: Racer Resurrection  (Read 60819 times)

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Offline bsracer

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Re: Racer Resurrection
« Reply #180 on: June 08, 2018, 11:42:53 AM »
Check the squish clearance. You don't want it too tight. I think the heads I have on now are at 8cc.


paul

Offline al_pritchard

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Re: Racer Resurrection
« Reply #181 on: June 11, 2018, 01:20:41 PM »
I dont think I'll have any clearance issues, if anything the "squish" area is non-existent. With no base gasket or shim, and no head gasket I get a 1mm squish at the edge of the piston. Raising to 1.9mm squish, 5mm out. This is probably +/- a little, it was difficult to accurately measure the edge of the solder.


No Shim, No Gasket
Base Shim: N/A
Cylinder Bore: 50mm
Engine Stroke: 45mm
Exhaust Port Height from TDC: 26mm
Exhaust Closes at: 90° BTDC
Cylinder Volume at BDC: 90.13cc
Cylinder Volume at TDC: 7.1cc

Squish:
At Cylinder Wall: 1mm
5mm From Cylinder Wall: 1.9mm

Uncorrected Compression Ratio: 13.45:1
Trapped Compression Ratio: 8.19:1


Small Shim, No Gasket
Base Shim: 0.61mm
Cylinder Bore: 50mm
Engine Stroke: 45mm
Exhaust Port Height from TDC: 26mm
Exhaust Closes at: 88° BTDC
Cylinder Volume at BDC: 90.13cc
Cylinder Volume at TDC: 7.5cc

Squish:
At Cylinder Wall: 1.61mm
5mm From Cylinder Wall: 2.51mm

Uncorrected Compression Ratio: 12.78:1
Trapped Compression Ratio: 7.81:1


Medium Shim, No Gasket
Base Shim: 0.80mm
Cylinder Bore: 50mm
Engine Stroke: 45mm
Exhaust Port Height from TDC: 26mm
Exhaust Closes at: 86° BTDC
Cylinder Volume at BDC: 90.13cc
Cylinder Volume at TDC: 7.8cc

Squish:
At Cylinder Wall: 1.8mm
5mm From Cylinder Wall: 2.7mm

Uncorrected Compression Ratio: 12.33:1
Trapped Compression Ratio: 7.54:1


Thick Shim, No Gasket
Base Shim:
Cylinder Bore:
Engine Stroke:
Exhaust Port Height from TDC:
Exhaust Closes at:
Cylinder Volume at BDC:
Cylinder Volume at TDC:

Squish:
At Cylinder Wall:
5mm From Cylinder Wall:

Uncorrected Compression Ratio:
Trapped Compression Ratio:


Al Pritchard
Highlands, NJ

BS175 Racer

Offline al_pritchard

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Re: Racer Resurrection
« Reply #182 on: June 25, 2018, 07:03:29 PM »
Started disassembly, and cleaning of the carbs. Thought I'd share some numbers:

SR Carb
Needle - 4J6
Needle Valve - 2.0
Pilot Jet - 30
Main Jet - 220

From the kit
Needle - ??? No idea, it's not stamped
Needle Valve - 2.0
Pilot Jet - 30
Main Jet - 130, 140, 150

Needle Jet - Wow am I not happy about this. It's has a bur inside

Overall not happy with the quality of the parts in this ket, and would only recommend if you needed some of the other bits.

Quick question, when striping down the carb. How do you safely remove the needle jet? I'v seen a couple of youtube videos that show it getting "lightly" hammered up - using a wood dowel against the seat. How much resistance should I expect? I'v given it a couple of taps, but nothing of any real force.
Al Pritchard
Highlands, NJ

BS175 Racer

Offline BRT-GTR

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Re: Racer Resurrection
« Reply #183 on: June 26, 2018, 09:39:10 AM »
       Al,
             I did push a couple of needle jets out of slightly corroded 350 carbs, 12 months ago, to see how easily they would come out and clean them.
        One moved with a couple of light taps, second required a little bit more welly.
       You will know this but make sure you first remove the thick brass washer under the main jet. I then put an old main jet back in and hit this, using a piece of hard wood, to move the needle jet, sure I used a piece of dowel to complete the push out.
      Seem to remember, they only needed driving for the first 10mm or so and then loosened up. They are a light push fit when replacing, main jet and washer was used to fully seat them.
      Difficult to advise on force require but feel you have enough hands on experience to know when to back off.                                                           Brian.
« Last Edit: June 26, 2018, 09:46:42 AM by BRT-GTR »
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Offline bsracer

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Re: Racer Resurrection
« Reply #184 on: June 28, 2018, 09:57:07 AM »
There is a pin in the carb body that locates the jet. The jet should have a slot. Sometimes there can be some crud making it difficult to remove. I think I used a small size nut driver and get them moving. Not ideal. You could make up a dowel out of delrin or something like that to tap on the jet so you don't damage the threads or jet.

paul

p.s. where did the kit come from?

Online moonpup

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Re: Racer Resurrection
« Reply #185 on: June 28, 2018, 10:15:11 AM »
On some difficult ones I had, it helped to boil up some water and let them soak in there for a bit. I also sprayed some WD-40 down that slot/channel Paul mentioned.

Some tapped out with a wooden dowel, while others required the sacrificial main jet like Brian used.
Confucius say... "Better to have Bridgestone than Kidneystone"

Offline OldSwartout

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Re: Racer Resurrection
« Reply #186 on: June 28, 2018, 02:09:24 PM »
I generally use a 1/4 ratchet extension. They're slightly rounded on the tip, just enough to prevent damaging the threads and nearly the same size as the hole in the carb.  The one disadvantage is they are large enough diameter to push the little brass locating pin partially out and you have to remember to push it back in later. 

I like the sacrificial main jet idea better.
Karl Swartout
Mooresville, IN
BS175 Roadracer
BS350 GTR

Offline BRT-GTR

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Re: Racer Resurrection
« Reply #187 on: June 28, 2018, 02:59:53 PM »
         Against expectations, the main jet didn't suffer any damage and is now back in my collection. It was a 160 I found in one of my spare carbs, likely a younger rider trying extract more power from his GTR back in the day.                                Brian.
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Offline al_pritchard

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Re: Racer Resurrection
« Reply #188 on: July 07, 2018, 04:16:38 PM »

Foiled again.

With the next week off, I was attempting to finish the engine build. And perhaps start the bike. But that does't look like it's happening.

Everything together, and lightly oiled. Everything spins smoothly. But.... I have a leak or two.

While pressurizing the left cylinder, I found a leak at the right crank seal. So I guess that means, I need a new crank seal. And I guess I need to swap out the crank for the NOS one. Hoping that seal is still good.

I send an email off to Richard, and I'll follow up monday with a call. But if anyone has any of the following, I'm interested.

#27
1451-8000
Crank Shaft Color
(This is precautionary, but it looks a little worn so if I can find one)

#32
09090-109
28 Oil Seal

Paul - The kit came from Diablo Cycles up in Canada.


Couple of photos to keep everyone engaged.



It looks like the rotary disk was already trimmed to the specification in the tuning guide




Translating degrees to the dial




And clean carbs. Reused the old jets - they looked very clean.


P.s. Managed to get the main jets out. Need to look closer at the parts diagram, I completely missed the washer - Thanks Brian.
Al Pritchard
Highlands, NJ

BS175 Racer

Offline bsracer

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Re: Racer Resurrection
« Reply #189 on: July 10, 2018, 09:10:01 AM »
Hi Al,

well I thought I wrote a response yesterday but it seems to be gone now?

paul

Offline al_pritchard

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Re: Racer Resurrection
« Reply #190 on: July 11, 2018, 08:15:47 AM »
I got the email notification you did. But I never saw the post.

On the plus side, a full set of Oil seals have been ordered. So the engine comes apart this week for a second rebuild. With my last crank. Let’s hope that seal is still good, otherwise.....
« Last Edit: July 11, 2018, 08:17:55 AM by al_pritchard »
Al Pritchard
Highlands, NJ

BS175 Racer

 


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