Author Topic: MPS-PG-650 build  (Read 46137 times)

0 Members and 1 Guest are viewing this topic.

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
MPS-PG-650 build
« on: November 19, 2011, 12:41:45 AM »
This bike will replace Dan Wagner's 2011 MPS-PG-650 record bike.  Engine improvements have been completed, chain drive conversion in process, new chassis is 1995 Honda CBR600f3.  The 1978 CX500 chassis used for this years bike was extremely unstable, which prevented Dan from using full throttle during his record runs.

- engine is leaned forward, similar to my APS-PG-750 record bike (which is now APS-PG-650 for 2012, with an identical "destroke" engine as seen in Dan's bike)
- rear shock tilted more vertical to accept large weight increase (the CX650 engine is much heavier than the 600 engine was, plus extra battery, water tank, electric pump, etc)
- photo of my square check to perfectly align rear wheel with steering head and front wheel.  This enables perfect engine alignment and countershaft sprocket alignment.
- new 14.3:1 piston shown with one of my previous 13:1 750 class pistons to show pin offset for the de-stroke crank.  The pistons crowns look offset, but are actually centered.  The angle across the crown/valves is 22 degrees turned from wrist pin alignment (strange engine).
« Last Edit: November 19, 2011, 12:44:27 AM by JimL »

Offline Beairsto Racing

  • Full Member
  • ***
  • Posts: 257
Re: MPS-PG-650 build
« Reply #1 on: November 19, 2011, 05:49:48 AM »
Jim,

I always enjoy watching and learning from your builds. :cheers:
Lots of interesting fabrication.

Cheers,
Scott
2 Club since '02
Sponsored by: Turple Bros.,
Palliser Chevrolet, Hose Headquarters, Bentley's Motosicle Pain Tin, The Window Man

Offline Koncretekid

  • Hero Member
  • *****
  • Posts: 1203
Re: MPS-PG-650 build
« Reply #2 on: November 19, 2011, 07:21:20 AM »
This is the motor (CX-500, CX-650) that will eventually hold many if not all of the pushrod gas class records.  Big bore, short stroke, twin cylinder, 4 valves per cylinder, water cooled.  Makes our old British bikes look prehistoric!  I recognized this before I started my BSA  build, but I am more familiar with the simplicity of the BSA single, so that's where I started.  So far, so good.  I might be able to hang on to my records for a little longer!

Your alignment technique looks interesting.  It looks like you're using the rear wheel as "true center", and aligning the rest of the bike to it - - seems difficult because the head stock and frame which are not necessarily plumb would put them in a different plane from than the wheels.  I used a straight line on my jig, actually the edge of my jig (like snapping a chalk line on your floor), off to one side of the bike's centerline, and used a spirit level vertical and measured over to center points on the frame, wheels, triple clamps etc. Ideally, a rotating laser level, like we used to use to erect 20 story buildings (which you can rent from a good rental store) would be nice.  They have a target that can be attached to a rod that is held horizontally at a given distance from the rotating beam, which beeps when on target.  They seem to be accurate to about an inch in 200 feet.  Or I thought about erecting a flat sheet of MDF board vertically at a given distance and using it as a reference plane. I don't know how other people do it - - no one here to ask. I don't believe that a small degree of error on a motorcycle frame makes much difference at the speeds I go in a straight line, but it's still nice to try to get things aligned properly the first time.
« Last Edit: November 19, 2011, 07:28:16 AM by Koncretekid »
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline 55chevr

  • Hero Member
  • *****
  • Posts: 2446
Re: MPS-PG-650 build
« Reply #3 on: November 19, 2011, 02:11:40 PM »
The way you do it is pretty much the way most do it ...

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
Re: MPS-PG-650 build
« Reply #4 on: November 20, 2011, 12:19:38 AM »
I used a build table for the APS bike, dead flat, plumb bobs, digital leveling, etc.  This particular bike was a running, straight, stock CBR.  The measurement method shown is checked both sides, 6 points of rear wheel rotation, to put the rear wheel dead straight in the bike.  That gives me my datum line for countershaft sprocket alignment.  The rear wheel is rotated to check various points (vertically) at front of the frame area (squaring tool must pivot on the axle line to do this).

Just in case, I also checked steering head, both sides, after dead true on rear wheel (perfect) and then checked front wheel, from both sides, for dead true at straight ahead (also perfect).  After several hours of checking, I find that...as usual...Honda builds nice bikes.
 :cheers:
Regards, JimL
« Last Edit: November 20, 2011, 12:29:27 AM by JimL »

Offline Koncretekid

  • Hero Member
  • *****
  • Posts: 1203
Re: MPS-PG-650 build
« Reply #5 on: November 20, 2011, 06:48:30 AM »
Jim,
I'm sure you got it right.  You might actually have some straight wheels as well, unlike the spokey things I use!
Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline nrhs sales

  • Sr. Member
  • ****
  • Posts: 976
Re: MPS-PG-650 build
« Reply #6 on: November 20, 2011, 10:09:17 AM »
Jim,
If you put the old motor into a modern chasis doesn't that make it an A bike not an M?

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
Re: MPS-PG-650 build
« Reply #7 on: November 20, 2011, 11:40:44 AM »
M- is a modified stock chassis (using "similar" geometry, which I won't change at all) with same brand engine (such as "Honda in a Honda").  They don't require the engine to be the same year and/or displacement as the original part.  Though I'm moving the upper rear shock mount, rear suspension isn't even required for M- class, so that also is non-issue (unless the seat height is set too low, but we'll probably use stock seat because it's in good shape).

Regards, JimL
 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5503
Re: MPS-PG-650 build
« Reply #8 on: November 20, 2011, 11:11:29 PM »
Wheel alignment does not need to be mental.  Simply coast down a long hill with no hands on the bars.  The wheels are out of line if you need to lean to one side in order to go straight.  Simply adjust the wheel alignment until you go straight without leaning to the side.

Offline Stan Back

  • Hero Member
  • *****
  • Posts: 5879
Re: MPS-PG-650 build
« Reply #9 on: November 21, 2011, 02:23:55 PM »
until you go straight without leaning to the side . . . or crashing.
Past (Only) Member of the San Berdoo Roadsters -- "California's Most-Exclusive Roadster Club" -- 19 Years of Bonneville and/or El Mirage Street Roadster Records

Offline Koncretekid

  • Hero Member
  • *****
  • Posts: 1203
Re: MPS-PG-650 build
« Reply #10 on: November 26, 2011, 08:15:41 AM »
Jim,
I'm sure you realized that the CBR used the motor as a stressed lower frame member, and your CBX motor doesn't connect to those lower spars in your photographs.  I think you will need to replicate the lost support from the non-existent motor. 

Wheel alignment does not need to be mental.  Simply coast down a long hill with no hands on the bars.  The wheels are out of line if you need to lean to one side in order to go straight.  Simply adjust the wheel alignment until you go straight without leaning to the side.

Unless you're on a BSA single cylinder bike, which has the motor offset to the left about 1-1/2".  Likes to turn left, OK on a NASCAR oval.  Interestingly enough, it still seems to handle pretty well at speed.

Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
Re: MPS-PG-650 build
« Reply #11 on: November 26, 2011, 11:45:23 AM »
Correct, I'm adding a lower cradle that will use the same mounting method that has worked well on my A- bike.  The V-twin has to "insert" from the left, due to the strange location of the motor mounts.  Actually, the mount pattern is "around the crankshaft" similar to a front wheel drive  automobile.  In the original shaft drive orientation, it appears that the back case of the engine is the strong point.  When the engine is disassembled, it reveals the "front" (my "right") side mounts are the beefy ones into the block.  The back case is a really thin shell (my "left" case).  That is why I'm able to make the chain drive conversion work....not much load on that left case.

Basically, the frame will have a cradle bolted to the original CBR engine mount areas.  Most of the engine load will carry in the cradle, and the cradle becomes the lower stiffener from steering head to swing arm pivot area, along with the CX engine block.

Regards, JimL

Offline Koncretekid

  • Hero Member
  • *****
  • Posts: 1203
Re: MPS-PG-650 build
« Reply #12 on: November 26, 2011, 12:52:06 PM »
Jim,
Actually, I probably miss-spoke when I said that Honda used the motor as a stressed lower frame member.  I don't know that and shouldn't have said that.  I should have said that it appeared that Honda used the motor as a stressed member.  Sorry, but you have taken the necessary precautions, anyway.  Sometimes the engineer in me gets ahead of my mouth, or my mouth get ahead of my brain.
Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
Re: MPS-PG-650 build
« Reply #13 on: November 26, 2011, 11:15:29 PM »
I'm waiting to hear from SCTA what build method will be allowed.  The new rule about the perimeter tubes could be interpreted a lot of ways, so it's time to wait and see.

Regards, JimL
« Last Edit: November 26, 2011, 11:17:40 PM by JimL »

Offline JimL

  • Sr. Member
  • ****
  • Posts: 799
Re: MPS-PG-650 build
« Reply #14 on: November 27, 2011, 11:18:47 PM »
Always amazing how the first idea is the best.  When I first started this, I envisioned the engine leaned forward and both carbs and exhaust below the perimeter frame.  Then, I thought "wouldn't it be cool to have the rear head above the frame".  Of course that idea led to questions about welding mounts to the top of the perimeter frame (and the new rules).

I was looking at the thing tonight, and realised the countershaft sprocket wouldn't line up.  To make a long story short, I dropped the engine lower, and forward, and everything will work.  A bolt on cradle will fit it to the stock CBR mounts, and the carbs and pipes will fit without reworking the gas tank.  Saves repainting the frame, also!

Meanwhile, got the APS-PG-650 bike fired up today.  It started well (I was a little worried about the starter running against the new 14.3:1 pistons), and sounds great.  Tomorrow I'll put the fiberglass back on and load it on the trailer, ready for Speedweek.  Gotta' move fast; won't have a work space or a house after the first of the year! :-P
« Last Edit: November 27, 2011, 11:26:41 PM by JimL »