eMTB Build Costs

This is just a little page to outline the total build cost on my homemade mid mount eMTB

Mid frame swap

Bearing Swap

HAL sensor issue

Crank Issue (original crank)

Build Costs

Rat Bike!

Graphical PXE Boot Menu example

Using syslinux 4.02. This example has nested menus that use separate menu files. Also a pretty background.

--

UI vesamenu.c32                                
PROMPT 0                                    
TIMEOUT 600                                  
TOTALTIMEOUT 6000                            
ONTIMEOUT local                              
#MENU RESOLUTION 1024 768
MENU BACKGROUND pxebackground.png
MENU TITLE Boot Menu    
MENU AUTOBOOT Will boot the next device as configured in your BIOS in # second{,s}.
MENU TABMSG   Press the key to edit the boot parameters of the highlighted option.
#MENU NOTABMSG Editing of this option is disabled.                                    
MENU COLOR screen      0  #80ffffff #00000000 std      # background colour not covered by the splash image
MENU COLOR border      0  #ffffffff #ee000000 std      # The wire-frame border                          
MENU COLOR title       0  #ffff3f7f #ee000000 std      # Menu title text                                
MENU COLOR sel         0  #ff00dfdf #ee000000 std      # Selected menu option                          
MENU COLOR hotsel      0  #ff7f7fff #ee000000 std      # The selected hotkey (set with ^ in MENU LABEL)
MENU COLOR unsel       0  #ffffffff #ee000000 std      # Unselected menu options                        
MENU COLOR hotkey      0  #ff7f7fff #ee000000 std      # Unselected hotkeys (set with ^ in MENU LABEL)  
MENU COLOR tabmsg      0  #c07f7fff #00000000 std      # Tab text                                      
MENU COLOR timeout_msg 0  #8000dfdf #00000000 std      # Timout text                                    
MENU COLOR timeout     0  #c0ff3f7f #00000000 std      # Timout counter                                
MENU COLOR disabled    0  #807f7f7f #ee000000 std      # Disabled menu options, including SEPARATORs    
MENU COLOR cmdmark     0  #c000ffff #ee000000 std      # Command line marker - The '> ' on the left when editing an option
MENU COLOR cmdline     0  #c0ffffff #ee000000 std      # Command line - The text being edited
# Options below haven't been tested, descriptions may be lacking.
MENU COLOR scrollbar   0  #40000000 #00000000 std      # Scroll bar
MENU COLOR pwdborder   0  #80ffffff #20ffffff std      # Password box wire-frame border
MENU COLOR pwdheader   0  #80ff8080 #20ffffff std      # Password box header
MENU COLOR pwdentry    0  #80ffffff #20ffffff std      # Password entry field
MENU COLOR help        0  #c0ffffff #00000000 std      # Help text, if set via 'TEXT HELP ... ENDTEXT'
MENU WIDTH 80
MENU MARGIN 20
MENU PASSWORDMARGIN 3
MENU ROWS 6
MENU TABMSGROW 18
MENU CMDLINEROW 18
MENU ENDROW -1
MENU PASSWORDROW 11
MENU TIMEOUTROW 13
MENU VSHIFT 8
MENU PASSPROMPT Enter Password:
NOESCAPE 1
ALLOWOPTIONS 0
LABEL local
        MENU LABEL ^A) Boot Local Disk
        MENU DEFAULT
        localboot 0
MENU BEGIN workstations
        MENU TITLE Workstation Images
        LABEL Previous
        MENU LABEL ^B) Previous Menu
        MENU EXIT
        MENU SEPARATOR
        MENU INCLUDE workstations
MENU END
MENU BEGIN tools
        MENU TITLE Tools
        LABEL Previous
        MENU LABEL ^C) Previous Menu
        MENU EXIT
        MENU SEPARATOR
        MENU INCLUDE tools
MENU END​

PXE menu black screen flashing cursor

Some older machines don't always boot past vesamenu.c32 on later versions of syslinux (>4.02).  This is documented on the syslinux machine, search for issues with LOCALBOOT.

I had this recently with a render farm containing some BIOS versions that wouldn't localboot. For this reason we could create a separate menu file for machines that network (0A02CC). This file is called render.default and symlinked.

lrwxrwxrwx 1 root root   14 Oct  8 09:46 0A02CC -> render.default
-rw-r--r-- 1 root root 2703 Sep 29 11:46 default
-rw-r--r-- 1 root root  214 Oct  8 09:49 readme.txt
-rw-r--r-- 1 root root   98 Oct  8 09:42 render.default

[root@zeus pxelinux.cfg]# cat 0A02CC
DEFAULT menu.c32
PROMPT 0
TIMEOUT 50
ONTIMEOUT local
MENU TITLE Render Node Menu

LABEL local
        MENU LABEL Boot Local Disk
        COM32 chain.c32
        APPEND hd0

The LOCALBOOT cannot work properly on some supermicro servers. The solution is using chain.c32 module and following syntax to boot up the first hard drive​

4 Stroking - Solved

I had a bit of an epiphany moment when I realised that the idle to 1/4 is actually adjusted in three ways, not two.

Once I looked at the diagram a little closer I noticed that 

1) The air/fuel screen controls idle to 1/4 movement through a hole down stream from the slide

2) The slide cut out effects the mixture in that range as well. 

3) However ALSO the size of the idle jet effects fuel coming out of a hole just inside the slide. It is not regulated by the mixture screw at all.

I had been thinking that the mixture screw would be enough to compensate for the difference between 55 and 50 pilot jets. In fact there are 2 sizes between those, being 53 and 52. 55 was too rich, and always was. 50 was too lean and I couldn't make it rich enough. It's obvious when I think about it now, but I thought the screw adjustment would be enough.

I have since ordered the in-between sizes and had a chance to install 53 today and the 4 stroking is almost completely gone.

Now the changes I make to the mixture screw are apparent and obvious.  I am able to find the 4 stroking by increasing the idle speed, lean out the mixture till the revs increase and even out, and then back it off (richen it) by 1/4 of a turn which helps pick up off idle.

I'm going to try a 54 when it arrives from Italy, but I am so close now I am happy. 

Happy days!

Useful SSH configs

Put these in ~/.ssh/config

They help with repetitive tasks and such

Host *
     Compression yes
     ForwardX11 yes
     CompressionLevel 7
     Cipher blowfish
     ServerAliveInterval 600
     ControlMaster auto
     ControlPath /tmp/ssh-%r@%h:%p
     StrictHostKeyChecking no

Host 100.7.*
     StrictHostKeyChecking no
     UserKnownHostsFile=/dev/null

Kytronic Smart Booster 2

After thinking about this for almost 20 years, finally someone made one!

Key features of Smart Booster2 include:

• Increases significantly acceleration and power
• Reduces mechanical stress and temperature at high-rpm
• Reduces gas consumption
• Plug-and-Play, simple to setup, no battery needed
• 16 ignition timing curves, tailored to your engine for best efficiency
• Protected under epoxy resin in a customized red ABS plastic case

http://www.kytronik.com/sb2

Here is a quick photo gallery of my install process and as a bonus I had to replace all of the wiring on the stator plate.

As it arrived, with free sticker!!

Old timing marks, I actually had it set more advanced than this as you can tell from the modified slots.

Real vintage wiring!

Reboot...

...with heat shrink

unit fitted (need to replace that dodgy looking coil though)

New timing Marks. My bike is kitted with a Polini so it likes to fire @ 2mm from BTDC, or around 18 degrees. This unit changes all that, it will advance it where it needs to then back it off at higher revs to lower temp, and smooth out the engine. I'm running a squish clearance of almost 2mm and I monitor the cylinder head temp so I feel comfortable running it at around 18 degrees advance at high revs, hopefully even in Sydney summer time.

Getting rid of 4-stroking - The quest

Overview

In my last post I said that I had been trying to get rid of my scooters 4 stroking for over 10 years. It's actually quite a lot longer than that actually, and it's really starting to but me. I've decided to jot everything down in this blog in at attempt to make it less baffling (no pun intended) and possibly help anyone else that has a similar issue.

In the last post I went over the port timing, this time I'll go over the carb jetting.

Descriptions of symptoms

The thing that I can't get my head around is that everything I read tells me that 4-stroking is due to being too rich (we actually the cause is that the scavenging effect of the 2 stroke process isn't getting a chance to work on the amount of gas in the cylinder, so we could look at retarding the timing - more on that later). The thing is, if I lean out the idle any more it is just too lean., very slow to die down to idle speed, uneven, no power to pull off. But if I get the mixture "just right", the idle is nice and constant at around 1500rpm. The problem is as soon as I am moving and I position the throttle "just" off idle, the engine 4-strokes.

Current settings

I have a Dellorto 28 PHPB with a Ram-Air foam filter. 
Main - 128
Pilot - 55
Choke - 70
Slide - 60 (modified)
Needle - x2 (middle ring)
Atomiser - AV262
White float


Today I tried once again messing around with the air mixture, and took the air filter off to see if that was causing the bike to run rich off idle. Neither helped.

Next I retarded the timing by a couple of degrees to around 17 BTDC, this actually seemed to make the engine more rough in other places (which I can understand, the low down torque would be better with more advance, my variable timing module is on the way). Anyway, the timing retard didn't help the 4-stroking issue.

Conclusion

I'm beginning to think that all kitted Vespas do this.

EDIT

I started to think that I might be overcompensating for the lean slide by an over rich idle mixture setting (it was around 3 turns out). The two circuits to overlap quite a lot, especially in higher idle screw settings.

So I changed my over lean 60 slide for a 50 (unmodified) and swapped the 55 pilot jet for a 50. 

At first it was over rich everywhere, but I after some adjustment I was able to get the idle pretty nice, screw is around 2.5 turns out which is correct for the PHBH carb. Middle openings where very rich so I lowered the needle to it's most lean position (top notch).

The engine pulls well now and the 4 stroking is much better. It is still there though, but at least I know the engine is not too lean!

Depending on the weather I might need to change the atomiser for a AV260 and raise the needle right up but I want to play it safe for now.

I did a plug chop and it's nice and brown. Max CHT was 149 degrees C after a good WOT blat.

I'm hoping that the variable ignition timing unit will help even more.

EDIT 2

See next post when I finally solve this!

Vespa - Polini 208 Port timing

Port Timings

Background

Ever since I put a 60mm crank on scooter I have been suspicious that the port timing had been messed up. I remember about 10 years ago I rang Terry at Taff speed, when he was still alive, and he told me that I should stick with the 57mm crank. I had already put the long stroke crank in at that stage so I couldn't bear undoing all of the work (or money).

Symptoms

• Difficulty getting the low speed jetting right. 
• Rough running just off idle (4 stroking)

Forward wind lots of years and I finally got a chance to take a proper look, hopefully anyone else with a similar kit will find my findings useful.

Current build

• PX200 engine 
• Cast iron Polini 208 kit, port matched transfer ports in the casings. 
• A Worb5 head machined for the long stroke crank (it has a 1.5mm squish and the plug is moved toward the centre). 
• A 60mm racing crank
• SIP 1.5KG full size balanced racing flywheel
• 28mm Delorto
• SIP racing clutch (very nice)
• SIP clutch bearing actuator
• Max. CHT temp. 160 Degrees C
• Max compression 150psi (warm, WOT).
• Ignition timing 19 degrees BTDC

I was running the kit with no base gasket and no head gasket. 

The squish was around 1.2mm which is about ideal for racing (Norris Ker recommends 1mm in his book). 

The jetting was about right (apart from the 4 stroking bottom end, usually found due to being to rich). I've been playing with jetting and slide modifications for years and still not got it perfect.

Ignition timing was around 19 BTDC (or around 2.5mm piston movement).

Stock Polini port timings

"Apparently" the stock Polini kit has port timings of 123° transfers to 171°exhaust timing with the 57mm crankshaft, but that information does vary depending on where I find it on the web. 

Another site said 161.2; 112.8; 21.2 which is miles off what I found and I do question.

My port timings

My initial port timings with this set up where:

• Exhaust port open: 262 degrees
• Transfer open: 238 degrees
• Transfer close:115 degrees
• Exhaust close: 91 degrees

The sums

Exhaust port open - Exhaust close = exhaust port duration

Transfer open -  Transfer close = transfer duration

Exhaust port duration - exhaust port duration / 2 = Blowdown

• Exhaust duration: 171 degrees
• Transfer duration: 123 degrees
• Blowdown: 24 degrees

This is pretty much exactly what I had found the Polini 208 kit to be, so the long stroke hadn't really effected the port timing much, if at all. I did want to get the rough running sorted though so I elected (easy to vote when there is only one of you) to install the base gasket which did alter the port timings a little.

Piston just clearing the transfer port.

Finding TDC

Modified Port Timings

"To alter or not to alter"

I chose not to alter the height of the exhaust port, even though my calculations found that I my ports timings where very close to the edge of what is recommend. I put this down to Mr. Polini knowing best and left it there. Besides, I want a grunty engine for riding around town, I've given up on the super high revving 2 stroke scooters.

Taken from http://www.race-base.com/2t-tools/steuerzeit/

So all I ended up doing was cleaning up all of the ports up a bit, and installing a 0.3mm base gasket and a 0.7mm head gasket. This gave me the following set-up.

• Exhaust duration: 174 degrees
• Transfer duration: 125 degrees
• Blowdown: 24.5 degrees
• Squish clearance: 1.9 mm

Some greasy scribblings

I also backed off the ignition timing to 18 degrees BTDC

Test ride

With the slightly revised port timing, the relaxed ignition timing and the reduced compression the engine feels smoother across the rev range, and does tend to reach high revs more easily (not a surprise as I have marginally raised the port timings. Given the reduction in compression I was surprised it still pulls very well. 

CHT measured at a MAX. of 151 degrees which is quite acceptable.

Conclusion

All in all it was worth while to go through this exercise, one to put my mind at rest about the timings, but also because the bike does go better. 

It does still 4 stroke a little just off idle though...