Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties auto timer

auto timer

Post Mon Aug 12, 2013 4:10 pm

Posts: 13
Location: UK
Hi there, only the second time I've put a question on this excellent forum,
building a popular motor -WL/K and intend using a Sportster auto timer.
How did Harley modify the timer for use on the Model G servicer?.
I have two timers , one has pegs underneath the bob weights, the other
has the pegs on top, assuming they both restrict movement.
I believe side valve motors have 15 degrees initial advance then a further 15 degrees
for full advance, maybe someone has fitted one of these to a flathead?.
As a side note is there electronic ignition still available for this unit?
Look forward to your opions

Post Wed Aug 14, 2013 8:58 pm

Posts: 1676
Location: Interlaken, NY USA

I think the ones with the "pegs" on the bottom is the later style. Easy way to restrict the advance, is to just change the "peg", which is actually a roll pin for the next size up pin. Knock out the present pin, drill the proper hole for a tight fit on the new pins, and just drift them in. They do a great job. I actually time my units at about 4-6 degrees advance static, and the full advance works out right. I don't have the actual figures here in the house, all the data is out in the shop. But that's the solution if you're actually starting out with a sporty auto advance unit. It knocks the timing range from about 20 degrees to 14. You can play with the weight springs as well. On the BTSV engines I've added the timer to, I prefer the later springs that don't give full advance right away, as the old 45 units did. Gives more low speed grunt," like a flathead should". I think full advance is around 2000 engine rpms with those newer springs.

Post Sat Aug 17, 2013 3:24 pm

Posts: 13
Location: UK
Many thanks for that information DD I noticed the earlier timer has a fixed amount
of movement where the later one doesn't seem to have a limit on the advance
unless I'm missing something?.
Thought I would just list the spec of the bike I'm in the process of building.
As mentioned before WL lower end and K cyls. and heads
stock flywheels offset bored for sportster pin and rods ,rebalanced
+050 pistons with bevel edge added
heads modified to KR profile and checked for volume
one piece stainless KR pattern valves
double mini valve springs , KR spring covers
45 parts depot tappet guides, lightened sportster tappets
full set of khk cams , needle roller bearings in cam cover
oil feed to front cylinder from return line ,inline cartridge filter
oil system fairly stock at the moment
Triumph pre-unit gearbox , duplex primary drive, stock ratio's
housed in Norton wideline frame ,new forks - external springs
1969 2ls front brake, T140 rear disc for better ratio options

That's it for now , still need to make some exhausts, not sure whether
two singles or two into one , and also to make a seat.
Hope this is of interest wryders

Post Sat Aug 17, 2013 3:52 pm

Posts: 13
Location: UK
Just to follow on from the motor spec as I'm running an extra 1/4 inch
of stroke , any idea's for ignition and cam timing , maybe start at 32'
btc ,somewhere between K and KHK . I've timed the cams to the
standard marks but this might benefit to a slight change , maybe
retard them one tooth, it might be a case of seeing how the
motor runs before second guesting the outcome?
Thanks for looking

Post Sun Aug 18, 2013 9:15 am

Posts: 131
Location: BRANFORD, CT

Hi Guys,
I thought I would add some information based on some dyno tests we recently did.
Bone stock WL except for pop up pistons and # 6 heads using my KHK profiles.
Advancing the intake cams only, 4º gives a increase on 3-4 HP over stock cam timing.
This is in line with Sifton information on the KHK profile from Jeff Diamond, aka Panic, & Victory Library that advancing the intake only by 1 tooth (6.4º) adds 3-4 HP.
We show a increase in low end torque and top RPM.
Measured on a DYNOmite crankshaft dynometer.
Bruce Argetsinger
AHRMA Dirt Track # 67J

Post Mon Aug 19, 2013 6:51 pm

Posts: 1676
Location: Interlaken, NY USA

Hi Bruce, Gee, wish I'd known that before I welded on my new lobes on Frankenstein last year :D Ah, so it goes. Missed you at Brookfield, nice meet, good weather.
I actually had a document for you in hand!

Post Wed Aug 21, 2013 3:25 pm

Posts: 13
Location: UK
Hello Bruce,
Thanks for sharing that interesting piece of information regarding
KHK cam timing , mine are set on the standard marks at the moment
would it be a benefit to advance my inlets even with the extra
1/4 inch of stroke in the motor? .
Using your excellent seals on the manifold


Post Wed Aug 21, 2013 4:23 pm

Posts: 369
Location: Bergen, Norway
Bruce. Thanks for sharing.
When I did my 4 7/16 stroker some yrs back I had Leineweber reccomending profiles and doing the regrinding. The cams are also advaced with an offset key on the pin.shaft. This was beforc Bruce started making the lobes. Now I have a set of his KHK lobes for the next project : )
The ginds Leineweber provided made the bike really happy. Only problem now are the brakes and the need for a steering damper. On the ingniton side I did some trials and set a high speed and idle advance. Btw this a magneto with and manual retarding controlled by the left twist grip. If of interest I can dig out the cam specs and ing spec once Im back home in a weeks time. Gus

Post Sun Aug 25, 2013 6:18 am

Posts: 13
Location: UK
Thanks for that , yes any additional information will be helpful as
I'm new to this in depth technical stuff and like to get the motor
set up as good as I can from the get go.
Found some roll pins , not sure the best one to use, stock size
appears to be .096 , next is .112 and then .0131 so the difference
between the first two is .016 half of which is the new limit on
the bob weight movement when retarded, am I right on this theory?
Thanks whryders

Post Fri Sep 13, 2013 6:08 pm

Posts: 112
all the auto timers give 15 degrees advance unless the holes or pins are worn out. the weights with the pins on top are probably out of a nosecone motor flipped upside down. some can be used if you push the pins through to the bottom side. note a sportster timer will need the shaft trimmed to fit down into a 45. and get a set of 2,000 rpm springs you will like them much bettor than the full advance as soon as it starts early stock springs.

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