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Tips for New RE5 Owners
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offlinePaulClarkRS
Tips for New RE5 Owners
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Jul 6 03 1:07 AM

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hi,

sounds like classic re5 behavior. there is indeed a dead spot between the opening of the primary and secondary carb circuits (your re5 has a two-barrel carb, like a car). i've pasted below some excerpts from past posts to this list , talking about tuning and adjusting.


realize that the very crucial adjustment on this bike is in the cables,
between the primary pull (carb) cable and the port valve pull cable. if it
runs, and there's no serious flat spot where the secondary throttle opens,
then you're very very lucky. (from the factory, it was pretty smooth, but
getting back to this sweet spot is the subject of the rest of our lives of
twiddling). so again, the crucial adjustments are the length of the carb &
port vavle pull cables. these control whether the port valve opens in sync
with the secondary throttle- the port valve is like another throttle
butterfly in the intake right before the combustion chamber. if it were open
at idle, the secondary intake passage would be a dead space and would fill
with exhaust, causing bogging upon acceleration. likewise, if the secondary
opens before the port valve does, nothing happens. either way there's a flat
spot, but of two different characters... if you think the rotary engine
sound is sweet now, wait until you've listened attentively to the most
subtle changes as you tune it... it's addictive, i tell you...
the way to make this adjustment is with a little protractor tool available
from rotary recycle, which you WILL need... it screws onto the throttle
shaft through the side cover and allows you to measure exact degrees of
throttle opening, so you can adjust the port valve to move in sync with it.

the fifth cable is for adjusting the metering oil pump (pull its cover and
line up the marks at full throttle) to ensure proper apex oiling. the other
two return cables are adjusted by tension, to take up the slack.

the other major adjustment to be made is the brass metering screw on top of
the carb, which seems to work in the 1/2 turn to 1 1/2 turn (outwards from
seated) range. this will affect idle performance and wide-open performance,
as well as whether the plugs tend to foul, but people do disagree on what
adjustment works best for them. timing is checked via the timing
inspection cover on hte engine left side.


I've posted the factory tuneup procedure at
www.nwlink.com/~paulcl/re5

------------------

However, it sounds like you are dealing with the classic port valve
adjustment issue. Unless you have thrown your carb down the stairs, or
crashed it, the secondaries should be opening exactly where they should.
It's not a matter of carb sync per se.

The port valve is a butterfly valve that is much like a throttle valve
(between what you could imagine as the intake and head if this were a piston
motor) The idea is that with the secondary throttle closed, the whole
secondary intake chamber becomes this big empty space where exhaust gases
can congregate from the power unit. Then, when the secondaries start to
open, it leans out badly. To fix this, the port valve seals off the
secondary intake chamber until the secondary throttle begins to open. If it
opens too soon, you get the leaning out effect as mentioned. If it opens too
late, there is a dead spot, because even though the secondary throttle is
open, the port valve still keeps that circuit closed.

This adjustment is made by adjusting the a throttle cable that runs to the
port valve area, just rearward of the carb (to the right when looking from
the left side of the bike) There's a little cover you take off, and two
wheels- one turns as the throttle cables pull, the other starts to turn when
the first wheel gets partway round. This should happen just as the
secondaries open, which is 35 degrees of throttle opening (measured at the
carb) The smart way to measure this is the classic rotary carb tool, which
is essentially a protractor attached to a fitting that attaches to the carb
throttle shaft behind that little rubber plug on teh rearward side of the
carb. Sam Constanzo sells them, or you might improvise your own (I like
Sam's version though). This adjustment is to be made on the pull (upper)
cable, then adjust the return cable for 1-2 mm of play.
--------------------

a couple words of advice-

-change the oil in the metering tank (under the seat)
-follow the procedure for checking whether the metering pump is indeed
sending oil to the carb (lubricating the apex seals, vital for the motor's
survival.
-if it runs right, DON"T touch the cables- adjustment ot the five throttle
cables is crucial, finicky, and if they are out of whack you will get the
famous 'flat spot' between the primary and secondary circuits upon
acceleration
-remember those wheels are not only narrow as those on a modern 400, but
they're flexy aluminum... the RE5 will way way out-accelerate it's own
handling, so be careful!
-run Castrol 20W50 everywhere in the bike- main oil sump, trans sump, and
metering tank.

you can get parts and advice from Sam Constanzo at www.rotaryrecycle.net

------------------------------------

> Secondly,How do RE5's lubricate Apex seals, are they premix, or
> oil injection?
>

oil injection into the carb. there is a tank of metering oil under the seat
with a hose that runs to the metering oil pump, which is on the engine
behind the radiator on the right side. this pumps a variable amount of oil
depending on engine conditions via a tube that attaches to the top front of
the carb (sam described this to me as the 'lifeline' of the re5 engine.)
One of the 5 throttle cables goes to the metering oil pump- under more open
throttle, more oil is injected into the float bowl to preserve the apex
seals. this is one thing that should always be adjusted on an unknown RE5,
or one in which the cables have been messed with. remove the metering pump
cover, and there is a little wheel that turns as the throttle is opened. at
full throttle there is a mark on the wheel that should line up with a
reference mark next to it- adjustment is made by a cable adjuster nearby. It
won't hurt the engine to fire it up for test purposes without this
adjustment, but it is important to the longevity of the engine to have it
set correctly, and it's part of the tuneup procedure.
there is also a test that shoudl be made to make sure th metering pump is
pumping enough volume- i believe it amounts to disconnecting the lifeline
and cranking the starter with the spark plug disconnected- there is a
certain number of drops of oil per minute you should get, but i cant recall
it offhand- one of the otehre list members will know, im sure.
the same metering pump also feeds the auto chain oiler which is so messy
and can be blocked off when you convert to a modern sealed lube chain.


> What is the current consensus on lubricants for the RE5, ie is
> Synthetic reccommended?

the best oil is Castrol 20W50 GT, becasue it has a far less ash content when
burned than otehr oils- keeps the combustion chamber from gunking up. Use
this oil in teh meterin tank, engine sump, and transmission.
There are a couple other brands I've heard of as substitutes, but i dont
recall them offhand.
----------------------------------
>When tracing the wires, I noticed that one wire (red/black) that
>comes from the left set of points (when facing the points), has
>been disconnected, and taped up, under the tank.

>Does the bike have 2 sets of points, to fire the plug twice,
>because of the elongated combustion chamber?

No, it has a second set so that under low-rev conditions it will fire half
as often, to scavenge exhaust gas. It didn't really work, so this was
discontinued the followign year.




>I assume the correct thing to do is to get both sets of points
>working properly.

Yeah... or disconnect the single-lobed set and block the line to the vacuum switch so it stays on the double-lobed points.

And check your timing. Use a regular automotive test light, and remove the
timing inspection cover on tehleft side. From memory, I'd say you want the
timing set at about 8-10 degrees BTDC.

Be warned that the timing is very cranky to set- basically, tightening the
holdown screws will tweak it enough to throw it out of whack. Just be
careful and patient.

---------------------------------

anything missing in there? i tried to copy as much useful stuff as i could find from old posts...

paul


>What is the difference between an "A" - -
>and an "M" ? What do you suppose my 1975 is? They have different
>carbs?

The RE5 M is the original '75 with the Giugiardo styling.


also:
www.rotaryrecycle.net/htm..._parts.htm

At the end of the year, however, it was a disasterous unsuccess. Dealers
were stuck with all these bikes no one wanted (remember, it went for 2400$
new, and that was a lot in '75! It had to compete with the BMW r90 and the
Kawasaki Z1 for the bang-for-your-buck in that league, a lot to ask for a
first-generation powerplant)

The Giugiardo styling had been a point of contention with Suzuki's RE5 team
anyway. They had developed their own design for it, which more or less
looked like other conventional bikes of the time. The top bigwigs had pushed
Giugiardo's involvement on the team pretty much against their will, so when
the M's didn't sell, they were quick to argue that by all accounts their
design would sell better.
So for '76, they switched back to the in-house Suzuki design. In
fact, a majority of the '76 model were '75's that were retrofitted with the
'76 parts. this meant changing the Instrument panel, the headlight bucket,
the turnsignals, and the taillight, and these were supplied as a conversion
kit, along with the factory service bulletin explaining how to make the
change. Also, two new colors (black and white) were available for the
sidecovers and tank, and a new decal set was available.

This was known as the RE5 A ('76 model year):

www.rotaryrecycle.net/html/catalog.html

It was also somewhat common to see people remove and discard the crash bars
and the plastic fins on teh side of the radiator. This makes the bike some
2" narrower, making it seem much more normal in width than the M.

Now, Suzuki had issued a series of service bulletins, calling for updates to
improve the RE5's performance and solve certain problems. When the '76 was
released, there was an additional set of changes, including eliminating the
second set of points and the speed sensor that switched them. The '76's were
shipped without these; converted '75's had them removed. This was also the
logical time for making the other adjustments called for by the updates.
This included advancing the timing from 8-10 BTDC to 5 BTDC, and changing
the advance positions marked on the alternator (I'll post details on this
when I get them). Improved cable adjustment procedures were also given.
The A also had a 'different' carb, which to my knowledge mainly has
a plastic spacer added between the carb and intake, to solve problems with
carb overheating from all the rotary engine's heat. If there are other
differences, I'd like to know about them.

As far as differences in performance, supposedly all the updates were
improvements, but I too have the experience that my 'M' feels like a much
different beast than the A's or converted M's I've seen. it almost makes me
feel like some of the changes might have improved smoothness but lost a
little performance edge? This is entirely subjective, I could be wrong, but
thats the feel to me. My plan is to go through the updates one by one on
mine and see if this is true- some things, like the dual points, I might
just keep the old way.

BTW- credit on this history rant is due to both my friend Andrew, and to Sam
Constanzo, as well as to a number of articles of the time which I've
recently been coming across, and assorted wisdom from you all on this list.
I'm forwarding info to the best of my knowledge, if someone can correct me
or fill in details, I'd enjoy it.





--------------------------------
The whole point of the dual point system, as you'll see when you pop the
distributor cover, is that one set has a cam with twice as many lobes- this
is the 'normal' set, which fires at every compression. The idea was then to
switch to firing half as often under certain conditions- high rev and high
vacuum, like upon deacceleration, or coasting. Apparently the idea was to
improve roughness in that range... though I think it's fair to suggest that
the results are very subjective.

The mid-year factory update called for disconnecting the half-firing points,
and 76's were all shipped that way (and to put it another way, points were
disconnected as part of the conversion of many 75's to 76's). Basically you
snip off and seal up the wire to the second points, and disconnect the speed
and vacuum sensor.

I didn't bother to disconnect everything, I just didn't install the second
points when I put the distributor back together, and I shut off the vacuum
switch crudely and rudely (though effectively) by clamping one of those
office butterfly report clamps, the black and silver things with the little
swinging wire handles, on the vaccuum line, a black plastic hose that goes
from the top of the carb (left side) to a diaphragm mounted on the front of
the frame.

At first, with only one set of points but the vacuum line open, the engine
would shut off completely and rather disconcertingly every time you'd
deacellerate- it would certianly fire up again with throttle, but the result
was rather jerky, and left me worried every time. By blocking the vacuum
line, it never senses a high vacuum condition, no matter what the speed
sensor says, and you stay on the main points all the time.

I'd kinda like to convert mine back to the original dual points, because it
would be interesting to compare the two- ride it under decelleration
conditions, then try it again while clamping the hose. Maybe those on the
list with working dual-point systems can tell us what they think. Although I
have to admit, this presumes that everything else about the bike is runnign
so well that i have nothing to tinker with...

-------------------------------




<< Previous Topic

[wayne]

Good to see it almost all in one place. The only thing I'd guard against here is the belief that the port valve opens at the same time or just after the secondary. That makes sense, and the reason given for the existence of the port valve in that information is correct.

However, apparently in a logic defying move, a correctly timed port valve starts to open BEFORE the secondary starts to open (by a minimum of 6 degrees in fact). Perhaps it's a fluid inertia thing, I don't know.

Use the angle gauge and remember that "Zero" is with the primary butterfly COMPLETELY closed. Make sure all adjusters affecting it are wound fully in not forgetting the one under the throttle block on the handlebars, even then, you may need to lightly push the butterfly closed with something soft to get a position to which you can reference the angle gauge to zero.

Otherwise, forget the fiddly angle gauge and time the PV to open precisely when the limiter plate (front right side of carby) starts to move. This should be the latest that it would be opening. So just work backwards from this position opening up the adjuster bit by bit until the transition becomes smooth (after you've thoroughly cleaned your carby).

As for the B points, I've ridden with a B point plug set up to hang outside the bike thus allowing me to disconnect and reconnect in a few seconds. I could directly compare B point running with no B point running instantaneously on fixed sections of known roads. I came to my own conclusion but based on directly comparable empirical testing. Same road, same bike, same rider, same day, same temperature, same fuel etc.