$4 gallon gas, thinking of leaning out mixture

[hb7]

from the german page you see that the last Tenerés had a smaller main jet, 122, to better comply with CO measuring. You can safely try that and it should improve mileage.
Changing to a Mikuni TM34-B65 flatslide will get you much better mileage and performance as well.

Enquiring mind asks how does the mikuni TM34-B65 flatslide get better mileage.....do they carburate the fuel better ?
Do you have any mpg numbers for TM34-B65 flatslides ? Better performance too or is that throttle response ?

I know from 75k miles that the stock Teikei gets 40-43 mpg on California bs gas with an 80L box attached at 70-75 miles an hour.
Plug is clean, but looks a little rich on the edges.

[harold]

From my experience, with Mikunis at least, your highway gas mileage has nothing to do with your main jet. You are only running on it when over 3/4 throttle, i.e. when accelerating. I have mine marked out at quarter points, and at 70 mph I am at 1/4 throttle. That means it is running on the pilot jet and some of the un-tapered part of the needle. Your results may vary.

[Bill Jurgenson]

Do you have any mpg numbers for TM34-B65 flatslides ?

european driving habits: 270-300km/tank, i.e. to opening the reserve, with the Teikei
at least 50km more with the TM34-B65
I have posted these numbers several time. You can figure the mileage out yourself

Better performance too or is that throttle response ?

both.
the TM34 with airbox/K&N and no snorkel returns about 5 more hp with a stock engine.
I ran my red one (engine completely stock, Remus Cup exhaust, Brembo SZR wheels, 15/43 gearing) from Milano to Torino on the Autostrada at a near constant 180kmh, sometimes 190 i.e. That is faster than a stock Skorpion will go at all.

[hb7]

Converting to mpg : Teikei 47 mpg or 4 gals for 300 Kms and the Mikuni 55 mpg or 4 gals for 350 Kms
or about 14.5% better economy. That's fantastic...
On California thin gasoline, you will never see 47 mpg, with the ethanol maybe 43 mpg. Mostly 39-40 mpg....

On the Mikuni , I understand you have to change the throttle linkages and control ? What parts do you use ?

[cat]

hmm, we could almost do the arithmetic and figure out how many km to cover the $500+ for the Mikunis.
Anyway, 3-5 hp sounds good, and throttle response too - even better.
I wonder how it would fit the Baghira. It looks like the height would not be a problem like with the Keihins. What is the difference with the throttle linkage? Different cable lugs?

[hb7]

Now add one more choice : 42mm Flatslide Mikuni Single Carb Conversion Kit
http://www.holeshot.com/old/mz/mz_sc.html

which way to go ? probably for the stock 660 road bike, the well seasoned TM34-B65.
I recall the 42mm Flatslide Mikuni Single Carb being described as a tight fit.

[basser23]

Ask Harold .....Baggie was a tight fit with homemade manifold,there are none available commercially,some use the Griz/Rhino manifold with an adapter plate ..

[edfmaniac]

Now add one more choice : 42mm Flatslide Mikuni Single Carb Conversion Kit
http://www.holeshot.com/old/mz/mz_sc.html

which way to go ? probably for the stock 660 road bike, the well seasoned TM34-B65.
I recall the 42mm Flatslide Mikuni Single Carb being described as a tight fit.

Those haven't been available for quite some time.

[edfmaniac]

If you are concerned with mileage and only mileage, adjust the screw that delays the secondary carb to it's maximum delay and never open the throttle enough to send vacuum to the second carb. You'll get around 60mpg. Either that or intentionally mount the diaphragm where it has a huge leak and doesn't work. When I bought my Skorpion from the previous owner, the secondary wasn't opening and I routinely got close to that 60 mark. Once I started doing the normal mods and maintenance, I quickly discovered the bad diaphragm seal, found tons of missing power and the mileage dropped to between 40 and 50 depending on my mood.

[cat]

Ask Harold .....Baggie was a tight fit with homemade manifold,there are none available commercially,some use the Griz/Rhino manifold with an adapter plate ..

He cut that cross-piece out of the frame - i'm not doing that.

[Bill Jurgenson]

On the Mikuni , I understand you have to change the throttle linkages and control ? What parts do you use ?

with the Skorpion, nothing of the sort.

hier in the red bike mentioned above, right into the original airbox.

Even still had the Grimeca wheels but had already gotten my custom rearsets that Chris Hunsicker later got.

hier in the blue Tour called the Toy:

here with one of those milled spacers between carb and head, this one from Barker.

You have to saw off the cable bracket that does not clear the tank:

and make your own simple one like in the photos above. The cables are the exact same ones that were always there. You can also hook up the choke from the bars to the left carb if you still have that little lever; I did not, having long since junked both the bars and the armatures.

I have no working knowledge of eh baggi beyond test driving but the dual setup as shown above will certianly fit just like in the shots. Anything longer gets into trouble, however as Harold found out.

There is really no use in discussing Galen Miller's (not Holeshot's- they only sold it) Bikeworx kit since it is no longer available. It was good on the Skorpion but does not fit the Baggi or SZR.
Of course, you can, like Harold, make your own but then one would not be asking these questions here in that case...

Bill

[hb7]

If you ask for this cable mount......it should be plug and play. No sawing...


One thing which is attractive about the 35mm FCRs is the slide rides on 4 needle bearings.
What are the differences between the Mikuni TM35-B65 and the Keihin 35mm FCRs, on the Skorpion ?
Are the FCR's taller than the Mikunis ? That would swing the advantage to Mikunis....
I read that Mikuni is regarded as better quality in Germany, but I can't see the difference.
The FCR's are easier to acquire in the USA....but if that means having a more difficult installation,
or tuning carbs under shade trees without a dyno or an o2 lambda probe : forgetabout it....

One thing, we have not discussed is that a 660 cc piston displaces 660 cc of air inside the crankcase. This is why we see
Bill adding larger venting hoses to vent the crankcase more effectively. It's effectively free ~2 hp....if the piston can displace the crankcase air
more easily at higher revs.

[Bill Jurgenson]

differences.
start with the price. the Keihins are much more expensive. they are also taller.

You can order the TM34-B70 for the Raptor which is a plug a play fit and it is also 100$ more expensive.
Doesn't cost me 100$ to modify for myself and besides, when I started this, the Raptor kit was not yet available.

the Keihins are generally regarded more highly than the Mikunis but many tuners like the Ms better cause they are easier to set up. The Ks are not nearly as well manufactured.
I personally think the high regard is a hold-over from the days of the CRs which were and are rightly held in high esteem. There is little connection between a CR and a FCR except the name Keihin. From 40mm on up, the Ms also have needle bearings.

[hb7]

Are there any other changes for the stock Skorpion with airbox ?
Update : These are not sold in the USA, looks like a Topham exclusive.

Mikuni TM34-65B : twin TM34 carbs with 65-70mm on center spacing
What is the setting for the accelerator pump ?

Main Jet: 115 (primary or left carb)
Main Jet: 125
Pilot jet: 25
CO-screw: 0.5 turn (3.0 to 3.5 vol%)

Needle: 9DZH5-50-3
Needle Jet: P-4
Injection tube: 0.35

[Bill Jurgenson]

Are there any other changes for the stock Skorpion with airbox ?

you need the larger right side hose for the left side as well and of course you have to enlarge the hole in the airbox.
Otherwise no changes at all. The carb fits right into the rubber mounts as it is if bought from Topham since he presses a sleeve on the right carb spigot to fit the mount.
talking about the standard TM34-B65 or 70 (are both the same thing) which is confectioned for this engine. If you order from Topham, you have to say which engine. The same carb for a TT or SRX with not have the sleeve since both mounts are the same.

Update : These are not sold in the USA, looks like a Topham exclusive.

"these" being the Raptor kit.
right, Steve makes this modification. Very small volume, so expensive.

b