R1 Carbs (lots of pics)

[ap72license]

9 minutes ago, frank88 said:

 

Change my master to which type?

 

Surely the vacuum canister would only be used for vacuum advance and not for the booster as well so wouldn't solve the problem?

 

Cheers

 

 

There's really no reason to not use a vacuum canister for both the brakes and the vac advance.  And depending on what you want to do with the brakes you can change to a larger or smaller master cylinder to change the brake pedal pressure.  If wanting a softer pedal to help compensate for a lack of power assist then you would want to go to a smaller master cylinder.  Pedal travel will increase though.

 

[datzenmike]

Hey what's the best way to start these things???

[G-Duax]

Well, after a long wait, finally got the Vance & Hines (Mikuni 39mm VM carbs, modified by V&H) smooth bores on.

Took a little work getting the 4 into 1 throttle cable to mate up just right.

Turned on the ignition, let the fuel bowls fill, and hit the starter.

Came to life instantly, and idled better than my damn Weber DGV ever did.

Just finished synchronizing them (in the rain).

As soon as it stops raining today, I'll go over all the fasteners again, seeing I have a couple of heat cycles on them, then pop the air filter on.

 

[datzenmike]

I know!!! That's the amazing thing with these, they idle cold at warm revs. Yesterday I swapped my jets again. Took some cranking to get the gas into them but fired right up with the 'choke' on and idled @ 600. Been sitting for weeks.

 

Starting is different than a carburetor though. At least on the R-1s. Needs the enrichment valve full on and don't touch the gas. Crank till it fires.

 

Still reading lean. Was at 1.8mm and WOT was mid 9s or maybe lower than the gauge reads. Went down to 1.4mm and came up to mid 10s. Decided to get below it and work my way up in jet sizes so down to 1.2 and severe lean 15-17s. Went up to 1.3mm and still lean. Any ideas why so lean?

 

Here's the jet diameter and the area worked out. Just like a muffler doubling the diameter increases the cross section 4 times. So I guess small changes make big differences.

 

First try 1.8mm............ 2.5434mm² 9.6 at WOT (lowest gauge can, read may be lower)

Second try 1.4mm....... 1.5386mm² 10.6 at WOT

Fourth try 1.3mm..........1.3266mm² 16-17 at WOT *

Third try 1.2mm............1.1304mm² 17-18 at WOT

 

* I'm here right now. Presume a 1.35mm jet is the next thing  but if not possible something between 1.35 and 1.4mm OR just live with the 1.4mm jets. 

[G-Duax]

The difference from a 1.3 to a 1.4 is .004" (.051" vs .055")

A #55 drill is .052".

You might try picking up a #55 drill, a pin vise for holding it, and a spare set of 1.3 jets, and opening them up.

[datzenmike]

Way ahead of ya. Amazon for 20 brass jets varying from 0.91 to 1.20mm for $12. I already drilled out he the stock 1.46mm R-1s to 1.8. So they are done. Drilled 4 jets to 1.4mm and then another to 1.2mm and then a set to 1.3mm.

 

! may be able to get a 1.35mm drill... 0.5319 or 17/32"....0.0532".

 

I can't understand why it suddenly went so lean going from 1.4mm to 1.2. I'm tempted to put the 1.4mm back in to confirm that it runs in the low 10s at WOT and that something else hasn't been altered.

[ap72license]

4 hours ago, datzenmike said:

I know!!! That's the amazing thing with these, they idle cold at warm revs. Yesterday I swapped my jets again. Took some cranking to get the gas into them but fired right up with the 'choke' on and idled @ 600. Been sitting for weeks.

 

Starting is different than a carburetor though. At least on the R-1s. Needs the enrichment valve full on and don't touch the gas. Crank till it fires.

 

Still reading lean. Was at 1.8mm and WOT was mid 9s or maybe lower than the gauge reads. Went down to 1.4mm and came up to mid 10s. Decided to get below it and work my way up in jet sizes so down to 1.2 and severe lean 15-17s. Went up to 1.3mm and still lean. Any ideas why so lean?

 

Here's the jet diameter and the area worked out. Just like a muffler doubling the diameter increases the cross section 4 times. So I guess small changes make big differences.

 

First try 1.8mm............ 2.5434mm² 9.6 at WOT (lowest gauge can, read may be lower)

Second try 1.4mm....... 1.5386mm² 10.6 at WOT

Fourth try 1.3mm..........1.3266mm² 16-17 at WOT *

Third try 1.2mm............1.1304mm² 17-18 at WOT

 

* I'm here right now. Presume a 1.35mm jet is the next thing  but if not possible something between 1.35 and 1.4mm OR just live with the 1.4mm jets. 

 At the ends of the spectrum O2 readings are not that accurate, wide band or not, if you drilled these jets there's also the issue that drilled jets are not always that accurate.

That being said it seems you found a way to get in the middle, I'd try that and see what happens.

[datzenmike]

A 17/32" drill is 0.05312" or 1.3492mm. That's half way between 1.3 and 1.4mm. Was adjusting the needle heights and lost one of the E clips. Ordered more. So next weekend, weather willing.

[hendrik6073]

i sold my oldtimer car that was equipped with this carburators. I still have a Dyno JetKit, new, not used, with set of DCO plugs. If somebody is interrested please let me know.

 

[G-Duax]

Over 100 miles on these, and no issues :)

 

[datzenmike]

 

Got my assortment box of E clips. Perfect fit, I think 2mm size. They go up to 10mm. Bet there are lots that fit the shifter pins.

[G-Duax]

Yea, I need to pick some up, as I'll be playing with mine soon, and those little buggers are hard to find after they hit the floor.

Just wish I could find the adjustable main jets that they used to make for the larger Mikuni VM carbs back in the '70s.

[datzenmike]

I spent 10 min. with a magnet on the lawn and said screw it and dialed up Amazon.

[Lozer]

Hey guys ive got a set of turbo needles from a snowmobile running r1s. I dknt have the carbs anymore so who wants em.

[G-Duax]

There is a set of Vance & Hines carbs like mine on eBay right now.

Vance & Hines Drag Bike carbs

 

With a set of rubber spigot mounts (mostly used on snowmobiles), they will bolt to any side draft manifold.

[sammy620]

Do i need to plug the coolant holes on the head, or will the manifold just seal them up?

[datzenmike]

 

Made my own manifold that doesn't need the coolant passages. The water can't go anywhere, it's completely sealed. If you want you can TIG weld them closed or tap and plug them but I've had zero problem, why would I? almost all L series have the holes and they don't leak unless you don't put it back on properly.

[sammy620]

Did you use gasket sealant mike?. Im leaking coolant even under no pressure. My manifold only came with bolt holes at the top and not the bottom.

 

cheers

[datzenmike]

 

The bottom row of 4 bolt holes will take a bolt that has a large thick washer that bridges across both intake and exhaust flanges. Each bolt holds one intake and one exhaust flange.

 

 

The 'washers' are called cone washers. because they are slightly curved.

[sammy620]

do you recommend using any gasket sealant as well, or is that not necessary?

 

Thanks

[datzenmike]

Only on the rarest of occasions do I use RTV. If your surfaces are clean and flat only a gasket is needed, that's what it's there for. RTV is for those who don't trust their own work when they should..