Dual carbs

[XRsteve]

I have a friend that has a 86 XR600 with the dual carb setup. The bike feels more powerful than a 1993 XR600 that I rode recently. Does the old design make more power or was something wrong with the newer bike? I'm hoping to hear from somebody that has owned or ridden both designs.

[SniperTeamBravo]

I have a friend that has a 86 XR600 with the dual carb setup. The bike feels more powerful than a 1993 XR600 that I rode recently. Does the old design make more power or was something wrong with the newer bike? I'm hoping to hear from somebody that has owned or ridden both designs.

Yes, the early dual carb versions are faster because they have about 5~8 more horsepower. Not only did they have dual carbs, and dual ports on both the intake and exhaust, but bigger intake and exhaust ports, and better flow thru the head. The dual carbs are also 28mm each, thats 56mm of hole to let intake in as opposed to about 40mm on the single carb models. In fact the early heads flowed so well allot of the early desert racer guys who bought the single carb models changed to the dual carb head off an earlier model. I own an early desert bike built by a former racer and his tech who did that very thing. Mine is a 1992 but has the early head, intake, and bigfin treatment on it.It is also got an HRC 630cc kit in it so it flies.

[AlbinoPig]

You need to calculate the flow areas of the individual carbs and add them together. Actually, the dual 28mm carbs would flow slightly less than a 40mm but, I suspect much more effeciently, over a much wider operating range, thus the better power output.

[timothypg]

I have an 86.carbs are awesome. have a 628 kit, cam. 140 mains and 42 pilot, (if i remember right). also the secondary carb is set to open with no stagger, it hits quicker that way, i was happy with that little tweakage of the link.

[platterdr]

i had an 86 xr600 and it was faster than single carb 600's, At that time there were 4 of us riding xr 600's and on fire roads i could leave them( which was good because all these guys were faster than me in the woods) LOL

[SniperTeamBravo]

If you go to Honda Americas website you can read alittle history of the XR600R as it is one of the few bikes Honda considers a milestion bike. It says the early ones had more horsepower because of the dual carb and flow charachteristics. As I said before many racers back when the XR600R was king of the Baja, desert, and was doing well even in the Dakar used the dual carb head and carbs on their later race bikes. My desertsled has the earlier head because of this. You can check it out at my website desertsled.com

Beware though, the sled is in the process of being restored, and the website is in it's infancy....being updated periodically....

[XR6's_rule]

I have owned/ridden both of the above. My opinion is this- Both bikes are very close in peak horsepower, but the twin carb models are definitely stronger in the lower-end of the rev range and have slightly better throttle response. This however doesn't make the '85-'87 models the pick of the bunch. The later '91-on versions have much better handling/suspension/brakes, which more than make up for the small power disadvantage.

[timothypg]

I agree with you xr6. the brakes definately need to be upgraded, stopping quickley when it counts most (traffic) can be a little scary:eek:

[CadGuy]

What the difference in XRL and XRR dual carbs ?
Which ones were 28mm ?
Is 28mm the big ones or is there a larger set ?

[Backwoods-Bomber]

What the difference in XRL and XRR dual carbs ?
Which ones were 28mm ?
Is 28mm the big ones or is there a larger set ?

83 and non California 84 xl600r had the larger dual carbs. Later xl600 and all xr600r had the smaller carbs.

[CadGuy]

So what’s the best carb to use ? 
looked and looked can not find a tru set of 83-84 carbs.   
Thinking single flat slide.  

[cyclewizard]

I run two 32mm Mikuni pumper carburetor’s on mine. Using a spilt cable. 

[CadGuy]

1 minute ago, cyclewizard said:

I run two 32mm Mikuni pumper carburetor’s on mine. Using a spilt cable. 

Cool do you have Picts of how they fit ?

 

[cyclewizard]

1 hour ago, CadGuy said:

Cool do you have Picts of how they fit ?

 

Here’s a set of mikuni carbs I ran on my flat tracker. Since then I went to the pumpers. 

[cyclewizard]

You can use your stock intake manifold with a set of 30mm carburetors.  

[RichieGoatGruff]

1 hour ago, cyclewizard said:

I run two 32mm Mikuni pumper carburetor’s on mine. Using a spilt cable. 

What do you do for the intake manifold? I have an 85  I'm thinking about resurrecting... The head was breathed on by a local pro. She was running pretty good, before I parked her. Probably need to find a good frame.

[RichieGoatGruff]

8 minutes ago, cyclewizard said:

You can use your stock intake manifold with a set of 30mm carburetors.  

That's what I needed to know, a pair of 30s, block off choke and pilot circuit of one? Now you've got me thinking...

[cyclewizard]

3 minutes ago, RichieGoatGruff said:

What do you do for the intake manifold? I have an 85  I'm thinking about resurrecting... The head was breathed on by a local pro. She was running pretty good, before I parked her. Probably need to find a good frame.

I make my own intakes but a stock one is fine. 

[cyclewizard]

2 minutes ago, RichieGoatGruff said:

That's what I needed to know, a pair of 30s, block off choke and pilot circuit of one? Now you've got me thinking...

Lol. I run two # 25 pilots but I thought about only one 45 or 50 jet

Motion pro can make you the cables

[cyclewizard]

Intake