Topic: Stock PD carbs on an 836.

[Gonzowerke]

Hey All,

I seem to remember someone back in the day telling me that the stock carbs, even when jetted properly, would not flow enough in the upper rpm range on an 836. Is this true? My 77F never ran that strong anyway, due to the PO putting a standard bore 736 headgasket on it! I'm in the planning process for the re-assembly, and was wondering about this. I need a good reason for my financial officer(Wife) to approve $750 for carbs if I go the CR route.


Thanks!

Gonzo

[Sam Green Racing]

If it's any hep Gonzo, the bike in my avatar had a stock motor with electronic ignition and open race pipes, with stock carbs, it produced 50bhp at the rear wheel.
With a set of CR31s it went up to 53bhp.
With the 836 motor with a ported head and mild cam, it shot up to 86bhp with 62ftlb of torque.
Cam it, port it and hang on.

Sam.

[Gonzowerke]

Sam,

Was that last HP figure with the PD's or CR's? I have a ported head laying around with broken fins, but I know how to fix that, and I have a cam that came with it that I think is slightly hotter than stock. When I am done getting the K going, I want to turn my F into a roadgoing CR. Not a replica, but what a Honda fan might have done back in the day. You know, fairing, rearsets, hot engine, etc.etc.etc. As the F has an 836 engine, I wanted to make sure I got everything straight before starting work.

Thanks for the reply!

Gonzo

[Sam Green Racing]

Sam,

Was that last HP figure with the PD's or CR's? I have a ported head laying around with broken fins, but I know how to fix that, and I have a cam that came with it that I think is slightly hotter than stock. When I am done getting the K going, I want to turn my F into a roadgoing CR. Not a replica, but what a Honda fan might have done back in the day. You know, fairing, rearsets, hot engine, etc.etc.etc. As the F has an 836 engine, I wanted to make sure I got everything straight before starting work.

Thanks for the reply!

Gonzo

It had the CR31s on it,get saving your pennies.

Sam.

[Tim2005]

Gonzo, this page might be useful too

http://www.satanicmechanic.org/dyno.shtml

looks like stock carbs will give 75bhp on an 836 and only go to about 80bhp on a 888

[Gonzowerke]

Gonzo, this page might be useful too

http://www.satanicmechanic.org/dyno.shtml

I had forgotten about him, he used to be all over this group when it was still a Listproc on Dorje.com.

[754]

 The K7/8 carbs worked good when I tried them (not as good as my Webers), and I remember a nasty quick 836cc at Sturgis with them and stacks on it.
 Consided them a budget improvement, everything else costs a lot more..

[Gonzowerke]

Don't I know it! CR's are $749 at M3 Racing, I believe they are the same price from Sudco as well.

[Retro Rocket]

Look at the RS34 Mikuni's that cyclex sell, they are infinitely more tunable than the CR's {which are designed for high revving race bikes and lack power lower down} The Mikuni's have a accelerator pump that is also tunable giving more scope for tuning a road bike than CR's. Both CR's and the RS34's will still take some setting up to get the most out of them, neither are just bolt on and go, its just not that easy....

[Gonzowerke]

Look at the RS34 Mikuni's that cyclex sell, they are infinitely more tunable than the CR's {which are designed for high revving race bikes and lack power lower down} The Mikuni's have a accelerator pump that is also tunable giving more scope for tuning a road bike than CR's. Both CR's and the RS34's will still take some setting up to get the most out of them, neither are just bolt on and go, its just not that easy....

Hmm...They do look nice! And they have a choke as well. I am building a street bike, not a racer, but I wanted the CR's for that CR750 look. However, I want performance and rideability more than I want looks.

[Retro Rocket]

Thats the ones....  CycleX sells them set up for our bikes...

[dragracer]

I've got a set of 36mm Flatslides on my F model. It has the 1030 kit in it though. I love the performance of those carbs for racing. I'm sure the smaller 34's will work well on the street for an 836. I've used anything from the 36's to 40's on street bikes and next to the FCR's, they are the way to go.

I plan to use a set of rejetted PD's on that 836 motor Big Jim so generously donated to me. It might take  while, but i plan to tweak them until i get it right= lots of info on how to tune those carbs.

[Retro Rocket]

Hmmmm, i may have to look at 36's for my 1000 then, it has a big port job, bigger valves, Mikes billet block and a 125-75 megacycle cam, i plan on a fuel injection conversion later on after run in then the carbs will be going on a 970cc build. What do you think dragracer.?

[dragracer]

Hmmmm, i may have to look at 36's for my 1000 then, it has a big port job, bigger valves, Mikes billet block and a 125-75 megacycle cam, i plan on a fuel injection conversion later on after run in then the carbs will be going on a 970cc build. What do you think dragracer.?

My carbs were not racked for the SOHC motor. They are actually for an FJ1100/1200 Yamaha. The spacing is also for a 85/86 Ninja 900. The Honda spacing is very, very close but they will not fit without some modification to the boots. I offset ground my boots with a die grinder until i got them to fit. Plus the spigot on Mikunis are a lot larger than even the F model boots so they have to be cut anyway. I used a heat gun initially to softened the boots to install the carbs and they slipped right on.

Keep in mind that i dragrace this bike only. Once i slip the clutch some off the line and rapidly roll the throttle to the lock position, i never let off until after i cross the line. Other than riding the bike around in the pits, i have no clue how well these big carbs would work on a daily dirver. Those 34's might be best for your all around application. The only reason i didn't buy the 34's at the time was because they were out of stock and i was under the gun to make a race with the bike. Otherwise i would be running 34's. Oh, and those carbs have been on that bike for over 15 years now and work flawlessly until last season. I think its time to remove them for a cleaning and maybe replace the needles because they leak fuel now. The little rubber tip is likely deteriorated where it fits into the seat. No way i can complain after all there years. Its a maintenance thing.  Great carbs- well worth the money and little tuning out of the box. Plus they come with jets and other installation accessories like fuel line and clamps.

Ironic, i talked to Ken about my bike over 10 years ago concerning a lockup clutch and when he asked about what carbs i was running i told him about the Mikunis. Funny, years later he is re-racking them  for the SOHC's and selling them-lol.  I see he is making lockups now too= cooooooooooooooool.

[Retro Rocket]

Thanks for the detailed reply mate, i'll stick with the 34's....