Air cooled R carb recommendations

[rugbyflanker]

Hey guys looking for input on what carb to get for my 84 250r. I will be putting it back together over the next week or so. The set up ill be running is Boyesen power reeds, ported jug, hot rod crank, 71mm piston (1.0mm over), gold DG head, DG head pipe & silencer.
I will be running stock air box and lid with holes drilled in. About 760' above sea level and majority of riding will be done in winter on the ice if that matters.

I was running the stock Keihin PE 30A before I tore it apart. Not sure if this 34 mm would be worth picking up.

http://sheboygan.craigslist.org/mpo/6246794706.html

Appreciate any advice. Thanks-Mitch

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[christph]

I also have an 84 250R with similar mods, i.e., ported, DG gold head, DG pipe, etc. I've tried larger carbs and the 34mm Keihin from the 3rd generation R is a definite improvement over stock. I tried a 38 mm Mikuni flat side and lost too much bottom end. I finally settled on a 35 mm Mikuni TMX and it works great. It has more bottom end than the 38, but it did lose a little overrev. In short, definitely go with a bigger carb and you won't regret it.

[rugbyflanker]

I also have an 84 250R with similar mods, i.e., ported, DG gold head, DG pipe, etc. I've tried larger carbs and the 34mm Keihin from the 3rd generation R is a definite improvement over stock. I tried a 38 mm Mikuni flat side and lost too much bottom end. I finally settled on a 35 mm Mikuni TMX and it works great. It has more bottom end than the 38, but it did lose a little overrev. In short, definitely go with a bigger carb and you won't regret it.

Thanks for the input. Anything I should for/inspect on that 34 mm keihin flat slide when i look at it?

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[christph]

You can still get a new 34 mm Keihin--just like the one on the 3rd generation R. I believe I've seen them on ebay and Sudco sells them. If you're getting one used, there's not much to inspect unless you can open it up. Just check its outward appearance for abuse and, if you can open it up, inspect the floats and the needle valve. If you decide to go larger than 34 mm, there is a guy on ebay that sells a nice billet manifold. I got one and it is a quality piece. Here is the link.

http://www.ebay.com/itm/1985-HONDA-F...xYSJ7y&vxp=mtr

This one works with the 32 to 34 mm.

http://www.ebay.com/itm/1985-HONDA-F...5YSJ41&vxp=mtr

[rugbyflanker]

I picked it up the 34mm today. The intake boot was my next question. Won't any work for it from an '85 - '89 250?

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[HondaRidr]

A 34mm will fit on the stock boot if you boil the boot to heat it up

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[christph]

I picked it up the 34mm today. The intake boot was my next question. Won't any work for it from an '85 - '89 250?

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No, the intake manifold for the 85-89 250R will not work with the air cooled R's. It comes off at an angle whereas the air cooled R is a little off center and runs straight back. The rubber on old manifolds gets stiff so it might be a challenge to fit the 34 mm on the original manifold. You might be able to stretch it by soaking it in a pot of near boiling water. Otherwise, try to find a used FL 350 manifold on ebay (or new, but they are discontinued and fetch a lot of money). That's what I used before I bought the billet manifold. They have the same offset as the R but accept larger carbs.

[OldNo437]

I'll have to dig out a picture of what I did on my 81.. it was on the other site that now is no more... I used the weird angle boot from a liquid, and a torque spacer. Nabbed an airbox boot of an old husquvarna in the junkyard, to bring the angle back, its worked for several years now... problem is the airbox boot is now showing its age, and I have no idea what husky it came off lol

[rugbyflanker]

Thanks guys. I have 3 or 4 air cooled intakes so i will try the hot water method first to see if that will work for me before i go the billet manifold route. That seems a little pricy to me. Ill keep you posted and hopfully have this thing back together in the near future.

[rugbyflanker]

Also... while i have the case split and replacing the crank bearings I picked up a set of Boyesen Power Reeds. You don't run the stock metal "petal guards" on the reed cage with these Boyesen reeds do you?

[rugbyflanker]

Also... while i have the case split and replacing the crank bearings I picked up a set of Boyesen Power Reeds. You don't run the stock metal "petal guards" on the reed cage with these Boyesen reeds do you?

Nevermind that was a silly question. I would like to follow that up with another. I see there are cheap set of jets out there and than name brand for $5-6 a piece. What kind of difference is there between them? The manufacturer tolerances or material made from?

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[christph]

Nevermind that was a silly question. I would like to follow that up with another. I see there are cheap set of jets out there and than name brand for $5-6 a piece. What kind of difference is there between them? The manufacturer tolerances or material made from?

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I wouldn't buy cheap jets--I've heard others have had problems with them. There are cheap Chinese knock offs of Keihin on ebay, e.g., carbs, jets, etc. If you buy genuine Keihin you're certain to have the right threads and size.