Triumphrat

carpelux · 03-20-2007

I've got myself a set of keihin carbs which I am planning to put on my 1996 thunderbird. I have searched the forums but still not sure about how they will fit.

I have previously changed the original restricted intake rubber to unrestricted mikuni ones.

Will they fit the keihins? And how about the rubbers between the carbs and the airbox, I suppuse they have to be exchanged?

The throttle and choke cables looks like the would fit, is that the case?

At last, how does the jet sizes compare between the two makes, are the equal?

Many questions to all You pros out there :-D

jimmyj900 · 03-20-2007

As I remember it, the Mikuni and Keihin rubbers are different lengths and diameters, but the connection to the cylinder head is the same.

You're going to need to replace both the inlet and outlet rubbers on the carbs but the airbox will fit.

I think the throttle cables are the same length and fittings, but you'll want to check with the dealer to verify part numbers.

Jim

Slinky · 03-20-2007

I went from Mikunis to Keihins a while back but I don't recall having to change any rubbers. I did fit unrestricted inlets but then went back to the stock restricted ones, and they do work fine with the Keihins.

Size for size, the jets are comparable (it's all metric, fractions of a mm). I was running #40 pilot jets and '102 mains with the unrestricted inlets.

[ This message was edited by: Slinky on 2007-03-20 13:28 ]

Spooner · 03-21-2007

Did the same swap myself

Throttle cable and choke cable will fit.

How's that cam change working out for ya man?

rayhyland · 03-21-2007

Whats the benefit of doing this swap?
Reliability?
Power?
All or none of the above?

Ray

Slinky · 03-21-2007

Quote:

On 2007-03-21 06:57, rayhyland wrote:
Whats the benefit of doing this swap?
Reliability?
Power?
All or none of the above?

Ray

Reliability, in my case. The Mikunis are cheaply made and not as reliable. They have quick-wear plastic slides, and the float bowls and tops are only held on by two screws and so are prone to warps and leaks. The needle jets are also prone to going oval in as little as 10,000 miles.

That's my understanding anyway, I got shot of mine before they gave me any problems.

vonbonds · 03-21-2007

My friend did this to a 98 Trident. He did it for the fuel economy. The Mikuni's consume fuel at a much greater rate from what I hear.

BigVinny · 03-21-2007

Ive done this and found that the fuel line, throttle cable and choke cable fit both types of carb no problems.

I changed inlet rubbers to the unrestricted ones (Keihin CVK type - no dimple) from the Mikuni restricted ones (with dimple) although the look like they will both fit.

Main issue I think is the connection of the carbs to the airbox as im sure the air intake mouths are different sizes. When I did the straight swap the old airbox didnt quite fit straight with the replacement Keihin carbs. hence the move to pod air filters.

carpelux · 03-22-2007

Thanks guys for all information.

I guess I'll just have to try it out and se how it fits before I'll order the missing parts.

The reason I change is because I never have been able to adjust the low speed on my mikunis. When I just get on the throttle they deliver much to fat mixture, and all efforts to fix it have been fruitless. I have replaced every o-ring, adjusted the floatheights a couple of times and even lowered the level about 2 mm. I have also synchronized them.

I hope the keihins will be better, and also give me a better mileage.

About the cams the butt dyno says it's a improvement. How much it does I really don't know, I took the bike to a real dyno last year and got 73.9 hp and 68.5 nm on the backwheel. If someone is interested I could scan the papers and put them up.

[ This message was edited by: carpelux on 2007-03-22 16:36 ]

carpelux · 03-23-2007