Carburettors

[James England]

Hi all.

I was wondering whether the carbs from an XJR1300 would possibly fit an XS1100 and therefore be an alternative to rebuilding 30 year old OEM carbs. Here in the UK, full banks of carbs are available on eBay at less than the cost of four diaphragms and a rebuild.

The XJR1300 is actually only a 1250cc, so the capacity is not much more than the XS1100. To my eye, the carbs look very similar indeed and the spacing looks to be perhaps the same or very close. The inlet manifolds also look similar. They are 37mm bore. The XJR1200 are 36mm bore.

As I've mentioned before, the XJR is based on, or developed from, the XS1100, so I'm wondering if the carbs would be a viable alternative to the OEM ones.....they are, of course more modern in design and most probably in much better condition than older XS ones. People here often put FCR flatslide carbs on the XJR and sell off their OEM carbs.....

[jetmechmarty]

It looks like you will be the guinea pig. XJR carburetors may not be a good choice on this side of the pond. There is likely little to no support.

IMHO, the stock carburetors are a durable design. Once they are properly sorted, they work well and last a long time. Neglect is their worst enemy.

You're going to have to pick up another XS11 and a set of carbs. Certainly, many of us will succumb to curiosity and follow your posts on the subject.

[natemoen]

Well, do some measuring for us.

Total total edge to edge of the carb bank bells is 285-286mm

Center to center on the 1-2 and 3-4 carbs is 78mm

Center to center between 2 and 3 is about 84mm

The carbs are 42mm

[FJ111200]

James,
come over to the UK forum and ask here. Quite a few of the lads have done FJ and XJR carb conversions to the XS.
I reckon you'll have more joy.

[TomB]

Yep, been there, done that




.

[James England]

You're going to have to pick up another XS11 and a set of carbs.

Definitely. The carbs aren't the problem, its getting a reasonable XS11 E or F at a realistic price. I've been looking for a while, on and off, whilst tweaking my XJR1300. I need a project....

[GLoweVA]

Definitely. The carbs aren't the problem, its getting a reasonable XS11 E or F at a realistic price. I've been looking for a while, on and off, whilst tweaking my XJR1300. I need a project....

Looks like James has an itch that needs scratching!

We're all addicts! help us please!

[FJ111200]

XJR carburetors may not be a good choice on this side of the pond. There is likely little to no support.
Certainly, many of us will succumb

James,

why don't you just swallow your pride and come on over to the dark side?

We won't bite, much.

Barking up the wrong tree over the Pond.

[natemoen]

Someone needs to get us some measurments from xjr carbs first before we go crazy....

[James England]

Someone needs to get us some measurments from xjr carbs first before we go crazy....

right...what measurements? I'm fitting Dyna coils, as usual, and have the tank off and access to the carbs. I don't want to take them off the bike though! I can measure anything externally though.......

[James England]

James,

why don't you just swallow your pride and come on over to the dark side?

We won't bite, much.

Barking up the wrong tree over the Pond.

Too dark for me, I'm afraid, Alex. It's not a pride thing and I wish you boys well with the site.

[DGXSER]

right...what measurements? I'm fitting Dyna coils, as usual, and have the tank off and access to the carbs. I don't want to take them off the bike though! I can measure anything externally though.......

Well, the center to center between carbs is the critical measurement, as all the mechanisms for synching and such are set on those spacings. Then of course the carb throat diameter on the engine and airbox sides.

The other dimensions and such can be made to work I would suspect. The most difficult part might be how the choke is actuated, if it differs from the manual method of the XS11.

[Rasputin]

Too dark for me, I'm afraid, Alex. It's not a pride thing and I wish you boys well with the site.

Been there done that. I also wish them well.

[natemoen]

Well, do some measuring for us.

Total total edge to edge of the carb bank bells is 285-286mm

Center to center on the 1-2 and 3-4 carbs is 78mm

Center to center between 2 and 3 is about 84mm

The carbs are 42mm

Airbox is 55mm

right...what measurements? I'm fitting Dyna coils, as usual, and have the tank off and access to the carbs. I don't want to take them off the bike though! I can measure anything externally though.......

Those meausrments.

[James England]

Allowing for slight error, using a tape measure across the carbs, I get the full bank to measure 290mm from the edge of one float bowl to the other side. Spacing on the outer carbs looks like 78mm with 85 on the middle . That's using a tape measure and over the breather pipes and throttle cables for the two middle carbs. The bore of the carbs is 37mm according to the manual. That's ID of course.

The choke is one slide across all the carbs, same as the XS1100, pulling one plunger per carb. On the XJR, it is cable operated to the left handlebar. I would have thought it an easy job to put a manual toggle or pull on it.

There's a throttle position sensor on the right carb. This would simply not be connected up for a non- TPS bike.

I can't get the OD's of the manifold and airbox side without taking the carbs off completely.....

OEM jet sizes are:

Main. 107.5
Main air jet 80
Jet needle 5D139
Needle jet P0M
Pilot air jet 140
Pilot jet 15
Starter jet 52.5

I had the carbs off the bike completely in order to install the a stage 2 Dynojet kits. At the time, I thought how familiar it all looked!

My bet is they go straight ........ Or maybe with a bit of bending the rubbers.......