Gone to the FCR Side

[AndyK]

I tried, I really did and in warm or even cold but dry weather my Weber was great thanks to all the advice given on here.
I didn't get to altering the pump cam as there was always a problem that would not go away in our UK climate - Freezing.

Motor starts stuttering and then you have to pull over and let the carb warm up

I have just picked up a brace of FCR 39 for £339
Super happy as was prepeared to go to £360

They came off a 900 Monster and I am putting them on the 750 with Gio Ca Moto exhaust and very little on the front end filter front at the moment.
I already had 750SS headers and was going buy Mikuni carbs and sort the oil heating to work on the Paso but couldn't pass up FCR at the price.

Is there anything I might need to change jetting wise? From what I have read if they come stock they need jetting down anyway so hopefully I already have 155 / 200 / 60 (or this is what I have read
Also, what is a good filter for the front end?

Andy

[Tamburinifan]

I`d contact Chris at. http://ca-cycleworks.com/contacts/ for jetting tips.
155 / 200 / 60 is for a 900.
Which manifolds?

[AndyK]

Hi Gert,

I had already bought a second hand pair of manifolds from a 750SS intending to fit a pair of Mikuni. They are stamped 7 on the flange so should be the correct ones

Will send Chris a message and see what he suggests.

Thanks, Andy

[Mc tool]

Why , given that the fcr's have the same operating principle as the Weber ,and your belief (ain't saying your wrong ) that the climate is the cause of your icing issue, would you expect anything to change ?
My 906 has snorkles off the bottom of the air box that sorta point at the top/rear of the front cylinder, on a 750 can you not tuck the open end in by the cylinder or behind the oil coolers ?. (instead of the radiator) I only ever rode my Paso in icy conditions once ( frost was forming on my shoulders and gloves ) but I don't recall any icing of the carb

[koko64]

Good score . They won't freeze.

[koko64]

If it's any help, a mate and I set up his M750 with open airbox with FCR39's. MJ 155, EMT needles #3, 60 pilot jets (you could try 55-58 sizes). Slow air screws were in the range of 1- 13/4 turns out from gently seated. Can't remember the idle mixture setting.
Good luck.

[koko64]

Take into account we tuned for kangaroo fuel. Maybe it will help as a baseline. The pilot jets were a bit rich and we possibly could have used 55's or 58's, but a slightly rich pilot jet can be compensated for by opening the slow air jet screws a 1/4 to 1/2 turn (if the carbs came with them, they're excellent).

Looking foward to hearing how the FCR's run.

[AndyK]

Big Thank You for the tip on the needles

Work and weather had stopped play for a bit but I got round to stripping the carbs for cleaning tonight and the needles they came with were OBFHM, quite a bit richer than EMT.

On the prefix bit of the needle code what I have found online seems to say the FCR39 is prefix OC (OCEMT) but then some mention OB but don't say what the difference is - Anyone know?

[koko64]

Look up Patrick Burns FCR Tuning Guide. Should be a chart there on the needle codes.

[koko64]

http://www.factorypro.com/tech/tech_tun ... s,Pat.html

[AndyK]

Hi all

I have just realised how much time has gone by since I started this post - Work / Life ballance not great this year

When I have been able to go for a spin the carbs have worked out really well and thanks again for all the help
It took minimal tinkering to get idle and midrange running smooth and the plugs look good. I haven't had a chance to really push it but thinking to take her for a Dyno run just to get a baseline snapshot - It's not very expensive and I like the idea of doing it in a safe controlled environment before the added distractions of the open road

All the best, Andy

[koko64]

How did you go with the dyno tune?