FCR upgrade?

[LozLul]

It seems Im leaning towards the sock as well. It's easy and it saves some weight which is important as I have been gaining some in form of yzf-usuals. Have to get back to the pressurised airbox later...really much later as I think the next moneypit in line is the chassis.

BTW, I have got some info from Sudco (Keihin distributor in US) that suggests that the FCR41s for TDM and TRX are pretty much identical including cables, spigots, mains and TPS-hardware.

[Artsi_L]

Do not buy a bank of 4 to split or 2 singles, it will cost you a bloody fortune!

---


Errrmm... hyphotetically speaking, assuming one would do such a mistake, how much work is involved with splitting a bank of 4 FCR's ?

Umm... I'm asking this on behalf of a friend.

[phuk72]

You need to tell your friend that he will need to find a way of spacing the carbs correctly, correctly positioning the throttle cables and sort the fuel lines.

Not difficult but ...

[Wombat]

Well...........after a year of feverish saving, it finally looks like I'll be buying a set in the next month or two. I rang Brenton at Show and Go in Adelaide about a month ago and he said that yes they are still available thru special order. As I am running stock airbox and pipes, I'm deciding to go with the carbs, the airbox adaptors and the cables + throttle. Later on if I decide to put a different set of pipes on I will jet to suit. Would it be wise to order a set of mains 1 or 2 sizes higher and lower than what they will jet it with? And what was the problem with the intake rubbers again? Will I have to dremel them?

Bob

[schmiffee]

Ok so I am also looking at purchasing a set of FCR's for my TRX (Wombat, maybe we can get a special order of two and try to get a deal...or more if anyone else would also like a set) but what do I need to take into consideration when ordering? I intend to be running a big-bore exhaust system, what else do I need to consider/what are my options?

Do I need to run the airbox I have? Can I run pod-filters (single or double)? Any cables I also need to order?

Or am I being paranoid and just need to order the FCR's through Brenton, and everything is there for my mechanically minded professional to fit? Any help and guidance would be much appreciated.

[Artsi_L]

Any idea on compiling FCR jetting size info database here on the forum?

I've collected some data on KTM forums, they run these on 400cc-500cc-620cc four strokers.

I'm planning on investing in a wideband lambdasensor to get jetting/needle profile selection narrowed down before taking it to a proper dyno. Dyno time is expensive. I bet I'll save half of the lambda's price in reduced dyno time alone, that's what I hope for anyways ...

On about fine tuning in general.
I called to a dyno shop the other day. Our conversation touched subject of engine knocking/detonation. I learned that these folks have an exhaust gas analyser, which will detect engine knocking via presence of certain gasses. Wow.. I didn't even know such analyser even existed.

How does your local dyno shops determine high rpm engine knocking/detonation?

[phuk72]

I would recommend junking the airbox and using pod filters / sock filter if you are going down the FCR route.

The airbox restricts airflow to the point that it robs you of 2-3 bhp with FCRs

[Kayla]

I would recommend junking the airbox and using pod filters / sock filter if you are going down the FCR route.

The airbox restricts airflow to the point that it robs you of 2-3 bhp with FCRs

Is that a drop of 2-3 bhp from standard or a 2-3 bhp drop relative to what can be achieved using FCRs and foam filters? I've got some to fit and I was going to use the airbox (slightly opened up) to start with.

[phuk72]

I would recommend junking the airbox and using pod filters / sock filter if you are going down the FCR route.

The airbox restricts airflow to the point that it robs you of 2-3 bhp with FCRs

Is that a drop of 2-3 bhp from standard or a 2-3 bhp drop relative to what can be achieved using FCRs and foam filters? I've got some to fit and I was going to use the airbox (slightly opened up) to start with.

2-3 bhp drop over what can be gained by using pod filters / sock filters.

FWIW, sock filters (like Ramair) seem to flow air slightly better than K&N pod filters requiring bigger main jets but (bizarelly) there does not seem to be any difference in power.

I have K&N pod filters due to the fact I don't trust sock filters not to allow rain into the carbs in the pissing rain

[Mincehead]

I can remember members having problems with Ramair on one of the many threads(might have been this one,I`m not sure) but I`m posting this to give ALL forum members a heads-up and a contact there:

Ring 0844 8584658 and speak to Dan.
Have your pc on this page:

http://ramair-filters.com/motorbike/fra ... rbike.html

And chat away to this most helpful and knowledgable bloke.
I told him I would be passing details on to the forum members and he assures me he`ll do all he can to help with your enquiries and needs.
By the way,apparently Pipercross and Raid/Janspeed(Ramairs new name)are working closely with one another AND the latest Ramair filters are now using a foam that flows even better than their old specification foam.
Another wee tip,my dyno engineer swears by the single and longer socks,MS-001`s.(150mm long)you can cut the open end down for fitment if required,this will give optimum surface/filtration area.
It`s horses for courses I suppose but he feels that the best fuelling is always achieved with single filters for each carb,I tend to agree with him too.

Ps,I`ve just ordered a pack of four single socks MS-001`s and the total cost £63.26.
Just over 15 quid each,it`s hardly worth me making some!
Time is tight for me just now,very busy in life and the FCR`s I`ve recently got for 200 quid are calling to me for fitment so I decided to plump for commercially made filters to save time.
AND with four I`ll always have a pair already clean and siliconed up to put on when those fitted become due for cleaning.

[Artsi_L]

Finally got around to pull out a set of four 39mm FCR's I bought on Ebay. Did the disassembly, and figured out the most obvious modifications. The main throttle shaft needs to be either modded, or have a new one manufactured. UK supplier wanted like 120 UK pounds for the shaft alone. I need to talk a local machinist instead.
The very reaon for modded shaft (or a new one) is to have a new spacing between slide driving mechanism , since on a TRX/TDM/XTZ Yamaha the carb spacing is greater than in an inline 4-cylinder engine.

Rest of the jazz seems less challenging than the throttle shaft. Fuel pipes between the carbs are plastic tubes, available from any spareparts shop. Rest of the garbage between the carbies are mechanical spacers, easy task for any machinist.

Tons of other jazz to do as well. We shall see if I get to have these installed during this driving season. I'll keep ya posted.

- A.

[Mincehead]

Indeed Artsi_L,now I have a pair of FCR 41`s in my grubby hands I can see it`s not too difficult to sort the spacers and fuel hose/overflow spigots.
As you say the top spindle requires a little more work but a good machinist/toolmaker would sort one out in no time at all.
I`ve got a pal with a small lathe,even with his kit I could no doubt knock one up given the time,which just now in my life is VERY tight.
There are some jet sizes quoted here on the forum that others have found to be in the general ball park(vicinity).
I`ve a thread `don`t drop this one` where I`ve asked for some guidance on starting points for jetting,as yet I`ve not had a response from any other members so now I`ve plumped to start with 155 mains and work my way up.

[Killerwhale]

Indeed Artsi_L,now I have a pair of FCR 41`s in my grubby hands I can see it`s not too difficult to sort the spacers and fuel hose/overflow spigots.
As you say the top spindle requires a little more work but a good machinist/toolmaker would sort one out in no time at all.
I`ve got a pal with a small lathe,even with his kit I could no doubt knock one up given the time,which just now in my life is VERY tight.
There are some jet sizes quoted here on the forum that others have found to be in the general ball park(vicinity).
I`ve a thread `don`t drop this one` where I`ve asked for some guidance on starting points for jetting,as yet I`ve not had a response from any other members so now I`ve plumped to start with 155 mains and work my way up.

well, i´m using 175 in the winter time....170 summertime. COULD be some changes to that as i´ve done the porting from hell since last dyno....

[Mincehead]

Thanks Killerwhale,I got bags of jets thrown in for my 200 notes,up to 180`s so I think I might have my requirements covered.
My speedo cable inner decided to part company today,mind I had just ripped past a ZX6R at about 120!
Ah well,more tinkering required and a rummage through a friends cable stock to see if I can use any.
A standard TRX cable is too short for where I have my speedo and tacho mounted.

[Killerwhale]

Thanks Killerwhale,I got bags of jets thrown in for my 200 notes,up to 180`s so I think I might have my requirements covered.
My speedo cable inner decided to part company today,mind I had just ripped past a ZX6R at about 120!
Ah well,more tinkering required and a rummage through a friends cable stock to see if I can use any.
A standard TRX cable is too short for where I have my speedo and tacho mounted.

Can add that i´ve lowered the needle one clip and went down one size on the slow jet and then adjusted the fuel screws for the new jets...