Picked up a set of FCR 39'sfor the '98yzf750. The bike is strictly a track day toy. Need to work on the impulse control a little bit. Have a few questions.
When I bought the '98, the carbs were pretty mucked up. Got them all cleaned up, but the emulsion tubes were on the outs. The bike runs pretty good other than that, much smoother than the '94. So instead of getting more tubes, I decided to go this route. I've read many threads regarding airboxes and pods. Don't really want to go all out, just make them work well.Would prefer the stock airbox with adapters, but don't know if anyone carries them. Any ideas? Experience with different pods?
As far as jetting goes, I plan on keeping the exup on with the Kerker slip-on. The carbs came off a bike with a big bore kit-the mains are 160's(sea level, now 5300ft). I'll be needing to get more jets. Should I get a few different sizes, or just have a local shop put in what they think it should use. Right now isn't the best time because of the temperature being in the 30's. And I don't have the airbox sussed out yet.
Next question. Where to get appropriate throttle cables?
Put the carbs on the bike today and it started right up(not much good without cables and air filtration!).
Same old story from the shop that sold them too me"customer didn't like them" and "only put them on to set up-practically brand new!" Though, they do look pretty new, and very crip action. Still not sure whether I'll keep them or not. I'll have to see what the whole deal is going to set me back first. Speed's addictive, but expensive. Should have stayed with mathematics instead of the coffee industry!
FCR's
i think you'll get better results from the fcr's if you run pod filters and ditch the stock airbox. you should be able to pick up a throtle cable and filters and jets from sudco.
get a good selection of jets and spend some money on dyno time getting them set-up.
konto has flat-slides on his bike and has tried a variety of different set-ups.
fcr's are hard to set-up.
get a good selection of jets and spend some money on dyno time getting them set-up.
konto has flat-slides on his bike and has tried a variety of different set-ups.
fcr's are hard to set-up.
Jason, aka: Hooligan
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100
So far so good. Decided to guve them a trial fitting. No return cable on throttle, wrapped pull cable around and it worked- just for trials. The jets are as follows Main 162all, pilot 80, main air 200, pilot air 100. Seems the main jet is huge. Just velocity stacks 35mm, and after cleaning pilot jets(3 were mucked closed) and it started right up. But after a minute I was standing in a puddle of fuel, seems the overflow vents at the tops of the carbs were over flowing pretty bad. Hopefully that is it? Will set up a fuel bottle next time, instead of tank, so I can see if there's any problem.
Probably need to check/clean the float valves, stuck open?
Was looking at Sudco's site, and they refer to fcr 39 airbox adapters, if they don't have the 750's-the spec's on a few others are pretty darn close.
Smelled awefully rich- but seemed to want to go for a ride, now about the air filter situation?
Probably need to check/clean the float valves, stuck open?
Was looking at Sudco's site, and they refer to fcr 39 airbox adapters, if they don't have the 750's-the spec's on a few others are pretty darn close.
Smelled awefully rich- but seemed to want to go for a ride, now about the air filter situation?
94 YZF750r
'98 yzf750r
95 YZF750SP
'98 yzf750r
95 YZF750SP
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KontoBoy
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I'd also recommend using just the K&N Pod Filters (I run them on my track bike) for non-racing track use, especially if you are foregoing an airbox. The FCRs will flow a lot more air than the Stock Mikunis, so the stock airbox is likely too restrictive.
When I called last spring SUDCO wasn't carrying the Airbox adaptors they list in their catalog. I believe those were for the YEC kit type airbox, not a the stock airbox.
However I bought a set of 4 pod filter adaptors from SUDCO for about $180. (They sell the K&N POD filters too.) The pod filters clamp on the same as the stock airbox, so you should be able to use them for both. That said, I haven't tried it so I don't know if there are any gas tank clearance issues with the stock airbox on top FCRs.
SUDCO no longer lists the YZF750 throttle cable in their catalog, but I would ask. They were $50 a couple years ago.
I can check P/N on the pod adaptors if you need them, but I'd recommned calling SUDCO. The guy I talked with was friendly and knowledgeable.
I'm running 152 mains, pilot 1.5 turns out, 100 on the slow air (one turn out on the adjustable jets--you can pick them up from SUDCO too), and 200 on the main air. This worked pretty well for my FCR39s with Pod filters and a ram air box.
I used the same settings with a velocity stacks and ram airbox and they did not work well. There was no power under 6K and then a huge surge as you got up to 8K. If you were running over 8K all day I guess it would be fine. I don't, so getting out of th epits was a bear (had to do drag starts) and rolling on the throttle through corners was scary.
Check this thread in the Tech Tips forum:
http://exupbrotherhood1.com/phpbb2/view ... highlight=
I'd like to get some dyno time, but haven't found an FCR knowleageable local shop.
If you are using this strickly for track, I'd defintely recommend the ram air box. Airtech still lists it on their website.
And yes, I'd start with checking for a leaky hose and the float bowls. And it does smell rich--no EPA emissions to worry about at the track.
Kontoboy
When I called last spring SUDCO wasn't carrying the Airbox adaptors they list in their catalog. I believe those were for the YEC kit type airbox, not a the stock airbox.
However I bought a set of 4 pod filter adaptors from SUDCO for about $180. (They sell the K&N POD filters too.) The pod filters clamp on the same as the stock airbox, so you should be able to use them for both. That said, I haven't tried it so I don't know if there are any gas tank clearance issues with the stock airbox on top FCRs.
SUDCO no longer lists the YZF750 throttle cable in their catalog, but I would ask. They were $50 a couple years ago.
I can check P/N on the pod adaptors if you need them, but I'd recommned calling SUDCO. The guy I talked with was friendly and knowledgeable.
I'm running 152 mains, pilot 1.5 turns out, 100 on the slow air (one turn out on the adjustable jets--you can pick them up from SUDCO too), and 200 on the main air. This worked pretty well for my FCR39s with Pod filters and a ram air box.
I used the same settings with a velocity stacks and ram airbox and they did not work well. There was no power under 6K and then a huge surge as you got up to 8K. If you were running over 8K all day I guess it would be fine. I don't, so getting out of th epits was a bear (had to do drag starts) and rolling on the throttle through corners was scary.
Check this thread in the Tech Tips forum:
http://exupbrotherhood1.com/phpbb2/view ... highlight=
I'd like to get some dyno time, but haven't found an FCR knowleageable local shop.
If you are using this strickly for track, I'd defintely recommend the ram air box. Airtech still lists it on their website.
And yes, I'd start with checking for a leaky hose and the float bowls. And it does smell rich--no EPA emissions to worry about at the track.
Kontoboy
fe911, not familiar w/your' carbs, but if you are having overflow probs and float levels and valves are in spec. offer these bits. if float valves are sealed to carb bodies by o-rings (as opposed to screw in seats) check them for deterioration/fit. also, have experianced debris from fuel lines keeping needles from sealing ( especially common when using automotive fuel line when coupled with use of race gas/alcohol/additives.) also early yzf600's had plasic floats which would swell enough to contact carb bodies and hinder travel when hot. maybe usless info, but problems I've encountered and happy to pass along. luck G
fcr's
There was some debris(black rubber fuel line bits). But the real culprit was the float needle wire wasn't on the metal float tab-correctly. Now they are running pretty good on the bike. Finally got it warmed up when they are on. A local shop just happened to have a set of fcr airbox adapters that they had machined for another project. When I took them home and measured them, they were machined to the specifications of my airbox, fit like a glove(If I ever wanted to use the airbox, that is). Sold them to me for $40.00!!!
The bike won't go over 6k, when you open the slides gas literally sprays out-huge main jet 162.
A few questions about the carbs, first the intake boots don't seem to be holding on very wel when tightened. Is there a trick to getting a good seal? The carbs do move around a little, and theres an obvious vacuum leak, sometimes.
Second, one of the slides rattles a lot more than the others. I can put a finger on number 1 cylinder slide to keep it from rattling, and there is hardly any rattle noise. The other three don't rattle at all! Could this be a another vacuum symptom, or is there problems with some slides rattling more than others?
Thirdly, I was talking to a friend and he suggested getting the carbs set up a little better before a dyno run. So as not to spend too much money on the dyno time. My mechanic mentioned that they would need to make sure it had the right needle. With needles and different jets, this could end up taking a long time. So, I was wondering if anyone had any suggestions for a good baseline to start?
Currently it has: K&N- 4 pods Altitude 5000 feet
Has: Suggested:
Main 162 145
Pilot 80 80
Main Air 200 200
Pilot Air 100 Adjustable
Needle OCEMV ???
Any ideas would be great.
The bike won't go over 6k, when you open the slides gas literally sprays out-huge main jet 162.
A few questions about the carbs, first the intake boots don't seem to be holding on very wel when tightened. Is there a trick to getting a good seal? The carbs do move around a little, and theres an obvious vacuum leak, sometimes.
Second, one of the slides rattles a lot more than the others. I can put a finger on number 1 cylinder slide to keep it from rattling, and there is hardly any rattle noise. The other three don't rattle at all! Could this be a another vacuum symptom, or is there problems with some slides rattling more than others?
Thirdly, I was talking to a friend and he suggested getting the carbs set up a little better before a dyno run. So as not to spend too much money on the dyno time. My mechanic mentioned that they would need to make sure it had the right needle. With needles and different jets, this could end up taking a long time. So, I was wondering if anyone had any suggestions for a good baseline to start?
Currently it has: K&N- 4 pods Altitude 5000 feet
Has: Suggested:
Main 162 145
Pilot 80 80
Main Air 200 200
Pilot Air 100 Adjustable
Needle OCEMV ???
Any ideas would be great.
94 YZF750r
'98 yzf750r
95 YZF750SP
'98 yzf750r
95 YZF750SP
-
KontoBoy
- Help!!! I need a LIFE!!!
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- Joined: Wed Sep 01, 2004 8:43 pm
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That's great luck on the airbox adaptors.
I really suspect that with a 162 main and the stock airbox/filter combo it is running way rich. That's even before you consider you are at 5000 feet. I have 152s with pod filters and ram air. Try dropping them a big chunk, or as a test, pull out your filter and see what happens. I suspect you'll see a big improvement.
For some base setting as 5000 feet you should try and catch ExupElvis (Bob). He know FCRs.
The acclerator pump will give a big shot of fuel when you twist the throttle, but that is independent of the size of the main jets. You can adjust it at the pump link. I wouldn't touch it though until I got my jets set, and then adjust it based on how it responds to throttle.
FCRs rattle. It scared the shit out of me the first time I heard them. I thought I'd dropped something in the cylinders. My only surprise is that all 4 cylinders aren't rattling.
I do find it hard to get them seated properly. Three carbs will seat fine the 4th will be an SOB.
Check that the carbs are flat across--the throttle tubes screw in and out on a fine thread. Also check that your boots are seated correctly on the intake manifolds--there are notches on the manifolds and boots that need to line up. Then I'll tighten the clamp the connectors to the manifold first, then press the carbs on with the help of a little 10w40. Finally take a look down the throttle bodies and outside around the manifolds to make sure they are flush before tightening the top clamps.
Kontoboy
I really suspect that with a 162 main and the stock airbox/filter combo it is running way rich. That's even before you consider you are at 5000 feet. I have 152s with pod filters and ram air. Try dropping them a big chunk, or as a test, pull out your filter and see what happens. I suspect you'll see a big improvement.
For some base setting as 5000 feet you should try and catch ExupElvis (Bob). He know FCRs.
The acclerator pump will give a big shot of fuel when you twist the throttle, but that is independent of the size of the main jets. You can adjust it at the pump link. I wouldn't touch it though until I got my jets set, and then adjust it based on how it responds to throttle.
FCRs rattle. It scared the shit out of me the first time I heard them. I thought I'd dropped something in the cylinders. My only surprise is that all 4 cylinders aren't rattling.
I do find it hard to get them seated properly. Three carbs will seat fine the 4th will be an SOB.
Check that the carbs are flat across--the throttle tubes screw in and out on a fine thread. Also check that your boots are seated correctly on the intake manifolds--there are notches on the manifolds and boots that need to line up. Then I'll tighten the clamp the connectors to the manifold first, then press the carbs on with the help of a little 10w40. Finally take a look down the throttle bodies and outside around the manifolds to make sure they are flush before tightening the top clamps.
Kontoboy
to the Brotherhood!!!!
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dragracer1951
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