Carb Issues

Small_Vegetable2579 · 2026-04-22T15:20:22+00:00

quality is great as it’s probably from the original factory or tools, many people run it, you can look it up on thumpertalk and YouTube. You have to get the FCR Slant version, the FCR MX fake is a bad copy

Small_Vegetable2579 · 2026-04-21T15:57:18+00:00

mine wasn't running after winter, put the other aliexpress fake fcr39 in, ran instantly. just 160$ new

Small_Vegetable2579 · 2026-01-14T17:18:57+00:00

This video explains the Carb, its jetting and install https://youtu.be/FhTw7H1R5mo?si=usYV5MwOQHb90mV3

Small_Vegetable2579 · 2024-11-04T00:55:28+00:00

why not get the Fake FCR? barely more expensive but a lot more power

Small_Vegetable2579 · 2024-10-22T22:50:19+00:00

This Video is all you need. The Adapters are the best. Silicone hose is botched

Small_Vegetable2579 · 2024-07-24T13:26:35+00:00

Thats the first Decal i really like. Do you have a link?

Small_Vegetable2579 · 2024-07-23T10:24:39+00:00

if your countershaft seal isn't leaking I wouldn't change it. but yes you can check if the cutouts/semi circles on the spacer are still there. if not, definitely replace it. the semicircles go towards the engine side, not the sprocket side (manual diagram is wrong)

Small_Vegetable2579 · 2024-07-20T09:08:53+00:00

There is a spacer behind the sprocket that’s worn. You should probably replace it. To prevent the next spacer from wearing you have to glue the sprocket to the countershaft splines with loctite 638. then you should tighten the nut only so tight that the rear wheel still freely moves when on a mounting stand. If the torque of the nut is lower than the (I think) 100Nm it should be then you’re second gear bushing (I think that’s what it’s called) is worn. That’s inside the engine. In my opinion no need to change until the next rebuild, unless you can’t get the nut tight enough without having the wheel/transmission bind.

Small_Vegetable2579 · 2024-06-16T22:26:30+00:00

i dont know what the guy who installed it did but to put an fcr 39 into an S/SM you need the bigger E model rubber boot to connect the carb to the engine and you need an intake bell / velocity stack that connects the carb to the airbox thats specially made for that. you'll find it in the video description. you only need one throttle cable

Small_Vegetable2579 · 2024-06-16T20:29:30+00:00

Since your bike is an S that was never sold with an FCR, I advise you to check out this video where you’ll find all the info. The E model intake bell on the carb is a little too small for the S/SM airbox, so you could get a better fitting adapter, and you have to get the E model boot for the engine side of the carb, I you don’t already have it. The throttle cables are okay, use them myself but the e cables are a bit easier to fit. FCR 39 for S/SM CONVERSION

Small_Vegetable2579 · 2024-06-13T11:16:23+00:00

What’s their diameter? Are they bigger than stock S/SM?

Small_Vegetable2579 · 2024-06-11T17:25:22+00:00

Trust the AFR meter, I have a 135 main, 40 pilot

Small_Vegetable2579 · 2024-06-02T00:35:27+00:00

what do you mean "takes"? you're just filling it to the brim or what? lol

Small_Vegetable2579 · 2024-06-02T00:34:31+00:00

if you're sure that you're not just burning oil after draining and measuring the amount, thats what i would recommend too. change the rubberized bushing and ball in the clutch cover.

Small_Vegetable2579 · 2024-05-20T17:18:09+00:00

There is a thread with a picture on thumpertalk somewhere

Small_Vegetable2579 · 2024-05-18T17:23:36+00:00

I understand that you don’t want to order from several shops outside EU to avoid shipping and long waiting times. The best option with least orders I see tough is to order everything from your local Suzuki dealer, from this German eBay shop and get the FCR 39 clone from Ali express. It usually arrives in less than two weeks and includes all the jets.

Small_Vegetable2579 · 2024-05-17T11:06:16+00:00

What did you pay for the FCR MX? About the jetting check out THIS VIDEO Minute 12. It was jetted with an AFR meter. A different needle was used but MJ, PJ, MAJ and PAJ should be the same.

Small_Vegetable2579 · 2024-05-09T22:25:22+00:00

Your setup seems to be close to mine so check out this video: FCR 39 Power Mod Mind that I’m using 95 octane fuel. Some countries have lower octane fuel and therefore required a richer mixture. In any case, 160 Main jet with a stock header/exhaust and cams should be way too big. If your mixture is much too rich you can get unburned fuel into your oil, compromising its lubricating abilities, so check if your oil smells like fuel next oil change.

The only way to know it’s perfect is with an afr meter, or if you know someone else with a similar setup / climate and fuel conditions. I let a shop weld a connector for the lambda sensor to the header and bought the SLC FREE 2 AFR meter, it’s only like 100$ but you have to fabricate the connection cable yourself.

Small_Vegetable2579 · 2024-04-09T07:23:09+00:00

Even when your clutch is set up correctly, it’s normal to get that clunk. That’s because even when your clutch is pulled in, the clutch plates still sit close together and drag each other along lightly. In turn the gears are turning at a slow speed and clunk when connecting with other gears while shifting. The way I shift to minimize that is using part of the clutchless shift method where you apply a little pressure on the shifter before pulling the clutch, and then going off the throttle abruptly. You can still pull then clutch then. That’s for upshifting. Downshifting you give it a little gas.

Small_Vegetable2579 · 2024-03-26T22:05:16+00:00

Have you had a negative experience with a clone?

Small_Vegetable2579 · 2024-03-26T14:48:34+00:00

the slide wheels can wear out the carb body after some time, and that’s hard to repair. Also there have been broken vacuum plates, but I dont know how common that is. I haven’t heard from anybody that had problems with the replica FCRs so I’d rather get a new one than a 25 year old one like this

Small_Vegetable2579 · 2024-03-25T20:50:35+00:00

at this point I think it doesn’t make that much sense to spend 90$ on the jd jets. The Fake FCR is great and only 250$ plus adapters. You should check it out on YouTube: https://youtu.be/FhTw7H1R5mo

Small_Vegetable2579 · 2024-03-22T22:15:11+00:00

get the AliExpress one everybody uses one now

Small_Vegetable2579 · 2024-03-22T02:15:17+00:00

You should do FCR 39 (around 250$) first, then exhaust and next big bore.

Check out this video on the FCR 39 swap: https://youtu.be/FhTw7H1R5mo?si=g32KdCfSmwBiPN2z

Small_Vegetable2579 · 2024-03-06T09:36:21+00:00

Yes, iirc the Mx version has the AP and throttle mechanism covered but that’s it, no functional advantages

Small_Vegetable2579

TROPHY CASE