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Mikuni TM ?????

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After seeing that it would cost about 600 dollars for a new carb i decided to look for a used one on Ebay. I found a Mikuni Tm 34mm flatside carb that was set up for a honda 300ex atv. Will this work? its a nice bit cheaper

Thanks

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No accelerator pump = huge, huge bog. No fun and dangerous to boot. There is a reason 4stroke carbs have an AP.

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Back in the '80s I had a C&J framed '75 XL 350 w/412 cc big bore. It had a Mikuni VM 34(round slide) & was an awesome machine. Back then we didn't have pumper carbs. With today's high performance 4 strokes, we have more options. My Dynojet kitted CVK worked very well, almost as good as the 37mm FCR(from an '03 WR250)I bought off Ebay for $235.

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Bob, give us some more details on your jetting on the 37mm FCR etc. I ran the dynojet on all our KLX's for years until I finally popped for a 35mm FCR and I've never looked back. It made a huge, huge difference once dialed in correctly. I've thought about a 37mm and would be interested in your jetting specs. My guess is that it's a tad bit large for a stock 300, but I'd like to give it a try sometime anyway. Cheers, Bill

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I bought it from a guy on Ebay who had it on his KLX 250. He said it ran great but that was an interference with the accelerator pump body hitting his Muzzy exhaust. He suggested that someone could come up with an offset intake setup. I figured that for $235 it was worth fiddling with, vs $600 for an FCR from Jerry. Getting it in was a bit of a bear, I had to remove the intake & the spigot on the carb had to be forced into it. I then had to use a SStl hose clamp. I also heated up my FSW header, & carefully peened it till it cleared the AP. At first, I thought the performance was down, until I realized I was probably a gear higher. I pulls better on the lower end, will explode out of corners now, but seems to crap out a little on top when doing power wheelies, but not as soon as the CVK. The jetting seems fine. My elevation is 2000' or lower. It is worth every penny, I believe I'm lucky on the jetting. It's off an '03 WR 250.

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Jetting on the FCR's is probably 500X's more complicated than the CVK's. There are several tapers on a needle, the AP interaction with the pilot, and then the air jets to boot. Then throw in AP timing starts and duration. Of course all interactive and you haven't even got to the MJ yet. I've found that minor alterations can make a MAJOR difference in performance. What seems to be OK on the WR can be made to be unbelieveable. It takes time, and experimentation though.

On a side note, the FCR35 is easier to get into and out of the frame than a CVK. That was one pleasant surprise for me.

Good luck with the 37.

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I have a 365 with 33mm mikuni, would I be better served going to 35mm fcr or 36mm mikuni? I like to get a little more out of the bike.

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YES! The 33mm is way too small for a 365. If you've got the $$, I'd suggest giving Jerry a call at FSW and have him jet a FCR35 for you. If that's too much, watch for a 37mmFCR on ebay that came off a YZ or WR. But you'll be on your own jetting wise. Plus they are a tight fit. Really, the 35 is the way to go.

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YES! The 33mm is way too small for a 365. If you've got the $$, I'd suggest giving Jerry a call at FSW and have him jet a FCR35 for you. If that's too much, watch for a 37mmFCR on ebay that came off a YZ or WR. But you'll be on your own jetting wise. Plus they are a tight fit. Really, the 35 is the way to go.

thanks Bill, I was afraid you would say that. I'll give jerry a call.

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Well.....if it works, it works. But if you want more, you'll definately get it with a 35 or 36mm. The engine is a lot larger and more high performance than a stock 300.

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Got the FCR 35mm off of ebay for $160. I am stoked. Seems to be in good condition. The current jetting is not good for my needs so I ordered the jets and needle that will make it work. I am going to start with Bill's jetting set up that I saw on some other posts and work from there. Since I live in ride mostly in So Cal it seems to be a good baseline. The carb has no choke so I do not know if others have FCR 35mm's with a choke. Hopefully it is OK to roll with no choke. Once I get it set up and installed I will give the crew an update. Any suggestions on a throttle cable. Can't wait to see the difference that I have been reading about.

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Don't worry about not having a choke. A few quick twists of the throttle when cold gets mine fired up every time. It's worked from temperatures in the teens to 100 +. After it's warm do not touch the throttle to start. I would suggest a two stroke single cable throttle and a new cable. Motion Pro has a lot to choose from and can set you up. The CR style seems to be popular. Jerry at Four Stroke Works could probably also set you up with what you need. I would also get a hot start which Jerry also sells.

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No problem about the choke. Like Argoosss said, a couple of blips of the throttle and it will start easier than your CVK did. Two things. Do the taffy mod before installing the carb, and make sure the squirt is about 1 second long. Also, make double sure the AP spiggot is not clogged. If it's old, I'd replace the AP diaphram as well. Get ready for a perma-smile grin on your face. 👍

Yet another convert.......

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