FXR carbs?

**John_H** · 17th September 2012, 20:52

I'm looking at upgrading the carb on my FXR. Couple of questions: My engine is totally stock, is it worth it? Also, any suggestions on what to buy? Hamish is running this http://www.akunar.com/CARBURETTORS.html the CBYPWK30 model.

Cheers

**Pumba** · 17th September 2012, 21:04

http://www.trademe.co.nz/motors/moto...-513347827.htm

Best option I have found, and I have played with a few different types. Others have had good success with the Mikunui 28mm flat side from a DR200 (VM28ss). I had one but never got it work, but that could have just been the carb I had. The OKO's are good as they are of good quality and brand new, so no dodgy second hand parts that you dont know the history of.

If your engine is stock stick with the 28. You only need to go bigger if you are doing any serious head work.

**koba** · 18th September 2012, 08:21

Originally Posted by Pumba

The OKO's are good as they are of good quality

I've seen some OKO's that aren't...

**Shorty_925** · 18th September 2012, 08:39

DRZ250 carb is another good option.

**hmurphy** · 18th September 2012, 09:47

John that carb is the exact carb I am using. It works well but I had to use a bit of sandpaper on it to make it run smoothly which is a bit shit. It's light, simple and easy to change jets. My mate uses the exact same carb (the 30mm, same as my one and the one you mentioned) and his bike is completely stock. It works perfectly fine on his bike. It also means you can upgrade your engine at some stage and know that it will be fine because I have no problems. So at least you know that if you go for that option, you know it should work.

**John_H** · 18th September 2012, 10:03

Originally Posted by hmurphy

John that carb is the exact carb I am using. It works well but I had to use a bit of sandpaper on it to make it run smoothly which is a bit shit. It's light, simple and easy to change jets. My mate uses the exact same carb (the 30mm, same as my one and the one you mentioned) and his bike is completely stock. It works perfectly fine on his bike. It also means you can upgrade your engine at some stage and know that it will be fine because I have no problems. So at least you know that if you go for that option, you know it should work.

Would you go for a 28mm or a 30mm?

**hmurphy** · 18th September 2012, 11:12

Well I know the 30 works so I wouldn't be able to say if 28 is better. The 30 is perfect for my modified bucket and seems to work okay on the stock. The only bad thing is the pilot jet is too rich and you can't get smaller ones. You can't just pin it from no revs but you don't ever do that anyway. My mates stock FXR is fast and all it has is the 30mm carb.

**hmurphy** · 18th September 2012, 11:26

Oh it also comes with a jet kit - 5 pilot jets and 5 main jets. All of them are pretty useless hahaha. The smallest pilot jet you get is the smallest available in those kinds of jets. The main jets are all too big unless you start tweaking your engine. I bought 2 smaller main jets to test with ($8 each or something) and I found the one that works best was an 18 or 15 or something and the smallest you get with the kit is a 20. I can confirm the sizes for you if you want. When I upgraded my engine I needed a bigger main jet so I used a bigger one from the kit I got and I think I gave the smaller jet to my mate who is using it for his stock engine.

**kel** · 18th September 2012, 15:31

Originally Posted by hmurphy

The only bad thing is the pilot jet is too rich and you can't get smaller ones.

keihin pilot jets range from size 25 to 60, the 35 pilot jet has always worked fine for us. As Koba says not all Keihin copies are as good as the OKO and there really are knock offs of the knock offs kicking around. Stu's OKO's are the good ones! (although a little pricey)

**Bert** · 18th September 2012, 18:47

Originally Posted by kel

keihin pilot jets range from size 25 to 60, the 35 pilot jet has always worked fine for us. As Koba says not all Keihin copies are as good as the OKO and there really are knock offs of the knock offs kicking around. Stu's OKO's are the good ones! (although a little pricey)

you can buy them off eBay; but support Stu (supplying good stuff and provides support)..

Generally there is a great selection of jets (mains and pilots) & Needles kits; if you hunt around (mainly in the scooter section) on Ebay....

**John_H** · 18th September 2012, 22:28

Thanks for all the replies, a bit of conflicting information. I'm gonna need this in idiots language though as I'm very basic in my mechanical knowledge - should I go for the 28 or the 30? What's going to give the best results on a stock engine?

**Muzzab** · 18th September 2012, 22:52

I brought one off Stu, he suggested a 28mm for my stock engine, it seems to work fine, I'm still playing with jetting, but it is better than the standard CV carb the bike came with for sure.

**mossy1200** · 18th September 2012, 22:53

I have the 30 OKO running the smallest jet i think 113 out of the 10 pack jet kit.
The idle jet was to small and it was lean at the bottom so I needed to drill one because it was danger lean until over 4k revs.

Mines on a 2 valve motor with stock cam so Idd say go the 30 and you have a usable carb for later when you trick that engine up.

If my points 70s engine can run one you shouldnt have many issues.

**Pumba** · 18th September 2012, 23:09

I would get the 28.

This is based on flow bench testing people I know have done on the head. Unless I was doing serious head work like bigger valves etc. I see no need to go bigger.

Bigger is not always better.