HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
Fingers

Any Mikuni experience with 650 R?

13 posts in this topic

I have a 40mm Mikuni Flat Side carb I bought from XRsOnly for my 650 L a couple years back. Does anyone know if this carb will fit and funtion on the 650 R (my new bike). I'm trying to save spending $300+ for the edelbrock upgrade.

Share this post


Link to post
Share on other sites

I loved the Mikuni TM40!!!!! It is a great carburetor once your rejet for "this bike" and not use the jetting most of then come with. Tis Carburetor was made for the Harley and they just change the pilot and main jet for the first TM's setup for XR's. How opened up is your bike? With a header, open type muffler (R4), Uni, holes in the side air filter cover. 25 pilot, 1.2 air jet, Y-4 needle jet, 90JY1 needle. Pump set a little late. 137.5 main. Awesome smooth carburetor. I ran mine a little rich at 27 pilot and 140 main. This was lean when I went to the 680 motor I have now.

Lot's of the carburetors come with a Y-8 needle jet and a 8DHY4 needle or a Y-6 needle jet and a 9DJY1-4 needle if they are real old. You can go to a Harley shop and get the right Needle jet and needle. The air jet is real important for our bike go 1.1 or 1.2 for sure. It is at the bottom of the intake side of the Carburetor and it is real small hard to read the number off the side once you get it out.

My XR650R Web Site, Click Here: :cry:

Share this post


Link to post
Share on other sites

Also, make sure the pump stream hits the needle. You can turn the pump nozle with a pair of needle nose pliers. I changed the top cap screws to allen head to make it easier to change the needle with the carbuetor still on the bike. That way I could use the allen wrench that you can use at an angle. I forgot the float adjustment and there is a little tap you grind off in the bowl on some of the TM40's to make the float work better. I'll look mine up and take pictures if I remember.

Share this post


Link to post
Share on other sites
I loved the Mikuni TM40!!!!! It is a great carburetor once your rejet for "this bike" and not use the jetting most of then come with. Tis Carburetor was made for the Harley and they just change the pilot and main jet for the first TM's setup for XR's. How opened up is your bike? With a header, open type muffler (R4), Uni, holes in the side air filter cover. 25 pilot, 1.2 air jet, Y-4 needle jet, 90JY1 needle. Pump set a little late. 137.5 main. Awesome smooth carburetor. I ran mine a little rich at 27 pilot and 140 main. This was lean when I went to the 680 motor I have now.

Lot's of the carburetors come with a Y-8 needle jet and a 8DHY4 needle or a Y-6 needle jet and a 9DJY1-4 needle if they are real old. You can go to a Harley shop and get the right Needle jet and needle. The air jet is real important for our bike go 1.1 or 1.2 for sure. It is at the bottom of the intake side of the Carburetor and it is real small hard to read the number off the side once you get it out.

My XR650R Web Site, Click Here: :)

I did a search for a 90JY1 needle in the Sudco catalog, I don't find it,there is a 9DJY1 needle,but you say it's an older/wrong type of needle.

Is there any dealer/on line store in the US where I can get Mikuni parts fast?I send several emails to Sudco for ordering and tech support but no answer :) I also need some needles for a TM36 (XR400),my 400 is standing stil for 3 months now because i can't get the correct needle . :p:D

Share this post


Link to post
Share on other sites
...and there is a little tap you grind off in the bowl on some of the TM40's to make the float work better. I'll look mine up and take pictures if I remember.

Can you tell me more? :)

Share this post


Link to post
Share on other sites

That might be a 9DJY01

I still need to dig out the carb. and open it up and take pictures.

Share this post


Link to post
Share on other sites
I still need to dig out the carb. and open it up and take pictures.

That would be very nice,thx :)

Please ,double-check needle type :)

Anyone a good Mikuni dealer ? :D:p

Share this post


Link to post
Share on other sites
That might be a 9DJY01

I still need to dig out the carb. and open it up and take pictures.

Any update? :)

Share this post


Link to post
Share on other sites

Hi my name is Thomas Fitzgerald. I have an 03 XR650r converted into a supermotard.

I recently came across your web sight www.borynack.com & have found it to be a very useful resource. I have a question for you that pertains to the TM 40 carburetor I recently installed. My problem is this, whenever I open the throttle quickly it bogs really bad, this happens when shifting in all gears. I have to shift very smooth and apply the throttle slowly or the motor falls on its face, kind of feels like it gets to much gas or not enough? this only happens when I’m opening the throttle fast , as soon as it bogs the power picks right back up. It runs great at full throttle starts fine to. I bought it from XR’s Only & installed it using the jetting it came with. I called them and them and they said it should run fine the way the bike is set up. I have it uncorked, full white BROS. E series exhaust and drilled air box cover. I have worked with my friend many times to fix this problem but no luck. I thought I’d ask you because you seem to be a VERY knowledgeable about the XR 650. Maybe you could recommend some jetting settings and other advice that might fix this problem. I live in Los Angeles

Thanks for your help, & thanks for the great web sight I recommend it to every one I meet with an XR650

T. Fitzgerald

tacf8@msn.com

Share this post


Link to post
Share on other sites

Try to drop the needle (leaner) on your TM40. I have the same thing with a Mikuni TM36 on my XR400 enduro bike.I dropped the needle to the leanest position.I can ride the 400 now but it's not perfect.I waiting for a leaner needle.The TM40 also needs a leaner needle (still waiting for some pics :) ).Al so try different pumper timings.Give a little gap between the pumper rod and the actuator.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0