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XR650R hard to start, even with tm40!

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Hey guys!! I am a long time follower of this forum, but this is my first post...cause I really need ur help :facepalm:

 

I got myself a XR650r with modified cam, big bore kit (dont know the compression) and stock carb... and it was a pain in the ass to start...so I change the carb for the well recommended mikuni tm40-6..

 

In brief, the starting got better, but still not quite..

 

It has a 25 pilot jet, fuel screw almost 2 turns. It starts without choke, so is rich enough...

 

I´ve been thinking about:

 

-changing from 91 to 98 octane fuel

 

-drilling some holes in the side cover

 

-going to the gym...  :crazy:

 

any tricks of how improve the starting?

 

thanks a lot!

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Checked valve clearances lately??

 

Appologies if I offend you but are you familiar with the starting technique with these bikes?

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I am not familiar with tuning on the tm40, but if it is off then that could make it hard to start. I have an fcr on mine and i twist the throttle twice find tdc of compression stroke. Pull decomp and push kick past compression stroke then kick it and it starts right up.

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This is what I do for cold start:

 

- 3 kicks with decomp in

 

- release decomp

 

- find tdc (when i hear the click or it gets hard)

 

- pull in decomp and move the kick start down slightly

 

-then realease de kick start to the top and a big kick!

 

*I dont touch the throttle

 

*yes valve clearance is fine 

 

thanks

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Is the compression good? Leak down test would be preferable, but you could first try standing on a kickstarter whithout kicking when it's compression stroke, will it hold you for at least 3 seconds? It was really hard to start mine when rings and valves were done for, cold and hot.

And now that you have a fuel pump you should also twist the throttle once or twice before making a big kick when cold. Also, try touching the throttle a little, does it start easier this way?

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now, I don't know anything about the TM40, but the 650R is easy to start even with stock carb if you do the correct procedure, and the procedure you described is the same one as I use, and my bike always starts the first kick no matter what.

 

I suspect something is off with your bike for sure, do the usual routine of replacing the sparkplug, cleaning the airfilter, and dumping all your gas and replacing it with fresh gas, do get some higher octane gas too, just to be safe.

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Ok, tomorrow I will try:

 

-Compression test

 

-replace the fuel for 98 octanes (it was in the tank for 5 months...not too fresh lol)

 

-I will try using the throttle

 

 

 

Thank you guys, hope it works!

 

 

 

PS. spark plug is new and air filter looks clean to me..

Edited by Brucenash2

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As was mentioned earlier... Is your valve lash in spec? Out of clearance valves will make a bike a cranky starter.

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Mine is hard to start with stale fuel, also with my TM 40 too low idle speed was a problem when starting. 2 twists of the throttle works for mine also. Ted

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mine was very hard to start,i checked everything 2 and 3 times had no luck at all.some one on thumper talk advised me to check my grounds. i cleaned them all found the one between the coil and the frame had turned the brass terminal black,i cleaned it sanded the frame and the coil reassembled it an the bike starts fine hot and  cold,not so good when it is layed down and gas runs out the carb. try this it is quick and ez. XX

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crap! my anckle hurts! I couldn´t start the bike today.. 

 

I changed the 91 octanes old fuel for 98.. and if twist the throttle, the bikes backfire..

 

gonna check the grounds "dos equis" told me, tomorrow and see how it goes..

 

Valve clearance was checked by two mechanics...mmm

 

 

thanks

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crap! my anckle hurts! I couldn´t start the bike today.. 

 

I changed the 91 octanes old fuel for 98.. and if twist the throttle, the bikes backfire..

 

gonna check the grounds "dos equis" told me, tomorrow and see how it goes..

 

Valve clearance was checked by two mechanics...mmm

 

 

thanks

check the valves yourself, just to be safe, mechanics make mistakes too.

do you have spark? proper blue strong spark?

and do check all the grounds, something is wrong with your bike, the 650R isn't a hard starter.

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Hello again, I cleaned the coil, but nothing happened..

 

I want to test the resistance of the coil, what´s the normal range? around 5000 ohm??

 

Can you walk me through the process?

 

 

 

thanks

 

 

 

 

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Just realized the coil is not OEM, it is this one:

 

http://www.ebay.com/itm/AMR-RACING-PERFORMANCE-MONSTER-IGNITION-COIL-UPGRADE-XR-PART-HONDA-XR650R-XR650-/141307962531?pt=Motors_ATV_Parts_Accessories&hash=item20e69c64a3

 

should I go back to the original one? does everybody knows how to test this specific coil?

 

Is this coil really superior to the OEM?

 

 

thanks

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