Help me diagnose my 650R

[scottro79]

Hi TT-

Two days ago I picked up an 02' CA street legal XR650R. Its in beautiful shape and bone stock as you can see below.

Initially I found a problem with throttle response and hesitiation when accelerating. Taking a closer look I found the fuel line leading from the petcock valve was sun-hardened and kinked. I replaced the fuel line with a high quality one (*not the stock pre-formed hose.) and it seemed to have an effect. Unfortunatly it did not completely solve the issue.

When accelerating the bike tends to suffer from hesitation. The engine does not completly cut-out, but clearly there is a problem. Acceleration would have to be described as sparatic, and when cruising on low-end power the bike sputters.

Next I'll open the bottom of the carb and take a look at the jetting and interior condition of the carb. This is my first 650R and Im not super confident about finding my problem... so any help from more experience riders would be great.

??

Thanks TT

[MegaThumper]

Hi TT-

Two days ago I picked up an 02' CA street legal XR650R. Its in beautiful shape and bone stock as you can see below.

Initially I found a problem with throttle response and hesitiation when accelerating. Taking a closer look I found the fuel line leading from the petcock valve was sun-hardened and kinked. I replaced the fuel line with a high quality one (*not the stock pre-formed hose.) and it seemed to have an effect. Unfortunatly it did not completely solve the issue.

When accelerating the bike tends to suffer from hesitation. The engine does not completly cut-out, but clearly there is a problem. Acceleration would have to be described as sparatic, and when cruising on low-end power the bike sputters.

Next I'll open the bottom of the carb and take a look at the jetting and interior condition of the carb. This is my first 650R and Im not super confident about finding my problem... so any help from more experience riders would be great.

??

Thanks TT

Never had that problem with my R but several things come to mind...

Too much oil on air filter which might lead to ...

Bad or fouled plug

fuel flow blockage (in carb or in tank)

Sounds like you are going to check the carb already.

[martinfan30]

Probably needs to be rejetted from the factory jets. Too lean can do this.

Go here...

http://borynack.com/XR650R/index.htm

[rdjohnson55]

You need to uncork that big pig...There should be some sticky’s or just do some searching on the site. The day I bought mine (04) I went and ordered the Quicksilver pumper card, uncorked (removed baffle and side vent on air box, buy the smog block off kit, new uni or K&N filter, 50 state intake manifold and at least get the HRC tip for the exhaust) Then she will come alive and I have never had the bogging and the snap off the bottom is perfect.

[Maroast]

Yeah, if the bike hasnt been uncorked then you will absolutely experience throttle problems.

Its kinda hard to tell where your problem is with the description you've given us. If its a fuel issue, the symptoms of a bike that runs too rich or too lean can be similar to an "untrained" individual....the difference is where in the throttle range and what conditions are associated with the problem.

If it is uncorked, you may be running too rich...you may have a main jet in thats too large and/or the needle height is too high. I found on my bike that when i was delivering too much fuel the low end sputtered, and the motor wants to cut out when the throttle is opened...open the carb up and see what kind of jetting is in there....also take a look to see if any uncorking mods have been done (intake and exhaust)

[scottro79]

I do plan to uncork it soon enough, but at the moment I need her running right as is. This model doesn't have a smog pump. The air filter is clean and mildly oiled... however is beginning to deteriorate from age.

I think the fuel line I rigged should be working fine, but it is not the pre-formed piece of hose you can get from Honda.

I'll be opening the carb to confirm my jetting and will check the condition of my spark plug

[scottro79]

Yeah, if the bike hasnt been uncorked then you will absolutely experience throttle problems.

Its kinda hard to tell where your problem is with the description you've given us. If its a fuel issue, the symptoms of a bike that runs too rich or too lean can be similar to an "untrained" individual....the difference is where in the throttle range and what conditions are associated with the problem.

If it is uncorked, you may be running too rich...you may have a main jet in thats too large and/or the needle height is too high. I found on my bike that when i was delivering too much fuel the low end sputtered, and the motor wants to cut out when the throttle is opened...open the carb up and see what kind of jetting is in there....also take a look to see if any uncorking mods have been done (intake and exhaust)

No uncorking mods... the airbox/intake is stock and there is no smog pump so I assume its simply a model from outside of California. Im headed out to the garage to open the carb and will note the jetting but to put this simply I am "untrained" and its gonna be difficult for me to tell if Jetting really is the issue.

[Maroast]

No uncorking mods... the airbox/intake is stock and there is no smog pump so I assume its simply a model from outside of California. Im headed out to the garage to open the carb and will note the jetting but to put this simply I am "untrained" and its gonna be difficult for me to tell if Jetting really is the issue.

Oh, your all good man, if the bike has not been uncorked then your job is pretty easy... Just buy the parts (under $100) and follow the jetting guide on this web page http://www.xr650r.us/jetting/ ...... You'll then have a dirtbike that is outright dangerous!! ?

Dont worry about not knowing too much about jetting....there are a lot of really good resources on this site and the one posted above.... good luck! ?

[martinfan30]

Thats got to be it. Everything else seems stock right? So the jetting is also.

You just need to open the exhaust and intake at the same time. Well, its recomended to do at the same time.

[Frank ZX]

When I got my XRR,it had the wrong plug in it,the pilot jet was clogged,and my fuel line was kinked also.The carb is super simple.Just be gentle taking it apart,remove all jets,and hold them up to a light to see if you can see light.If clogged,run a torch tip cleaner thru them or compressed air to clear them out.I would step up the main,and pilot jets,and put the clip in the 3rd grove from the bottom.Your bike should run great.Make sure the plug is a tan color.White is too lean,and black is too rich.I hope this helps!

[dylanr]

to solve all your carb problems, take a rope with a big anchor tied to the end, tie one end to the stocker carb, and get it up to to 92.4mph, and throw the anchor around a tree, this is the proper way to remove the stock carb. Then buy an Edelbrock! it solved all my carb problems. Youll want to uncork too of course.

I claim no liability if you actually try this

[scalejockey]

After your stock carb is "right",(clean and jetted) they work fine!(I rode one next to mine with an edelbrock.)

Save your money for some real tires and suspension.

As in "fine',I should of said for open areas.

The eddie would have a advantage in the tight slow trails.I'm such a clutch rider it would take a while for me to adapt to a pumper carb.

[dylanr]

i forgot to mention, i am a jetting idiot, and kinda lazy, so the eddie is for me

[scottro79]

Well...

I took the carb apart and found the pilot jet had a small clog. Probably didn't need to replace the main, but since it was in stock locally and I opted to buy one. I replaced the spark plug with a new NGK (BKR7E).

Once I had everything back together I noticed I had much better throttle response but the bike still stutters/hesitates in the range of 1/4throttle. My new spark plug was a pretty shade of black.

The bike is clearly running rich, but that suprises me.

Don't they tend to run lean when new or in a stock Jetting? My elevation is around 250-400ft.

Tomorrow I'll confirm the position of the clip on my needle valve and make adjustment if necessary.

I'm not sure which direction to turn the fuel/air screw to lean it out a bit. Does turning it the screw clockwise richen the mixture or lean this bike out.

Thank for all the help guys...

I'm making a ton of progress and learning all kinds of things about this bike. I've wanted one for too long!

[martinfan30]

Your stock exhaust with the new MJ could keep it on the rich side. You went up in size on the MJ?

[scottro79]

Your stock exhaust with the new MJ could keep it on the rich side. You went up in size on the MJ?

No just replaced it with a new 125 (stock) main.

Honestly that part was completely unecessary, the original one was clean and could have been re-used. The pilot jet had a minor clog which I removed with my air compressor.

I haven't checked my needle setting yet... but I am suprised to be running rich after hearing that most stock bikes run a bit on the lean side.

[martinfan30]

Keep in mind, with modern fuel and the additives in it... Really hard to get a good plug reading.

Read this.

http://www.strappe.com/plugs.html

[Maroast]

I replaced the spark plug with a new NGK (BKR7E).

Did you gap that new plug? If not, then thats the wrong plug....the 650R takes the BKR7E II plug. But you dont have to run out and buy a new one, just open the gap up .11 I believe.

A stock xrr will always run lean.... unless something else is going on that shouldn't be. The bike will never really run right unless you uncork it...thats how Honda designed it, but the bike didnt meet emission standards in the US...so Honda sold it running VERY (even dangerously) lean so that it could meet the emission standards.

Honda knew full well that once the consumer bought the bike they were going to uncork it, they even supplied the Tech Bulletin with part numbers!! Uncorking will not harm your ride, its actually better for it.

Seriously, the only way your going to get this thing tuned properly is to do it all at once and do it right.... suggestion:

Order all the parts needed for uncorking (if your on a budget you can do it for about $25-$30). Pull the carb off the bike and make sure all the passages are clean. CHECK THE VALVES. reassemble. get arms ripped out of sockets!

If you follow the directions and jetting guide, the bike should fire right up and run like a monster....maybe you'll need to do some minor tweaking, but very little. This is the guide I used to uncork my brand new 2006 xr650r some 20,000+ miles ago....still runs like a monster despite vicious beatings..... http://www.4strokes.com/tech/honda/uncork_brp/

[scalejockey]

No just replaced it with a new 125 (stock) main.

Honestly that part was completely unecessary, the original one was clean and could have been re-used. The pilot jet had a minor clog which I removed with my air compressor.

I haven't checked my needle setting yet... but I am suprised to be running rich after hearing that most stock bikes run a bit on the lean side.

Wow 125 main? when your done with the mods you should have a 170-172 in it.

MODS:Intake manfold,air box restrictor,pipe end cap mod,yada yada.?

[XRMANU]

Is your choke completly off when you ride it (warm) ..?

Riding with the choke on (or half on) will give you the same symptoms.Over rich condition.