xr70 idling/power issues

Well this is my first xr70 (had a xr50 before) and I just cant seem to get the thing to idle. It will idle better with the choke on but with it off I have to keep playing with the idle screw to keep it running. It seems to idle good for a minute and then wants to die. I already cleaned the carb out and it has stock jets. Is there any issues with these bikes like valves or anything of that sort, thanks.

There aren't any issues with the valves going out, but if they are set to tight, it wont want to idle right

Have you checked the clearance? I forget the exact specs by the book, but I run so .002 fits and .004 wont..

I think the valves are something like intake is .002-.004, and exhaust is .003-.005, but I'm not 100% sure.. My specs are fairly close, close enough that if they are set that way it'll run fine

Other then that, the pilot jet is soo small, you might need to run a piece of wire through it to make sure its clean, its a TINY pilot, and its built into the carb.

Thanks for the info. I'll take a look at it this weekend. BTW is it pretty easy to adjust the valves? I'm going to change the oil and take a look at the valves.

Thanks for the info. I'll take a look at it this weekend. BTW is it pretty easy to adjust the valves? I'm going to change the oil and take a look at the valves.

yeah they are REALLY simple, just pop the two caps off the head, spin the engine over tell it's at TDC (so the cams don't have a load on them) and check it.

The "proper" way to do it is to remove the cam cap also, the cam is on the left of the engine, the bolt to remove the round cap is on the right side its a 10mm..

But if you look at the cam lobes, you can just tell when the engine is close to TDC, when the lobes aren't pressing against the rockers.

IMO the carb pilot circuit is still stopped up. If it runs with choke on and not off it is to lean. If you never have checked the valves you should do that too but what you are saying points to the carb.

Well it does run with the choke off but once its warmed up it starts to almost lope and wants to die. Im going to change the gas and then check the valves and pilot hopefully this weekend, thanks for the tips.

I mean to say at idle. If you can get it reved up its not on the pilot circuit any longer. I have seen bikes where the owner keeps screwing the idle speed screw in so the thing is trying to idle with the slide held up. Real hard to control idle speed that way.

Take the pilot jet out heat with a propane torch to burn off any varnish, then stick one wire from a wire brush through it, should fit easily, If it does not it is clogged. Mixture screw should be 1 1/2 turns out and get a new plug. Get surgical with the carb make sure it is so clean the factory will have nothing on you or you can just get a new pilot jet. Mine did the same now runs like a champ after I cleaned the carb almost 3 times and heated the jets the last time, sprayed carb cleaner and dried w/compressed air.

Edited by BRPHondaRider
sausage fingers

Well this bike still isnt running good. I ended up just buying a new pilot and yet it still has idle issues. I'm wondering if its the floats? To me it almost seems to be running rich. I did also adjust the valves (a little loose) but it didnt seem to help. I did notice an exhuast leak from the head so I will have to fix that here soon. Anything else it might be? BTW I also drained the gas tank and put some fresh 91 gas in. This thing is becoming a real PITA.

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