Rough running

monkeybikegirl · Post by **monkeybikegirl** » Fri Jan 26, 2018 11:22 am

Hi Everyone
I hope this is not too vague. My R90s was set up very recently, with Dellortoes rebuild and balanced. Timing set correctly also. The bike was running great, when out on an short ride, the bike was hard to start back up, sounded terrible and would stumble and want to die. It ran better after reving it past 3000 rpm. That is how I made it home again.
Any ideas on what might be happening?
Thanks very much for any input.

schrader7032 · Post by **schrader7032** » Fri Jan 26, 2018 12:58 pm

Poor idle and rough starting is a symptom of closed valve clearances. Easy check...might be time to do it anyway.

monkeybikegirl · Post by **monkeybikegirl** » Fri Jan 26, 2018 4:52 pm

The problem occurred suddenly and the valves had been set within a 100 km.

schrader7032 · Post by **schrader7032** » Fri Jan 26, 2018 5:14 pm

Then look at the carbs. Maybe the low speed jets are plugged up. I would also recheck the valves...every time I set my valves, it's on my mind "did I get that lock nut tight last time?" It bugs me for a while...

monkeybikegirl · Post by **monkeybikegirl** » Fri Jan 26, 2018 11:20 pm

I also thought a plug in the carbs somewhere, because the bike was running great and then started to act up suddenly. Thanks for the tips. a valve clearance check is probably a good idea. Now you have me thinking "Did I tighten the locknut enough".
Thanks Kurt

monkeybikegirl · Post by **monkeybikegirl** » Sun Jan 28, 2018 6:51 pm

I checked the valves and they are correct. Took all the jets out of the Dellortoes and made sure they are clean. The problem stayed the same.

monkeybikegirl · Post by **monkeybikegirl** » Sun Jan 28, 2018 7:44 pm

Also checked sparkplug gap and points gap.

schrader7032 · Post by **schrader7032** » Sun Jan 28, 2018 8:21 pm

What about trying a new condenser? I assume you still have the stock points ignition system.

Twocams · Post by **Twocams** » Sun Jan 28, 2018 8:22 pm

I would check for vacuum leaks. Clamps tight,no cracks in plastic tubes ( rubber) to carbs. Carb mounting flanges flat and good gaskets at head to carburetor. Are both carbs getting the same amount of gas in the fuel bowl. Are both filters in the shut off valves clean? If used. Both spark plugs are firing with nice blue spark. Plug gap correct and nice clean electrode area....no soot/gas fouled. Thats all I got for now.
Spark,fuel & air at the right place at the right time in right amount....should run.

twocams

monkeybikegirl · Post by **monkeybikegirl** » Sun Jan 28, 2018 11:05 pm

Still on points, yes.