R5 Left cylinder intermittant running.

[rded]

I got this 72 R5. I have had rd's and Yamaha 2 stroke dirt bikes in the past, I love them.

On to my issue. Got the bike non running but good compression. The PO said he has had it running

I got a new battery, cleaned the carbs and airbox with new foam filter. It started first kick and will easily pull the front wheel up.

Then something makes the power and throttle response decrease. I put new points, timed to 1.8mm btdc and new plugs.

The decrease is intermittent and seemingly electrical I clipped my timing light on the left side and it strobes normally but the left cylinder is not "hitting". No smoke and the rh cylinder gets much hotter than the left.

My question to the experts is why?  The bike is all stock with the exception of the foam air filter and it has a six speed!

[m in sc]

assuming the carbs have been  cleaned,  etc, look at the coils,  wires and plug caps. also a few other things: ignition condition & charging voltage can play hell here .  hopefully the filters aren't cone emgos or k&ns,,all foam unis or a y boot will be better. also, needs to be jetted to suit

[rded]

Thanks. I have the SV650 coils on order just in case. The bike has stock airbox and I wrappped it with the uni foam. It has to be electrical the way it's acting.

When its running killer, I noticed that there was a hesitation when going full throttle. I went up to 140's on mains.

[m in sc]

with basically the sane setup aside from cheers, I was at 150 mains and needle cip in the middle

[AAAltered]

You have *got* to look at charging voltage and generator brushes.  In the past my R5 would die on the road, the battery was slow draining.  You need to maintain a full charge to run well.

[rded]

It's charging fine. This problem is with a brand new battery, fully charged.

[idr5c]

Did you replace the condensers when you did the points? I've had a bad condenser behave like this, work fine and then start missing/cutting out when warm. 

[m in sc]

true, I had a new one recently do the same flung as well

[rded]

I did not replace the condensers. I will check that.

[rded]

Changed the condenser and no difference. Still waiting on the Caltric SV650 coils.

[SoCal250]

I didn't see it mentioned above, but have you tried swapping parts between left and right (making only one part switch at a time) to possibly isolate the cause?
-Swap plug caps
-Swap HT leads
-Swap coils
etc.

[rded]

I will try this! Thanks!

[rded]

OK so swapped around on coils, plugs and leads. I just received the SV650 coils. It started with seems like a half kick. Never was really hard to start, but you can tell those new coils are hotter. It was running relly well and then whatever kicked in. I notice when the condition is there, the LH carb does not have the vacuum that the RH carb has. I am testing without the air boots. At idle, I can hold my hand over the LH and hardly any vacuum compared to the RH side. WITF

[m in sc]

well.. check compression and that the baffle isnt clogged.

[rded]

Good call. I didn't even think about the baffle.