Hey guys,

In the past couple days I've gotten some funny behavior out of my engine. I'm hoping that you folks can offer some suggestions.

Let me preface this discussion by saying that this was a basket-case engine and was reassembled by me, and the carbs were cleaned but never tuned. I don't have the sync tool. Anyway, as long as I've had it, the low-end has been kind of weak. Acceleration would be slight "jerky" below about 2700 rpms. Less than 4k rpm yielded somewhat slow acceleration, although smoother. After 4k everything seemed pretty happy and good. Idle was around 1400 rpm and always sounded kind of rough to me.

Today, it felt as though I was riding with the choke on. That is, if I let off the gas at 3k rpm, the engine speed would hover around there for a second and recover back to idle too slowly. And the bike felt like it had even less power around the <4k rpm range. Again, after 5k everything felt fine.

I believe I need a carb sync/tune. When I first put the carbs together I used the stock 2-1/8 turn instructions from the manual. I believe it may be running rich, causing it to behave as if the choke were still on. (I'm reasonably certain the choke isn't malfunctioning, because it has the same "feel" it always did). What do you all think?

(also, it was running a bit hotter than usual, but today was probably the warmest weather I've ever had it out in, 80 degrees) Does heat generally hit performance pretty hard? Because it felt like a totally different bike today.

 

Yes heat can drop engine peformance. My bike does great on a cold morning and isnt as good in the late afternoon since its warmer. It all has to due with air density and im sure there is more crap as well. That why people put cold air intake(CAI) on their cars. Keeps it slightly cooler.

Anyways i would say to start with a sync. If you dont have the tool ebay can provide them fairly cheap. I picked mine up for about 90 bucks. If you dont want to buy it i may consider renting it out if you can be real careful and replace if you break. Ill have to think about it a bit more though. lol

 

I remember seeing someone around the forum with this exact same problem last summer. do some searching, see if you can find it.