I love this bike.
I bought in the middle of 2020.
The project was to mod in a bobber but i have some issues to adjust.
PS: writing from Italy: my english could be unperfect...

I am the 6th owner of this 27 years old bike (actually 21000 miles).
When i bought seems everything was working right but have some scratches over the tank. I bought a used tank, replaced, and register the bike as motocicle of historical interst (i have some economic and pratical advantage in doing that)! Also extended the chain tensioner.

I'm bad with engines, so i call a thrusted mechanics for every work (he take care of all my bikes).

But one day, driving to Asiago (at height 1000mt over sea), the engine shutted down.
I supposed was carburation: i used to live in Vicenza (50mt over sea). It restarted immediatly. But after short time, again, it died.
And it "burned" some sparkle plugs. They was totally black (greasy carb).
In 400 miles, 4 sparkle plugs replaced.

After a superficial carburator cleaning things was better. But after 480 miles i had to change another spark plug: was black again.
Replaced original fuel with a sort of 15$ raptor petcock, deep carb cleaning and replacing pieces with a keyster carb kit (it matches default jet of 94).

Done about 400 miles without problem... No more black sparkle plugs!
But after that, again the engine have issues. Installed sparkle plug with iridium.

Actually i have small engine issues about every 30 miles, while driving (any problem starting cold engine):
-engine shut down and fuel explode in exhaust pipe (usually happen this)
-engine lose power like carb too lean (similar when start engine but closing choke to soon: if you give gas engine die.)
-engine lose power just for a couple of second, fuel explode in exhaust pipe but the bike keep going.

When engine shut down i must wait some time before restarting, apparently whitout problem.

Possibile problems i supposed reading this forum:
-Economic, 15% false raptor 660 petcock
-Fuel cap valve issue (no air enter and fuel don't flow to carb)
-Overheat (coil? control unit? some cable near engine?)
-High tension sarkle plug cable damaged

Just to know: i usually keep track of fuel usage when i refill the tank (with a google sheet). Considering my slow driving style i expected a fuel usage about 54-59 mpg

Fuel consumption before cleaning carb: 35 mpg
Fuel consumption after cleaning carb: 51 mpg
Average fuel consumption in hot months 51 mpg
Average fuel consumption in cold months 47 mpg
Best fuel consumption done in 124 miles durinf summer 2021: 63 mpg (!)

Actual mileage 21785 in 2022
1859 drove by me from september 2020

Thanks in advance

It's great that you have a mechanic. But they cost a lot and you have people here who are experienced with carburetors and can help you through all of your problems.
The 650 Savage has a flakey petcock. If it's okay today, there is no reason to believe it will be okay tomorrow. The problems they can cause are many. The description of your problems aren't outside what it can do and the age of the petcock is reasonable to expect trouble. Get a Real, Yamaha Raptor petcock, not a cheap Chinese knockoff,replace the petcock. Last time I bought one it was around thirty bucks. The online petcock for fifteen bucks has skinny fuel lines and won't work out.

Thanks to all.
Is incredible that a simple petcock could give all those problem.

-Original vacuum petcock worked only in PRI. in ON e RES shut down the engine very fast. Replaced because i also was scared about have no reserve fuel

-I've replaced with a 15$ "simil raptor".... i must provide replacing it with original Raptor 660

-i suppose no fuel mixed with oil: usually generate black smoke from exhaust pipe.

After replacing and testing (i can cover 300 miles in a couple of week if wheather is good) i will give you a feedback

The one i get  is already 8mm

Today in afternoon i had a 12 miles run: nothing happened.
In evening, same circuit, engine stopped after 9 miles.

Immediatly tried to restart. Nothing happened. Just some big exhaust explosions: i supposed the carb receive enough fuel, but spark plug can't ignite in piston chamber. Fuel unexploded goes to hot exhaust and then detonate.

Waited some minutes.
Restarted Bike. Everything was fine.

Could coil overheat and stop working? until became cold enough?

Have you installed an inline fuel filter between the fuel tank and carb?

If so.....take it out as they can air lock and stop fuel flow.

May your cheap coil endure forever. Have fun,,

The cost of oil is nothing compared to a wounded engine. Usually a bad petcock puts gas in the crankcase. Keep the filter, if you need to, but if the petcock failed, I'd dump the oil. It's not that expensive. Gasoline in the oil seriously diminishes the function of the oil.
You can pull the filter out and let it drain, put new oil in,,


I'd like to know more about where you live, how you found yourself riding a Savage, how many years you have been riding, just, tell us about you.
Unless you don't really want to,, it's just questions.. I'm glad you are here, I hope you win and ride without getting run over.. And, yeah, if You aren't situated properly, they Can turn left in front of you and cause you much pain.

The front of a line of traffic?
They don't want to wait and will go.
The End of a line of traffic?
Tired of looking at cars,they Go!
You splatter..

Be aware of when You are invisible to the people who will run over you.
Behave accordingly.
Get visible, be seen.

I can talk about that, because I got run over.
My Only claim of innocence comes from
I had No Idea there even was a left turn opportunity for traffic where I got mashed.
Had I known how the road worked I would have either dropped back or moved left,to be seen by oncoming. As it worked out, I was behind a beer truck, almost as big as an 18 wheeler,and in a lane to his right, which in America put me in his Shadow for the people who wanted to turn left.

Don't Do That!

150 miles until installed new coil.
0 engine shutdowns
54 mpg stable (before was fluctuating between 50 and 45)
When i will be more sure i will check for better carburation (if possible, to lower consumption)

Consider (if remain stable) this case could be inserted in troubleshooting.
I haven't found the same symptoms in the list.