I need some input...

After a late night of working on the bike (i just got in the house and it is 3 in the AM) I have some odditys I need help with.

First of all, compression is unknown...I know I need to check it.

A 4 into 1 pipe and pods have been added and I have yet to re-jet

Valves are all shimmed except one which has a clearance of .20mm, I don't happen to have the size smaller sooo it will have to do for now.

Ignition timing is spot on (according to the cheapo timing gun I got at princess auto)

Cam timing, well it is as close as I can get it... I tried 3 times tonight to get it spot on, but I am guessing wear of the cam chain has made it impossible to get both timing marks spot on...


Now the problems,

1) plugs #2 and 4 were black and carbon covered while plugs 1 and 3 were white (what I expect because I have yet to rejet for the pipe and pods). What could make those 2 foul.

2) no power over 7,000 RPM's it will sometimes surge with a moment of power then go flat again...

3) poor idle, it does idle reliable at 1,000 rpms it just sounds bad, and I can hear a sucking from one side of the carbs.... also adjusting the air screws on the carbs does not seem to make any difference which I find odd.

I think my next step should be to go up some jet sizes (2 or 3?) and sync the carbs. DOes anyone have any other input?

I'll let some 650 owners give you some numbers but you are going to have to go up on your jet sizes.

Swap out the plugs you now have installed.Put 2 and 4 in 1 and 3 and see if they change colors.

Are your carbs clean?

Just some thoughts. Roy

If not already done, would assure floatbowl fuel level is not too high in #2 carb and #4 carb.

An otherwise perfect carb will suffer from an incorrect fuel level.

Some pods obstruct entrance to pilot air passage.

Dirty, clogged or over-oiled pod can cause sooty plug by restricting air intake.

Could be wrong, but doubt carb sync would resolve soot issue on #2 and #4 plugs.

Air screw adjustment having no effect indicates something wrong in the pilot circuit.

Good Luck!

it seems like you are on the right track, get a good base line of everything.
also have you checked the voltage at the coils and check the coils also.

I would replace the plugs with new ones, dont just try and clean them, just dosent work anymore.

what have you done to the carbs if anything? a good cleaning is going to be very important, and replace the fuel filter also

The carbs are clean, I have checked them at least 3 times and run thin wires through all the passages.

I have checked the fuel level with a tube, but with pretty poor results. I picked up the special tool and I plan on checking the float bowl level properly when I pick up some jets.

I have not checked coil voltage I will check that next time I am working on the bike.

ok, with the bike running, spray some water on the pipes, they all should steam the same, if not you will see which ones are giving you the problem, start there,

hardr0ck68 wrote:

The carbs are clean, I have checked them at least 3 times and run thin wires through all the passages.

I have checked the fuel level with a tube, but with pretty poor results. I picked up the special tool and I plan on checking the float bowl level properly when I pick up some jets.

I have not checked coil voltage I will check that next time I am working on the bike.

I don't suspect coil voltage, because the two sooty plugs are from different coils.

Until assured otherwise, I would still suspect pods obstructing entrance to pilot air passage at rear of carb. Especially if not using K&N pods. Usually not an issue with K&N pods.

Imo the plug sooting issue should be resolved before installing larger pilot jets which will just worsen the sooting problem. Using the clear plastic tube test to check floatbowl fuel level may be performed with the carbs remaining installed on the bike and without any disassembly (except removing the drain screws).

Good Luck!

its been my experiance that soot is usually a result of low compression now that you got valves shimmed id run a compression test if that checks out put in a new set of plugs and try again pods are more trouble than their worth but if you insist spend the extra money on the k&n filters and get a bucket full of jets

I have had the carbs on and off about 15 times in the last 3 weeks, some of those removals were due to the pods, but honestly the one time I took the air box off was enough for me to decide never again.


I just dropped in the new jets today, and I picked up some fresh plugs. My new stainless pipes were bluing so I decided it was time to fix this lean condition.

I checked the float levels #1,and 3 were perfect. #2 was a touch high but close enough, and #4 was fairly low so I adjusted and now it is spot on.

I am now running 107.5 mains, and whatever pilots z1 recommended.

Is it worth the work to change the needle height?


Other information. I have checked for intake leaks many times, to always find all the boots sealed up tight.

Still wondering why those two are sooty...


If the pods are blocking the pilot circuit how do I fix it? And is there any way to check? How do I fix the problem without dropping $140 on K and N pods? I have emgo pods if that matters.

Rock, not to be insulting, but ignition probs, run in pairs.carb problems from left to right. unmolested ignition coils, L/h coil wires go to cyls#'s 1&4. r.h to 2-3. often wires are only long enough to be proper, but sometyhing to check. G

Have you inspected your coils for cracks? Are they original? If they are replacement is a good idea. What ignition are you using? I just ordered a set of dyna green coils with new wires for just a shade over 150. Hope it helps

I am using 3 ohm Dyna coils (the green ones) and a dyna S ignition... the ignition timing was perfect as of last night.


I agree Gane, I doubt this is ignition related either however; would a combination of poor spark (maybe incorrect coil voltage) and was also running lean cause some plugs to be white and others black?


I just took it for a ride with the new jets... some good some bad. The midrange seems more powerful, It is night and I didn't wanna kiss a deer so I cannot comment on WOT yet except when I peg the throttle open quickly the bike stumbles now... this was not a problem before.

Overall it feels better, except for the stumble when I go to WOT.