98 Suz RM-125 FMF Exhaust issue...help !

[fatalxsunrider43]

We recently replaced our stock muffler on our very low hour 1998 Suzuki RM-125 with a FMF Turbine Core 2 Spark Arrestor.
Ever since we made this change we are getting alot of
black spotting from the exhaust all over the rear of the bike.
It's a mess and takes time to clean. We have tried to trouble shoot the problem in conversation and here are some of the ideas we have proposed. PLEASE... If you have any ideas we'd be grateful for you to post them here so we can hopefully get this problem resolved.

1. We have always run Golden Spectro Synth. Concentrate at 52:1 as the bottle recommends. 12 ounces to 5 Gal fuel.
Is our oil mixure TOO rich ?
How much would you reduce it (ounces) if indeed too rich ?

2. Suggestions have been made to NOT use Spectro as it is a dirty oil compared to something like Yamaha Lube 2R,
any opinions on this ? Use different brand Synth ?

3. FMF never stated anything about re-jetting, we doubt this is a problem.

4. Another option in conjunction with these above might be to repack the Turbine Core and see if this help stop the spitting.....???

5. Does the FMF unit have a tendency to hold back exhaust
oils which might explain the build-up ?

6. We pulled the stock NGK R8 plug to have a look see and the electrode, insulator & side electrode are all dark brown in color, the threads on the spark plug were black with oil.
Does this also indicate oil mixture too rich ?

Thanks in advance to all that might be able to help.

fatalxsunrider43

 

[Rich Rohrich]

6. We pulled the stock NGK R8 plug to have a look see and the electrode, insulator & side electrode are all dark brown in color, the threads on the spark plug were black with oil.
Does this also indicate oil mixture too rich ?

It indicates the JETTING is way too rich.

Some related info can be found here : http://www.dirtrider.net/forums3/showthread.php?t=92818&page=1&pp=10

 

[2-Strokes 4-ever]

As said... jetting. Re-pack the silencer too, it's most likely contaminated by now.

We've still got a 98 around here, the bike's a ton of fun... those conventional twin chamber Showas are the nuts.

Keep a close eye on the clutch basket, it wears quick. And... watch the footpeg mounts too, many frames were recalled because the mounts were breaking, ours was one of them.

Set the rear sag at 100mm, slide the forks 5mm up, it's one sweet handling bike!

 

[fatalxsunrider43]

Well, I went and got the repacking material for the FMF Turbine Core. The old packing wasnt as bad as I thought it would be, but we'll change her out anyways. Also new plug....NGK R8, dealer said that this original plug was almost $40.00 !!!! What ???!!!! They sold me an NGK Ridium IX BR8EIX for under $10.00, which was an equivalent. I hope they are right !
I might also leave the Spectro behind and run Yamalube 2R ? Several have said it might run a little cleaner, I hope I can go from one Synth to the another without any problem.
We are going to get some jets too so we can be prepared to make changes, also some plug readings might be in order.

I read various reviews on the 98 RM-125 and it seems to be a very strong year for Suzuki, I know I have always felt that this bike runs very strong. Maybe with a little carb tuning, set the sag and forks and we'll be ready to shake her out next weekend.

fatalxsunrider43

 

[fatalxsunrider43]

It indicates the JETTING is way too rich.


I was able to find MXA's jetting recommendations and
it indicates exactly what you said, too rich.

1998 SUZUKI RM125
Jet...Stock...Recommended
MAIN...175...168
PILOT...55...58
NEEDLE...1470...1468
CLIP...4th...3rd
AIR SCREW...1 turn...stock

Overall correction factor jetting predictions indicate same thing, excluding the pilot jet, stock jetting overall is too rich for 2000 ft elevation.

Both you guys were right, I appreciate the good tips !

fatalxsunrider43

 

[fatalxsunrider43]

Still spitting stuff out.

This week end was a great opportunity to see if the changes we made had any result.

Got rid of the Spectro
Went to Yamalube 2R 3.3 oz per Gal.
75% 91 pump premium & 25% 110 Racing Fuel
New Plug
New Air Cleaner
New Repack in FMF Turbine core

Bike ran FAST but still spitting stuff out the tail pipe.

Slight suspect might be a right side seal allowing oil into the
crank.
The performance says otherwise.
A leak down test might come later

We didnt do any jetting change on purpose to see if the spitting would stop.

So now we will re-jet and see ...

175 to 168 main
Clip on needle from 4th to 3rd clip position
pilot 55 to 58
air screw 1 turn add 1/2 turn out

If its still spitting then it has to either be the FMF Turbine Core 2 Unit or a crank seal ?


fatalxsunrider43