98 Blaster. Just bought it. Need help to identify what it is.

[Jim Palen]

I just bought this 98 Blaster. Ran OK when I test rode it.
Got it home and my son did quite a bit of riding and some concerns came up.
Once warmed up completely it idles low to the point of dying.
Never seemed to come on the pipe.
Went to turn up idle screw and it broke. Started looking at the carb. Seems to have a 34mm flat slide Keihin. Has an FMF pipe and a 6 hole intake.
Got a 28mm Mikuni and stock intake manifold but the intake manifold is too small for the barrel and only has 4 holes.
Seems as though it may have a big bore kit on it, but I have no identifying marks on head or barrel. Also burns a tank of fuel in an hour of riding.
Any help out there?

 

[Awk08]

pics of cylinder, intake and carb ?

 

[Jim Palen]

Heres some pics. Thanks

 

[Awk08]

CT 240 cylinder that uses CR250 intake and reeds, running correctly this may be too much for your son, depending on his age and riding skills.
you'll need to stick with that keihin carb for that setup. the 28mm won't feed that beast.

see what pilot, needle, main jet and slide # is in that carb and report back so we can help decide if it's jetted correctly

 

[Jim Palen]

CT 240 cylinder that uses CR250 intake and reeds, running correctly this may be too much for your son, depending on his age and riding skills.
you'll need to stick with that keihin carb for that setup. the 28mm won't feed that beast.

see what pilot, needle, main jet and slide # is in that carb and report back so we can help decide if it's jetted correctly

Thanks for the info. This is a bit tame for my son. His YZ250 had 44hp at the wheel. Hes scaled back now to an IT175. Hes 27 now.
Now I start my research into why it isnt running right.
Thanks again.
Jim

 

[Awk08]

That CT cylinder is capable of 40-ish+ HP with the right pipe, carb, and tune

 

[Jim Palen]

That CT cylinder is capable of 40-ish+ HP with the right pipe, carb, and tune

Thanks.
If we can get it going right, I may be making it my ride.
I'll get to the carb soon and post what I find inside.
Its 110 and 30% humidity here so it wont be today.

 

[Larry's Shee]

While 110 is hot, I don't think it ever gets down to 30% humidity in Michigan

That's a beastly engine for a Blaster !!

 

[Jim Palen]

OK guys. Finally got a few minutes to get into this Keihin.
The slide has the numer 5 stamped on it. The slide needle is set to 4th ring down from the top out of 5 and has DG1 number. The jet for the slide needle is a 165. The other jet is a 55.
Plastic idle screw is broken in the housing and was fully seated all the way in and idle was too low warm to the point of stalling. Are the jets close for this CT 240 with FMF Gold pipe?

 

[Jim Palen]

Correction on the needle, DGH. Sorry, old eyeballs...

 

[Jim Palen]

Correction on the needle, DGH. Sorry, old eyeballs...

Tried to use the jetting link posted on another thread but can't make it work. Any help on this would be appreciated. Thanks.
Also new to forums and still trying to figure out how they work.

 

[Jim Palen]

In looking at this more in depth with proper measuring its a 35mm PWK.
Slide is a #5.
Needle is a DGH.
Main jet is a 165, set on 4th ring down from the top.
Pilot jet is a 55.
Fmf gold pipe.
3440 ft elevation.
CT 240 big bore kit.
Unknown if it has been ported.