Blaster power problems after new exhaust install

[tristan prokop]

Hello! I read blaster forum all the time for help when working on my blaster. So I figured I would make an account and ask for help with a problem I’m having. I’m pretty new to four wheelers in general but I have learned a lot and I’m a really faster learner. That being said, I installed the Toomey b1 exhaust kit on my 1995 blaster and ever since I have been having problems. So for some background information:
My blaster is a stock 1995.

- brand new carb and set it to all stock specs
-no leaks
-air screw 1.5 turns out
-needle groove clip 3rd down
-new spark plug
-air box lid removed
-newly installed tors eliminator kit,with new throttle cable, with idle screw directly into carb (I was having problems getting it to idle with the tors system so I removed it and now it idles perfectly)
-perfect compression on top end
- #310 main jets
-Toomey b1 exhaust kit
-everything else is stock and normal.

Now with that on to the problem. So, the problem is in simple terms a lack of power. More specifically if you press the thumb throttle all the way to give it full throttle it has no power and slowly speeds up. However if you hold the throttle half way and let it gradually rev up to the max before switching gears it has pretty good power and runs well. If you give it full throttle at any time while driving, it immediately bogs down and doesn’t ride correctly.
It’s weird because at times it will explode with power randomly. Also if you are in first and rev it all the way up and let go of the clutch immediately it hardly even goes. Where as before the exhaust system you would end up on your back because it popped a huge wheelie. That is pretty much what’s going on. It’s hard to describe without riding it yourself. But I hope it made sense and someone might be able to help me? Also if I posted this in the wrong spot I’m sorry this is my first post. Thanks in advanced for any help! If you need any more info just ask!

 

[Awk08]

"air box removed" < If that means what it says, there lies your problem

if you have the air box removed ? how do you have a filter on it ?

filters directly onto the carb are known to cause jetting headaches in all but full throttle (main jet)
and in that case, the Toomey recommended 310 is not correct for that amount of airflow

it's best to have a 4 to 6 inch-ish tube (pvc) between the carb and filter to allow the air time to "straighten out" before crossing over the jets and picking up fuel.
filter directly onto carb produces turbulent air that doesn't pick up enough fuel.

I suggest an airbox, put the stock stuff back on or a CFM airbox if you cut the stock one out.


"-perfect compression on top end" < It won't be for long if you keep running it like it is.
the stock 32.5 pilot, needle in middle clip setting, and airscrew set for highest idle between 1/2 and 2 turns out will work with the Toomey, confirm all main jetting with plug chops ....
https://www.blasterforum.com/threads/how-to-plug-chop.53237/

 

[tristan prokop]

"air box removed" < If that means what it says, there lies your problem

if you have the air box removed ? how do you have a filter on it ?

filters directly onto the carb are known to cause jetting headaches in all but full throttle (main jet)
and in that case, the Toomey recommended 310 is not correct for that amount of airflow

it's best to have a 4 to 6 inch-ish tube (pvc) between the carb and filter to allow the air time to "straighten out" before crossing over the jets and picking up fuel.
filter directly onto carb produces turbulent air that doesn't pick up enough fuel.

I suggest an airbox, put the stock stuff back on or a CFM airbox if you cut the stock one out.


"-perfect compression on top end" < It won't be for long if you keep running it like it is.
the stock 32.5 pilot, needle in middle clip setting, and airscrew set for highest idle between 1/2 and 2 turns out will work with the Toomey, confirm all main jetting with plug chops ....
https://www.blasterforum.com/threads/how-to-plug-chop.53237/

Thanks for getting back to me! Sorry I probably used the wrong terminology I have the stock airbox in and there is a rubber tube connecting it to the carb and an air filter in. I attached a picture of the one I have, I think the cover top is just missing. Would it be better to have the top on? I think we have a spare air box top? Also we were riding it more today. The best way to describe it is, the power is very inconsistent. It randomly explodes with power at times and bogs down at other times!

 

[Awk08]

Ok, airbox lid removed

is that filter oiled with a K&N type oil for gauze filters ? it should be

I think the 310 Toomey suggests is for an airbox lid on but with their 6 air vent holes in it ?
I'd go 1-2 sizes larger for no lid and 1-2 sizes smaller for a full lid with no holes.
plug chops must be done to confirm the main jetting.

how are the reeds ? no chips, cracks, or gaps ?

you haven't mentioned your elevation or current temperatures ?
both play major roles in jetting

I'd at least duct tape that hole up from the oil injection bottle, thats in direct line for the rear tire to throw water and mud up in there

I see the oil injection is deleted, is the injection brass nipple on the kicker side of the carb blocked off as it should be ?

 

[tristan prokop]

The filter is not oiled! I will do that!

Would it be better to go bigger on the main jet and keep the lid off? Or would it be better to put a lid on and go smaller? I can do both options.

I will do a plug chop and check the reeds on Tuesday, I am going riding then. I store it at a friends so I don’t have ready access to it. I can check it and get back ASAP.

Also The temperatures are currently around 40-50degrees and the elevations are around 237m- 410m above sea level. We try not to ride in anything colder than 40degrees.

I believe the oil injection nipple is not blocked I can definitely do that as well. What would you suggest blocking it with?

 

[Awk08]

no sense in doing any jetting until you get that oil nipple blocked, that's a major airleak and going to fry your top end, soon.

airbox lid on or off is sort of a riding condition choice, very wet n muddy I'd run the lid, dry-ish riding areas I'd leave it off and jet up for the increased airflow and power.

 

[tristan prokop]

I will get that taken care of before my next ride! Thank you so much for the help I am going to fix all the things you mentioned and do a few tweaking. I will post if I see any differences or problems!

 

[tristan prokop]

no sense in doing any jetting until you get that oil nipple blocked, that's a major airleak and going to fry your top end, soon.

airbox lid on or off is sort of a riding condition choice, very wet n muddy I'd run the lid, dry-ish riding areas I'd leave it off and jet up for the increased airflow and power.

OKAY! So I replaced the #310 main jet with a #330, I sealed the oil injection nipple, I oiled my air filter, my pilot air screw is at 2 turns. I checked the reeds too and they are in good shape! I rode for a while today and I have to say it’s running ALOT better, however it now will not idle? I can’t seem to figure it out? Also I don’t know if this is a big deal or not but the seal that connects the silencer to the exhaust pipe is kind of loose it wiggles but doesn’t come apart? It’s the green seal attached. Here are some more pictures attached to make it easier to see!

 

[tristan prokop]

Okay! Just an update! So it still wasn’t running running right after many adjustment and experimenting, so I took off my carb and completely took it apart every single piece. I used a manual and put everything back together exactly how it said and I replaced the 330 main jet with the 310 because it was going through gas way too much! And SO,I have to say. It’s actually scary how well my blaster runs now. The power and performance is outstanding and it now idles again! As soon as I switched the main jets! I didn’t expect the amount of power when I tested it, so I gunned it from first to second and almost flew off the back from popping a wheelie! Lots of fun haha!

 

[Awk08]

Hang on Tristan !
good job figuring it out

 

[tristan prokop]

Hang on Tristan !
good job figuring it out

Thanks again for all of your help! Blaster forum has a great community and I’m thankful!