baffled??

Are the factory mufflers on a 750 maxim flow thru? The after market ones the PO put on mine dont have baffles... I installed a set of Harley ones and they do have baffles.

 

Believe me, the stock mufflers have more than just baffles; they are FAR from "flow-through."

 

:?: well, i'm curious because the new ones that were installed on my bike just before i purchased it... i can see straight thru. They are after market and brand new. The harley ones i just put on have a baffle in them. I havent fired it up yet as its in hybernation for the winter. The carbs were tuned last season but as the weather started geting cooler my bike was acting up a bit. just wondering if maybe those were the wrong type to begin with?

 

hmm...nobody has an answer?

 

Acting up how? Any other modifications on your bike that aren't stock?
You probably didn't get many replies because your post was kind of vaque.

Aftermarket pipes don't usually cause lots of problems all by themselves, but they can change the air/fuel mix by reducing/enhancing backpressure and this affects air velocity in your carbs. You generally have to re-tune these bikes when you begin to change from stock configs. Just like the Yamaha logo (the tuning fork) these bikes were carefully tuned to run right straight from Yamaha-so change this you must change that-like rejetting or at the very least re-synching your carbs.

Give us some more info on your bike and it's behavior and we can advise you better. One thing if it was running fine and you didn't change anything and then it went to 'acting up' its likely you have either a 'carbs getting dirty/gunked issue' or it could be electrical. Colder temps will cause harder starting with XJ's but once warm and tuned right the cold is no problem.

 

when i first got her she was running really nice...then as the season up here got cooler the rpms would ramp up..i adjusted the idle screw between the carbs. But at 1200 rpm idle she would want to almost stall. so i turned her up a bit more. After that she was hard to start.... someone suggested it may be due to the lack of back pressure from these after market mufflers.

 

Colder air = Dense thick air. This will cause the air/fuel mixture to lean out when the air gets colder. A carb dialed in at normal summer temps will have a hard time running in the winter.

Changes to the exhaust will further agravate this condition.

This is where the starter curcuit in the carbs comes into the most use. It adds fuel to the mixture to help compensate for the cooler air.

Increaseing rpms is an indication of a vacumm leak either at the shaft seals, or intake boots. you will need to locate, and correct this before trying to get the carbs straighten out again. Do not forget to check the rubber plugs on the vacumm ports also.

Ghost

 

right on...will investigate

 

Does this bike have its stock airbox and filter, or some sort of intake mod?

 

no, shes pretty much stock. I put the Harley mufflers on today, noticed small exhaust leak where they bolt on...tighted them up and still leaking...hmmm. U think the exhaust leak is my prob?

 

The Harley Pipes don't have BAFFLES.
The Hog Pipes have SUPPRESSORS.

The Suppressors are "Straight-through"
They are supposed to take the Explosive Note of the Exhaust and take the harshness off the concussive sound as the force of the explosion passes-over slots and holes surrounding the "Note" as it passes through the Pipe.

Our Bikes have Baffles.
The Baffles are Partitions, Tubes, and Flow-direction Altering Chambers within the Silencer.

Since the Exhaust go through Reduction and Expansion Chambers and has its FLOW Direction reversed before getting funneled to the Exhaust Pipe, ... there is considerable BACK PRESSURE which affects overall AIR Flow and Carb Mixture Settings.