I was wondering if anyone has ever removed their ballance shaft, for less rotating mass which equalls more HP and better, faster, reving. I was just asking because I also build alot of DSM cars/ Eagle Talon, or mitsubishi eclipse Turbos, most being all whell drive. One of the mods I always do when building a motor is remove the ballance shaft which helps free up a few HP and also helps the reving of the engine. What I do is remove the shafts, then I install the shaft bearing 180 degeers off so the oil holes are blocked off to maintain oil pressure, and this actually increases the oil psi also which is a plus. Then I have a machine shop compleatly ballance the entire rotating mass ie. the crank, flywheel and anyother part that rotates with the mass, Once this is done your engine should be just as ballanced if not better than stock, and all this really is not that expensive if your already rebuilding your motor.

 

Well that just sounds like rubbish to me, in theory maybe it would work but as engine revs get higher 2nd 3rd 4th order vibration harmonics will come into play at a sustained engine speed, if these mach up at a certain rpm/freq then say goodbye to your engine, every rotating component has its natural resonent frequency, and the balance shaft is there for a reason, may luck continue to be on your side.
Oh yeah and your bearings are going to live a lot shorter as well. nuff said from me.

 

Well buddy I beg to differ. Ive been building these car for years and it is a very popular and trustwerthy mod. I have built numerous engines with exact mod again this is to a 4g63turbocharged 4cyl, I in fact have an AWD eagle Talon that runs 10.37 in the quarter and still gets me to work everyday for the last 3 years with no problems what so ever, rain shine , or snow. If you would like to take a look at this procedure for a 4g63 motor here is the site. Vfaq.com

 

Lowering the mass of the rotating parts in a quad motor has long been a racer's trick to make a quicker revving motor, usually done by turning down the flywheel, or replacing it with a lighter model. While this does give a much quicker revving motor,the downside is it prevents the lower rpm "lugging " of the motor, making it prone to stall in tight,slower running trail situations, or if the track is a tight, twisty one, you could run into stalling in the tight turns if the rpms and forward momentum drop too much. If you keep feathering the clutch and keep the rpms up, lightening the rotating mass will give you a much peppier motor,just at the cost of low rpm "grunt".

 

but i think on a big single cyl motor a balance shaft is a good thing... i dont think you can remove it completly on the rotax 650, i think some guys on here have lightened them??? anyway,
lighten the flywheel thay weigh a ton and a 520 chain conv. and get rid of the stock piston for a nice lite one [img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/beer.gif[/img]

 

<div class="FTQUOTE"><begin quote>Well buddy I beg to differ. Ive been building these car for years and it is a very popular and trustwerthy mod. </end quote></div>
There is a BIG difference between a 4 cylinder and a 1 cylinder engine with regards to balance.
A 4 cylinders crank is neutral balanced 180 degree apart. In other words, when one piston is up the other is down.
This is not the case with a 1 cylinder engine.
With our racing 4 cylinders one of our cranks has all of the cheeks cut off. It looks like a bent stick. Try that with a single cylinder and your going to have problems.

Can you do this with a single cylinder engine? Sure!!! How long will it last is anybody's guess. I would not want to be on this quad at 8K with my manhood on top of the engine. I have seen a big block Chevy once that the machinest screwed up the bob weight when he balanced the crank. The car felt "fuzzy" over a idle. The engine sawed itself in half at 6K. Cam came out in about 5 pieces. Engine broke in many pieces. One of those take the carb off and throw the rest away deals.

 

i got a stock 99 gsx spyder with turbo spoiler with 81k miles! wana race?!?!

 

FDL check ur PM's...

 

it's been done, it wasn't very successful. it caused a lot of vib and that and other things caused oil blow by on the vent breather line. Sandbomber had it. gary at tvi worked on it a lot never much luck.

 

Exactly right. It will kill your motor.