Engine Fitness - Refresh your pistons/rings (Big John)
Engines - Running 2000 700 in 04/440 - any help?
Engine Fitness - Leakdown test "engine compression" what does it do?
Engine Porting - I'm porting the engine, do I have to change flyweight?
Exhaust - Adding a pipe and/or y-pipe
Jetting - Engines of higher rpm than stock
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Engine Fitness - Engine has high miles. Compression check?
Question) Joe, my sled has about 6000 miles on it. What can wear, what can I look for?
Answer) With 6000 miles on your sled, how many miles does engine have? I want to know what kind of shape your piston rings are in. If your rings and pistons are worn out then it will be difficult to calibrate the clutch kit, it will run good when the engine is cold but when engine hot then will not run good and that is usually an indication of the piston rings or complete piston needs to be changed.
Take a Cold vs. Hot compression test.
1] Start the sled and let it run for about 30 seconds and kill engine.
Take compression with 6 pulls at wide open throttle.
What are the values?
2] Start the sled and let it run until the coolant is at operating temperature and flowing. Go take it for a run if you can and out there when engine operating temperature, shut it off and check the compression with 6 pulls at wide open throttle.
What are the values?
It does not matter if your gage is accurate or not as long as you use the same gauge when cold vs. hot temps.
Indications of rings going bad:
cold compression - 5lb(35kpa) or greater difference from mag to pto.
Hot compression - 7lbs (48kpa)(or more less than when it was cold then you need rings.
Hot compression - 10lbs(68kpa) or more less than when it was cold then you need pistons.
Example:
Cold @ 145lbs (999kpa)
Hot @ 138 lbs (951kpa) or less than...
Value difference more than 10lbs (68kpa)
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Engine Fitness - Refresh your pistons/rings (Big John)
One thing I been stressing is if owners of sleds from 02~05 are keeping their sleds or owners with any 600/800 engine that has around 5000 miles, then check the engine compression cold vs. hot and ensure the engine is fit before you move forward and get a clutch kit. It’s tough to calibrate a kit or calibrate any clutch tuning when the engine gets hot and compression values diminish.
You will observe correct rpms when running cold or warm but as the engine gets hot, may or will observe rpms drift low; an example the engine runs 200 rpms lower at full throttle due to failing compression.
If keeping the sled, then it is an "Investment" to freshen up the top end of the engine. Big John has some great trail torquer engine products that I have used and I recommend and they are economical.
http://www.sledheadracing.net/products/index.html
Engines - Running 2000 700 in 04/440 - any help?
Question) I have done a 440/700 swap with a 2000 mxz 700 and it's clutches. I also have the 04/440 clutches. Do you make a kit for this with either clutch setup?
Answer)The 2004 440 c/w TRA-3 primary clutch and t-secondary clutch.
The 2000 700 come with a TRA-2 primary and formula button secondary.
Sorry to mention that I do not make a kit for either sled....but....
If you were to go out and find an RER secondary off of a 2002 (600/700/800/809) or a 2003~2007 (600/800) then I could set you up with a kit that will work excellent. The secondary name is HPV-27(BRP name) however affectionately known by sledders as the RER secondary. Then you could use your 700 primary and the RER secondary and I could make a nice kit for you which would consist of a primary and secondary spring, helix and pin kit.
Those RER secondary can be found on the internet used for anywhere from $45 to $125 dollars and work excellent.
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Engine Fitness - Leakdown test "engine compression" what does it do?
Cylinders never wear even as you know. Therefore, you will have minor deviations in the walls of the cylinders and as a result less ring seating occurs. The piston speed makes up for this deficiency as it passes the offending area quickly. Even with plated and SCEM (Boron Composite) cylinder walls that literally as hard as diamonds, you have these offending areas.
The leakdown test finds offending areas on the cylinder walls and can show the truest measurement of ring fitness.
It shows if pistons need to be replaced?...could be skirt collapsing?
Yes, of course...look in the corners where the skirts start and see if you witness and microscopic cracks. A magnifying glass helps as these a very tiny and often not able to be seen with the naked eye.
Your Big Bro, Freddie Klies
www.easterncycleperf.com
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Engine Porting - I'm porting the engine, do I have to change flyweight?
Question)Hi Joey, i have your kit with stock engine and running it as your instructions recommended. the sled was dialed pretty decent last yr. here's the deal i am getting my cylinders back with some trail porting & vf-3 reeds. The port grinder says add 1 gram of weight to the primary. Do you think i will have to change the flyweight around or do you think i can just turn down clicker a number? Thanks for any info Joe.
Answer)1st off when getting engine modifications, you have to know what rpm the engine will run at. Did the engine rpm increase or decrease from porting?
IF the rpms stays the same with the porting - THEN go run the sled with present clutching – check rpms. IF the rpms are high - THEN add a ½ gram or 1 gram of flyweight.
You must run the sled first to see what it will reveal upon the new engine calibration - Don’t go for changing clicker; clicker has greatest influence on response in the system [how quick the engine will accelerate “from one rpm to a higher rpm”]
*Change the overall rpms with flyweight and test under full throttle*.
You can keep adding flyweight and it will accelerate harder, add more and will accelerate harder yet, however there will be a point where the backshift will suffer in the environment you are running in. IF the backshift suffers, THEN reduce flyweight back to previous value.
Don’t put the cart before the horse – Run the sled with present clutching – Evaluate results – make calibration change after. Cya Joey
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Exhaust - Adding a pipe and/or y-pipe
Answer)So say with stock engine you run 8150 rpms. Add an exhaust system and now the vendor wants you to run 8300. The additional hp is by virtue of rpms and now not necessarily have to add more flyweight.
Remember the principle about finding rpms - IF need higher rpms, THEN reduce flyweight.
You may be at a balance point to where with the addition of an exhaust system and higher power rpm that you don’t have to change the flyweight at all. Whatever you go do for modifications, 1]know the new rpms the engine must run at. 2]Run the sled with your present calibration to find out if you need to make a change.
Better to run the sled first, observe rpms, what are they? Then make a flyweight change if needed.
You could make a change right now like adding a gram prior to running the new exhaust mods, but what if you have only 8000 rpms? Now what? Ok no problem; Remember the principle about finding rpms - IF need higher rpms, THEN reduce flyweight. Me personally I would rather run the clutch calibration as is with the new mods, then make a run, observe operating rpms, then make a change if needed.
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Jetting for engines of higher rpm than stock.
Engines that use high rpm pistons or are high rpm big bores; to get the engine with these mods to run at their full potential 8300~8500, the tuner has calibrate the carburetor jetting correctly for the engine to start to make correct combustion temperature to reveal the potential power the engine has after the rings are broken in.
If the engine is rich, it won’t run at correct rpm, the tuner will observe low rpms. A common rpm for a rich engine to run at will be near the rpms of peak torque which can be from 250rpm to 450 rpms low of the actual potential peak hp rpms. An example 8400 rpm engine with rich jetting calibration can run at 8000~8100. Once the tuner starts to get the jetting correct for the engine then the rpms will start to want to turn higher rpms.
I only recommend jetting with a borescope, like the PV-618 . The borescope is not a cost, its an investment. You learn to use this scope and jet calibrate wisely, nobody will ever tell you how to jet an engine, you will tell them how.
Example piston wash diagram .
Thanks to: Al Shimpa, Freddie Klies and Dalyn Maxwell for jetting information.
Don’t be fooled by more hp = more flyweight because if the engine is making hp at a higher rpms then you won’t want to change the flyweight.
Run the engine first, dial the jetting in then start to spend a dayride to get the flyweight dialled in if-needed.
