89 Exciter Transformation!

thefullmonte said:
Yes, very nice. Often times these projects can end up looking cobbled together. Yours looks very professional. If you paint it black it will almost look factory. Keep up the great work I for one really appreciate all the pics and details of your build. ;)!
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Thanks for the nice comments guys! I'm trying my best to make it look factory, but still keep subtle hints that I did it myself. I had certain, specific concept in my mind, and I wanted to make sure I kept my build in line with that. I wanted to retain the placement of the rear brake light, not re-position my rear rad, or cut the angled part(which may or may not have affected my cooling). And I wanted a very functional and solid deep-sh*t bar.

Tonight I'll probably rivet in the tunnel support, I'll take more pics once I get that done. I can take my time seeing as how we don't have any snow, and I don't expect my flattened rad back until between Christmas and New years.
 
YES! Nice work, i totally agree it looks really factory:) Looking forward to some more pics! That thing really rocks! I hope mine will be just as nice when i´m done with it:)
 
come on, update me! What´s happening, how´s it going? Saw the results of the tunnelextension on your photobucket, awesome!
 
Alright! Time for an update guys!!

So, I finally got a good weekend of snowmobiling in! I had a few issues, as can be expected. First off, my gearing is way off. an 18tooth Upper and 31 tooth lower only nets me a 1.72 gear ratio, which is way to low. I've ordered a 16tooth upper, and 33 tooth lower, and a brand new 66 link chain, which will net me a 2.06 gear ratio :) 70km/h is no fun when everyone is passing you :(

Stay tuned for that update!

Next, one of my cylinders was acting very sluggish, fouling plugs on idle, and low speed. When I finally decided to pull the carb on that side, as soon as I removed the slide, I noticed my needle was bent!!! Obviously this caused the needle to poorly block off the main jet, which caused the cylinder to run rich until I went WOT, and then everything was great! Try and find a 6FL68 needle now...... IMPOSSIBLE! Would the 6DH3 needles work??????

Next, my belt. I figured since I was rebuilding everything, I would get a new belt - well.... the dealer sold me the "stock" belt that came with an exciter... the problem is that, Im far from stock! The comet clutch should have a wider belt than the standard exciter, so after a ton of belt squealing, and only reaching speeds of 70km/h, I have come to the conclusion that I shoud stick with the belt that came on the machine when I bought it, or as LASSE pointed out, order a exciter-II belt, which would work nicely.

Finally, after all that, I still managed to rack up over 150km's in one weekend! The machine works great in any amount of snow, it's great to be able to get off the trail and go wherever I please. My cobra track gave me amazing acceleration, and stopping power, I'm really pleased with it! The welded rear rad also performed admirably, and did not leak - so my welder is a keeper ;)

The valving job done on the front struts is RIGHT ON, schimdt brothers did an awesome job! I can hit snow drifts, and jump small cliffs, and the landing is SO SMOOTH! I can't wait for more snow!!!

For some reason my handle bar warmers don't work, so I need to look into that, and my chain case leaks - but I've found some cheap gaskets on ebay, and will clean all that up once the new gearing is in.

So - this weekend, I'm trying a wider belt... not much else I can try since the gearing isn't in yet - but atleast once it gets in I can try different combo's,
18/33, 16/31, 16/33 and see what feels right (and gets me over 100km/h!).

18/31=1.72
18/33=1.83
16/31=1.93
16/33=2.06

here are some pics of my wicked weekend - enjoy :)

Doesn't she look sick!
ex570.jpg


IMG_1674.jpg


IMG_1668.jpg


IMG_1660.jpg
 
stanage said:
1. My gearing is way off.
An 18tooth upper and 31 tooth lower only nets me a 1.72 gear ratio, which is way to low.
I've ordered a 16tooth upper, and 33 tooth lower, which will net me a 2.06 gear ratio :)
70km/h is no fun when everyone is passing you :(

2. Next, one of my cylinders was acting very sluggish, fouling plugs on idle, and low speed.
When I finally decided to pull the carb on that side, as soon as I removed the slide, I noticed my needle was bent!!!
Obviously this caused the needle to poorly block off the main jet, which caused the cylinder to run rich until I went WOT,
and then everything was great!
Try and find a 6FL68 needle now...... IMPOSSIBLE!
Would the 6DH3 needles work??????

3. So - this weekend, I'm trying a wider belt...
not much else I can try since the gearing isn't in yet -
but atleast once it gets in I can try different combo's,
18/33, 16/31, 16/33 and see what feels right (and gets me over 100km/h!).

18/31=1.72
18/33=1.83
16/31=1.93
16/33=2.06
Click to expand...
1. Do not expect wounders before you also have tested a lot of clutching !

2. If it is imposible to get a new needle from Yamaha try to buy a complete
carburetor from an snowmobile scrap/salvage yard.
But be sure that the used carburetor have the updated needle ( 6FL68 ) before you buy it !!

3. Adjust your carbs until the engine run crisp at all revs.
Go for the 16/33 gearing.
Do the tuning/testing/adjusting of the clutches last.

thefullmonte said:
Just picked up an EX-570 ( 1988 ).
My research tells me that the jetting on these was somewhat of a disaster.
I will make sure the Power jet is disabled.
I'm open to any and all advice.
I'm also going to modify the air box.
Looks like a poor design even for then.
Say what you will, but I think I can get it to run more consistently.

Any other tricks or tips on these sleds.
I'm interested in anything.... cooling, suspension, jetting or whatever you have found to work.
Click to expand...
1. Clean up among all the funky fuel and oil lines that Yamaha put on these sleds.
Delete the whole Oil Injection system including the oil pump.
Run 1:40 premix instead.

2. Completly disconnect the warming system to the carburettors.

3. Disconnect the T.O.R.S.-system from the carburettors.
remove the powerjet function and parts from the carburretors.

4. Jetting: Updated jetting for the Yamaha Exciter-I ( 87 / 88 / 89 / 90 )
Pilot jet : 40
Main jet : 320
Air screw : 1.0 turn out ( +-½ Turn )
Slide : 3.0
Needle jet : 480 P-6
Needle : 6FL68 ( Yamaha part # 239-14116-68-00 )
( And of course all the things regarding the "Power Jet" system is deleted ! )

5. Set the engine idle speed to 1600 Rpm

6. Seconary clutch:
Secondary spring : WHITE
Secondary setting : A-2
Helix angle : 45 Degr.
Helix pre tension : 50 degr.



:2strokes:
 
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Your sled turned out great! ;)! As for your needles. If you come up not finding much you should be able to get a 6fl14 needle from any Parts Unlimited dealer. I had gotten a set thinking that is what I was going to use instead, but ended up with a set of 68's. The 6fl68 is slightly longer, but they should perform in a similar fashion.
 
Thanx for updating us, really nice pics! Found out that the comet we use likes 35 mm belts. U can use a 32 but than you have to use spacers to make the gap less wide. I´m in the same position myself right now. Don´t know if i gonna use the one i had last year or buy a 35 mm belt when i´m heading to the garage tomorrow...... I will take a testrun with mine tomorrow.... had some troubles finding a new brakewire though i need a long one beause of raiser. My flatslides is finally installed and i hope they will work just fine,let u know tomorrow:)
 
stanage said:
I figured since I was rebuilding everything,
I would also get a new belt - well....
the dealer sold me the "stock" belt that came with an Exciter-I
the problem is that, Im far from stock!
The comet clutch should have a wider belt than the standard Exciter-I.
LASSE pointed out that I should order a Exciter-II belt,
which would work nicely
Click to expand...
prankster said:
I found out that the Comet we use likes 35 mm belts.
You can use a 32 mm belt but than you have to use spacers
inside the Comet clutch to make the gap less wide.
I'm in the same position myself right now.
I do not know if I gonna use the one I had last year or buy a 35 mm belt when I'm heading to the garage tomorrow...
Click to expand...
Use the Exciter-II drive belt if you running a Comet drive clutch on your Exciter-I


Exciter-I ---> Part # 87X-17641-00
Exciter-II ---> Part # 89L-17641-00

 
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well lasse you´ve done it again! Perfect:) i´ll find that belt tomorrow then, think i choose the 89L. How many shims do u think i have to put in my secondery then? Is there a maximum limit?
 
prankster said:
Well Lasse you have done it again! Perfect:)
I will find that belt tomorrow then, think i choose the 89L drive belt.
How many shims do u think i have to put in my secondery then ?
Is there a maximum limit ?
Click to expand...
You may also buy the following things...

# 3. ( Yamaha part # 8X6-17688-00-00 ) ---> 3 pieces. Tend to be worn out.
# 22. ( Yamaha part # 90201-345G2-00 ) ---> 2 pieces. , You will need it since you will get a wider belt.


Since you now going to use the Exciter-II drive belt
( which is wider than Exciter-I drive belt )
you must adjust the drive belt deflection in your secondary clutch.
That is why you will need a couple of more adjustment washers....

You will need between 2-4 shims depending on how worn out the drive belt is.
You start with 4 and work your way down from there.

 
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Some basics about gearing :


How gearing affects clutching and rpm by: "MrViper700"

Allot of times someone will get a clutch set up as a suggestion and it does not work the same or perform quite how it was described. There’s something else that affects your clutching, it’s your chain case gearing. By the amount of ratio you run in your chain case has a direct result in the amount of clutch weight the engine will be able to effectively pull to rpm.

Lets say you’re running a steeper gear set up(larger numerically) for tight woods riding, short blast across hay fields to get to another section of "trails" thru the woods, running a smaller top gear is what most will do. This does accomplish the task but it also has a few down falls if taken too far (too small of a sprocket). Anytime you bend the chain in the chain case tighter around a smaller sprocket you require more power to turn the chain around the tight radius. This is the same exact thing as a larger rear idler wheel for the track or even the same as running the belt in a better ratio in the clutch's, a tighter radius takes more power to turn the object in a tighter radius. Also something to watch for is the bend you’ll get in the chain when using a small top sprocket with less teeth and the stock chain length, the more bend you apply to the chain via the chain tensioner to get the slack out of the chain is also eating up power.


Back to gearing ratios for the type of riding you do 90 % of the time. By gearing lower, you first are taking load OFF of the engine by doing this, it multiplies torque, when you gear down, but too much can be a step backwards as mentioned before. What you need to do is find a ratio that satisfies’s your speed requirements for the distance and type of terrain you encounter the most.

Most all stock sleds will be geared higher (lower numerically) then the mph they can obtain, the reason for this is too simply keep the belt speeds down. A higher belt speed is dangerous and leads to blown belts. The other plus of gearing tall is the free power you get by making the clutches more efficient, they grab more of the belt and bend it in a larger radius requiring less power to turn the belt thru the radius in the primary and secondary clutches. Taller gearing also LOADS the motor more, there are some engines like the srx700 that just loves to be loaded hard and let it tractor its way up to peak hp rpm. So gearing taller actually is an advantage with that particular engines personality.
The exact opposite can be true for a peaky higher strung engine, a peaky engine will need the gearing to be steep to keep the engine on its peak, by falling off then peak the engine may lose a ton of power, this was very much true for the older srx440's, get off the power curve and the race was over, very narrow power band, allot easier to run/clutch with a deeper gear in the sled.

So knowing we are taking the load off the engine the engine by gearing lower, the engine will now easily pull MORE clutch weight to maintain the same rpm as before, so this is where someone may suggest you run the clutch weights at say example: "60 grams per arm" or whatever and they didn’t work in your sled (wrong rpm), you might need to change the gearing to match the other persons gearing if you can’t seem to make the set up run correct rpm. If the gearing of the other person and the gearing you wish to run are 2 different to compromise then you’ll need to adjust the flyweights to run the correct rpm, by either removing weight or adding it.

// MrViper700
:2strokes:
 
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back of my helix was ground down for wider belt but id try the shim thing if it needs it,im not an expert on this but i do have the parts i took off,where were you guys 5 years ago when i went threw all this?lol
 
Hahaha, i was studying human behavior and building on my cabin (i guess u had way more fun):)
 
luv 455 said:
Wonder why nobody mentioned that the ~ 2,00 gearing will make the sled slower then the ~ 1,70 gears by a bunch.
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Well, from a theoretical point of view it should be slower,
but in reality it may be different !

Not necessary slower if the engine not manage to get the 136" track spinning with that ~ 1,70 gearing.
The ~ 2,00 gearing is better suited for Stanage's use.
See below......

stanage said:
My sled has :
* Comet 108-EXP clutch.
* 18/31 gearing.
* PSI pipe,
* Stock 9-teeth drivers.
* Stock pistons.
* Cylinders are port and polished.
* I also extended the track/tunnel from a 121" to a 136"x15"x1.3" track.
* POD airfilters.


My goal is to :
* Have a good all round sled that will get me though some deep snow at a fairly decent speed.
* Achieving atleast 70-90MPH on flats.
* I want to be able to go through the woods (Deep snow) at low speed,
and still fly through powder when its around.
* I also plan on pulling a sleigh with some fishing gear when I decide to go fishing...
but it's not a huge sleigh.
Click to expand...
Stanage will not get it all !!
To get the best allround performing sled it is best to aim for ~ 2,00 gearing,
the sacrifice will probably be the top speed.


:2strokes:
 
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