Author Topic: Rotax 793 engine in to pilot  (Read 24507 times)

lee1969gb

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Rotax 793 engine in to pilot
« Reply #15 on: November 30, 2006, 06:07:46 PM »
Thanks Livewire you are correct. Now Wondering if I should use 15 teeth small sprockets to make up for the smaller rear tyres.
I was wondering how the different clutches ratios would work out. the clutches I have bought are from a ski doo 800 with rer, when they show up and I sort out the rer I can make a start.

LiveWire

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Gearing
« Reply #16 on: November 30, 2006, 11:21:17 PM »
The reason people suggested Arctic Cat clutches is tuning parts are cheaper. That in turn lends itself to more people using them. Many snowmobile owners replace their original clutches with Arctic Cat.

If raising the gearing, I would probably do it with the final sprocket to increase ground clearance if it is bigger than the rear brake rotor.

lee1969gb

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Rotax 793 engine in to pilot
« Reply #17 on: December 01, 2006, 01:51:22 PM »
A 42 tooth sprocket will not hang below the frame, so that should be ok. i want to mount the rear break disc on the end of the lay shaft so I can use a smaller disc but spining faster with more breaking power, unless the final chain snaps then no rear brakes :shock:
I have taken some photos of my standard pilot before I washed it and the rotax engine exhaust and radiator I will be using.
Still no luck with the RER.

lee1969gb

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Rotax 793 engine in to pilot
« Reply #18 on: December 02, 2006, 10:12:03 AM »
I have started to strip down my pilot ready to put the rotax engine in but the cv joints will not come out of the transmission :(  , I am sure there is only a snap ring holding them, They may be seized in because of the wet conditions they are often used in, I have left it on its side with penatrating oil on it to see if that helps :? Any suggestions ?

lee1969gb

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Rotax 793 engine in to pilot
« Reply #19 on: December 03, 2006, 02:01:05 PM »
I can not get the inner cv cups out of the transmission, so i took off the rubbers and clips and took the cv out of the cup so i could lift out the the engine and tranny :)
now i can have a look how much room i have to get the engine, jack shaft, lay shaft, final drive shaft, and clutches in, the answer is not a lot. But i expected that, one of the biggest problems is the two in to one pipe on the front of the rotax engine, it takes up to much room so i will need to modify it or go to 2 seperate pipes. luckily i know a man who makes two stroke gearbox kart racing pipes, and he knows his stuff so i will ask his advice. you have to be very carefull with 2 stroke pipes, get it wrong and it can cause all sorts of problems.
I do not have my clutches or jack shaft yet so i am guessing at the moment, if any one could give me the dimentions of ski doo clutches that would help me get on with this project.
I am still needing some advice on the RER and getting the inner cv cups out of the tranny.Thanks Lee.

LiveWire

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CVs
« Reply #20 on: December 10, 2006, 12:40:23 PM »
You can try putting a couple muffler clamps on the CVs and hook a slide hammer to that to get them out. If all else fails, dill a hole through the stub of one to put a rod through and pound the other out. Then use a larger rod to pound the first one out.

Ozpilot

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Rotax 793 engine in to pilot
« Reply #21 on: December 10, 2006, 07:40:03 PM »
I've measured up TRA clutches as used in about 2000 - 2002 with the reed valve carb engines (593, 693 etc).  It seems the cast clutches were used on the smaller engines and some larger engines got the forged clutch which is a bit stronger (one of each is shown in one of the pics).  I measured three - a cast which was new, a forged one which was new and anothercast one that was used and machined (reco).  I'm not sure how they compare to the RER clutch - as it has to work backwards as well I imagine it may be different.

One note - in one photo of dimensions on the white board it shows the thickness of the clutch parts - obviously the 65mm is not to scale (nothing is to scale but the 65mm is not even near in proportion)

odypilots

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Rotax 793 engine in to pilot
« Reply #22 on: December 11, 2006, 06:10:48 PM »
Here's some more pictures that may help. These are of a 2001 Ski Doo MXZ600, not an RER engine. The driven was about 10 1/2 inches in diameter. The drive was covered by the bodywork so I couldn't eyeball it very well, but it is smaller than the driven.
The usual 'my two cents' disclaimer applies. :)

atvnut

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Rotax 793 engine in to pilot
« Reply #23 on: December 12, 2006, 12:31:12 PM »
I use a bearing knife and a 5lb slide hammer with a pigeons foot and have had good results.... to pull the cv cups from the trans just hook the knife in the boot groove and attach the puller and thump away...or you could buy this tool http://www.etoolcart.com/index.asp?PageAction=VIEWPROD&ProdID=361
Thank you
"The Nut"

lee1969gb

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Rotax 793 engine in to pilot
« Reply #24 on: December 12, 2006, 03:52:56 PM »
Thanks for all the help and advice :D
I have had a re think on the layout and I am going to use a limited slip diff :shock:  I will take some photos tomorrow and explain what I am doing.
The good news is I got my R.E.R. Rotax electronic reverse working  today so that is one problem solved :D

lee1969gb

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Rotax 793 engine in to pilot
« Reply #25 on: December 13, 2006, 02:15:43 PM »
Some photos.

FL670R

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Rotax 793 engine in to pilot
« Reply #26 on: December 13, 2006, 02:38:22 PM »
Very Interesting to say the least...

What is the Tranny from ?

Keep us posted....

lee1969gb

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Rotax 793 engine in to pilot
« Reply #27 on: December 13, 2006, 02:59:34 PM »
I am now going to put the engine side ways on, with output shaft to the rear, with drive clutch. The secondary clutch will be on a jack shaft ( where white tape is) with a sprocket on the other end driving to a sprocket on the diff input shaft. sprockets 2 to 1 and diff is 4.1 to 1 will give me 8.2 to 1.Is that correct livewire.
It is all a bit tight, but I think it will all fit in, the engine is higher than I wanted but I think I can put an air box under the engine which will give better access to top of the engine.
If the limited slip diff is not to my liking I can get an after market one or weld it up solid.
The exhaust will come out of the side by the rear mudguard then loop around under the roll cage rear braces. This means I can use the pipe I have, It was going to cost ?500 thats about $1000 to have 2 pipes made with the engine in the original position.
When I first looked at using a car diff I thought it would be to heavy but I weighed the pilot engine and tranny and that is 65 kg, my rotax engine and diff are 57 kg so with clutches engine/diff mounts and a few other bits it will not weigh a lot more.
Doing it this way saves me about ?1200 and I can use the pilot fuel tank, it also may be better with the limited slip diff to cut out some understeer (pilot push)
I was very lucky to find the cv cups on the pilot are the same size as the ones on on my car diff, the splines are different, but I can use the pilot drive shafts.

Odyknuck

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Cutter Brakes
« Reply #28 on: January 03, 2007, 10:25:50 PM »
What is the diff out of? By using the diff you could run cutter brakes and have a machine that will turn on a dime. Mount seperate brake roters on each outer or inner CV  and hook the cutter brakes to each wheel after the Master cylinder

greasemnky

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Rotax 793 engine in to pilot
« Reply #29 on: January 04, 2007, 04:21:52 PM »
Looks like your doing a suburu diff like the mini rail guys run. I was looking into doing something very similar, but was warned the chain on the jackshaft would be too short, and would likely over heat. Can't wait to see how yours comes out. I would love to go chain drive.