74 JDX8 runs but doesnt move

jhecht · Post by **jhecht** » Mon May 08, 2006 11:29 pm

Hi guys hows it going. Ill get right into it. I have a 1974 JDX8 that runs but doesnt move. I can start it and it idles fine and will rev. When i put it on a warm up stand the track moves but as soon as I put it on the ground it doesnt move at all the engine will hit the engaging speed and just rev right there. ANY IDEAS??? im so confused. Also i know this is suppose to be the kohler page but I have one of my buddies sled with the same problem 86 SRV540 that moves until it hits snow or like today when I screwed around on it, grass, but anyways I think its the clutch but not sure its almost like the clutch cant push the extra weight.ANY CLUE?

400brian · Post by **400brian** » Tue May 09, 2006 1:32 am

What has been done to the sled?

Has the carb been cleaned, fuel system, pickup screen inspected, cleaned?
Are the fuel lines hard and cracked? Are they clamped at the connections? Is the pulse line in good condition and clamped at both ends?

Your fuel pump may not be delivering enough fuel to give you power. Your pump is part of the carb.

While you could have a clutch problem, from your description, I'm betting that isn't the case.

Post by **Matt** » Tue May 09, 2006 7:32 am

Has the belt been replaced? It could be worn out.

jhecht · Post by **jhecht** » Tue May 09, 2006 8:24 am

Hi guys,I rebulit the carbs with a kit from mfgsupply.com good site, and I inspected it twice just to make sure i didnt screw something up. I replaced all the fuel lines and the vaccum line. Lubed everything and checked all the suspension-just to make sure there were no bearings gone before i hit the trail.could i have missed something?

jhecht · Post by **jhecht** » Tue May 09, 2006 4:37 pm

Hey guys, if it helps these two sleds were sitting outside for 5-6 years not running. I first got the JDX8 and the SRV 540 in summer-they were free. Like I said when they are on a warm up stand without any weight on the track the run fine. but when you put weight on the sleds the just sit at the engaging speed of the clutch-like it doesnt engage or it doesnt have enough power to move the weight? ive worked on lots of race sleds including my two and never had this problem before. HELP!!!!!
Josh hecht
JL motorsports
Horicon
382-8630

400brian · Post by **400brian** » Tue May 09, 2006 7:39 pm

Just so we're clear on this; You can turn the drive train by hand with the belt off?

jhecht · Post by **jhecht** » Tue May 09, 2006 9:53 pm

Yup with the belt off I can turn the track and if I put wheels under the skis and have someone sit on the sled I can pull the sled without anything binding or getting stuck. I did notice that the spring looks to be replaced on the srv540 it appears to be a .5" to short but the spring in the JDX8 is the original.

400brian · Post by **400brian** » Wed May 10, 2006 12:32 am

You probably know as much about this stuff as anyone here, but if we bounce some ideas around, maybe something will jell.

Next obvious question: With the belt off, ( or with the sled on the stand ) when you blip the throttle, will the clutch cycle? The clutch is supposed to engage at 3800 rpm , The SM cautions against this with the belt off, as over revving is quite possible, with a bad result.

The obvious concern would be that you have corrosion, wear, or damage, that is preventing proper cluth operation. I assume you don't know the history of the sled, for example why they quit riding it?

A quick peek inside the clutch might tell you something. You should have a Comet 100C clutch.

Danzig · Post by **Danzig** » Wed May 10, 2006 12:47 am

The problem with the sled not moving is due to the clutch not shifting. I had this same problem on my 73X8. Take it apart, clean it , lube it and try again. Do the secondary also.

JDFanPa · Post by **JDFanPa** » Wed May 10, 2006 12:53 am

jhecht wrote: engine will hit the engaging speed and just rev right there. ANY IDEAS???

Does it just rev at that rpm or will it rev right up to maximum rpms? Like Brian asked does the clutch snap closed when revved with the belt off? Does the belt smoke when you try and move the sled on the ground?
Any idea if its the right belt?

Im thinking it could be a stuck clutch but you need to see if it closers with no belt. May also be a tired motor and its not revving as high as you think like maybe running on 1 cylinder.

Will wait and see what your answers are before throwing out any more ideas

ProJd69 · Post by **ProJd69** » Wed May 10, 2006 4:28 am

OK, Like jhecht said the track moves if its up in the air. One thing, have you done a comp. test on the motor? If so and it's all good then just like my 72 400's w/ wlboro carb's there not set right. Don't set the carb. with the track up or no load. I did the same thing when I first got mine. Every thing was going great untill I got on and put a load on it

I couldn't get it out of the gerage unless I was walking next to it at full throttle

. So if you need setting spec's on the walbro carb go to the home page of this site under Tech. Info, then tuning carbs Walbro/bendix. For initial settings and tips.

jhecht · Post by **jhecht** » Thu May 11, 2006 11:15 pm

ok so i lubed, grease, polished, buffed every i could think of the on the clutches and ran them. it still didnt move so i think ill mess with carb sometime this week end. ill letyou guys know compression is good on both cylinders. no oil/gas leaks from the gaskets or anywhere else for that matter.

Danzig · Post by **Danzig** » Thu May 11, 2006 11:36 pm

Are you sure its running on both cylinders?

Danzig · Post by **Danzig** » Thu May 11, 2006 11:40 pm

Look under my name and find the topic "X8 problem". There is alot of info on your problems.

jhecht · Post by **jhecht** » Sat May 13, 2006 11:08 pm

ok so i went out and messed with the the sleds and let me tell what happens. the sled will just sit there at the engaging speed and it wont go higher, i know i said this before but it bears repeating i guess. anywho it will jump in the "gear" and it I mess with the trottle like move the trottle close and open really fast the sled will take off. could it be the cdi or maybe a seal out? the seals look find but it is an old sled and plastic/ rubber wears out. this sled is really making me mad. not used to thinking this hard about an engine.