Low power good compression

[turner15]

So my 78 Cyclone fires right up now and I have just under 140 compression in both cylinders (good right?) However when I give it full throttle the sled move slowly. Do I have a drive belt problem? I also get a lot of black discharge from the exhaust. The sled has sat for a few years and I think it is just carbon build up. I am running 50:1 for a half a tank just to make sure it gets a good lube so that could be the problem. (right?)

I am going to sell this for 600 - 700 is that a fair price? Body is in VERY good shape. I have just put almost $200 into it so I figure that price may be fair.
thanks for any help.
Mike

[harleysportster]

Your compression is fine. Are you sure both cylinders are firing? Sounds like one is fouled.

[turner15]

Both plugs appear to be ok and the motor sounds great. Lots of power (sounds like) I'll try pulling the wires off one at a time.

[harleysportster]

Both plugs appear to be ok and the motor sounds great. Lots of power (sounds like) I'll try pulling the wires off one at a time.

That's a bad idea. You can burn out the CDI box. Get an in-line spark tester.

[JDT]

You don't get carbon buildup from just sitting in storage.

I would agree with Harleys accessment. Probably not getting good fire on both cylinders.

At least it is a great place to start.

You can also check the Y-pipe (exhaust manifold) from a cold start and idle.

Does it get equaly warm on both sides?

[turner15]

Well too late on the spark plug wire removal when running. I seems to be running one both cylinders. There was no noticeable difference when either one was removed. In fact I was surprised at how well it ran on one cylinder. Hope I didn't kill the CDI box. I think I'm okay. I put a block under the back end and really gave it throttle and it kicked in fine. My mind may be playing a bit of a trick on me but I don't think so. I may take her out onto the street and try again. I was worried about to much speed as I have the break leaver off right now.

Any comments on what this sled is worth would be great as I am thinking of selling once everything is ship shape.

[discus]

Check to see if you don't have a mouse nest in the pipe.

Dale

[turner15]

Good point but I have lots of power the engine does not bog. I have lots of exhaust and its blue (I mixed 50:1) I little oil heave for the first tank. It seems like the belt is just not catching? However when I lift the weight off the sled she flies?

[discus]

If your'e confident it's not in the engine then take the belt off, jack up the sled and roll the track by hand to make sure it's free. If it is,it could be the primary clutch is frozen. If you have the means to pull it for inspection it would be worth while. Are you smelling belt when trying to get it to move?

[SpitfireKing]

Deffinately sounds like frozen drive bearings or a clutch that's not engaging, but when the primary freezes I always thought you got high revs but no movement as its screaming but won't grab the belt, now if the secondary was stuck your belt should be smoking and squealing.

I have a 1980 spitfire that does this exact thing...but I have yet to ever look at it.... tried it once when I bought it and it's been sitting ever since.

[turner15]

Okay guys thanks for the advice. I do get full drive and belt movement when the track is lifted. High speed belt movement. I am a new owner and I am not sure how long the sled had sat before I took ownership. I'll look into the clutch on the weekend after I drag it to the road for another test drive. I am wondering if it was a little stuck from sitting and freed itself up? That would be ideal now wouldn't it.

Mike.

[turner15]

I decided to drag the machine to the road and fire it up and really give her. So I got up to a good speed like 25 MPH before I had to glide to a stop as my break lever is busted. I think I was doing a "Burn out" in the garage. I have a epoxy painted floor that has no traction and being a doo guy I am not use to the metal in the track. I think I'm okay on mobility now with this JD, (I love it BTW) Next is that pestie black discharge. My small engines guys says its nothing but I'm thinking maybe there is something to it? Basicly when I run it I get a black mark on the ground. In the garage it almost looks like spray paint on the floor.
Any Idea's on that issue.

Mike

[liquitisplit80]

Sounds like the carb is running too rich. Check the mixture screws.

[turner15]

Ya could be. Those are always hit and miss for me. Any way to set the lean/rich mixture?