440 trailfire clutching

[Ryker Carruthers]

Well,
Got my trailfire out on the snow with the sporty clutch awhile back and it just didnt have enough power to get up to speed quickly. I put the correct U weights in the clutch and now the engine struggles out of the gate and after it gets to around 20 mph it finds its happy place and takes off till about 40 and that is all it will do. What should I start with to fix this? My dads 440 will spin the track from a stand still to 55 mph and then top out at 65 or 70. I want response like that. Right now its not running like a deere, more like crawling like a limp deere lol. Hopefully I can get it resolved in the morning and ride all day.
Thanks, Ryker Carruthers

[JD600]

Have the crank seals been replaced in this engine?

DE

[Ryker Carruthers]

Yep. And O rings. Resleeved cylinders and parts unlimited pistons

[Liquifire 4/6]

I'm not a big fan of resleeved cylinders myself, but they should work ok in a Trailfire engine since some of the older Artcic Cats used a very similar engine with iron bores. Is your clutch in good condition? Anything binding? Flyweights running strait and true and contacting the rollers properly and not rubbing against the spider? It's sounding to me like it just may be a matter of the drive belt being too loose. Pop the driven clutch off and try removing one or two of the anti-creep shims located behind the retaining washer and see if that helps. It can make a huge difference in bottom end power if the belt had been sitting too low in the driven clutch. I usually removed the shims one by one until I found that the belt was too tight ( dragging/squealing ) at idle, and then added one shim to make the squeal go away.

[JD600]

I've been thinking hard about this, and something just occured to me. While this may not have anything to do with the problem you are experiencing, i figured i'd bring it up. Don't the PU/SPI/Lemanns pistons for a Trailfire come with cast iron rings? I know you can buy the chrome rings seperately and install them yourself, but i've never seen a kit that had them. That being said, cast iron rings in a cast iron bore will wear at an excellerated rate, correct? Hopefully Peter will weigh in on this as i know he is very smart when it comes to this stuff.

DE

[kenwaters]

Dustin,

I am not Peter, but I will give it a shot...

Rings for a Chrome Bore are cast iron material. Rings for Cast Iron bores are hardened material and chrome faced. Rings for Nicasil are hardened, and can be Ti-Nitrided for extra wear prevention. Regular replacement pistons for a chrome-bore Kawasaki motor would have cast iron rings, but if they were overbore pistons, they are probably hardened material and chrome faced.

Cast iron (soft) rings, would wear excessively quick on a cast iron bore, probably be a problem in 2-300 miles of riding.

Generally, the rule on wear interfaces (ring against jug) is that the softer material (rings) wants to be 15 points softer on the Rockwell C scale. With proper lubrication, wear is minimized with this difference in hardness.

Ryker,

I am sorry I didn't get your phone call the other night. Measure the amount of deflection your belt has, there should be about 1.5" of deflection at the midpoint between the primary and secondary clutches. Also, check how much space is between the moveable sheave on your primary and the outside edge of the belt, this should be about .030" You also want to make sure you have the correct helix in the secondary, which is a 38 degree for 340 cc engines, and 44 degree for 440 cc engines. With the belt installed, start the sled, and with some help, carefully, pick up the back of the sled, engage the primary clutch, and let the sled coast to a stop. Set the sled back on the ground. Do this to make sure the secondary is fully backshifted. Now, make sure the belt is slightly out of the secondary, not more than a 1/16". If it is not, adjust the shim stack like Liquifire 4/6 suggests.

After that is complete, do you know what gearing is in the chaincase? That will affect top speed. Making sure your clutching package is all Trailfire and adjusted properly will probably fix this.

Honestly, when I read this post for the first time, I think this replacement clutch that you have, is hanging up at first engagement. That, is a job for two people, put the sled on a sled jackstand, and watch the primary clutch shift out, after engagement, the shift should be smooth. If the primary clutch shaft was rusty, or otherwise oxidized, the shift out won't be smooth because now you are overcoming extra friction.

[JD600]

Dustin,

I am not Peter, but I will give it a shot...

Rings for a Chrome Bore are cast iron material. Rings for Cast Iron bores are hardened material and chrome faced. Rings for Nicasil are hardened, and can be Ti-Nitrided for extra wear prevention. Regular replacement pistons for a chrome-bore Kawasaki motor would have cast iron rings, but if they were overbore pistons, they are probably hardened material and chrome faced.

Cast iron (soft) rings, would wear excessively quick on a cast iron bore, probably be a problem in 2-300 miles of riding.

Generally, the rule on wear interfaces (ring against jug) is that the softer material (rings) wants to be 15 points softer on the Rockwell C scale. With proper lubrication, wear is minimized with this difference in hardness.

Thank you, thank you, thank you! That is much clearer now.

DE

[Ryker Carruthers]

I never thought of the cast iron rings in a cast bore... I guess I didnt think anything of it because we have cast iron cylinders and cast iron rings in our steam engines and they last for forever. The primary is smooth, I had it apart and checked that. The secondary cam angle i will check tonight. I had it our 50 miles today and the way it acts i want to say the gears have been changed in the chaincase. It will power thru 5 foot powder alot better than dads but from a stand still it has no power untill maybe 20 mph. and if you get on it in a drift or deep stuff when you arent going faster than 20 it will just stay at that speed and will not spin the track. Going out now to have some good quality time with dads.
Thanks!

[That Girl Racing]

Sounds like a clutch issue to me. Does the Trail use the same primary spring as the the Sport? My guess is the Sport uses a lighter spring and it is shifting too fast for the Trail motor. Is the shim pack under the spider also different?

[Ryker Carruthers]

How many teeth are supposed to be on the gears in the chaincase? Are they different for a liquifire?

[johnnycyclone]

There are several possible combinations based on model, engine size, and elevation. Follow this link, to the service manual, and you can look up the recommended combination for your model. Hope this helps.....Terre

http://www.vintagesnow.com/John_Deere.html

[Ryker Carruthers]

Sounds like a clutch issue to me. Does the Trail use the same primary spring as the the Sport? My guess is the Sport uses a lighter spring and it is shifting too fast for the Trail motor. Is the shim pack under the spider also different?

If the sporty has a different spring, the clutch i got had the wrond spring for a sporty. It is silver and I replaced it with a nicer one I had. It had F weights when I got it so i put the correct U weights in.

[johnnycyclone]

Here is what the John Deere service manual recommends for a 1980 Trailfire 440

Spring - Silver
Cam Arms - AM54281, or AM54920 (high altitude), From what I can tell the AM54281 is a U weight, and the AM54920 is an R weight. This is just what I found on the web, so take it for what it is. Maybe others can confirm if the numbers are correct or not.
Gears - 21 tooth, and a 39 tooth.

The online Comet calibration guide recommends

Spring - Purple
Cam Arms - B

[Ryker Carruthers]

Ken and I both think it is engine problems. I have a set of cylinders that ill drop in and hope that fixes it.
Thanks!!!

[WinnipegStPaul9]

Guys, I have found that the "Fine Tune Manual" blue cover is the greatest when working on clutching. It fully explains what's in each sled and what can be done to "tune" clutches etc. This is the one book my library could not be without.

DA