79 Trailfire 340 vs 440 parts

JDFanPa · Post by **JDFanPa** » Wed Jul 27, 2005 7:33 pm

I recently rebuilt the motor in my 79 tf 340 and put a 440 topend on it. I have a few ?s on some other parts if theres any difference between a 340/440. First is the pipe/muffler any different between the 2 sleds? Is the secondary different? Im thinking the chain and gears would be different also like the 340 would be geared lower.

I have all the 440 parts to swap from another tf I took apart. I am just wondering if I need to. My thoughts are to leave the 340 gearing in place to give the sled more low end as it seems now on the grass it really wants to pull the skis up. I have plenty of sleds to ride and am not concerned about it hurting top end speed. More concerned if the 340 pipe and secondary are hurting the 440s performance. thanks

Deere Daze · Post by **Deere Daze** » Wed Jul 27, 2005 9:46 pm

The muffler on both the 340+440 are the same pipe.The secondary is also the same.The 79 trailfires also came with a 94c duster clutch, if it did, use the 102 from the 440 so you will have a better final drive. Gearing will more than likely be the same, but if there is a difference, it will not be much.Ed

B)

JDFanPa · Post by **JDFanPa** » Thu Jul 28, 2005 12:49 am

Thanks for the info Ed. Thats cool that everythings the same. I do have the 102 from the 440 on it

JDDDeere · Post by **JDDDeere** » Thu Jul 28, 2005 7:54 am

HI there.

Since this thread mentioned clutches, I hoped it wold be OK to add a question. After much soaking, gentle prying and banging with a rubber mallet, I finally got my 102c "free". The sheeves slides freely. Upon closer inspection, there seems to be some sort of "fabric"... on the part of the post/spindle between the spider and the outside sheeve (admitedly, it is difficult to see). I would almost compare it to the thread you would see if duct tape were worn away, but it is not duct tape. Has anyone seen this? Is it part of the construction of the comets clutches? I don't think it is preventing the sheeve from opening all the way, but I do find it strange.

Thanks
Dan

Deere Daze · Post by **Deere Daze** » Thu Jul 28, 2005 9:46 am

The part you are talking about is the movable face bushing.They are an "organic"type bushing.If you can see some of the bushing falling apart, you should replace the bushing.They are all the same from the 102c,108c and the 108 exp.You should be able to get one at any snowmobile supply store cheap.Ed

JDDDeere · Post by **JDDDeere** » Thu Jul 28, 2005 1:04 pm

Thank You Ed

JDFanPa · Post by **JDFanPa** » Fri Jul 29, 2005 10:57 pm

Also a possibility given you said it looks like duct tape stuff is that. When a drive belt blows apart specialy at high rpms its not uncommon to have thread from the blown belt get wrapped up in there. More than once I can remember kneeling in the snow with my trusty pocket knife trying to cut this threads out of there on the trail. The more the clutch sheeve rides over this back and forth the more it gets wedged in and and compacted until it almost looks as if it belongs. If enough gets wrapped up on there the clutch wont move either.

JDDDeere · Post by **JDDDeere** » Fri Jul 29, 2005 11:28 pm

Andy,

Great (thanks). I think it may be (as you say) part of the belt. It is gummed up (sort of) and there are defintely "threads" and the clutch was orignally very badly stuck. I started to clean it out with a wire brush, but i didn't want to ruin anything if it was supposed to be there. Anyway, I am planning on taking apart the clutch for a good cleaning andpossiblit to repalce the bushing referenced by Ed. I hope this is easy. Speaking of which, are there any secrets. What holds it together??? The weights will come off easy enoough. Does the sheave twist off???

Regards,
Dan

Rodimus Prime · Post by **Rodimus Prime** » Sat Jul 30, 2005 4:31 am

comet spiders are threaded in place they are torqued to 250 foot pounds and of course must be removed to replace bushing. just to add so more headache is the fact that unfortuantly some also have red locktight on them which in many cases usually means that part of the threads strip. upon reassembly do not put locktight on before you torque it down but after ie ontop of the threaded area. a little will leak in and it will never come apart. order a pin and roller kit for it.. keeping in mind that you will sometimes get the wrong kit on first try..

JDDDeere · Post by **JDDDeere** » Sat Jul 30, 2005 9:50 pm

Thanks Rod...

Geez, now I am less inclinded to take it apart (stripping threads, 250 ft-pds torque, etc).

If anyone wants to propose to refurbish (clean, lubricate, and change out a bushing) on this clutch, i would pay them for their time/effort. Anyone with expereince and the right tools for this???

Dan

JDFanPa · Post by **JDFanPa** » Sun Jul 31, 2005 3:28 am

I usally just use a razor blade to cut the wrapped up belt threads. If you can just cut a few and get ahold of 1 you can actually just unwind them it may take some time but you can get it. Asfar as the bushing its 1 on those things I take the "if it aint broke dont..............." approach to. Rebuilding the outer part with new pins etc as RP said isnt a bad idea.

JDDDeere · Post by **JDDDeere** » Sun Jul 31, 2005 10:09 am

Thanks you both. It is gummed up (with a few threads mixed it). I am sure I can get it off (now that I know it doesn't belong there). I was going to try to attach a picture, but it would be difficult to get a shot of that part of the clutch....

Very good! Until next time..... (ha, ha, ha)

Dan

Rodimus Prime · Post by **Rodimus Prime** » Wed Aug 03, 2005 1:17 am

i ususally use two 8 foot pipes and a 3/4 inch drive set with my clutch tools to get them apart. this is only nessary if you have to fix the spider or bushings most times you shouldnt have to.. please note that i have broken good quality big vices before trying to take these aprt. i am also getting good at welding cast because of that...

note if the cam arms wobble alot back and forth they may have grooved the spider.. a little fileing will clean up the grooves so that new arms and pins wont jam.

JoeRainville · Post by **JoeRainville** » Wed Aug 03, 2005 6:01 pm

Hey Guys,

This note is in reply to the differences from a 340 to a 440 TF. First, the secondary clutches are the same, like Ed said, but the 340 uses a different helix. I think it's around 38 deg, but would have to check. Switch to the 440 helix if you have it. Also, I "think" the wieghts are different in the Comet 102, but both used the same spring. I might have a weight and pin kit NOS if you need them.

The 340 should be geared a little steaper than the 440, but again I would have to look up the exact tooth counts. Shooting from the hip here.

As you found, the bottom ends were exactly the same for the 340 to the 440cc Kawi T-1 motors. The 79 (steel tunnel) 340's had a unique version of the Comet 94-C duster with it's own puck and cover plate (again, as Ed said). Funny enough I have those NOS too, but you really should use a 102-C on the 440, as the Duster is only good for around 30 -35 hp max.

Have fun with your sled,
-Joe Rainville
"Tech-Ed"

JDFanPa · Post by **JDFanPa** » Thu Aug 04, 2005 12:17 am

Thanks Joe. I have the 440s primary on will install its secondary just to make sure alls the same. I have all the 440 parts Ive just been workin on so many other old sleds lately I didnt want to spend time switching stuff on this If I didnt have to. I know most of us know what its like to have to many irons in the fire. I had never had any Rupp sleds in my 33yrs of breathing. Now I have aquired 3 in a few months. Trying to get these going up to sniff to sell them off in the winter for some DEERE cash. Then theres the 2 skiroules,2 lynx 292's,a 634 panther. A Homelite Frontier, some old yamahas, a few deeres id like to get going. Just to much going at 1 time ooh forgot my zr580 and my storm could use some work also. These are all stored at a freinds so I only get my hands on them on weekends luckily the wife does not bitch about this aslong as we have food and the tv's on LOL.

I think I whined enough so I wont even mention the 5-6 motors in different stages of not fixed going on in my basement. Sometimes when Im really bored I try to tag all the parts on the shelves so I know what they fit before they hit ebay this winter. I think my landlord likes the idea that I have been stripping sleds in the back of my van instead of his yard though. Oddly enough most people dont understand this addiction I have with things that I can only ride 3 months a year. They seem to say you should get a quad. Mt reply is I have 1 its a yard horse to drag snowmobiles around the yard I just dont enjoy trailriding it. Fingers are sore later.