70 fox trail tramp

#1
Hello all,
I’m having problems with the clutch on this bike. I read a earlier thread and it didn’t help.
My inner gear works great but when I put the chain on the outer gear it drags the motor and wants to jump off the line when starting up.
I just bought the bike to restore so hopefully someone can help with this clutch issue.
Thanks.
 
#2
I've never had a fox bike.
Post some pictures it will help big time on figuring out your issues.
Worn out sprockets & chain
Poor alignment. Could come in to play.
Bearings.....
Have fun with your project!
 

1971_MB1A

Well-Known Member
#3
Hello all,
I’m having problems with the clutch on this bike. I read a earlier thread and it didn’t help.
My inner gear works great but when I put the chain on the outer gear it drags the motor and wants to jump off the line when starting up.
I just bought the bike to restore so hopefully someone can help with this clutch issue.
Thanks.
You could try reaching out to @copyman on here. He was having the same type of clutch problems with his Fox and I think he may of somewhat figured it out.
 
#7
@Biffmini good call on the bearings. I never had to deal with a clutch problem so I was in the dark. @copyman sent me pictures and then I noticed the outer sleeve bushing was locked in the outer hub. Spent some time polishing the sleeve bushing and the outer hub and finally the bike doesn’t take off when starting and I have second gear. Took some pictures of what they should look like when operating correctly in case someone else has issues.
Thank everyone.
 

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#8
So my fox is running good on a predator motor, my son can enjoy his summer riding.
So I can concentrate getting the motor all cleanup and running. So I started rust removal on the wheels whenever I had free time, they were bad. Moved on to the motor. The housing was so rusted out couldn’t even read the housing tag. I cleaned the housing and noticed that the numbers looked odd. I message @markus and he gave me some good feedback. The numbers on the housing looks like a h30 or Briggs and Stratton housing. Thanks @markus
 

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#9
It's definitely a Tecumseh engine but looks like a Sears model # on the plate. I remember seeing a cross reference chart showing Sears / TEC engines, maybe someone knows where to find that? It looks to be the correct HS40 engine with diaphragm carb that came on the Trail Tramp. Looks like it was made in 1971 so that is correct time for the Fox Trail Tramp. Not sure how but the flywheel fins are broken, not sure how critical this is but someone else should know. Also can't see if it's a lighted engine which is what came on the trail tramp?
 

markus

Well-Known Member
#10
as per your PM, it is in fact just a swapped shroud......which is why all the fins on your high dollar lighted flywheel are blown off :D Lighted engines in that timeframe used specific shrouds with studs on them for the recoil because the fins on the wheel stuck out farther. It almost looks like it is a small head pattern HS40, If it does in fact have a 3" long crankshaft It is the original HS40 if you bike is a 2 speed model, If it is small pattern head block its not really later than mid 1969, I want to say by September (but I would have to dig out my date codes) they were using the updated Big head blocks with more surface area on everything except the snowblower engines-they just used up the small head blocks on those.

again if its got the extended shaft PTO the Fox spoke wheeled 2 speed engines used, it would be HS40 55266A for the small head, to mid '69 and HS40 55266B mid 1969 for big head, not sure how long that # carried though 1970, there were some cam desigen changes around that timeframe, engine numbers changed a bunch through 1971 because so many changes were taking place (but that bike was done during 1970 from what I have seen)

If its a standard short PTO it would be a different model number but even the numbers above will work and pull up key parts for what you have just the crankshaft # would be different.
 
#11
Its
as per your PM, it is in fact just a swapped shroud......which is why all the fins on your high dollar lighted flywheel are blown off :D Lighted engines in that timeframe used specific shrouds with studs on them for the recoil because the fins on the wheel stuck out farther. It almost looks like it is a small head pattern HS40, If it does in fact have a 3" long crankshaft It is the original HS40 if you bike is a 2 speed model, If it is small pattern head block its not really later than mid 1969, I want to say by September (but I would have to dig out my date codes) they were using the updated Big head blocks with more surface area on everything except the snowblower engines-they just used up the small head blocks on those.

again if its got the extended shaft PTO the Fox spoke wheeled 2 speed engines used, it would be HS40 55266A for the small head, to mid '69 and HS40 55266B mid 1969 for big head, not sure how long that # carried though 1970, there were some cam desigen changes around that timeframe, engine numbers changed a bunch through 1971 because so many changes were taking place (but that bike was done during 1970 from what I have seen)

If its a standard short PTO it would be a different model number but even the numbers above will work and pull up key parts for what you have just the crankshaft # would be different.
Markus is
 
#13
It's definitely a Tecumseh engine but looks like a Sears model # on the plate. I remember seeing a cross reference chart showing Sears / TEC engines, maybe someone knows where to find that? It looks to be the correct HS40 engine with diaphragm carb that came on the Trail Tramp. Looks like it was made in 1971 so that is correct time for the Fox Trail Tramp. Not sure how but the flywheel fins are broken, not sure how critical this is but someone else should know. Also can't see if it's a lighted engine which is what came on the trail tramp?
The numbers on the tag of the housing come up Briggs-h30. I now know why it’s not the smoothest thing to pull the cord.
 

markus

Well-Known Member
#14
Markus so with the flywheel is the flywheel damaged enough to be replaced?

It’s not ideal, but that’s a hard item to replace. that takes it out of balance And reduces its ability to move air. It would be smart to thoroughly inspect the wheel as best you can to make sure cracking does not go past outer fins, and if there are any loose or crack lined fins that could come loose when you get it running again if your gonna use it/ try it. Lap flywheel to the crank, use the updated nut/washer as they are better than the original stepped nut, watch that you seat the cup in the right spot ( that is harder to do on lighted flywheels) and correctly torque it to spec to give the best shot at not having problems. Hopefully it didn’t get taken too far out of balance when the damage happened.
 
#15
It’s not ideal, but that’s a hard item to replace. that takes it out of balance And reduces its ability to move air. It would be smart to thoroughly inspect the wheel as best you can to make sure cracking does not go past outer fins, and if there are any loose or crack lined fins that could come loose when you get it running again if your gonna use it/ try it. Lap flywheel to the crank, use the updated nut/washer as they are better than the original stepped nut, watch that you seat the cup in the right spot ( that is harder to do on lighted flywheels) and correctly torque it to spec to give the best shot at not having problems. Hopefully it didn’t get taken too far out of balance when the damage happened.
So buy the right housing will any hs40 work?
 

markus

Well-Known Member
#16
So buy the right housing will any hs40 work?
from my post above"
Lighted engines in that timeframe used specific shrouds with studs on them for the recoil because the fins on the wheel stuck out farther.
the shrouds in that timeframe are shaped the same though and made to fit all the small frame sized engines. so you can cut/drill out the rivnuts off the shroud and replace them with studs, I use the proper sized/thread pitch philips headed screws, weld them on in the inside and then use an end mil bit to work them down to pretty much the same depth of the original weld on studs Tecumseh used.
With all the fins broken you can probably just use the way you have though, just make sure there is space and maybe use screws/bolts that do not proturde past the nut if its running clear currently. But you really need some safe clearence, as the crankshaft assembly in a bushing engine does in fact travel side to side. Stock measurement for the that in the book is up to .027" so every time you rev the engine etc. the flywheel is pushing out that much farther.
 
#17
So I been trying to get the old motor running. I have no spark, check points a hundred times and even bought new points and condenser after my coil tested bad. I still have no spark with new coil and I tested the new coil with ohm meter it’s up to snuff. Any advice what my new step should be? I been reading the flathead manual on here and just missing something.
 
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