1980 440 drifter bogging bad - need help

[arcticcat941]

Hey guys! I have a MINT 1980 440 drifter that im having issues with bogging at full throttle. I live in southern Wisconsin and just south of me there is a race track that they have been racing vintage leaf spring sleds at. Well I entered it this last Saturday and had major issues. I was battling the sled all week on trying to get it to run right. I was changing the jetting but everytime the temp would change it would run crappier and then I would get it to run good again but I was also at my house on flat ground. Basically Friday night (about 3 degrees outside) after I messed with it all night I seemed to get it running good. Saturday morning it was about 30 degrees and it ran like crap, rejetted it and it seemed to run fine. Got to the track that night (went down to about 10 degrees) and of course it ran like crap again. Rejetted it to what I had the night before and it ran real good on flat ground. The track has a pretty decent hill that you go up and down twice (roughly 150-200 feet up). For the most part it was running real good on flat ground but coming out of some corners it would bog down bad and then going up the hills I would lose basically all power, I was lucky to reach the top most times. Is there anything you guys think I can do to get it to run better, im at a stand still here. I really don't know much about jetting so I could use some help with that if anyone has like a chart or something. The plugs are new, compression is at 150 in both cylinders, carb was cleaned multiple times, fuel tank flushed out, ran all new fuel lines, im just completely lost and I really want it to get running at full performance. Also if I get this figured out I would like to regear it to have more acceleration than top speed, were lucky if we get up to 35-40 mph and this is all im doing with the sled besides bopping around at the house so the question is does anyone know where I can get new gears and a chain from or are they somewhat universal with other brands. I would really appreciate the help. thanks guys!!

[arcticcat941]

also looking for a stiffer rear shock. are the rear shocks universal on most older sleds? or do I need to find a shock made for the drifter?

[arcticcat941]

Someone has to has some input here? anyone?

[Lloyd (ljm)]

Your bogging issue could be MANY things.

 Could be fuel or ignition related.

 Is the exhaust restricted?

 Did you change the crank seals?

 Did you replace the fuel pick up in the tank?

 Shacks for Drifters are no longer available. You have to find one that is close to the right length, both open and closed.

 Why would you want a stiffer shock? Unfortunately you might have to be satisfied with what will fit for a shock.

 Is the suspension free?  did you remove it and grease the shafts?
 How tight is the track?
 Are the idler wheels in good shape?

 As you see your post left more questions than answers.

 I have a 80 440 Drifter that I got new as a teenager.  That is a great all around sled and the best sled in powder that I have driven

 

[arcticcat941]

I have not checked the exhaust for restrictions but that will be my next thing. I have not changed the crank seals and I don't know if they have been before me. The sled is in immaculate condition and was very well taken care of but I guess that doesn't mean they still couldn't be bad. I did not replace the fuel pick up in the tank but I did flush the tank out. Is there any screens or anything in the pickup that I may have missed? I also should note that I have a parts drifter that was in bad shape and I had to rob the carb off of that one and the carb is in pretty poor shape which could be part of my issue. The carb that was on it was in excellent shape but somehow one of the tabs that the pin goes through that holds the float plate broke which led me having to put the other carb on. I ordered a new vm32 carb for it so I guess I wont know if that was the issue until I get it. I guess im just stumped on why it was only happening going up the hill, it ran phenomenal on flat ground. Some people told me that the float plate might have been closing the needle when i was going up hill and that i should bend the tab a little bit?? does that sound right?? I have a new ignition coil that i will put on to. And as for the suspension it is also in immaculate condition and the track looks brand new. The reason i asked about the shock is because one of the days i was riding around the yard it froze closed on me and it free'd up after it sat in the heated garage. I havnt had any issues since but i figured i should get a new shock for it.

[invader87]

Are you able to operate the choke or primer when it acts up? Does that change anything? Keep us updated.

[Joel]

I got my last Drifter shock from Image Enterprises. Joel

[arcticcat941]

When I would run it around the yard and it would bog I would hit primer and it would keep running. I would then jet it for more fuel and then have no issues on flat ground. Only issue came into play going up the hill at the track and it was to hard to try and prime it. And thanks Joel!

[kawhead]

crank seals go bad with time, the rubber rots....those seals have had oil on them for , oh, lets see.....1/3 of a century.keep running it this way and tou'll need a piston to, at least.

[gixxer6]

kawhead is right.  Those seals need to be changed!  I have seen sleds run exactly how you described because of bad seals.  The fuel pump is driven from the pressure pulse created in the crankcase.  If the seals are leaky, the pump can be weak or intermittent. 

[arcticcat941]

Only happens going up hill tho. Like I said earlier they very well could be bad but what would bad crank seals have to do with going up hill. It runs better than my old 07 race sled on flat ground. I'd think it'd be bad all the time if they were shot.

[booblover]

After messing with these sleds for a few years now, I have learned one major lesson, which you will find on half of the threads on this site. REPLACE SEALS. I have three invaders now. The two that I keep running exhibited many different issues before I did the seals. Issues that I would never have guessed would be caused by seals. I changed them, and both times, the problems went away.

[arcticcat941]

OK I am ordering some now and will do them this weekend. How long should I expect it to take? Do I need any special tools besides clutch puller?

[gixxer6]

That's a good place to start...   You'll need a puller and some good grade 8 bolts for the flywheel.  And some good sealant for the crankcase, something rated for gas immersion.  2 to 4 hours should do it. 

[arcticcat941]

thanks everyone!!! Any of you guys know where I can get a 17 tooth 11 wide 15 spline top sprocket??? Cant find one any where..i think they came on the 340 drifters..anyone have one lieing around??? If anyones interested I would trade my 21tooth top sprocket and 92 pitch chain for your 17t top sprocket and 90 pitch chain out of a 340 and throw some extra money in..