squonk 41,104 #26 Posted August 9, 2022 The height the idler pulley is in this picture tells me the belt is now too long for this set up and would explain why it works with the belt guard off. You an also see the old engine mounting holes. Replacement engine is closer to the transmission than the original. 2 Share this post Link to post Share on other sites
Pullstart 62,852 #27 Posted August 9, 2022 This is what your belt guard should look like to your engine pulley. Does it fit well? 1 Share this post Link to post Share on other sites
Pullstart 62,852 #28 Posted August 9, 2022 10 minutes ago, 857lover said: it’s 6 inches I measure 4-3/4” to the center of the crank. 1 Share this post Link to post Share on other sites
Pullstart 62,852 #29 Posted August 9, 2022 Measuring from the dash tower /shifter box to the centerline of the crank, it should be 17-3/4”. 1 Share this post Link to post Share on other sites
Monstrosity 1,128 #30 Posted August 9, 2022 (edited) Maybe a stronger spring on the clutch return maybe it's weak and causing to slip under heavy load. Not enough tension. Edited August 9, 2022 by Monstrosity 1 Share this post Link to post Share on other sites
moe1965 738 #31 Posted August 9, 2022 Just a thought remove the fresh paint on the new pulley where the belt touches it. Shouldn't make a difference but one more thing to rule out and easy to do. 1 Share this post Link to post Share on other sites
857lover 291 #32 Posted August 9, 2022 1 hour ago, squonk said: The height the idler pulley is in this picture tells me the belt is now too long for this set up and would explain why it works with the belt guard off. You an also see the old engine mounting holes. Replacement engine is closer to the transmission than the original. i had a 1/2 by 69 on it and it seemed alright tension wise but i just put a 1/2 by 68 and it seems to tight now Share this post Link to post Share on other sites
Pullstart 62,852 #33 Posted August 9, 2022 33 minutes ago, 857lover said: i had a 1/2 by 69 on it and it seemed alright tension wise but i just put a 1/2 by 68 and it seems to tight now I think we should position the crankshaft in the right spot, then figure out the belt. 1 1 Share this post Link to post Share on other sites
857lover 291 #34 Posted August 9, 2022 (edited) 1 hour ago, Pullstart said: I think we should position the crankshaft in the right spot, then figure out the belt. i just noticed that the “finger” on the idler is hitting the belt shroud why is that happening? Edited August 9, 2022 by 857lover added photo Share this post Link to post Share on other sites
Pullstart 62,852 #35 Posted August 9, 2022 Because the belt is too big for the engine location. 2 Share this post Link to post Share on other sites
Snoopy11 5,714 #36 Posted August 9, 2022 All of the issues that Mike @squonk has noted in this thread are 100% correct. Normally, when I swap engines... swap pulleys or anything like that... engine belt guards have to be fabricated... and 1 major item has to be added to resolve this type of problem. Check out this edited picture. So, the top yellow mark is where the clutch idler pulley should be. The bottom yellow mark is where I advise putting a static flat idler pulley to tighten up the belt tension (move the clutch idler pulley forward)... and provide extra surface area for the transmission pulley. Put the flat idler pulley somewhere in that area, ensuring that there is clearance between the clutch pulley movement and this flat idler... Go to tractor supply or some farm store, and pick up a flat idler pulley like this: Here is what I cannot guarantee. I cannot guarantee that the belt that you currently have on that machine will work, you may need to pick up a longer belt after performing this modification. Having said that, to get the belt to stop... you may need to add more belt guards on the engine area like I did on my 800 Special... (you can check out my modified machines if you need some ideas. It is also POSSIBLE that you may need a belt guard on the backside of the transmission pulley to get the belt to fully disengage. All of this just depends on how modified your pulley system is, and how everything turns out. Don 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #37 Posted August 9, 2022 Oh, and don't forget... whenever you buy idler pulleys, pull the dust guard flap thingy out of the bearing area and pack some Lucas grease in there on BOTH sides of the pulley... those pulleys only come with a TINY bit of grease in them... as the manufacturers fully anticipate them failing... and you going to buy another when they do fail... Don Share this post Link to post Share on other sites
squonk 41,104 #38 Posted August 9, 2022 3 minutes ago, Snoopy11 said: All of the issues that Mike @squonk has noted in this thread are 100% correct. Normally, when I swap engines... swap pulleys or anything like that... engine belt guards have to be fabricated... and 1 major item has to be added to resolve this type of problem. Check out this edited picture. So, the top yellow mark is where the clutch idler pulley should be. The bottom yellow mark is where I advise putting a static flat idler pulley to tighten up the belt tension (move the clutch idler pulley forward)... and provide extra surface area for the transmission pulley. Put the flat idler pulley somewhere in that area, ensuring that there is clearance between the clutch pulley movement and this flat idler... Go to tractor supply or some farm store, and pick up a flat idler pulley like this: Here is what I cannot guarantee. I cannot guarantee that the belt that you currently have on that machine will work, you may need to pick up a longer belt after performing this modification. Having said that, to get the belt to stop... you may need to add more belt guards on the engine area like I did on my 800 Special... (you can check out my modified machines if you need some ideas. It is also POSSIBLE that you may need a belt guard on the backside of the transmission pulley to get the belt to fully disengage. All of this just depends on how modified your pulley system is, and how everything turns out. Don Yup. Check out this video. 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #39 Posted August 9, 2022 I should clarify 1 more thing that Mike and Kevin touched on here... The clutch pulley tab should be ON TOP of the pulley... as... with the pulley all the way back where it is now, the tab itself is likely tagging the belt, wearing it on the top side... This is where it should be... Don 1 Share this post Link to post Share on other sites
oldlineman 1,481 #40 Posted August 9, 2022 Could the pulleys used be too small, thus not giving the belt enough friction area to maintain good driving force. Just a thought. Bob 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #41 Posted August 9, 2022 (edited) 5 minutes ago, oldlineman said: Could the pulleys used be too small I think not. I have done a good range of experiments with pulleys... and haven't had an issue with a pulley being "too small" (unless it is under 2.5 inches) Would it be better if the pulleys were bigger...? Yes, undoubtedly... but I think he can work with what he has. Don Edited August 9, 2022 by Snoopy11 Share this post Link to post Share on other sites
Pullstart 62,852 #42 Posted August 9, 2022 If the engine just gets moved to where the crank needs to be, all these fabrication ideas can go away. It’s not super pulleyed up, it’s not super high speed or horsepower, it doesn’t need all that. I can be corrected, but @857lover is a teenager without access to a welder. We need to keep this repair as simple as it possibly could be. @857lover if you’d like a different idler arm with a not welded tab on it, I’m sure I’ve got one I can send you - otherwise the engine can be moved to stock location and life can go on in simple format 1 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #43 Posted August 9, 2022 4 minutes ago, Pullstart said: otherwise the engine can be moved to stock location HAHAHAHAHAHAHAHA Aftermarket engines make that a true PITA to actually do that as none of the bolt patterns match... good way to go nuts trying to get it back into stock position... I think... Mike's point about the pulleys not being stock size doesn't help either... as that doesn't look like the stock 7 inch pulley on the transmission. If we really want the easiest idea here... that would be to increase the transmission pulley size or the engine pulley size, keeping in mind there will be speed changes. I can't remember the ratio off the top of my head... but for ever inch (plus or minus) of pulley change... you have to add or subtract 2.5 inches... (I think) to the overall belt length... which is a relatively large change with minimal effort... Don Share this post Link to post Share on other sites
squonk 41,104 #44 Posted August 9, 2022 24 minutes ago, oldlineman said: Could the pulleys used be too small, thus not giving the belt enough friction area to maintain good driving force. Just a thought. Bob Yes. A smaller pulley = less surface area of the belt gripping the pulley. 2 Share this post Link to post Share on other sites
squonk 41,104 #45 Posted August 9, 2022 Lets also remember this tractor is not used for mowing or put put around a yard. it's for trail riding if I remember right. A lot higher stress and loads on the belt. 2 Share this post Link to post Share on other sites
Pullstart 62,852 #46 Posted August 9, 2022 12 minutes ago, Snoopy11 said: as that doesn't look like the stock 7 inch pulley on the transmission. it’s proper size in relation to the engine pulley though… and a 60’s 3 speed. Share this post Link to post Share on other sites
SylvanLakeWH 25,557 #47 Posted August 9, 2022 No expert, but I’ve done two Predator swaps with no issues doing exactly what @Pullstart suggests: mount engine exactly where crank and pulley was “stock” and everything lines up… simple measurements and simple to create a mount that does so. Of course, I used same sized pulleys. Change pulley size(s) etc. then time to fabricate as noted… 3 1 Share this post Link to post Share on other sites
Snoopy11 5,714 #48 Posted August 9, 2022 11 minutes ago, squonk said: it's for trail riding if I remember right OH... well that is telling. I guess... really we have given the OP some ideas on ways to solve the problem. It's really up to him now... 3 minutes ago, SylvanLakeWH said: mount engine exactly where crank and pulley was “stock” I wouldn't know where the crank was "stock" on my modified machines... 'cause none of them had engines on them when I started... BUT... if I did, it wouldn't have made a difference... 'cause when you plan to put different size pulleys on a machine... you better be ready to keep right on modifying the pulley system... Me personally, I probably wouldn't want to move the engine again, so I'd just fool with pulleys until I got it right... Don Share this post Link to post Share on other sites
Snoopy11 5,714 #49 Posted August 9, 2022 My other thought about this thread is... is it possible that we are overthinking it? Why doesn't the OP just go buy a smaller belt and keep going down in size until he gets it right??? Don Share this post Link to post Share on other sites
857lover 291 #50 Posted August 9, 2022 5 minutes ago, Snoopy11 said: My other thought about this thread is... is it possible that we are overthinking it? Why doesn't the OP just go buy a smaller belt and keep going down in size until he gets it right??? Don i’ve went down a inch and it’s wayyy to small Share this post Link to post Share on other sites
