TM450 5 Posted July 5, 2023 Hi all, this is my first post on here. I'm excited to see that there is more technical talk on this site than on other forums. I'm currently working on a 2004 450s that I just bought and it was pretty much clapped out from going under water and mud bogging, so I'm going to revive this machine the best that I can going back with mostly OEM parts that I can. First thing I found was that the piston and cylinder were from Niche and from what I see there sold on eBay made in China. The wear and tear didn't look bad, but the top and mid rings had about a 1/4" end gap which explained the no compression. The PO said it had white smoke coming from the exhaust before it died. I've went ahead and removed the engine from the frame and split the case to clean and inspect everything inside. I wasn't going to do this, but the crank rod had excessive side to side play plus the wrist pin bore allowed to the piston to wobble side to side. I recently rebuilt an 87 250 Big Red and had no problem replacing the rod on the crankshaft with a Vesrah rod kit because the crank pin could be pressed out one side, but this 450s doesn't allow that, so I ended up using a cut off wheel to get the rod off then used a Blue tip wrench to cut the crank pin in half, then I could press the half peices out. The crank pin is made of very hard material, so I don't think my band saw would touch it. Both crank halves cleaned up good. I've ordered a new Vesrah rod kit VA-1017. What other methods are used to replace the rod other than using a blue tip wrench? Here's a couple of pics of the removal. Share this post Link to post Share on other sites
TM450 5 Posted July 5, 2023 Ooops! Sorry, I posted in the Sport forum instead of the Utility forum. Share this post Link to post Share on other sites
jeepwm69 7,618 Posted July 5, 2023 That's a good question. I have sent my cranks off to Vince at Mr Crankshaft. He charges me $135 to clean, install rod, and true a crank, including shipping it back to me. I've love to see how you rebuild a crank, not because it's something I'd be likely to do myself, but just because I'd like to know how to do it if I ever had to. I'd imagine you'd have to have a pretty stout press, but I'd think you'd have to be very precise on placement of the crank halves while pressing them back together. Moving this to the utility forum for you. 1 Share this post Link to post Share on other sites
TM450 5 Posted July 5, 2023 Thank you jeepwm69. On the other crankshaft for my Big Red when I installed the new crank pin and rod, was to make sure that the cross drilled oil hole in the crank pin was aligned with the oil hole on the crankshaft half that the centrifugal clutch is on. I used a 20 ton press from HF and it has enough force to do the job. When I get the new rod installed and get the side clearance close, then put the crank bearings on and set the assembly on two V-Blocks to rotate the assembly. I then setup a Dial indicator on each end of the crankshaft and rotate it to see how much out of alignment the two crank halves are to each other, then use a brass hammer and smack the counter weight in the direction to bring it closer to align the two halves, this may take a few times to get it, but the closer I get it to specs, the lighter the blows to the counter weight. Also every time the crankshaft is moved, it can also change the rod side clearance. When I done the Big Red crankshaft, I got it in 4 tries, and almost .001" less than what the specs call for on each half. The biggest fear on this particular crankshaft that I see is making a mistake after fully pressing in the crank pin in on the second crank half , because I would run into the same situation when I was removing the old rod and crank pin. 1 Share this post Link to post Share on other sites
jeepwm69 7,618 Posted July 5, 2023 Definitely a precise thing to get to. On the Big Red, was the pin more easily pressed out? I have the same press you do, but I have always let Vince do my cranks. I figure getting those even a hair off balance will grenade the whole engine. Worth the peace of mind I get paying a pro to do it. 1 Share this post Link to post Share on other sites
TM450 5 Posted July 5, 2023 Yes, the Big Red crank pin hole was fully open on one half, making it easier to press apart. The most critical part is aligning the oil hole, so I just used a yellow marking pin showing where each hole is, that way it makes fairly easy to align. The difference between the Big Red crank and 450 was that the crank pin bores were not drilled all the way through on the 450, and the Big Red was on one half and not the other. I have confidence that this will work just fine after doing one crankshaft. The part that I don't like is using heat near the crank halves when cutting the crank pin in half, even though as you can see where the pin turn blue, i don't think it effected the crank halves, but I still don't like it. The next time I do another one, I'll probably just use a large cutting disc that will pass all the way through. 1 Share this post Link to post Share on other sites
TM450 5 Posted July 5, 2023 Heres something else while rebuilding this engine. Would it be ok to just flush out the oil cooler or be better to get a new one? I know the new ones are a little pricey, but if it's worth it I might just buy a new one. Share this post Link to post Share on other sites
jeepwm69 7,618 Posted July 5, 2023 I've always flushed them, never had any problems doing it that way. 1 Share this post Link to post Share on other sites
TM450 5 Posted July 5, 2023 (edited) I found some pictures of the Big Red crankshaft with the new Vesrah rod and crank pin. The first and last picture is with the old crank pin. Edited July 5, 2023 by TM450 1 1 Share this post Link to post Share on other sites
TM450 5 Posted July 9, 2023 Here's a small update. Been cleaning up the case halves scrapping the old gaskets off and cleaning all the debris out of all the oil passages like three times to make sure it's super clean. When I got to the rear case half, and removed the gears and found a thrust washer down in the bottom that goes on the shift drum along with bit's and peices of what was left a timing chain. There was so much crud and metal in bottom that the filter screen plugged up enough to suck it up out of the grooves that holds it in place. 1 Share this post Link to post Share on other sites
shadetree 5,884 Posted July 9, 2023 10 hours ago, TM450 said: Here's a small update. Been cleaning up the case halves scrapping the old gaskets off and cleaning all the debris out of all the oil passages like three times to make sure it's super clean. When I got to the rear case half, and removed the gears and found a thrust washer down in the bottom that goes on the shift drum along with bit's and peices of what was left a timing chain. There was so much crud and metal in bottom that the filter screen plugged up enough to suck it up out of the grooves that holds it in place. thats from being sunk !..been there..seen it a million times !. 1 Share this post Link to post Share on other sites
Ajones704 0 Posted July 11, 2023 (edited) Hey man can you text me 7048701640. thing is kicking my tail. 2016. No lights on dash will show when key is turned on but will headlights/taillights work fine. New relay. New battery. New fuses including main(30). Light No power at ignition plug when switch is in run position. What am I missing?? Bike was starting/running fine until wash and moved it inside for some maintenance. @shadetree Edited July 11, 2023 by Ajones704 Share this post Link to post Share on other sites
