Guest treitz Posted July 16, 2014 Share Posted July 16, 2014 After riding this bike for 1 day there are a few things I need to address. This being my first EVER liquid cooled bike, I'm not sure where to start. Issue Number 1 Bike appears to be running lean when cold and warm. Rev won't come down quickly especially when shifting. On my air cooled bikes I would just adjust the air screw and it would help. However on this bike I don't see any air adjustment screws on the carbs. Is there something else I should be looking for? If not I may just need to clean the carbs out. Issue Number 2 Bike overheated a bit today. First place to start would probably be the thermostat. Right? I imagine it hasn't been replaced in a really long time, if ever. Thanks in advance for any input! Link to comment Share on other sites More sharing options...
Member Contributer Duc2V4 Posted July 16, 2014 Member Contributer Share Posted July 16, 2014 Although these can be "generic" questions, for better results, please indicate year, model, mileage of the vehicle. Are you referring to the XS850 in your profile or ??? Link to comment Share on other sites More sharing options...
marriedman Posted July 16, 2014 Share Posted July 16, 2014 And when you say over heated, do you mean it shut down or the overflow reservoir puked? What was your coolant temp? Link to comment Share on other sites More sharing options...
Guest Posted July 16, 2014 Share Posted July 16, 2014 Sorry about that. I forgot I hadn't updated my signature. Bike is a 1984 VF750F with around 37k miles on it. It didn't shut down, it just puked coolant. It was running between half and 3/4 temp on the gauge when I shut it down. Then it spit coolant from the reservoir. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted July 16, 2014 Member Contributer Share Posted July 16, 2014 T-stat stuck .. Link to comment Share on other sites More sharing options...
Guest Posted July 16, 2014 Share Posted July 16, 2014 T-stat stuck .. That's what I assumed. I guess I'll pull the thermostat tonight and replace it. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Didn't have a chance to get to the t-stat last night, but I did replace the spark plugs. Made a fair difference in how the bike runs. Don't know when they were last replaced, but the ones I pulled were ugly. I'll probably get to the t-stat this weekend. What do you guys think about the lean symptoms? Basically when I shift, the RPM's are slow to drop. They stay about where I revved to until I complete the shift. In my 70's bikes I'd adjust the air mixture screw, and if that didn't do I'd clean and consider rejetting the carbs. On this bike it appears that there isn't a air screw. So should I just pull the carbs, or is there something else I should be looking at? Link to comment Share on other sites More sharing options...
marriedman Posted July 17, 2014 Share Posted July 17, 2014 Can't help on the lean condition, if that is the problem. Back to your coolant though, might consider getting a new rad cap too. Not expensive and could help. Also double check and see if there is an air bubble in the coolant system. Burp if need be. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Can't help on the lean condition, if that is the problem. Back to your coolant though, might consider getting a new rad cap too. Not expensive and could help. Also double check and see if there is an air bubble in the coolant system. Burp if need be. To show how new I am to liquid cooled bikes, I'm going to have to tell you that I do not know what a rad cap is, or how to burp a coolant system. Catching on to your lingo... rad cap = radiator cap. Burp the system by leaving the cap off running it till it's warm? Link to comment Share on other sites More sharing options...
TNRabbit Posted July 17, 2014 Share Posted July 17, 2014 Burp: run up to temp with the bike on the SIDE stand (forces air to the cap/high point) & the radiator cap off. Blip the throttle a few time while doing this, adding coolant as the level drops. Once it's hot, cap it & let cool completely. Check again when cool & top off if necessary. Don't forget to put some in the overflow container on the left side~ Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted July 17, 2014 Member Contributer Share Posted July 17, 2014 And for giggles I shake my bike side to side on the center stand . Its helps get the bubbles to the top of the rad. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 And for giggles I shake my bike side to side on the center stand . Its helps get the bubbles to the top of the rad. All of this with the bike running and the cap off? Link to comment Share on other sites More sharing options...
Member Contributer Sparrow75 Posted July 17, 2014 Member Contributer Share Posted July 17, 2014 Didn't have a chance to get to the t-stat last night, but I did replace the spark plugs. Made a fair difference in how the bike runs. Don't know when they were last replaced, but the ones I pulled were ugly. I'll probably get to the t-stat this weekend. What do you guys think about the lean symptoms? Basically when I shift, the RPM's are slow to drop. They stay about where I revved to until I complete the shift. In my 70's bikes I'd adjust the air mixture screw, and if that didn't do I'd clean and consider rejetting the carbs. On this bike it appears that there isn't a air screw. So should I just pull the carbs, or is there something else I should be looking at? Treitz, this is what I would suggest you try, If your carbs ain't synced then one or two will keep pulling a fast idle. First check your carb-engine rubber boots for tightness and cracks with some solvent like carb cleaner. Then see if there are any gas leaking near the carb needle covers (some residue on mine suggested the diaphram wasn't sealed tight and gas was leaking out). Then sync the carbs to the #4 carb (the one you can't adjust). The three screws for the carbs are tricky to reach ( I use a 7mm long crescent wrench). The idle adjust screw is between the front two carbs. (reaching in between the hot engine and carbs is a real pain in the ... hand.) Turn down idle speed after synced. Then start removing things if you feel the problem is internal somewhere. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Didn't have a chance to get to the t-stat last night, but I did replace the spark plugs. Made a fair difference in how the bike runs. Don't know when they were last replaced, but the ones I pulled were ugly. I'll probably get to the t-stat this weekend. What do you guys think about the lean symptoms? Basically when I shift, the RPM's are slow to drop. They stay about where I revved to until I complete the shift. In my 70's bikes I'd adjust the air mixture screw, and if that didn't do I'd clean and consider rejetting the carbs. On this bike it appears that there isn't a air screw. So should I just pull the carbs, or is there something else I should be looking at? Treitz, this is what I would suggest you try, If your carbs ain't synced then one or two will keep pulling a fast idle. First check your carb-engine rubber boots for tightness and cracks with some solvent like carb cleaner. Then see if there are any gas leaking near the carb needle covers (some residue on mine suggested the diaphram wasn't sealed tight and gas was leaking out). Then sync the carbs to the #4 carb (the one you can't adjust). The three screws for the carbs are tricky to reach ( I use a 7mm long crescent wrench). The idle adjust screw is between the front two carbs. (reaching in between the hot engine and carbs is a real pain in the ... hand.) Turn down idle speed after synced. Then start removing things if you feel the problem is internal somewhere. Good advice. I will do all of the above. Sometimes with a unfamiliar bike you forget all of the things that you know how to do that will translate directly from one bike to the other. I have a carb syncing tool, so I have no reason not to sync them. I imagine they have vacuum nipples somewhere near the top so I have to remove the tank first? Link to comment Share on other sites More sharing options...
Member Contributer Sparrow75 Posted July 17, 2014 Member Contributer Share Posted July 17, 2014 Yep. Syncing is relatively easy. So sitting on the bike, front two cylinders (left-right) are 2-4, and back two are 1-3, if I recall correctly. The #3 vacuum port screw is behind the thermostat housing. You can reach the screw with a long screw driver, and need a longish sync extension tube to get to it. I made my own, but I think there are ones for sale that are long enough. The rest are easy to get to, and no tank/fairing removal is required. It is well explained in the factory manual. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Yep. Syncing is relatively easy. So sitting on the bike, front two cylinders (left-right) are 2-4, and back two are 1-3, if I recall correctly. The #3 vacuum port screw is behind the thermostat housing. You can reach the screw with a long screw driver, and need a longish sync extension tube to get to it. I made my own, but I think there are ones for sale that are long enough. The rest are easy to get to, and no tank/fairing removal is required. It is well explained in the factory manual. Right on. I need to track down a factory manual for it. You're saying you can actually sync it with the tank on!? Link to comment Share on other sites More sharing options...
Member Contributer Sparrow75 Posted July 17, 2014 Member Contributer Share Posted July 17, 2014 Yep. You can see the phillips screw heads near the bottom of each carb. There is a washer on each screw. Use medium Locktite to secure. I will see if I have an electronic version of the manual to send you. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Yep. You can see the phillips screw heads near the bottom of each carb. There is a washer on each screw. Use medium Locktite to secure. I will see if I have an electronic version of the manual to send you. That would be fantastic. Thanks for the help sir! Link to comment Share on other sites More sharing options...
marriedman Posted July 17, 2014 Share Posted July 17, 2014 treitz - sorry man, I was being lazy and should have been clearer. TNRabbit explained it perfectly though. Link to comment Share on other sites More sharing options...
donnykaboom Posted July 17, 2014 Share Posted July 17, 2014 After riding this bike for 1 day there are a few things I need to address. This being my first EVER liquid cooled bike, I'm not sure where to start. Issue Number 1 Bike appears to be running lean when cold and warm. Rev won't come down quickly especially when shifting. On my air cooled bikes I would just adjust the air screw and it would help. However on this bike I don't see any air adjustment screws on the carbs. Is there something else I should be looking for? If not I may just need to clean the carbs out. Issue Number 2 Bike overheated a bit today. First place to start would probably be the thermostat. Right? I imagine it hasn't been replaced in a really long time, if ever. Thanks in advance for any input! try lubricating the throttle cable, cables? Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 After thinking about it, I think it may be a air leak in the carb boots actually because it changes how it acts based on the RPM. At higher RPM it is slower to come down. At lower RPM, like 3K or lower it drops much faster. Making me think that the higher pressure at higher RPM is bring in more air, leaning the system out. Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted July 17, 2014 Share Posted July 17, 2014 Rad cap could be pooched and not holding pressure. That can cause puking. Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2014 Share Posted July 17, 2014 Tried burping the system and I think there could be 2 issues. Themrostat &/OR fans. I ran the bike to running temp with the cap off. Once the coolant level dropped I added more coolant. Did this successfully about 3 times. Then the bike kept getting hotter, and hotter until it just started pouring all of the coolant out of the radiator (open cap). Bike was at about 50% on the gauge. The fans never came on. Thoughts? Link to comment Share on other sites More sharing options...
TNRabbit Posted July 18, 2014 Share Posted July 18, 2014 You can short the fan to ground to test if it works. Otherwise I'd guess a bad temp sensor. Link to comment Share on other sites More sharing options...
Guest Posted July 18, 2014 Share Posted July 18, 2014 You can short the fan to ground to test if it works. Otherwise I'd guess a bad temp sensor. Considering the burping was working until it overheated, would it be safe to assume that the t-stat actually does not need replaced? I would assume it was opening because as the engine got warmer the fluid would go down. My guess is the lack of fan made the engine heat up too fast for the t-stat to keep up? Link to comment Share on other sites More sharing options...
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