XL1200 boggs bad on accelleration

[SoCalMike]

Well...I will tell the whole story...in short form. The ski is used for tow-in surfing. It sucked a plastic bag up in the intake while at Todos Santos (while trying to get out of the impact zone) and ended up getting pounded on the rocks in 20 ft+ surf. 80+ hours later and lots of fiberglass and bondo and the exterior is back to new. however it had flooded quite a bit and I when I got it home there was water in the cylinders. got it all out and got it started. added a water trapper to the fuel and some carb cleaner as well. ran it for a while in the driveway. Took it out today for first time since crash - it boggs down horribly on acceleration - to the point where it will die. It idles perfect and full throttle is great. Seems to me like the needle/seat got corroded cause idle and main jets seem to be okay. I have been riding dirt bikes my whole life, and done many engine/carb rebuilds - so not worried about that. I just don’t want to dive into it, and have it be something simpler like water-sogged fuel filter or something. This site has helped a lot already...thanks everyone who contributes and I hope I can help out too!!!

Mike

[dank]

Re: XL1200 boggs bad on accelleration

Do a compression check first after that much water ingestion. Next drain all fluids and start fresh. If it still boggs bad then don't ride it like that you may burn a piston. Pull the carbs you may have water inside. The only way to get it out is to take the apart since the low speed jets are so small they will trap the water inside the float chamber.

[1fastski.com]

Re: XL1200 boggs bad on accelleration

check your oil and fuel tanks for water for sure . clean out the carbs . if your compression check is good you should be ok after the carb cleaning . keep in mind you might have crank damage if you only ran on a hose after it was sunk . it takes a lot to dry a crank whenever possable a sunk motor should be run on the water for 30 min or more asap .

[SoCalMike]

Re: XL1200 boggs bad on accelleration

Thanks for the quick response guys. I will do a compression check today. I wish I had been able to run it on the water - but the entire steering column had busted off from being on the rocks - couldnt do anything until that and the hull were fixed. It was run (on a hose) for over an hour and a half, with occasional slow revving to try and make sure i was pulling junk through all of the jets (sounds like that didnt work). It was also ran 4 or 5 more times after that on a hose before i took it out. I will start tearing into the carbs. I think I helped it somewhat because I used enough wd-40 inside the cylinders to kill a small army. One other thing I had forgot to mention was that when it is bogging down if you just pull the choke maybe 1/4" out really quick (a short burst) then it accellerates like a madman - which was a good sign to me that it is purely a mixture problem. I will keep everyone posted on my findings - and am sure I will have a few more questions along the way. Thanks again!!!

Mike

[ScottD]

Re: XL1200 boggs bad on accelleration

Its possible that you damaged the bearings in the drivetrain and they are trying to sieze.1 1/2 hours on the hose is not recomended.I think that its a carb isue but I would look at the bearings.There is a grease fitting and if the bearings are good I would give it a healthy shot of grease.
SCOTT...

[SoCalMike]

Re: XL1200 boggs bad on accelleration

I was going to purchase carb re-build kits today, along with new needles and seats from Riva. I believe i read somewhere the stock needles were 1.5's. I know the carbs are Super BN's 44mm - but are the the I version? There is a different kit for the Super BN and Super BN-I. Thanks again guys. I will be tearing into it tonight, also got a D-Plate and PV clips to put on it. This is a little off my normal topic - but I am sure you have much more experience. Since this is used in whitewater most of the time hooking up can be a real problem in the highly aerated water, would the RIVA intake plate or a different impeller make a difference in helping it hook up in this situation. Thanks again guys.

Mike

[Technical Support]

Re: XL1200 boggs bad on accelleration

N&S are all the same for all SBN series carbs.

[SoCalMike]

Re: XL1200 boggs bad on accelleration

Thanks! The re-build kits are diff though - so i am still unsure. Great place you got here - i have learned more in 1 day then i ever thought possible. If theres anything wrong with the engine beyond carb problems I can assure you have a loyal customer here.

Mike

[Bill O'Neal2]

Re: XL1200 boggs bad on accelleration

You need SBN 44 rebuild kits, 1.5 needles and seats.

[dank]

Re: XL1200 boggs bad on accelleration

Send you carbs to these guys for a rebuild and modify them to get rid of the lean spot in the mid range. They did a great job for me.
http://www.islandracing.net/pages/792736/index.htm

[SoCalMike]

Re: XL1200 boggs bad on accelleration

dank...thanks for the advice...but jsut a few hours too late. Already order the rebuild kits, D-plate, CAT-CON chip from Riva. I am tearing into it right now, stuff will be here tomorrow and hopefully have it back together tomorrow night or saturday. Thanks again for all the help guys. I will let you know what the outcome is. Also I will post some pics of the repairs i did on this thing. God knows getting slammed on the rocks in 20+ foot waves does not do good things to a ski.

[SoCalMike]

Re: XL1200 boggs bad on accelleration

Well we tore into it last night and got the carbs off. CAT-CON was toast too, good thing we had taken everyones advice before hand and ordered the d-plate. What a horrible design by yamaha. And getting that rear exhaust section out is such a pain, you have to rotate and flip that thing jussssttt right to get it out. If the opening was like 1/4" bigger it would be a piece of cake. Carb kits should be here in the AM and will work on them when I get off work at noon. The only thing is I dont have a pop-off gauge so i will have to take them to the local ski place or dealer and have them check it - not a big deal though.

From what I have read there is a chance that the crank was toasted from the water ingestion. It seemed to run fine when i tested it (except for the misture problems. If you turn the impeller shaft it is nice and smooth - so seems that bearings are still good. Compression check read okay too. Heres the question though - would it do any good to pull the reed cages off and try to look in the case with an inspection mirror and flashlight, or even a video camera hooked to a TV. I doubt I would be able to see any indication as to if the crank is jacked, but thought I would ask your opinion. Once again thanks for all the help. Hope everyone has a great weekend.

Mike

p.s. - anyone know off hand what the pop-off pressure is supposed to be?

heres a shot of me from the day the ski went on the rocks.

[Bill O'Neal2]

Re: XL1200 boggs bad on accelleration

There are two issues associated with crankshafts and water injestion. One is rusting bearings, the other involves the indexing of the three rod journals. Each journal needs to be exactly 120 degrees apart in their rotation of a 360 cycle. Injested water in the clyinders can try to be compressed when trying to start the motor. Water does not compress, so it can force the crankshaft to twist slightly. 3 clyinder motors are very susecptable to twisting, because the cranks are longer and have more pressed joints in them. If slightly twisted, it will run very rough. If really twisted alot, it won't run or run and backfire alot.

To check crank indexing is fairly simple. You can put the center clyinder at TDC and both end pistons should be exactly the same depth in their bores. Removing the reeds should give you a decent view of the crankshaft rods, but not the rod and main bearings.

[SoCalMike]

Re: XL1200 boggs bad on accelleration

Thanks so much bill. I can rule out indexing because It was never cranked until after i had been home and pulled the plugs - I knew there was water in and around the carbs and was trying to not suck it in the engine as much as possible. I will pull the reeds and take a look, but might end up just pulling the engine since most of the time-consuming work has already been done to get at the carbs. Another thing I forgot to mention is this crazy thing I did to get water out of the engine. I tooke the plugs out and cranked it - water shot out - but just spray - not a stream. So I took my wet/dry shop vac and put it over the hole for the plug and let it suck while i cranked the engine. I did this on all 3 cylinders until there was absolutely nothing comming out of the plug holes. I would periodically spray gobbs of wd-40 in the cylinders as well. I am hoping that this helped my cause. After I got the cylinders dry, i put 3 drops of gas in each one and put plugs in it. It started on the first crank of the engine. Okay so that aside

ANYONE KNOW STOCK POP-OFF PRESSURE FOR THESE CARBS???

Thanks again guys!!!

[SoCalMike]

Re: XL1200 boggs bad on accelleration

Okay, well the rebuild kit only came with one spring - and its gold like the original - so i guess choosing the right one wont be a problem. As far as the condition of the carbs - there was enough salt in there to flavor a dinner for 4. I took some pics of the build-up and will post them. checked the compression again - it was 110,110,105 front to back - came up exactly the same through 3 tests. Seems to be in specs from what i hear. Reed valves look beautiful, but there is a little bit of rust on the metal parts above the petals - which makes me wonder about the crank. I sprayed a ton of fogging oil in through the holes where the reeds were and in the cylinders, it cranks really smooth and quiet - turned the shaft by hand it is feels great. Going to shine a flashlight and video camera in there tomorrow to check things out. Checked the index with the shaft part of a digital caliper - came out perfect. Thanks again for all the help guys - pics and news tomorrow.

Mike