xlt1200 carb settings for sbt engine

[mfromm]

I installed a 1200pv SBT engine in my 2001 XLT1200 and need help with the initial carb settings. Engine has not been started yet.

The previous engine had heavy piston scoring in cylinders 1 & 2 and crank bearing failure in the bearing between 1 & 2. (i bought it cheap in this non running condition). Presumably the engine failed due to lack of oil or running too lean.

I have switched to pre-mix (1:32) and removed the oil pump to minimize the chance of not enough oil getting to the engine.

The carbs had popoff pressures of 1 (75#), 2 (75#), 3 (100#) with a 1.2 needle/seat. I would like to switch to the 1.5 needle/seat for a popoff of 55#.

What initial low speed and high speed settings should the screw adjusters be? The manual says the carbs should be SBN44 but the local Yamaha dealer says a 2001 XLT1200 would be BN46i carbs. I can't tell the difference other than they match the Yamaha manual pictures.

Is it possible to adjust the carbs in the craft? The exhaust system is huge and blocks easy access to the carbs.

Thanks

[Technical Support]

Re: xlt1200 carb settings for sbt engine

You do not have carb adjustments stock, unless you have modified the carbs. They are I body taper bore 46-44mm, they take a special Yamaha I body rebuild kit. No adjustment is needed for pre-mix. Dropping pop-off with the 1.5 would make no difference on a stock ski. If you suspect it ran lean, test/change the needle & seats with the stock part, and rebuild the carbs, that's it.

[sgearhart]

Re: xlt1200 carb settings for sbt engine

I have this ski, same motor, do I have different Carbs? Mine have High and Low adjustment screws on the side? I was going to buy the EZ-tune screws from RIVA (t-screws) to try and make it easier to adjust without tearing them down.

[Technical Support]

Re: xlt1200 carb settings for sbt engine

I dont belive you have a power valved motor, do you?

[sgearhart]

Re: xlt1200 carb settings for sbt engine

If you were referencing me, I most definitly do have a powervalve motor, at least that was the given reason for failure, and I bought a 1200pv motor from SBT to replace it. I thought 2000 and under had non-pv's, and 2001 and up had pv's. I think from what I read, the company made a crossover mid-model or something, because some people say they have 2001's, and don't have pv motors, and some others that have 2001's say they do. I'm positive mine does though.

[Technical Support]

Re: xlt1200 carb settings for sbt engine

The 1200r motor had carbs with fixed setting from the factory, the adjuster screws are blocked off with caps. If they are removed they should be set at 1-1/8 out on all lows. Highs set at MAG cyl 1-1/4 CTR cyl 1-1/4 PTO cyl 1-1/2.