2005 750 Brute Force motor swap to 03' Prairie 650?

[suprasonic]

Would a 05' 750 Brute Force motor fit in 03' Prairie 650 with no modification?

[RCW]

Depends on what you consider modifications. Physically you can exchange the engine/transmission unit, but it will not run without the wiring harness, control electronics, and fuel system from the Brute Force.

If you know what you are doing you can make it work. If not, you will be spending far more money for an engine that is not as good as what you have.

[suprasonic]

Depends on what you consider modifications. Physically you can exchange the engine/transmission unit, but it will not run without the wiring harness, control electronics, and fuel system from the Brute Force.

If you know what you are doing you can make it work. If not, you will be spending far more money for an engine that is not as good as what you have.

Thanks, I got this bike as a parts bike that is in good shape. Everything works except the motor. I was told it will need a rebuild because it smokes and the timing chain was taken off for some reason and is still off. Do you have any idea on how much a rebuild cost? Thanks.

[RCW]

There is no practical way to estimate the cost to rebuild the engine without disassembling it and determining the parts needing replacement and the extent of any damage done to the engine.

Do the work yourself, and simple timing chain, pistons, rings, and gaskets needed to refurbish an otherwise good engine will only be a few hundred dollars. If the cylinders or valves are damaged the cost will go up considerably. Tools will be extra.

I never trust someone's assessment of what an engine needs, but do the diagnostic work to ascertain what is really required. When they are missing the timing chain and not running, the best bet is a complete engine disassembly and inspection. Not at all difficult if you have a good repair manual at hand and follow the instructions.

I have seen a number of the 650's come in with smoking engines and the whole problem is nothing more than carbon built up in the cylinders and frozen rings. That is caused by old fuel (by old anything more than a few weeks old causes problems because of the alcohol in the gasoline), from poor tuning, missed maintenance, and operator induced issues. Those sometimes can be cleared with chemical carbon cleaning, but some require a gasket kit, and careful disassembly and reassembly with new rings after the head, valves, pistons are cleaned.

The larger later model engine is almost always in need of cylinders as well as pistons and rings when they begin to get a bit weak. That is because the engine runs way too lean and 99% of the owners do not understand that the OEM EPA tuning on the larger displacement engine is a sure fire way to cook them when they ride them hard, and they do not properly jet them so they will live.

The unfortunate reality is that these higher powered ATV's appeal to guys that really cannot afford them, so they buy them on contract, and do not have the money to properly tune and maintain them. They cook them, lose interest, then dump them on someone else after they set for a few years collecting dust.

[cookie_monster]

If you can fix the 650 engine, do it. The 750, although based upon the 650's basic design, is a pile of scrap, IMO. You never see a 650 with issues other than user-related issues (sinking, dirty air filters, lack of maintenance) but the 750, on the other hand, seems to break itself on a (more or less) continual basis in these parts. We, as technicians, love the 750's because we get to work on them more than any other single model, kawasaki, yamaha, honda or suzuki (and if you want to include the power equipment, JD, Kubota, Bad Boy and others too).