I’m looking at upgrading from my 95sn, that has had nothing but issues since bought, and found a 99rn for sale that looks to have some engine mods. The kid selling is second owner and doesn’t know what it has done. Looks like air intake, pipe, head, am I missing anything? I am fairly new to these. What should compression be with it being aftermarket?
What Engine mods have been done?
- Thread starter EricM
- Start date
mgander17
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- Location
- Lemoore, CA
Head looks to be stock, which would be 150 psi on the compression, however, if it is milled, they usually get bumped up to 180-185 psi
Compression depends on the domes for am heads. That head is the stock head and I don't think it has been cut to raise the compression. That person would have installed double cooling on the head and manifold or at least I would have. Compression should be around 150psi where the absolute reading is relative the difference between the two cylinders should not be more than 10%.
No not at all. As far as I know there are other factor that play a much bigger role for longevity of the engine like water ingestion while riding and water in the waterbox making its way up to the engine while sitting for a long time and not being cleared out. When riding saltwater flushing is important...