Gas Gas FSE/FSR 450 engine longevity/mileage

[mekket]

I was wondering about the mileage/hours people are getting out of their 450s. I use mine as a supermoto mainly for city riding. A friend riding behind me noticed blue/white smoke coming from the exhaust on harder accelerations. I let him ride my bike and sure enough it smokes. I use 10w40 and I put in exactly 1 liter every oil change(this should be correct for my bikes year). I usually change the oil every 30h/1000 km but I noticed that the oil pressure light starts flickering at around 700 km into the oil change indicating lower oil level. This sort of oil consumption does not seem right to me. The piston is a Wossner piston and has been in the bike for ~4000 km/113 h. Is it time for a change already? I was taking reference from DRZ400 guys and some of them are doing double or triple mileage on one piston.

Bike has ~11500 km/280 h on it total. Valve seals were done at ~6500 km/120h

Is this a normal time for piston/rings to wear out when doing mainly city riding? No high rpms for extended periods.
At what point should I think about changing the crank/bearings? Hoping for some input from others that are still using this old bike and have experience with maintaining and keeping the bikes running so for example piston/ring lifespan etc.

Also interested in seeing who has the highest mileage/hours on their FSE/FSR 450.

 

[SS109]

Bike has ~11500 km/280 h on it total. Valve seals were done at ~6500 km/120h

Is this a normal time for piston/rings to wear out when doing mainly city riding? No high rpms for extended periods.
At what point should I think about changing the crank/bearings? Hoping for some input from others that are still using this old bike and have experience with maintaining and keeping the bikes running so for example piston/ring lifespan etc.

I would first like to say that these bikes weren't designed to be street driven bikes and were actual high performance engines unlike any DRZ400 ever made. They are two totally different kind of machines. That said, it seems like you might have, possibly, answered your own question in that first line.

"Bike has ~11500 km/280 h on it total. Valve seals were done at ~6500 km/120h"

The total hours are over twice as long as the first time you replaced them. Seems an awfully short service life to me but I'm not real familiar with the engines they were using so maybe that's normal.

Of course, your 30 hours between oil changes could be the real issue. 30 hours between oils changes is a really long time IMO. I would probably be changing the oil every 10 hours (some think I'm crazy for going that long!) if it was mine. On the piston, the same things apply to it being a high performance engine. Cast pistons don't last that long and should be swapped out around 100 hours. I prefer forged pistons as I can get twice as many hours easily. I only change them out when I start to see some compression loss. I wouldn't worry too much on the bottom end hours. You literally could see a 1000+ hours with no worries. Just check all bearings for being within spec when you do a top end and run it!

 

[mekket]

I do understand that the bikes are designed for off-road use and not street use. As far as I know the engine is very similar to DRZ 400. The cylinder head might even be a 1:1 replacement and I think someone on this forum actually used a DRZ cylinder, piston and cylinder head. Thats why I was comparing it to a DRZ 400. GasGas manual does not specify a service interval for valve seals I think. I just did them at that time because I was already fixing an issue with valves. The Valve seals I put in are actually from a DRZ400 because GG parts were not available. The 30h oil change might seem crazy but that is actually the service interval from the manual. I really think that street riding compared to trail/track is not as hard on the engine. Most of the time my bike is between 3 and 4 k RPMs, there really isn't too much dirt that can cause issues with air filter etc. I was hoping to get some input from users that are using this bike and how much time are they getting out of their engine components, do they have to add oil between their(however long) oil service intervals and so on. I will most probably be taking the engine apart over the winter and measuring everything but maybe someone can share their experiences for my future knowledge.

 

[SS109]

Oh, yes, I forgot that those early 4T engines were basically a DRZ clone. Sorry about that. Sadly, not many people have experience with those bikes. The 2T were sold in very small numbers and the 4T bikes even less.

Things you can do before disassembling anything is to do a compression and/or leak down test(s) on it to see what kind of condition the engine is in. It might help get you moving in the right direction.