Hi,
I recently bought a 2009 Yamaha Banshee. Actually it's a model 2006 that has been new in a crate until 2009. I bought it from the first owner who didn't ride it much. The quad looks almost new. When I went for a test drive it was hard to start. The seller said it usually starts the first time (looked honest to me) but it has been sitting in the garage for a while and he cleaned it. The test drive was fine so I bought it.
The quad is completely stock except for Toomey T6 full pipeset and I got the remainders of a jetkit, it has 280 mainjet in it. It is still on the original pistons never been opened.
Last owner always mixes 1:30 I have improved the oil quality and went to 1:39 on the first tank.
At home it was hard to start again. Like 30 kicks. I don't have a lot of Banshee experience but it feels easy/light to kick it over. After some fiddling with the cabling, choke and reserve it started right up. It idles well, left it for 10 minutes without the choke just idling. I rode for 40 kilometers without any issues. No bottom end but it when it gets into the rpm's it pulls strong, front wheels off the ground and you can feel it pulling in your arms. There is no sputtering just accelerates really well up until about 120kmh. I also have a Raptor 700 and a V-Force 700 that should be about equally fast and it feels like that. Doesn't feel like I am missing power (only in low and mid but the Toomey seems to do that).
After I got back I checked the plugs, they were nice porcelain coffee with milk with a little bit of fresh oil around the edge of the plug.
While the bike was cooling down I changed the transmission oil. The day before I already had changed the coolant. After changing the oil I did a compression test;
Ignition off
Unplugged both sparkplugs
One plug out, connected compression test (screwed it in, finger tight), left other plug in to avoid sucking in dirt
While full throttle kicked around 15 times
The compression test went straight to 60psi but it does not get higher. Same reading in both cilinders.
Put some oil in the hole, did not do anything to the result.
Also tried with fuel on and off.
I repeated this test a few times also after starting the engine and letting it idle with some revs for around 10 minutes so the engine was warm. Always 60 or just below 60 psi.
Since I saw in this forum I should have 120 plus and often compression test sets are rubbish I connected the tester to a compressor. Let it go all the way up to 120psi and the compression tester shows the same value as the meter that is built into the compressor. So the meter should be fine as it gets above 60psi.
Next day the quad started on the first kick. I cleaned all contacts (I had some ground issues with the turn signals and also with the trailtech) there was some corrosion. I also cleaned the contacts for the ignition coil. The day after the Banshee needed 10 kicks to come to life.
Now I am cleaning the air filter and the reeds+carbs are next.
So summed up;
- Starting is sometimes hard sometimes easy
- Idles good, jetting looks right, runs well
- Compression appears to be very low. How can the quad run this well when the compression is only 60psi?
Any suggestions?
I am not eager to open it up since it runs well when I get it started but don't want to blow my engine.