jasonp
Well-Known Member
Well went riding this weekend. As you can see the mod list below for my engine that I've been working on all winter and finally got it back together. It's back appart now and I'll tell you why.
First, I got to learn more then I thought I knew about engines and it seems like every engine I do makes me more confident on the next one.
The weekend went, well fourwheeler ran ok. I jetted it really rich on the top end for the first tank of gas. I got the low side correct in my garage and found that it wouldn't idle very good. Even when I had it dialed in just right... I found that weird. I didn't think much of it just ran the idle up a little higher then previous thinking the cam had a little to much overlap to idle down with the lightend flywheel. After about of half an hour of checking for leaks making sure I had oil and breaking in the cam I took it out for a spin, got on it a little... Didn't seem like it had all that much more then stock. I was a little dissapointed but figured it was jetting.
Well after the first tank of gas I thought now was a good time to lean it out some and see if I could get some more power. I went down a couple sizes right away on the main, as it wouldn't even rev up past 1/2 to 3/4 rpm. Took it out and man, what a difference. Really woke it up and I'm still out a couple sizes. I was very happy. I left it alone as I was having trouble with keeping a smooth idle and the bike just wanted to kill right off idle. It was almost back firing through the carb and it was running really rich on the low side. Also when it would kill or I'd stall it, the bike would die and almost run backwards. ******* degree key advanced the timing to much. So right now I had to bring it home and put the stock key back in. I'm really dissapointed. Ah well. I thought I would be able to get away with it as I'm running a little lower compression but I should have known when I started to lower the deck height to get .040" that I was also making my combustion more efficient so I need less spark advance because I was actually speeding up my point of peak pressure and point of burn. Anyway so it went well, I'm suprised that it wasn't detonating or pre combusting. I took the plug out and it running rich but no signs. I give it up to duncan racing for really smoothing out the combustion chamber.
So I'm happy there is a more left in the motor and can't wait to get it back together again and start to really get this thing tuned it right. Amazing how just a little jet change effects power. I would also like to say that I ride in the woods and I'm really thankfull that we have FAQ around with the oil cooler setup. It was about 65 degrees out and the oil cooler was crazy hot. I was happy as it was doing it's job.
The cam is actually a little to big for what I was doing today. I actually wish I would have went with Megacycle mid range cam as it has a little less overlap and duration and give me even more torque on the bottom end. I love that pull right off of idle... This cam does it but it hits more something mean right in the middle of the rpm band. I was finding myself wheeling all the way up steep hills where I started right at the bottom. I was impressed.
Anyway this is getting long.
Happy modding.
First, I got to learn more then I thought I knew about engines and it seems like every engine I do makes me more confident on the next one.
The weekend went, well fourwheeler ran ok. I jetted it really rich on the top end for the first tank of gas. I got the low side correct in my garage and found that it wouldn't idle very good. Even when I had it dialed in just right... I found that weird. I didn't think much of it just ran the idle up a little higher then previous thinking the cam had a little to much overlap to idle down with the lightend flywheel. After about of half an hour of checking for leaks making sure I had oil and breaking in the cam I took it out for a spin, got on it a little... Didn't seem like it had all that much more then stock. I was a little dissapointed but figured it was jetting.
Well after the first tank of gas I thought now was a good time to lean it out some and see if I could get some more power. I went down a couple sizes right away on the main, as it wouldn't even rev up past 1/2 to 3/4 rpm. Took it out and man, what a difference. Really woke it up and I'm still out a couple sizes. I was very happy. I left it alone as I was having trouble with keeping a smooth idle and the bike just wanted to kill right off idle. It was almost back firing through the carb and it was running really rich on the low side. Also when it would kill or I'd stall it, the bike would die and almost run backwards. ******* degree key advanced the timing to much. So right now I had to bring it home and put the stock key back in. I'm really dissapointed. Ah well. I thought I would be able to get away with it as I'm running a little lower compression but I should have known when I started to lower the deck height to get .040" that I was also making my combustion more efficient so I need less spark advance because I was actually speeding up my point of peak pressure and point of burn. Anyway so it went well, I'm suprised that it wasn't detonating or pre combusting. I took the plug out and it running rich but no signs. I give it up to duncan racing for really smoothing out the combustion chamber.
So I'm happy there is a more left in the motor and can't wait to get it back together again and start to really get this thing tuned it right. Amazing how just a little jet change effects power. I would also like to say that I ride in the woods and I'm really thankfull that we have FAQ around with the oil cooler setup. It was about 65 degrees out and the oil cooler was crazy hot. I was happy as it was doing it's job.
The cam is actually a little to big for what I was doing today. I actually wish I would have went with Megacycle mid range cam as it has a little less overlap and duration and give me even more torque on the bottom end. I love that pull right off of idle... This cam does it but it hits more something mean right in the middle of the rpm band. I was finding myself wheeling all the way up steep hills where I started right at the bottom. I was impressed.
Anyway this is getting long.
Happy modding.
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