224 help!!
- Thread starter kart74
- Start date
If you assembled you engines correctly they should be making the most power starting around 4K to 6K yet you are flattening out at 5K and both motors act identical? Did you check any of the folowing, lift at the valve, rocker geometry? Fixed fulcrum rokers require setting valve side geometry first then pushrod side. The stamped champions have the adjuster at the valve is that correct? If so that gives you the ability to set valve side geometry by using the adjuster to set the rocker perpendicular to the valve stem at mid lift. Once that is set then you can measure what length pushrod is required. What pushrods did you use?
Just been minding my business, reading along. Can I make an uneducated simple common sense suggestion? Since you have two bikes, why not put a bigger sprocket on the tire of one of them and see which one is faster? Seem to me like everybody is studying the geometry inside the valvetrain, when I think you all suspect the rear sprocket is too small. Let it spin!
Just my 2 cents worth. Have fun and be safe.
Just my 2 cents worth. Have fun and be safe.
Didn't he already do that? He said he dropped a tooth on the driven from 10 teeth to 9 teeth. I asked about the difference and never got a very specific answer but he said it max rpm didnt change much. . Kind of a non answer. People need to give good details to get a accurate analysis. However a 9tooth and a 55 rear is over 6 to 1 so I would expect it to pull a load higher that 5K rpm unles he is 300+ pounds
Sorry forgot to check this yesterday. Both motors are out and I am going to check all of the valve train suggestions here. Those are the rockers I used. They have stock length chromoly pushrods. Last night we went to local flat track races and there is a huge mini bike group. Talked to many of them as well. A few common things... Almost all use a 7 inch driven clutch with the juggernaut primary. Second most have 60-75 rear sprockets with a 10 up front. They running taller tires but still. I do have a 60 rear on the shelf so may try that as well. I will post back with what I find in the valve train and go from there. Thanks everyone for the help.
Ok both motors torn apart. What I left out in the beging was that one of them was worse than the other. Well that one rounded off the exhaust cam lobe! So will be calling dyno tomorrow. Other one measures out just fine. The rocker geometry looks good. The spring height was .880 on intake and .900 on exhaust so will be ordering shims. What pcv valve are you using? I will get the baffle in the cover removed and add them. On the bike that the motor isn't damaged I am going to try gearing and possibly the 7 inch driven clutch.
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Those shims will definitely help.
I havnt lost a lobe in some time now. I find the 1st 30 mins of run time is the most important when breaking in a cam.
I use straight 30 weight oil, keep rpms above 2500, and alot of up and down throttle, not letting it sit at a steady rpm very long. Change the oil the 1st hr. Let it sit over night, go around and check at bolt torque specs, valve lash, and run it another hr. Change oil and do it all again, til bolts stay tight, and valve lash stays. I usally have an engine on the stand for 3-4 days before mounting it to the mini bike.
Heres the 1 way check valves I use. Keep em high and away from the valve cover. No need for a catch can, but a filter at the end will help keep dirt out.
https://www.ebay.com/itm/2-Pcs-12mm...p4429486.m46890.l6249&mkrid=711-127632-2357-0
I havnt lost a lobe in some time now. I find the 1st 30 mins of run time is the most important when breaking in a cam.
I use straight 30 weight oil, keep rpms above 2500, and alot of up and down throttle, not letting it sit at a steady rpm very long. Change the oil the 1st hr. Let it sit over night, go around and check at bolt torque specs, valve lash, and run it another hr. Change oil and do it all again, til bolts stay tight, and valve lash stays. I usally have an engine on the stand for 3-4 days before mounting it to the mini bike.
Heres the 1 way check valves I use. Keep em high and away from the valve cover. No need for a catch can, but a filter at the end will help keep dirt out.
https://www.ebay.com/itm/2-Pcs-12mm...p4429486.m46890.l6249&mkrid=711-127632-2357-0
Magnetic oil drain plugs are a good investment.
These engines where built last September. Had at least 3 oil changes on the test stand during the break in period. The oil gets changed every 10-15 hrs of run time, then is usally brown.
I use mobile 1 10w30 full synthetic after break in. Has not had any bolts come loose or valve adjustment needed.
I 'll be pulling em back off and checking piston, rings and cylinder wear probably this coming September.
As you can see, there's still plenty of metal coming out.
The ducar 212 has the CM cam with 26# springs, and .280" lift at the retainer.
It's gov'ed at 5400 rpm, but gets there fast and hard with 3600 rpm engagement springs and 4.54:1 gear.
These engines where built last September. Had at least 3 oil changes on the test stand during the break in period. The oil gets changed every 10-15 hrs of run time, then is usally brown.
I use mobile 1 10w30 full synthetic after break in. Has not had any bolts come loose or valve adjustment needed.
I 'll be pulling em back off and checking piston, rings and cylinder wear probably this coming September.
As you can see, there's still plenty of metal coming out.
The ducar 212 has the CM cam with 26# springs, and .280" lift at the retainer.
It's gov'ed at 5400 rpm, but gets there fast and hard with 3600 rpm engagement springs and 4.54:1 gear.
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Thank you. Ordered. Break in was done on both as you described with the addition of a zinc additive. I have hot rods with flat tappet cams and is needed there so figured it couldn't hurt. Both have magnetic plugs. They always have metal on them. The one that the cam was fine had a layer of black metal sludge in the bottom of the case. We have changed oil almost after every day of riding. So not sure.
@kart74
Here's something we found testing with a dial back timing light.
I dont know if you are aware, but the stock coils will pull timing out at higher rpm.
We tested probably 10 or so stock coils. All of them started pulling timing out in the 4k-5k rpm. Some as much as 8* at 6000 rpm.
These were tested with the ngk bp9es and autolite 3910x plugs.
ARC, PVL, and the tilly 212r cast aluminum flywheels.
Coil air gaps set at .045"-.075".
Timing set 28-30*
We tested 3 dover power coils, and they only pulled 1-2 degrees at 6000 rpm.
A noticeable improvement in 0-600 ft testing.
We only tested them with non-resistor plugs. We didn't have any resistor plugs for testing.
I wouldn't recommend something I havnt tested and use myself.
I won't be using any other ignition coils.
http://www.doverpoweronlinestore.com/catalog/item/9100750/10483555.htm
Here's something we found testing with a dial back timing light.
I dont know if you are aware, but the stock coils will pull timing out at higher rpm.
We tested probably 10 or so stock coils. All of them started pulling timing out in the 4k-5k rpm. Some as much as 8* at 6000 rpm.
These were tested with the ngk bp9es and autolite 3910x plugs.
ARC, PVL, and the tilly 212r cast aluminum flywheels.
Coil air gaps set at .045"-.075".
Timing set 28-30*
We tested 3 dover power coils, and they only pulled 1-2 degrees at 6000 rpm.
A noticeable improvement in 0-600 ft testing.
We only tested them with non-resistor plugs. We didn't have any resistor plugs for testing.
I wouldn't recommend something I havnt tested and use myself.
I won't be using any other ignition coils.
http://www.doverpoweronlinestore.com/catalog/item/9100750/10483555.htm
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