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Discussion Starter · #1 ·
Figure I would share my motor build with everyone. Decided to use Allen Knowles at CT Racing for the work. I have a CT 330 kit on my 250R, so have dealt with Allen some in the past, figured I would see what he can so with a four stroke. I know Allen can build a motor for desert racing, so I told him I would be racing the expert class in the Best in the Desert series and to build me a good reliable motor and let him have at it. Didn't really know what I would get untill it showed up on my door step! haha

Got a ported cylinder head with Kibblewhite oversize valves and spring kit, Webb 290 cam and hardened rocker arms, and a CP 12.5:1 piston. Hope to get it all together and take it out to break it in on Sunday.

Attached a couple of pics below. First is how my 700XX has sat for the last couple of months, second is some of the parts, just waiting to be installed. Hope to get it all together and take it out to break it in on Sunday. Allen will be sending me a map for my PC5. Plan on getting it dyno tuned once it is broken in, but figure the map will be close enough for a easy break in ride.

Doug



 

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Discussion Starter · #2 ·
Sorry for the one pic, it didn't look that dark on my computer. Will make sure I get some more with better light as I reassemble.

Doug
 

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Discussion Starter · #4 ·
what heel guard is that?
It is the Houser peg/nerf combo, I just have the front portion of the nerf off the quad, since they go through the radiator shrouds and I had to remove the shrouds.

Doug
 

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Sorry for the one pic, it didn't look that dark on my computer. Will make sure I get some more with better light as I reassemble.

Doug
That's okay looks sweet so far. I thought you were just trying to hide the Polaris, with the lighting trick!
 

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Discussion Starter · #7 ·
I thought you were just trying to hide the Polaris, with the lighting trick!
Nahh, no reason to hide it, been a good machine. (RZR-S) It is actually my wife's, but it is pretty fun. Amazing the kind of chances you will take with a cage around you!

Whats the difference with like the 11:1 and the 12.5:1.

Advantages/disadvantages so im a little new to this engine stuff :)
More compression should produce more power, but you will have to use better fuel. As far as how much more power, can't answer that one, have never just compared pistons before.

Doug
 

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Whats the difference with like the 11:1 and the 12.5:1.

Advantages/disadvantages so im a little new to this engine stuff :)
There is very little noticeable difference with with the two different compressions. I have built both with the exact same supporting mods and from the seat of the pants I could not tell any difference.

Bergstrom can we see a pic of the port work Im interested to see what it looks like, your going to really enjoy the power that bike is going to put down.:tup:
 

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Discussion Starter · #11 ·
Best of Luck in the BITD series, I'll keep an eye on the results.You doing Ironman or teaming up with some other riders ?
Thanks Lee, plan is to race Ironman Expert all year and go after the championship. First race of the year was back in January, Parker 250, ended up 5th in class, raced my TRX450R. 160 mile race and started having transmission problems at mile 10, by mile 30 fourth gear was gone. You don't realize how much you use fourth untill you don't have it! Since I am going for the championship, I HAD to finish, so I just cruised the rest of the race to make sure I did finish. I had my GoPro on for the first 27 miles. I will post the Youtube link in the video section when I get a chance. If you don't see it in a day or two, remind me.

Only the best parts used:tup: Let me know if you want a map for the pcv to use for your base map.
Thanks for the offer of the map, if I need it, I will let you know. Allen has one, he just has to send it. Has already built a couple 700XX's with the same mods and tuned it himself on his dyno, should be a good map.

Bergstrom can we see a pic of the port work Im interested to see what it looks like, your going to really enjoy the power that bike is going to put down.:tup:
Sorry, no pics of the port work. I know some builders don't like porting pics being posted, I don't think Allen would have a problem if I did, but don't want to take the chance if he does. If I remember, next time I talk to him, I will ask if he is alright with it.

Doug
 

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Sorry, no pics of the port work. I know some builders don't like porting pics being posted, I don't think Allen would have a problem if I did, but don't want to take the chance if he does. If I remember, next time I talk to him, I will ask if he is alright with it.

Doug
yea i got in trouble with the place that did my head on my 450. i posted pics and 10 minutes later they emailed me saying what the hell?? i took down pics right away.
 

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Yeah Bo's head is awesome I have that head now.
 

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I was looking at the trx450r 05 head and found that they look like alot of the xx port, I wonder if racer edge can do something like those epoxied ported 05 450r head??

Just saying, cause I know we got both the same toys;)
 

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Discussion Starter · #16 · (Edited)
So a little update. Got this thing back together a few weeks ago. Went to start it and could tell something wasn't right. I like to put a couple of heat cycles on a new motor before I actually ride it. Qiuad was hard to start when cold (Once warmed up it would fire right up.) and the valve train noise was pretty loud. When in neutral, you could tell it didn't like to rev. Double checked timing, valve clearance, etc. Everything looked good. At that point, had other stuff going on and I was annoyed and just didn't want to look at it.

Let it sit for a couple of weeks and then got back to it. Put the crank on the timing mark and then looked at the piston through the spark plug through while rotating the engine, could tell the piston was not at top dead center. I was on the wrong timing mark! The cam ended up being off by one tooth. Got it fixed ant put it back together and it runs like it should. Took a couple of easy rides around the block and can tell the motor is much stronger then stock. Want to warm it up one more time, do an oil change, put the panels back on and will take it out to the desert next weekend and give it a good workout.

One thing I did notice, it seems to be burning a little oil. After I start it and let it idle to get warmed up for a few minutes, I then "blip" the throttle and a puff of smoke comes out the exhaust. That is the only time it does it, once I do the first intial rev, there is no more smoke. Any one else experience this with a CP piston? This is the first time I have ever used one, and I have done some reading on them and it seems CP uses low tension rings and it takes a bit for them to seat. Seems they don't like to seat untill you really rev the thing. (Figure my neighbors would be little annoyed with me if I did that in front of my house!) Plan on riding it hard next weekend, will keep an eye on the oil level and see if it is buring oil.

Doug

 

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Guess you found the "F" mark instead of the "T".lol. Still don't know what the "F" is for.

The puff of smoke happens with the stock Honda piston also. I just put it too everything in the motor warming up. It usually does it once on start up and never appears again.

The 700xx hates been warmed up stood still. I found it better to warm it up by riding it at a casual pace. Not always possible but found it to be the best way.IMO.
 

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The smoke could also have been from the oil when you put it together and it hasn't all cleared out yet. When you go to break in the rings down shift some to slow down to put pressure on both sides of the rings to get a good seat. Nothing crazy just a little speed and then gradually down shift to slow the bike down
 

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Discussion Starter · #19 ·
Is that an "F" mark Lee? I have decided looking through a 1/2" diameter hole with a flashlight reflecting off the polished surface of the crank can play tricks with your mind! I was looking for a "T" and could have sworn that was it, untill I actually saw the "T"!

Thanks for the info on the rings, plan on taking it out this weekend and giving it a good break in. I have read quite a few reports that it takes a bit to get the rings seated on a CP piston, we will see how it goes.

Doug
 

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Good luck with it and enjoy the bike man it's good be a blast. That 290 cam revs to moon
 
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