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CRF50 Multiple Diagnosis

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So after finishing my explanation of the issue, i realized how long it is. So here is a quick summary, of course which is followed by a detailed description of the issue.

-How loud are the valves in the race head supposed to be? How much noise is too much?

-The bike wont start after running and being shut off, accompanied by seemingly excessive force to kick the engine over.

-Could force from a poor fitting exhaust pushed into place cause performance issues or damage the engine?

So, i am new back to thumper. I used to be a member a few years ago, but after bending a valve during an install of my Tb 88 kit, i set the bike aside till i had more money and time to work on it. Well, that time has come, and now i struggle with a few more issues im not so sure about.

I'll start off with a bit about the bike.

2005 Crf50

88cc Trail Bikes big bore kit

2005 (smaller valves than new) race head /w race cam

High volume oil pump

20mm Sheng Wey Carb

Two Brothers Racing Big Bore exhaust pipe.

The first thing i was wondering about is how much noise should the tiny little valve train make? At idle, i can hear it over the exhaust, which is pretty loud. Its not disturbingly loud, it is just a consistent clicking that i think should probably not be there. If it is more than should be, i have the two suspicions of excess valve clearance and/or lacking oil flow. Though i doubt oil flow is the problem since it should have been solved by the high volume oil pump.

Again though, the bike sat for probably 2 or 3 years without even being moved more than 2 or 3 times total. When it was rebuilt recently(unfortunately not by me, which is a whole different issue), the person doing so had successfully installed the same kit 2 or 3 times, and had a bike himself that had been running with the kit well for years.

The second issue is after running, it has difficulty starting. I just noticed this 10 minutes ago when i took it for a spin around my apartment complex while considering how high to gear the bike up. I let it warm up for a minute or two, even though it pretty much immediately had no trouble transferring to no choke. I rev it out pretty hard a few times, avoiding getting to high in the RPM range to avoid being assaulted by an angry mob of neighbors.

I hit the kill switch while the bike was moving, and it didnt shut off till i stopped moving. Dont know if this is of any consequence as i have nearly no experience with centrifugal clutch bikes.

I brought it over the curb into my apartment breezeway and decided to start it real quick to get a better idea of the valve noise i described earlier. The first attempt to kick it over seemed to require more than normal force. It didnt start, which is odd since it has been starting from cold on the first kick. Now, it seems to be hard to kick over, and every time i do i just get a sputter and the bike wont start. I havent tried to start it to much, because im afraid of kicking it over real hard since the last time it was like this i bent a valve.

Any ideas why this could be?

And the third issue has to do with the exhaust pipe. when i got it and fist tried to install it i noticed that once the exhaust flange was torqued pretty tight, that the pipe was pretty far off from being easy to bolt in place. After looking more closely i realized the flange had TTR-50 etched in it, though it was anodized the red that all the CRF50 versions were. I called in, and they said it might be a TTR-50 exhaust with the flange anodized the wrong color or a CRF50 exhaust with the wrong thing etched on the flange. Well, i got lazy and didnt exchange it before the return period ended, so now im stuck with an exhaust that is off by about 1/2 to 3/4 of an inch near the can when the flange is bolted tight. Basically, to get it all to bolt up properly, i have to put 10-25 pounds of compressive force on the muffler itself and then tighten down the bolts like this.

Could this amount of constant force applied to the head after the exhaust is in place cause leaks in the head? Could it harm performance in other ways? And more importantly, could that constant force on the head damage the engine as a whole?

Thank you guys so much for the help.

Edited by epowell7

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