Valve Clearance Issue

[who_gives_a6]

First off, I'm not motor builder. I've had my Dale since early 09 and it hasn't ran. Brand new rebuilt engine but no go. After countless advise that timing was off, I dropped motor yesterday and tore into it with the updated manual I downloaded. The dots on the cams lined up perfectly where they should be and looked right so guessing that's not it. However, checked valve clearances when at TDC and seemed a bit off. The manual says .36-.41mm exhaust clearance and I got .30mm. Intake says .18-.23mm and I got .12mm. So obviously the clearances are not correct and will need different shims it appears.

My question is: would this be a cause for it not to start at all and backfire badly? Or would this still have been an operable thing if it had been left alone? I've switched out virtually every electrical part, coils, regulators, stators, flywheels, fuel injectors, etc, and nothing. The injectors spray and appear good, it gets good spark, but just turns and turns until you get a big backfire. Usually out exhaust but have had a few out intake.

The quad is a 450 piston kit, Z400 crank with ported head, I think the Boomer intake, and some other odds and ends but nothing huge. Just a standard 450 build per previous owner. I can see the piston and it still does not have a spec of carbon on it as it hasn't ran. Shiny as can be, but haven't removed head yet, just looking through ports and spark plug hole. Just at a loss for what to do and nobody is local except one guy who wants like $400 just to look at the engine and check it over, not including any repairs if needed.

Basically it turns real easy by hand but when the piston comes up to the top, it gets real hard to turn over. You almost have to force it, like the valves are pressing the piston. Would that be a valve shim issue as mentioned above or possibly something else? I did find a former employee of the C'Dale plant a few miles from me who is willing to help who had some cool designs to improve oiling of crank and some other random mods, but he seemed like he doesn't want to touch the engine. Will help get running for fees if engine is in frame he said though. Just trying to get this thing going without busting the wallet if possible.

Any suggestions, comments, or ideas? Can take photos of anything requested.

[claas900]

With that valve clearance it should run more then likely not your problem.
The motor should turn over nice and easy,with the spark plug out, and starter out also. The only resistants you should feel is when the valves are opening.
Who built the motor? There's a lot of shady work out there just knowing who built it would be a good starting point.
The very best way to know if the cam timing is right is with a degree wheel,some cams are made wrong.
Also where are you out of?

[kdeal]

When it gets harder to turn over at TDC is that with or without a spark plug installed? If it's without the plug installed possibly something is bent or out of round. Based on the little information above, I agree that the motor is most likely out of time. If you want to pay the freight each way, I'll look at it for free. I wouldn't pull it down any further without someone at least eyeballing every thing where you are at so far. Where are you located?

[who_gives_a6]

Located close to San Diego. When hard at TDC to turn it's with the spark plug removed. Don't know who built the engine. Previous owner couldn't get it running and sold quad to me. Said he believes it was a shop in Utah which from my understanding was Black Widow ATV. Bought it rebuild from the shop direct off Ebay if I recall correctly.

Would like to try and not ship it out but if it comes to it then will give it a shot. I think I could do the cam timing with degree wheel and such, but kind-of want to just let an expert do it. I'm going to take a look at it and such and see about that, and if no idea or am worried, will ship to someone. I'm not against paying for peoples' time/work, just would like to take care of it myself if possible. Just unfamiliar with these things and want some advise to try and solve myself. Thanks so far guys.

Oh, by the way. The previous owner said the cams were ran for about 10hrs in the motor previously. Only reason for build was for Z bearing, porting, 450 piston, etc. So I would think that the cams would be made right, but again, it's all heresay of another person/shop. So you never know what got exaggerated.

[cannondale27]

Lining up the dots is not good enough, You have to line up the dots and count the teeth from center. I bet you missed that and guy who put it together did also. Reason it probably turns hard at tdc is because decomp is activating. That is normal.

[who_gives_a6]

Ok, thanks 27. What do you mean by counting teeth from center though? Probably sounding dumb but want to get this right.

[rayspeed]

If you want to make the short trip to Glamis when I go next time then I can take a look at it for you out there... I have the degree tools. If you don't have anything to ride then I could probably help there too. Only set trip right now is between xmas and new years but the weekend after thanksgiving is looking good also.

[who_gives_a6]

I may have to take you up on that Ray if the time comes and get some free time. Christmas is out due to leaving area till early in year, but may be able to work something out weekend after Thanksgiving. Hopefully I can get something figured out before then, but I'll keep that idea in mind, thanks!

[cannondale27]

If you notice the numbers in pic on center drive gear. That is the tooth count. Pay attention to the tooth in center it should be almost perfectly straight up. Also notice where lobes are pointed at the cam cap bolts. Line up dots, tooth count are critical. Tooth count is ALWAYS necessary even when massivly changing stock cam timing and disregarding the stock markings.
[attachment=10955:Tooth_count.jpg]

[kdeal]

I don't count the teeth personally, but I do something just as effective. If you look at the picture two things, first make sure the timing marks on the double gear match up as well. I then look at the window in the idler gear bracket as my "tooth count". If you look closely, you can see a slight offset to the gear behind it (in other words the two holes do not exactly match up). There will be a subtle cresent shaped moon in the upper right corner in that hole. (this is actually a part of the gear being seen thru the window in the bracket as the gear hole is slightly offset towards the 6 o'clock position) I have gotten where I can tell how far the timing is going to be off by the shape of this opening! For now use the tooth count, but as you do more and more motors you will notice what I am talking about. Good luck.


[attachment=10956:Cam_gears.jpg]