NCScooter's 1000 build

[NCScooter]

Back in post #13, when I replaced my timing belts, and I rechecked today, there was something a little odd on the right side. The flywheel is perfect TDC #1 and the left side matches the mark perfect; however, the right side is off about a third of a tooth/cog/whatever which is probably 1 to 2 degrees. Any experience with this? :shock: :read:

 

[joedrum]

yes ... this is what randall and others mistakingly call cam wobble ....it is not having timing belts tensioned right .....there is a neutral freen spot on each side of the motor where cam can be put where theres no pressure from the valve traine this is where belts should be tension to about 1/4" deflection ... then motor move to other side neutral spot and done the same way ... do this and the cam will quit wobbling and the motor will be in better timing... just kidding on the cam it dosnt wobble at all some think so though :smilie_happy: :mrgreen:

 

[NCScooter]

joedrum » Wed Sep 04, 2013 3:14 pm[/url]":3bm605j7]
yes ... this is what randall and others mistakingly call cam wobble ....it is not having timing belts tensioned right .....there is a neutral freen spot on each side of the motor where cam can be put where theres no pressure from the valve traine this is where belts should be tension to about 1/4" deflection ... then motor move to other side neutral spot and done the same way ... do this and the cam will quit wobbling and the motor will be in better timing... just kidding on the cam it dosnt wobble at all some think so though :smilie_happy: :mrgreen:

If I may, sir, call you a butt fungus? I was all excited and jumpin' and so on. :sensored: :lol: :lol:

 

[joedrum]

thanks for the complement ... truth always take a beating

 

[NCScooter]

. . .but is this a problem and if so, is there a fix?

 

[dan filipi]

NCScooter » Wed Sep 04, 2013 1:23 pm[/url]":1c707lvw]
. . .but is this a problem and if so, is there a fix?

In post# 162 Joe explained the fix.
It's a better method of adjusting the belt tension.

I haven't done it this way myself so I can't say one way or the other if it fixes that 1/2 tooth off problem.

 

[joedrum]

yes read the post I made ive watch wing motors run when one belt was tensioned different than other belt ... there no way that timing is right when one flops around more than other .... ive also retension belts to where there the same and in every case the motor runs better ... plain and simple ... this is the biggest reason by far that makes oldwing seem to be off timed on two clylinder and one set of cylinders weaker on good motor ... good motor ran like this for long time leads to loss in in othere areas .. spit back from wasted spark and so even loss of compression from totally garbage conditions in these cylinders .... tension the belts right and use atf in the gas and it will slowly clean up on its own simple ... I hope you understand what im saying ... a lot get lost in my typing skill word use

 

[mcgovern61]

NCScooter » Wed Sep 04, 2013 3:23 pm[/url]":3m6fvy36]
. . .but is this a problem and if so, is there a fix?

Yes it is a problem and yes it is normal when putting the belts on. The right side cam has spring tension on it so there is a tendency to install it where it fits rather than be sure the cam is rolled back to the pulley mark.

When I do timing belts, before I take the belts off, I make sure the flywheel is at the correct timing mark (T1) and the cams are in the right place and I use white out to mark the crankshaft position at the top and bottom (0 degrees and 180 degrees) and then mark the arrows on the cam pulleys to be sure when the belts go back on everything can easily be seen lined up correctly.

What often happens is when the right belt (looking from the seat) is being put on while holding the cam against spring pressure, we tend to jump a tooth (sometimes two) and assume it is correct. What I have experienced is that one tooth may be off at the cam, but in the struggle to get the belt to go on the pulley the crank gets a minor turn and then it is a tooth off there too! That one tooth off has smacked a lot of valves around here! That is the reason I mark the crank pulley as well as the cam pulleys.

I always put the right belt on first. I mark a tooth on the belt to line up on the crank pulley mark at 0 degrees (for easy reference). I then turn the right pulley back so that the mark is slightly above the arrow mark and then put the belt on. The spring pressure always brings the belt right where I need it and the visual marks make it easy to see. Left belt is a breeze after that!

(BTW, some guys loosen their valves completely to do their belts. I have not had to do that yet.)

 

[NCScooter]

Well, I have run it some after changing belts and I checked my compression recently and it is ~135 for all 4 cylinders. I don't think I smacked any valves, hopefully. I reason the center pulley on the crankshaft is one piece, and if the pulley on the camshaft were shifted one cog it would be farther off. I followed this procedure >>> https://www.ngwclub.com/forum/viewtopic.php?t=3544 <<<carefully, nothing shifted. I held the right pulley with the spanner and loosened the valves, I also had the center pulley marked as recommended. I wish I had looked more carefully at the marks before removing the old belts, when the flywheel mark was lined up and the left side mark lined up, I looked from across the bike and saw right side pointing out and did not check its exact alignment. Currently, the mark is not a whole cog off ( wish I'd taken a picture) and the tension on both sides is equal, as best as I can tell. I may take the cover back off and post a picture later.

 

[NCScooter]

DSCN1359C

• NCScooter
• Sep 4, 2013

I thought it looked worse, maybe I just had my head in the wrong place (no comment, please!) The left side matched exactly and so did the flywheel.

 

[dan filipi]

Looks near perfect :clapping:

 

[mcgovern61]

Looks good up here in New Jersey! :clapping: