Jump to content
Sign in to follow this  

Installing hotcams - chain is tight

Recommended Posts

I have a drz 400s and I'm installing hotcams stage 2 in & ex.  I finished installing the big bore and now I'm onto putting in the cams. I can't quite fit both cams into their respective seats.  I had the intake in first, tightened down the cam retainer, and then tried to install the exhaust cam into its seat... it just won't fit in.  Is there some trick to doing this?

 

I was going to try installing the exhaust cam first, but I had to go to work.  When I did the big bore install the chain did get tangled but I untangled it.  If I stretch the chain as far as I can vertically it reaches just above the bottom of the bike's frame.  The MCCT is out.

 

Tips?

Share this post


Link to post
Share on other sites

Install both cams before installing the journal caps.  Ex goes in first. Time it, install the IN cam count the pins to time it. Recheck the timing, install the journal caps. Install the tensioner. Roughly set in the tension. Rotate the motor 2 revolutions, recheck the timing.  

Share this post


Link to post
Share on other sites

Install both cams before installing the journal caps.  Ex goes in first. Time it, install the IN cam count the pins to time it. Recheck the timing, install the journal caps. Install the tensioner. Roughly set in the tension. Rotate the motor 2 revolutions, recheck the timing.  

How do I rotate the motor a revolution?  Use the kickstarter, or use a ratchet to the countershaft nut in 1st gear?  The cam chain can spin on its own when there are no cams there.

 

How do I check timing?  I thought you just have to make sure they are in a 10-2 position and that the chain is 15 links apart... well apparently 14.5 with hotcams.

Edited by iggy320

Share this post


Link to post
Share on other sites

How do I rotate the motor a revolution?  Use the kickstarter, or use a ratchet to the countershaft nut in 1st gear?  The cam chain can spin on its own when there are no cams there.

 

How do I check timing?  I thought you just have to make sure they are in a 10-2 position and that the chain is 15 links apart... well apparently 14.5 with hotcams.

 

if you use the drivetrain to rotate the engine, put it in top gear. more wheel rotations with fewer engine rotations = easier to find TDC

 

remove the spark plug so there is no compression, and you'll only be fighting the cam lobes instead of 160+ psi ;-)

 

the reason for checking timing after multiple rotateions is to make sure the chain has proper tension, and it hasn't slipped during the process. 

Share this post


Link to post
Share on other sites

iggy - No offense meant but you sure you are up to installing cams?  Maybe you should get some help or take your motorcycle to someone.  There are 2 access plugs on the left side of the motor.  One to access the crankshaft for rotation and 1 to access view of the timing mark for engine position at TDC (top dead center.  Piston at the exact top of the stroke)  There is no 14 1/2 pins.  Pins can only be counted in whole numbers.  15 pins for Hot Cams IN cam timing.

  • Like 3

Share this post


Link to post
Share on other sites

The cam chain can get caught up on the crank gear. hold the chain up and pull slightly while rotating the crankshaft back and forth a small amount. Take the Allen plug out of the left side and use a 17 mm socket and short break over bar. Don't force anything. Chain should pop loose and give you more room. Make damm sure you know the piston is on top dead center. TDC first, if that's not right your in for trouble.

Share this post


Link to post
Share on other sites

iggy - No offense meant but you sure you are up to installing cams?  Maybe you should get some help or take your motorcycle to someone.  There are 2 access plugs on the left side of the motor.  One to access the crankshaft for rotation and 1 to access view of the timing mark for engine position at TDC (top dead center.  Piston at the exact top of the stroke)  There is no 14 1/2 pins.  Pins can only be counted in whole numbers.  15 pins for Hot Cams IN cam timing.

just out of curiosity. what is the difference if the cams are set at 15 pins and 10/2 at the exact opposite of tdc? 

Share this post


Link to post
Share on other sites

By opposite do you mean 180 deg or 360 deg?  I assume you mean 360 deg. There is only 1 TDC.  Stroke is determined by the cams.  Piston at TDC cams on the marks (more or less 10 and 2) that is the TDC compression (or firing) stroke.  There is no opposite TDC with the cams out.   With the cams in there is TDC compression stroke and TDC exhaust stroke.  Cams out only TDC, no stroke reference.

  • Like 1

Share this post


Link to post
Share on other sites

By opposite do you mean 180 deg or 360 deg? I assume you mean 360 deg. There is only 1 TDC. Stroke is determined by the cams. Piston at TDC cams on the marks (more or less 10 and 2) that is the TDC compression (or firing) stroke. There is no opposite TDC with the cams out. With the cams in there is TDC compression stroke and TDC exhaust stroke. Cams out only TDC, no stroke reference.

I just wanted to know how someone could mess it up accidentally. Like what variations of timing someone could do. I haven't done it myself. I'm just curious. That makes sense though. I was thinking the T would line up 180 out for some reason. But it can't right?

Share this post


Link to post
Share on other sites

I just wanted to know how someone could mess it up accidentally. Like what variations of timing someone could do. I haven't done it myself. I'm just curious. That makes sense though. I was thinking the T would line up 180 out for some reason. But it can't right?

I think I understand what you are thinking. The crank only has the timing mark in one spot. The crank itself has no idea if its on the intake stroke or exhaust stroke. The camshafts control that. So while its bad practice you can take everything apart while NOT at "TDC", then turn the crank so the timing mark lines up, and throw the cams in correctly and it's fine. The cams are the "key" to the timing.

  • Like 1

Share this post


Link to post
Share on other sites

I think I understand what you are thinking. The crank only has the timing mark in one spot. The crank itself has no idea if its on the intake stroke or exhaust stroke. The camshafts control that. So while its bad practice you can take everything apart while NOT at "TDC", then turn the crank so the timing mark lines up, and throw the cams in correctly and it's fine. The cams are the "key" to the timing.

Yea. That's how I do it. I was just checking to see how other people might have done it..

Share this post


Link to post
Share on other sites

By opposite do you mean 180 deg or 360 deg?  I assume you mean 360 deg. There is only 1 TDC.  Stroke is determined by the cams.  Piston at TDC cams on the marks (more or less 10 and 2) that is the TDC compression (or firing) stroke.  There is no opposite TDC with the cams out.   With the cams in there is TDC compression stroke and TDC exhaust stroke.  Cams out only TDC, no stroke reference.

Great Explanation

Share this post


Link to post
Share on other sites

Thanks for all the help so far.

 

My chain was indeed jammed in the bottom end, I had to take the brake side of the engine off and unjam the chain.  The chain has enough slack now. 

 

The cams are in and I found where the timing window is and how to give the engine a few revolutions...  It seems very easy.  However I'm too tired to finish but I will complete this tomorrow.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×