Technical Discussion Topics related to Technical Issues

How to find TDC easily ?

Old 08-15-2005, 07:30 AM
  #1  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
How to find TDC easily ?

To change a CCT we have to find the "good TDC" for each cylinder.
For one cylinder, the good TDC is when the intake and exhaust valves are closed (no tension on valve spring) : end of compression stroke.
the "bad" TDC is at the end of exhaust stroke (exhaust valve opened).
We can see these two different TDC at the fly wheel (FT mark for the front cylinder).

At 6th gear, turning the wheel, we'd be able to feel the compression stroke (difficult to turn the wheel) of the two cylinders.

If we know which cylinder fires first ccw, we can know which cylinder is at compression stroke and then know which cylinder is at "good TDC".

Checking FT or RT mark at the fly wheel would confirm us that we are right... isn't it ?

Is there a way to find TDC ?
Which cylinder fires first ?
Does the motor run counter-clockwise ?
What is the timing between the compression strokes of the two cylinders ? 1/4 turn, 3/4 turn, 1-1/4 turn, 1-3/4 turn ? cw, ccw ?
roadrun_fr is offline  
Old 08-15-2005, 07:37 AM
  #2  
Senior Member
Back Marker
 
Join Date: Jul 2005
Location: Mississippi
Posts: 123
VTRFISH
Re: How to find TDC easily ?

Not to poke fun ....but I had to laugh as I read this.

Which cyl fires first??

Reminded me of a chicken and an egg story I once heard.
Good luck on the timing issue.....seems I'm no help here......


















Mike
VTRFISH is offline  
Old 08-15-2005, 07:43 AM
  #3  
Senior Member
Back Marker
 
Join Date: Jul 2005
Location: Mississippi
Posts: 123
VTRFISH
Re: How to find TDC easily ?

Just remembered....Gerrit did a piston install....he may chime in to help ya out...

Good Luck
Mike
VTRFISH is offline  
Old 08-15-2005, 08:27 AM
  #4  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
Re: How to find TDC easily ?

I mean... I want to know if it goes something like that :

Beeing at the left side of the bike, motor is running ccw at the fly wheel, ccw at the rear wheel, timing is 0 Rear cylinder fires, 450 (1 turn 3/4 ccw ) front cylinder fires.

Based on what I read in other posts, is this the correct timing ?

Rear :
0 : Rear at "good" TDC, both valves closed, end of compression stroke
180 : Rear at BDC, end of explosion stroke
360 : Rear at "bad" TDC, exhaust valve opened, end of exhaust stroke
540 : Rear at BDC, end of intake stroke

Front:
90 : Front at "bad" TDC, exhaust valve opened, end of exhaust stroke
270 : Front at BDC, end of intake stroke
450 : Front at "good" TDC, both valves closed, end of compression stroke,
630 : Front at BDC, end of explosion stroke
roadrun_fr is offline  
Old 08-15-2005, 10:18 AM
  #6  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
Re: How to find TDC easily ?

Yep ! Great !
roadrun_fr is offline  
Old 08-15-2005, 11:10 AM
  #7  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
Re: How to find TDC easily ?

So the timing goes like this :

Front :
0 : Front at "good" TDC, both valves closed, end of compression stroke, FT Mark
180 : Front at BDC, end of explosion stroke
360 : Front at "bad" TDC, exhaust valve opened, end of exhaust stroke
540 : Front at BDC, end of intake stroke

Rear:
90 : Rear at BDC, end of intake stroke
270 : Rear at "good" TDC, both valves closed, end of compression stroke, RT Mark
450 : Rear at BDC, end of explosion stroke
630 : Rear at "bad" TDC, exhaust valve opened, end of exhaust stroke

Would it be possible that TDC for the rear would be 270+360 later than Front TDC with such a V90 motor ?
roadrun_fr is offline  
Old 08-15-2005, 11:54 AM
  #8  
Senior Member
SuperSport
 
Join Date: Dec 2004
Location: Nananimo, B.C.
Posts: 764
NOrrTH is an unknown quantity at this point
Re: How to find TDC easily ?

Can't you just take off those little plugs on the left side crank case and it tells you through the viewing window?
NOrrTH is offline  
Old 08-15-2005, 01:04 PM
  #10  
Senior Member
SuperSport
 
Join Date: Dec 2004
Location: Nananimo, B.C.
Posts: 764
NOrrTH is an unknown quantity at this point
Re: How to find TDC easily ?

Then you look down the spark plug hole?
NOrrTH is offline  
Old 08-15-2005, 01:15 PM
  #11  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
Re: How to find TDC easily ?

no still 50% ..... There is 2 different TDC per cylinder, then the spark hole does not help...
You must find the TDC at compression stroke. To feel it you must leave the spark plug.
roadrun_fr is offline  
Old 08-17-2005, 11:44 AM
  #12  
Senior Member
Back Marker
Thread Starter
 
roadrun_fr's Avatar
 
Join Date: Jun 2005
Location: Paris
Posts: 116
roadrun_fr
Re: How to find TDC easily ?

roadrun_fr is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
vtr1000long
Technical Discussion
7
10-04-2012 07:08 PM
smokinjoe73
Technical Discussion
11
05-30-2012 05:48 PM
Cheesedrug
General Discussion
8
11-14-2006 06:49 PM
The spring man
Technical Discussion
10
06-12-2006 01:20 AM
AZZKIKER
Technical Discussion
1
04-11-2005 09:34 AM


Thread Tools
Search this Thread
Quick Reply: How to find TDC easily ?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.