| Author | Message | ||
     Opto |
In preparation/planning for new ignition system (XB12), have a couple of questions. When setting the ignition timing the manual says there are 2 times that the flywheel mark will line up in the timing inspection hole, once for the front cyl at TDC on comp. and once for the rear cyl at TDC on comp, this means there must be 2 different markings on the flywheel. I think this is a typo? 2nd question: When all the cam gears are lined up when setting the cam timing, in what position is the engine, e.g. front cyl TDC on comp? or where? In the photos in the manual the keyway of the front intake cam gear shaft that locks into the ignition rotor cup is shown in the 7 o'clock position when all the cam gears are lined up. I will be fitting a new sensor onto this shaft and keyway hence all the questions. I know I'm going to have to work this out for myself eventually but some backup confirmation would be nice, if I get the timing wrong there could be serious damage. Also I don't want to remove the front rocker cover just to be 110% sure of TDC on compression for the front cyl. (but will if I have to). Any info appreciated... | ||
| Blake |
If the XBs are no different in their timing mark implementation than my Cyclone, that sounds like an error to me too and would agree that it should instead read "once for the front cyl at TDC on comp. and once for the front cyl at TDC on exhaust." No need to remove rockerbox, use the finger in the spark plug hole method to figure if front cylinder is on compression stroke or not. There won't be any mistaking it as on the upstroke it will generate significant pressure, then if you remove your finger, then replace it and continue on the downstroke, significant vacuum will ensue.  (Message edited by blake on January 19, 2006) | ||
| Blake |
Best get confirmation from one of the experts here though. | ||
| Panic |
1. there cannot be a single mark for TDC for both cylinders - they're 45 degrees apart. 2. if there is 1 mark, Blake is right. In general the cam alignment marks aren't related to firing position. | ||
| Xsarge |
Sorry this is late. But I just joined BWB's. There are two sets of marks but only one timing mark.It takes two full rotations to get back to where you started.If you make only one rotation you will be 180 deg. off. Your XB manual is 100% correct.No typo. | ||
| Opto |
Thanks sarge, so it sounds like there's a proper timing mark for the front cyl TDC and a different mark for the rear cyl TDC. That would be good. Unfortunately the ignition project is on hold at the moment, but definitely not cancelled. | ||
| Alex |
There is no rear cylinder TDC mark. Best regards Alex | ||
| T9r |
Alex, So your saying that these directions are not accurate? http://www.badweatherbikers.com/cgibin/discus/show .cgi?tpc=3842&post=284357#POST284357 1. Rear up on stand. 2. Remove seat. 3. Remove timing mark inspection plug. 4. Gently pry back the silicon rubber seal to gain access to the terminals of the gray connector on the ECM. You'll need to stab your DMM leads in from the back, and this makes it easier. 5. Set DMM to read DCV, 20V range. Insert black DMM probe into pin 7 (black wire with white tracer) and red DMM probe into pin 3 (if I racall correctly -- anyway, it's the green wire with the white tracer) 6. Sidestand up, key on, ignition switch on, transmission in 5th gear. You should hear fuel pump come on and then time out. 7. Looking through the timing mark inspecion hole, turn the rear wheel in a forward direction until the timing mark is visible at the left edge of the hole. You should see zero (or close to it) volts on the DMM. If you see +5V, then you're at TDC for the rear cylinder -- rotate the wheel until you see the mark again. 8. The meter should change from 0 to +5V just as the timing mark passes the center of the hole. As a bonus, the fuel pump comes on at the same instant, providing audible feedback as well. Turn the wheel slowly, and if you overshoot the mark, back it up until the mark is again at the left edge, and then go forward. Don't try to check/adjust it while turning the wheel backwards. 9. If the timing is advanced (transition occurs before center), nudge timing plate CCW. If the timing is retarded (transition occurs after the mark passes center), nudge the plate CW. | ||
| Alex |
T9r, at least point 7 is not correct. If You see the timing mark (which actually is the front cylinder TDC mark) in the timing hole the rear cylinder is 45° past its TDC (and there is no rear cylinder TDC mark). What is ment in the instruction point 7 is the following: if the DMM shows 5 Volts dropping to 0 Volts with the timing mark running through You´re near the front cylinder TDC but at its OVERLAP TDC (where both valves are open at the same time). If the DMM reads 0 Volts going up to 5 Volts with the timing mark running through You´re at the front cylinder COMPRESSION STROKE TDC which is the correct one to adjust the pickup. If You adjust the pickup with the front cylinder overlap TDC You will be some degrees off. Don´t ask me if this instruction is correct but I believe it is (regarding to finding the correct TDC). Still I use a different method: I remove the sensor plate and take a look at the rotor cup that is mounted to the front intake cam. It has a slot that aligns it to the cam. If You position the engine that the slot is pointing roughly in the 01:00 o´clock position and the timing mark is centered in the timing hole the engine will be definitely in its front cylinder compression stroke TDC which is the correct position for pick up sensor adjustment. Hope this helps. Alex | ||
| Reepicheep |
Well, thats covered by 8 isn't it? And in practice, if you timing is even close to begin with, you look for the mark in the window when you are going from 0 to 5 volts anyway. That's what I did. I just followed those instructions, and they worked like a charm. I hooked up the meter, but hearing the fuel pump come on was much more useful. The bike runs better then ever now. Thats a fussy little setting though, move that plate a hair and you can be out of the ballpark. I was too lazy to pull the plugs as well, which made it even harder. I could hear my cylinders bleed down though as I held the wheel in position. |
