Hmm. Suggest treading carefully here. Tytronic seem to have disappeared?
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72 xs2 bogs down and backfires out of carbs, out of ideas
- Thread starter RaceCar1983
- Start date
And tytronic.com
I suggest investigating TriSpark and Boyer Bransden.
I suggest investigating TriSpark and Boyer Bransden.
RaceCar1983
XS650 Enthusiast
Rawhide are made in the USA and make well known kits for Harley’s. Tytronic are Chinese made and sold as far as I know. MikesXS electronic ignition I hear mixed things on and they don’t seem to make it anymore. Rawhide seems like the best bet, but if it doesn’t work I’m out $350. I just want to narrow my problem down. Very strange that 2 carbs would develop an identical bog out of the blue after running good for so long, and replacing them results are the same.
RaceCar1983
XS650 Enthusiast
Any suggestions from folks here on the Boyer: https://tcbros.com/products/boyer-bransden-micro-power-digital-ignition-system-yamaha-xs650
Vs the Rawhide? https://www.lowbrowcustoms.com/prod...nition-for-1970-1984-yamaha-xs650-dual-pickup
I can only afford one lol
Vs the Rawhide? https://www.lowbrowcustoms.com/prod...nition-for-1970-1984-yamaha-xs650-dual-pickup
I can only afford one lol
Using a timing light is your spark timing advancing and retracting smoothly as you run the engine up and down from idle to 3K RPM?
Have you marked your timing on the XS charge PMA rotor?
Have you rechecked that the timing marks are still correct? AFAIK the XS charge rotor does not use a key so it Could move on the crankshaft causing any previous marks to now be in the wrong location. Verify TDC (with a sparkplug out)
way too many stock advance springs have been replaced with inferior aftermarket parts because of faulty "static" testing. The gold standard for spring (advance) action is a timing light. The advance rod/cam bore also need to be removed, cleaned, lightly lubed as an "occasional" maintenance item.
We've explored most of the usual suspects so we're now looking under normally undisturbed rocks for clues.
Have you marked your timing on the XS charge PMA rotor?
Have you rechecked that the timing marks are still correct? AFAIK the XS charge rotor does not use a key so it Could move on the crankshaft causing any previous marks to now be in the wrong location. Verify TDC (with a sparkplug out)
way too many stock advance springs have been replaced with inferior aftermarket parts because of faulty "static" testing. The gold standard for spring (advance) action is a timing light. The advance rod/cam bore also need to be removed, cleaned, lightly lubed as an "occasional" maintenance item.We've explored most of the usual suspects so we're now looking under normally undisturbed rocks for clues.
RaceCar1983
XS650 Enthusiast
I have not tested timing while engine running yet, I will do that when it gets above 0 degrees here. I have done everything else you mentioned though including replacing the advance springs. The new ones are much tighter and have the proper snap back I see in member videos here. I could try cutting a coil off the stock ones I took off that were too loose and see what that does. The reason I replaced them was I had a lingering idle and the replacement springs fixed that problem.
AUTOMAN
XS650 Addict
RaceCar1983
XS650 Enthusiast
Do you have anything useful to add?
AUTOMAN
XS650 Addict
Try a timing light while the engine is spinning and key on.
That was your first step. I will go from there.
cliff
RaceCar1983
XS650 Enthusiast
That is what I did, engine off, key on, turning the engine with a wrench. Timing was perfect. I will try with the engine running and warmed up next time.
AUTOMAN
XS650 Addict
RaceCar1983
XS650 Enthusiast
Yes I have points, and confirmed the gap and power going to them.
AUTOMAN
XS650 Addict
OK
Many do not know point gap is what you set for approximate dwell-not timing.
Gap is maximum point opening when set. This is based on point lobe lift to point rubbing arm, which wears.
After looking at timing with timing light, which could be completely wrong just based on point gap setting alone, adjust timing with the points.
If you get that far, the point gap is what it is, and so the dwell. Live with it.
If timing light inspection is wildly varying, the points are arcing. Either not closing completely or condensor is shorting/not connected.
Assure points are clean!
One thing at a time.
Let's not throw the kitchen sink at it.
We are speaking of
When we say timing light.
Static timing with a lightbulb is a great way to start, but engine running, checking with one of these is best for confirming advance timing, correct action of the springs etc.
Did you remove and clean re-lube the advance rod?
Do you have TDC marked on your rotor?
When we say timing light.
Static timing with a lightbulb is a great way to start, but engine running, checking with one of these is best for confirming advance timing, correct action of the springs etc.
Did you remove and clean re-lube the advance rod?
Do you have TDC marked on your rotor?
RaceCar1983
XS650 Enthusiast
Yes and yes, I will check with a light when I can.
RaceCar1983
XS650 Enthusiast
I should also mention points are new and open and close properly, no arcing visible across them. Will re check with a light gun when it warms up here.
RaceCar1983
XS650 Enthusiast
update: checked timing with a light and it was off, thanks AUTOMAN. My problem now is I maxed out my adjustment on the plate and it is still firing ahead of the mark. I won’t get the chance to use the light again until next weekend so please any suggestions of what I can do in the meantime.
To clarify further, timing marks on the PMA are just to the left (1/4 inch) of the fire mark, and the points plate has been rotated as far as it can go to the left bringing the marks 1/4 inch apart. It started about 1/2 inch to the left when I first timed it.
The limited adjustment did yield an improvement riding though, so I feel like I am on the right track thanks again to AUTOMAN and gggGary.
To clarify further, timing marks on the PMA are just to the left (1/4 inch) of the fire mark, and the points plate has been rotated as far as it can go to the left bringing the marks 1/4 inch apart. It started about 1/2 inch to the left when I first timed it.
The limited adjustment did yield an improvement riding though, so I feel like I am on the right track thanks again to AUTOMAN and gggGary.
Confirm your TDC matches the mark on the rotor, a PMA rotor can move on the crank (no keyway)
Advance timing mark is more important than idle how does that look?
Time BOTH sides, adjusting the point gap down a bit below spec to get the timing right is acceptable.
A worn cam chain or the front guide rubber falling off will mess with the cam timing. If the rod on the cam chain adjuster isn't more or less flush when properly tensioned that's a clue about the front guide.
Advance timing mark is more important than idle how does that look?
Time BOTH sides, adjusting the point gap down a bit below spec to get the timing right is acceptable.
A worn cam chain or the front guide rubber falling off will mess with the cam timing. If the rod on the cam chain adjuster isn't more or less flush when properly tensioned that's a clue about the front guide.
Last edited:
Advance Unit locating pins and so ?
https://www.xs650.com/threads/advance-unit-installation-am-i-missing-something.41144/
https://www.xs650.com/threads/advance-unit-installation-am-i-missing-something.41144/
Sorry if you've already done this, (I didn't find mention of it in the thread), but as you are unable to get the points plate to line up have you checked that the timing chain is adjusted correctly? If the timing chain is badly worn or incorrectly adjusted you won't be able to align the points plate fully, exactly as you describe.
