Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,218
![United-Kingdom Country flag](https://www.accessnorton.com/images/flags/shiny/32/United-Kingdom.png)
What marks are you strobing to ?
Did you get this tip from this VW Ad? :The only way a Sprint (and I use that term loosely) 250 would do 90 mph is if it was pushed out the back of a C130.
The marks on the rotor and the scale in the outer primary cover.What marks are you strobing to ?
They claim a 250 Sprint won't wheel stand either but I wiped out the taillight the 1st day.The only way a Sprint (and I use that term loosely) 250 would do 90 mph is if it was pushed out the back of a C130.
But I thought your earlier point questioned the accuracy of your scale ?The marks on the rotor and the scale in the outer primary cover.
When I used the strobe on the original setting, the mark did not even appear in the opening.
Very confusing. If the timing is accurately set at 29 degrees statically, it will strobe at 29 degrees at 3500 rpm. I've installed many of them and never been off more than 2 degrees in either direction.The initial reading with the strobe light showed ignition retarded off the scale. A static check with the Tri-Spark indicated 20* BTDC.
Setting the static timing at 29* BTDC yielded adout 22* with the strobe light.. That would suggest that the initial timing was running at around 13* BTDC.
21tWhat front sprocket?
Yes I did but not having any other alternative readily available at this time I used the marks for reference. The bike runs fine snd starts easily st 29* BTDC as indicated with the strobe. I can now play with it to fine tune given that I have a starting point reference.But I thought your earlier point questioned the accuracy of your scale ?
Then the engine is pretty sick or jetted badly since 90 mph with a 21T is about 5200 rpm and it should make it to at least 6000 rpm in 4th gear. RPM/MPH with 21T front sprocket in 4th gear:
With the timing being retarded 17* from ideal I think that would rob a lot of power. I haven't had a chance to do a 4th gear pull since advancing the spark timing.Then the engine is pretty sick or jetted badly since 90 mph with a 21T is about 5200 rpm and it should make it to at least 6000 rpm in 4th gear. RPM/MPH with 21T front sprocket in 4th gear:
4000 68
4500 77
5000 85
5500 94
6000 102
6500 111
Perhaps my static timing technique isn't accurate.Very confusing. If the timing is accurately set at 29 degrees statically, it will strobe at 29 degrees at 3500 rpm. I've installed many of them and never been off more than 2 degrees in either direction.
What ign system are you running?Perhaps my static timing technique isn't accurate.
Let me try to clarify ignition advance using Tri-Spark (nearly the same as points and auto advance unit)The initial reading with the strobe light showed ignition retarded off the scale. A static check with the Tri-Spark indicated 20* BTDC.
Setting the static timing at 29* BTDC yielded adout 22* with the strobe light.. That would suggest that the initial timing was running at around 13* BTDC.