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Makotosun
1971 Yamaha AT 1 ...runs with pilot screw all the way in.
- mpritch41
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1971 Yamaha AT 1 ...runs with pilot screw all the way in. was created by mpritch41
So I finally have the 1971 AT 1 running.
cranks easy idles smooth. Revs quickly...but only with airscrew turned all the way in. If I adjust it out at idle even 1/2 turn it dies.
It will crank up but bogs at 3-4k.
so I'm thinking lean. Standard jet is #30 ( and I have tried that) now have #35 in.
main jet is#150( tried #160 and ran worse) and I have needle clip on lowest position after trial and error.
Plug looks rich.
Checked for airleaks around carb etc.
Carb is clean. Timing is correct.
compression feels adequate.
so with the screw all the way in...runs clean to 3k...sputters 4-6 k then revs on out.
Any other ideas?
cranks easy idles smooth. Revs quickly...but only with airscrew turned all the way in. If I adjust it out at idle even 1/2 turn it dies.
It will crank up but bogs at 3-4k.
so I'm thinking lean. Standard jet is #30 ( and I have tried that) now have #35 in.
main jet is#150( tried #160 and ran worse) and I have needle clip on lowest position after trial and error.
Plug looks rich.
Checked for airleaks around carb etc.
Carb is clean. Timing is correct.
compression feels adequate.
so with the screw all the way in...runs clean to 3k...sputters 4-6 k then revs on out.
Any other ideas?
21 Jun 2021 06:26
#1
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- Pete-RT1
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Replied by Pete-RT1 on topic 1971 Yamaha AT 1 ...runs with pilot screw all the way in.
Did you replace the flywheel side crank seal in the end?
Might be worth doing a leak down test, there are a couple of current threads running about the process.
Experts will be along later to help you, I'm sure.
Might be worth doing a leak down test, there are a couple of current threads running about the process.
Experts will be along later to help you, I'm sure.
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21 Jun 2021 09:21
#2
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- msavitt
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Replied by msavitt on topic 1971 Yamaha AT 1 ...runs with pilot screw all the way in.
in my unqualified opinion I suspect either a plugged primary circuit or an air leak.
The following user(s) Liked this Post: Mothersbaugh, RT325, asco
21 Jun 2021 09:25
#3
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- mpritch41
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Replied by mpritch41 on topic 1971 Yamaha AT 1 ...runs with pilot screw all the way in.
Yes...replaced all seals.
Thanks
Thanks
21 Jun 2021 17:56
#4
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