Hard start after below freezing temps.

[Thornt1]

I picked up a 2020 axys 850 last year it came with a SLP Power Dome head, stock pipe, and SLP can. No other mods that I can tell. It runs great except if it sits over night in below freezing temps. It won't start unless I take the plugs out and warm them up in an oven or in the mr. buddy grill and put them back in super hot. At that point, if I time it right with the pull start and open throttle it will usually fire up like normal. Once it reaches operating temp, I can shut it off and it'll fire right back up like normal. Not that compression on a 2 stroke is a super accurate indicator, but both cylinders are at 80psi at 65F-70F ambient temp. Any thoughts on the situation would be appreciated. Thanks in advance.

 

[Murph]

Compression is low— have you checked with another gauge?

At 6000’ ,holding throttle wide open, I typically see 105-120 depending on gauge looking for cylinders to be within 5psi of each other.

2020s also had a later flash available for easier starting/ less plug fouling— available through your dealer.

 

[Thornt1]

Compression is low— have you checked with another gauge?

At 6000’ ,holding throttle wide open, I typically see 105-120 depending on gauge looking for cylinders to be within 5psi of each other.

2020s also had a later flash available for easier starting/ less plug fouling— available through your dealer.

I haven't used a different gauge, good idea. I am testing compression at 4500'. Compression isn't affected by throttle position in anyway.

 

[TRS]

Standard test ritual is 5 pulls with wide open throttle.

 

[Thornt1]

Standard test ritual is 5 pulls with wide open throttle.

I did 8 pulls each side, with throttle closed and 8 on each side with throttle wide open. Same result.

 

[tuneman]

Compression isn't affected by throttle position in anyway.

No, it's not, but compression testing sure the hell is!

 

[Thornt1]

No, it's not, but compression testing sure the hell is!

You didn't actually read the whole thread did you? Of course compression testing is affected by throttle position. Open throttle equals more air in the combustion chamber. I stated that my pressure in each cylinder didn't change based on throttle position. 80 psi closed 80 psi full open.

 

[TRS]

I would pull your ex valves and look at your pistons. 80 is very low.

 

[Jay]

I've always checked just the first pull numbers, then I give it 4 or 5 more.