PDA

View Full Version : 1986 250r compression



Jr_79
10-17-2020, 11:32 AM
What’s up everyone I’m new to this and idk if I’m posting this in the correct forum but plz let me know. Ok so I’m restoring a 1986 250r, took it all apart did everything. Now I’m putting it back together the motor seemed good so I didn’t mess with it but the clutch, it kicked good turned good but I never started the trike before the restoration. It was in bad shape (cosmetic) so now that I put the motor in I went to kick start it but it’s really hard just to even kick like it has a ton of compression. I take the spark plug off and it kicks perfect, no funny noises or anything like that the piston moves freely. Took the jug off inspected everything once again everything moves like it’s supposed too. Put it back together tried it again and no luck keeps doing the same thing. I’m only able to kick it if I remove the spark plug. Please help it’s very frustrating. Thanks! And I checked the compression kicks good but it only hits 90psi. Low! I put I plug back and unable to kick

El Camexican
10-18-2020, 01:55 PM
Hey there. Yeah, Trikeslyvania is where you want to post technical questions.

Having trouble understanding your issue.

First off a compression test requires that you kick the engine over just as though you were trying to start it with a plug installed, so if you can thread in a compression fitting and still kick the engine it’s as though you have the wrong plug installed and it’s hitting the crown of your piston and acting like a piston stop. I find that highly unlikely as you probably use a three-quarter inch reach plug to start with, so is it that you absolutely can’t turn the engine over with a plug in it, or it’s just difficult?

Are you doing the compression test properly? You should install the tester, hold the throttle wide open and keep kicking until the needle stops moving up. If you only turn the engine over once then 90 psi would make sense, but you’ve got to keep going until it absolutely won’t go any higher.

If the tip of your plug hasn’t been crushed, eliminating the gap then your piston isn’t making contact with it and that isn’t the problem.

Like I mentioned, if you could install a compression tester and kick the engine over then there is no reason that with the correct spark plug you shouldn’t be able to kick it over just as easily.

Red Rider
10-18-2020, 05:39 PM
Did you plug the exhaust port while the engine was out, and forget to unplug it?