I swapped out the pilot jets yesterday and went for a quick boot around the block. /I was looking the bike over afterwards and noticed that there was no oil in the oil line feeding the left cylinder. It was a few inches back. I'm guessing it dripped out while I had the carb out. Now I'm thinking ive scarred the sides of the piston or rings. I'm going to removed the head and have a peak at the cylinder walls to look for transfer but I wanted to ask....
Whats compression supposed to be on a stock RD400c?
There probably will not be anything wrong as normally there is quite a residue of oil held within the crankcase, I which case you got away with it.
If it didn't seize why mess with it?
I went through this same issue last year. My conclusion was that I either didn't properly prime the pump or that when I removed the nozzles I didn't get a good seal due to working them out and not pulling them straight out.
Good luck
It's running fine, thankfully. Just paranoia that the piston wall is smudged now.
These little motors are actually pretty tough.
While sometimes it may seem they are prone to failure they can actually handle quite a bit of abuse without serious damage.
Quote from: pdxjim on April 27, 2020, 11:56:30 AM
These little motors are actually pretty tough.
While sometimes it may seem they are prone to failure they can actually handle quite a bit of abuse without serious damage.
Reminds me of my bike when I first got it running (right after buying it). Grinding away, sounded angry. It was idling with no cages in 2 of the main bearings, a giant crack down the cylinder wall, and a piston so scorched it had chunks missing from it. Oh and no base gasket on the burnt piston side.
when in doubt, pull the exhuast pipe and look at the cyl/piston thru the exhaust port with a bright flashlight. :twocents:
but i bet its ok.
Good idea. I'm gong to do a leakdown anyways so I'll have a peek.
Edit.... yup... had a peek up the ports before doing a leakdown and the pistons look perfect. No blowby passed the first ring either :) Very happy to see that.
Quote from: Czakky on April 27, 2020, 07:22:21 AM
If it didn't seize why mess with it?
I went through this same issue last year. My conclusion was that I either didn't properly prime the pump or that when I removed the nozzles I didn't get a good seal due to working them out and not pulling them straight out.
Good luck
I recall this. Glad you figured it out!
Quote from: rd400canuck on April 27, 2020, 03:25:14 AM
Whats compression supposed to be on a stock RD400c?
to answer your initial question - compression should equal about 125 +/- 10