Page 1 of 1
Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 1:34 am
by ashlanky
I just finished rebuilding my 87 Spree motor and it starts up and runs with no problem, and when I take it out around the block it only goes about 25mph flat and down hill and 15mph uphill. When its full throttle it seems like it chokes up and doesn't feel right. I kept the same piston and re-honed the head. I've read about a break in procedure that I am supposed to do before riding this thing, what is that procedure for a stock 87 Spree motor? I've also read that I need to add more oil than the oil pump will give on a new motor, how much? I am not very experienced with small motors so any advice is greatly appreciated.
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 2:04 am
by bakaracer
did you get new rings? did you check the compression with a gauge?
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 2:06 am
by ashlanky
Yep new rings, my old compression tester says 20 psi, however if it was that low I don't think it would run at all so it could be that my tester is bad.
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 2:12 am
by Bear45-70
Did you hone the cylinder? It would not even start with only 20 PSI of compression.
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 2:21 am
by ashlanky
Yes everything was honed.
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 2:54 am
by ashlanky
I'm thinking my poor performance is because I haven't followed any kind of break-in procedure. What would be proper procedure to follow to break this motor in? It has the original piston and head, just re-honed, and new rings. The engine is stock with no bbk or aftermarket parts. Would I need to add any extra oil aside from what the injector is giving?
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 4:49 am
by bakaracer
climbing hills with a fresh bore and rings with no heat cycles(at lease 3-4) and low speed throttling up and down while riding about 2-3 tank fulls is a no no. do a compression check to see where your at if its under 114psi you got a problem. 114psi is the service limit for stock setup.
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 11:04 am
by ashlanky
So I go through a few heat cycles, and then only ride on flat land no higher than 1/2 throttle varying speed for around 2 tanks? After the heat cycles when I take it on trips trips of 1/2 throttle, do I need to keep those trips short or does it not matter if I take it around a flat neighborhood for an hour or so?
Re: Newly rebuilt motor not running at its full potential.
Posted: Mon Jun 14, 2010 9:17 pm
by ashlanky
Also the area where I live is nothing but rollings hills, which makes breaking the engine in quite difficult, any suggestions with that?