Stock Spree with Taz gears..RESULTS!!

[Meatball]

Do you mean pressure test the crankcase? Ive only tested the compression and it was in the 150psi range. My motor is clean enough to eat off of and Ive never seen a drop. I know the case isn't holding buckets of oil but there surely is "some". Id imagine there would be at least some seepage if there was a leak anywhere. The pilot theory sounds plausible since it cant be adjusted and was never intended to be used with a motor other than stock. So someone needs to do a write-up that has had success with a bbk and XXX carb and include what main/pilot/air filter they use. I see on Taz's Ebay auction for the bbk's it shows 81 kits sold. Where are these people and what are they using?!?!

[jakubman1]

Yes we need to know which Aftermarket intake , and Carb to fit the spree to stop burning up engines.

[Ultraliner]

As I mentioned in another thread I had my 'problem' occur after a substantial WOT run on a semi broken bore by going from WOT to fully closed, as Wheelman says overwhelming the pilot circuit and soft seizing the engine.

On my 50mm Af18 taz BBK I have found blipping the throttle after any WOT runs has been sufficent enough to avoid any overheat spike/soft seize problems. Might be worth doing this on the spree kits up until the recommended 100mi break in period is over?

The instructions also mention about not holding the throttle in the same position for extended periods during the break in time

[Meatball]

My seize came after my break-in was around 70mi into it. It took weeks to get there with short trips of varying speeds but nothing over 20mph. It ran great the entire time and purred like a kitten. Acceleration was much improved from 0-20mph and I was giddy as a school boy over the improvement. As soon as I tried wot for the first time for a mere 6 seconds the temp spiked faster than my cht could read and it seized. The motor needs sufficient fuel delivery to stay within safe operating temperature paired with the correct balance of air. Achieving that balance seems to be more difficult than rocket surgery.

[Meatball]

Installed an AX23 today. Take-offs were bad enough with the Taz gears and the new belt made take-offs impossible. Takes forever to get up to speed and its just not practical to ride around like that. I put the stock belt back on and wont re-install the AX23 until a bbk goes with it. Im sure the belt mod by itself is a good upgrade but I just cant use it with the stock bore AND gears.

[benji]

An air leak is what I think too- maybe an air leak that's only present at the high vacuum of wot or the high temp... my mom had a civic a long time ago w a blown head gasket, but if you let the motor cool down it would pressure test great, then a leak would open up at running temp. Maybe the cylinder is expanding at a different rate than the block causing a leak at high temps.

Too bad you couldn't rig up a power jet to the stock carb... that'd give you the extra fuel at wot you need haha.

[jakubman1]

I didn't have any leaks. I sprayed brake cleaner everywhere around the bike. I was desperate to find one but nothing happened .....It just idled the whole time. No raise in rpm.
Im just gonna leave it stock. If you want faster you buy a faster bike.

Thank god I have a 83 aero nh80 that's bullet proof and does 45mph all day stock. I can lean like crazy on turns. Plus its a 2 seater.

[Meatball]

What we know about expansion of different metals at high temps is ultimately the issue. The aluminum piston expands at a higher rate than the steel bore so when theres a spike in temperature at wot, the piston expands faster than the bore and causes excessive friction. Since friction equals heat the lubrication breaks down and even more heat ensues. That's when very bad things happen.

Simply put, the proper balance of fuel/air keeps the entire assembly running at safe operating temps and/or raises/lowers temperatures at a rate moderate enough for the cylinder and piston to expand/contract together without causing tolerances to become too tight and overcoming the lubrication abilities of the oil.

Finding that balance is easier said than done.

[Meatball]

Getting a little cosmetic work done. Black wheels and belt cover.

[benji]

Looks good, I like the red sprees.

Ya the aero 80's were a great bike I've heard, like a 50 w a bbk but factory reliability. I'd like to snag one someday.
Hey, maybe find an aero 80 motor n swap it in? That'd be kick *

[doug9694]

I have a 86 Spree that seems to soft seize after 5 minutes on the grass. No title so just for off road use. Compression is only 80 and is hard to start cold. It starts one or two kicks when warmed up.
Has no filter and runs without then slows to 5mph like I said about 5 minutes. What is the proper temp?. and can I use one of those hand held I.R. units? I figure the exhaust part is the hottest.
What would the head read or the cylinder by the base? Did a leak test and can hear some hissing out when I turn the flywheel a little backwards. No wiggle or in and out in the shaft detected.
I think I am going to take it all apart to find leak and get a new piston and rings and filter.

[Meatball]

Compression minimum is 110 I believe. Sound like it needs a top end rebuild. Tazland sells them on Ebay for a great price.

[doug9694]

110 PSI ?? Maybe that is built into a BBK rebuild. or excessive carbon? The Spree service manual says 7.2: 1. That = 105.8. Have read some quote 120 and 150.
They haven't said where they got that info.

[vintagegarage]

Doug.. page 3-1 under maintenance lists the minimum compression at 113 PSI, so the manual is a bit confusing, wrong, or something else comes into play. I do see in the specifications on 1-3 that early years of Sprees are 7.2 to 1 and later ones are 6.8 to one, but only one minimum compression is listed, i.e. 113. Using sea level atmospheric pressure of 14.696 PSI, I see how you came with 105.8 at sea level for the early Sprees. That would also mean that compression on the 86 and 87 Sprees would be about 100 PSI in spite of what the manual says on 3-1.

The same confusion exists in the SA50 manual, where compression is supposed to be between 114 and 171 PSI while compression ratio is either 6.9 or 7.0 depending on engine. I have no idea where the 171 comes from.. maybe it is a dyslexic typo and should be 117?

In any event, I think 113 is a good number to use as minimum compression on an unmodified Spree or SA50 engine when turned over on the starter.. at least that is what I see.. maybe my gauge is reading high..

[patthesoundguy]

Installed an AX23 today. Take-offs were bad enough with the Taz gears and the new belt made take-offs impossible. Takes forever to get up to speed and its just not practical to ride around like that. I put the stock belt back on and wont re-install the AX23 until a bbk goes with it. Im sure the belt mod by itself is a good upgrade but I just cant use it with the stock bore AND gears.

can't use an AX23 on stock setup if the gears are installed on a stock bore. As you found out. With both its like trying to start your car in 4th or 5th gear. You could run the ax23 on its own if you have some mods done for some.more low end grunt. Like the 84/85 head and the 86/87 domed piston or if you don't mind slower take off