BBK questions

[hammer]

I think I made a mistake. I have been doing some spree rebuilding. I am actually doing 2 spree's. I just finished one that I added a 43mm piston from Pro X through Wiesco The mistake I think made was to bore a 1984 spree jug. This is the first time I have worked with an 84 motor so I don't have a real baseline to go from. I am looking for bottom end. that the reason I was build ing the 84 model with the lower ratio gears. It runs okay but it a dog from a dead stop.

I have tried several jet and airbox combos and the motor has no bottom end when I compare it to my 86 models. Can anyone offer any insight into the 84 motors. Will a 87 or 87 jug solve my problem?

I have a TAZ kit that I was going to use on the other spree project I was working on. I could use it but I really want to make this 43mm combination to work if possible. I don't care if my finished project only runs 30mph but I want it to have some guts.

Anyone out there have any advice?

[bakaracer]

You have to give the full details on whats on the bike and what jet sizes you used and what was done to the engine in detail.

[hammer]

The motor is all stock. I used the 84 head. No porting with the exception of a little cleaning of the passages under the reed valves. I used the reed valves and manifold form an Aero. I think it an called SB50?

The piston looks like a clone of the TAZ piston only 43mm instead of 44 mm.

I tried a stock jet and a drilled main jet @.031. Running the motor with .031 and the air box cover off performed the best but just on the top end. On the bottom it might of even been worse. I used a cover that had been open up some too.

No matter what I did made the bottom end any better. I have read on this board that the 84 sprees had some bottom end issues so I decided to wait until I found out more before trying anything else. I have a 86 jug I could have bored if that is an issue.

[bakaracer]

I'm not sure on the drill bit size but it sounds like the jet is too big.find a jet size thats 2 sizes larger than stock and go from there.did you also cut the head squish area to the size of the piston?

[hammer]

Stock jet is closer to .025. The head was not cut. I have not put a compression gauge but it is better than the 2 stock 86 sprees that I have.

.031 is a lot smaller than what TAZ sends with his kit. I could understand .031 being too big but with stock jet it pretty much the same thing on the bottom end. The mid-range power band is good with everything I have done. It just won't take off on the bottom end. I have also tried 2 stock pipes that are known to be good. One off an 84 and one off and 86. Both about the same.

Also the motor starts and idles very good. I tried several needed valve adjustment and nothing seems to changes the take off.

[bakaracer]

Stock jet is closer to .025. The head was not cut. I have not put a compression gauge but it is better than the 2 stock 86 sprees that I have.

.031 is a lot smaller than what TAZ sends with his kit. I could understand .031 being too big but with stock jet it pretty much the same thing on the bottom end. The mid-range power band is good with everything I have done. It just won't take off on the bottom end. I have also tried 2 stock pipes that are known to be good. One off an 84 and one off and 86. Both about the same.

Also the motor starts and idles very good. I tried several needed valve adjustment and nothing seems to changes the take off.

A spree doesnt have valves!

[hammer]

Needle valve on the carb smart *

[hammer]

It is clear I don't need your help.

[bakaracer]

sounds good to me

[Bear45-70]

Stock jet is closer to .025. The head was not cut. I have not put a compression gauge but it is better than the 2 stock 86 sprees that I have.

.031 is a lot smaller than what TAZ sends with his kit. I could understand .031 being too big but with stock jet it pretty much the same thing on the bottom end. The mid-range power band is good with everything I have done. It just won't take off on the bottom end. I have also tried 2 stock pipes that are known to be good. One off an 84 and one off and 86. Both about the same.

Also the motor starts and idles very good. I tried several needed valve adjustment and nothing seems to changes the take off.

A spree doesnt have valves!

Actually they are called reed valves.

[hammer]

Guys I know where the reed valves are! I know where the needle valves are.

The 84 spree jugs are different than the spree 86 jugs. What is the effect of that difference on the spree's bottom end performance?

If you know please say so......... if you don't know don't bother.

My god it was a typo.

[Bear45-70]

Here you go.

[hammer]

Correct I have seen this chart.

Do the numbers suggest you could expect better bottom end performance from a 86/87 non Iowa spree jug over an 84 spree jug?

Would the difference be enough to notice a change in the performance or it is so slight you wouldn't even be able to tell?

[Bear45-70]

Actually theory would say the smaller ports of the '84 should make better low end power than the bigger ports of the later motors. But in real life some times the engine combo (carb, intake, reeds and exhaust) just doesn't work that way. If it was me I'd go for later jug, but I skipped the Spree jugs to use an SB50 jug for my Spree.

[hammer]

Is there a sb50 jug that is a bolt on swap?