Reed spacer question

[hotrodaj_2]

The way I understand the reed spacer can do two things. If you put spacer between cylinder and reed cage it helps top end, if you put it between reed cage and carb it helps bottom end. Is that true? If so, I'm looking for some more bottom end. I rebuilt topend of engine and when it was apart I cleaned and matched everything in cylinder. The only mod I did was I raised the exhaust port 1mm. That is a small change to help the topend. After riding, it feels like it has alot more topend but has lost more torque than I like. Will a spacer make much of a change or do I have to do it another way. Damit, I never should have touched the exhaust port.

 

[Joey_Stacks]

I had the same question and I hope someone answers this!!!

 

[mopar1rules]

anytime you raise the exhaust port, you're gonna wack away some bottom end. your blow down time might have gotten a little long now, and create a peaky/pipey feeling engine.

 

[super noober]

huh, thats interesting. i always thought the spacer had to go after the reeds, didnt know you had a choice. anybody got some extra info on this??

 

[slickerthanyou]

The way I understand the reed spacer can do two things. If you put spacer between cylinder and reed cage it helps top end, if you put it between reed cage and carb it helps bottom end. Is that true? If so, I'm looking for some more bottom end. I rebuilt topend of engine and when it was apart I cleaned and matched everything in cylinder. The only mod I did was I raised the exhaust port 1mm. That is a small change to help the topend. After riding, it feels like it has alot more topend but has lost more torque than I like. Will a spacer make much of a change or do I have to do it another way. Damit, I never should have touched the exhaust port.

This can't be true. I'm not an expert but Unless you are racing you want to gain tenth of a second i think the spacers are a gimmic, just like the boost bottle. Or throttle body spacer on a vehicle. i do have experience with those and had one on my 351w engine dyno'd before an after guess what no change. i wasted $80 bucks on a piece of aluminum. my 2cents!

 

[98blaster+4]

if you want more lower end get a smaller front sprocket. i have a 12 tooth i'd sell for real cheap

 

[kep3vin]

dont think itll make a diff either way maybe give u a bumper length in a race, usually just used for clearance for bigger carbs

 

[hotrodaj_2]

I can go with a 12t sprocket but I am tryn to keep some top end speed. I have the smallest bike out of all my friends. I'm tryn to not get my ass kicked. If I can get back a little bottom end then I'll be good to go. Compression should be around the 150-160psi and its a BB. Can a timing advance help or hurt, I can go 2degrees to start. I grew up around 4-strokes of all kinds, I'm a novis when it comes to 2-strokes. How else can I get some bottom end back. I'm not sold on the spacer idea, their only 3/8" thick. If they were 1" thick I can see a change.

 

[Little-J]

really, what you should look into doing, is raising your compression ratio. By raising the exhaust port, you essentially decrease the amount of mixture that is squeezed into the head cavity. ( the port is open longer and later in the stroke, so more fuel/air mix gets pumped out of the port)

raising the exhaust port is like increasing your cam overlap in 4-stroke terms. Look into getting your head re-chambered and raising your compression ratio a tad.

Boost bottles do work, but they work on a pressure wave system. imagine you blow air over the top of ur beer bottle, and it hums.. this humming frequency is the frequency at which a boost bottle of that geometry will provide boost. Generally, bigger bottle for low revs, and smaller bottles for high revs. the bottles also boost at the harmonics of the fundamental frequency, so if u tune a bottle right, it will give u a bit of a hit in the low end, and a bit of a hit up in the higher revs. you should make one out of copper tube, and adjust the size till u get what you want out of it, then get someone to make it out of lightweight aluminium for you.. This is a great way of avoiding the calculations for the bottle and its harmonics.

Enjoy Fiddling!

Jason

 

[Joey_Stacks]

in the dennis kirk catalog it says the reed spacer when put between the reed cage and head will produce slightly more low to mid range power. but all their products promise power gains

 

[hotrodaj_2]

I decided to do a head mod. I'll send it off to be done and that will fix the problem. That was the best explanation of a boost bottle I've heard yet. rep 4 that.

 

[Little-J]

thanks dude, I appreciate it!