Super Jet can you flip reeds???

[Little Trumps Super Jet]

i ran my comp at 175psi last ride and 3 weeks later i checked my compression, it went down to 130 and i just put in top end kit. so i pulled carbs and reeds and found some space in my reeds causing me to lose compression, there am reeds but im unsure which. i was told you can flip them to fix this??? is it possible. thanks LT

 

[TheBuzzard]

a lot of aftermarket reeds hang open a bit. some hang open as soon as you tighten the screws down , installing them. the local guru and source of some of my knowledge, doesnt think that hanging open, has any effect on performance. i personally havent noticed any performance increases, going from stock reeds to aftermarket. i also heard that carbon fiber reeds work when new but wear out very fast and then perform worse than stock reeds.
oh yea, and reeds have nothing to do with your loss of compression pressure. reeds are for keeping the crank case and fuel/air mixture pressure from backing into the intake. that pressure is what pushes the air /fuel up the transfer ports and into the cylinder as the piston comes down. nothing more!

 

[Little Trumps Super Jet]

problem is there all uneven and open and some are close, doesntlook like they should

 

[Matt_E]

Regardless, that's not the reason for your loss of compression.

 

[Little Trumps Super Jet]

ok. what do you think it could be, exhaust doesnt matter right? if i had 3 bolts out of my manifold. i didnt think it did. and im still wondering if i should flip the reeds no matter what

 

[Matt_E]

Yes, you can flip reeds. If that doesn't fix the reeds not sealing, get new reeds.
As for your compression, pull the head and check the bores.

 

[Little Trumps Super Jet]

will do, thanks Matt, much appreciated. i will get back to you in an hour, anything specific i should look for or just scoring and ware?

 

[dbattersby20]

You can flip the reeds. I only see a couple down sides to doing it. They would be more likely to break, it's like when you bend plastic back and forth and then it snaps, and they might weaken a bit.

 

[Vumad]

Reeds don't always sit tight to the cage. It's like a scupper. Scuppers don't close unless they have pressure on them. Reeds are the same way. When the case makes pressure, they close right up.

The only things really involved in your compression are pistons, rings, cylinder walls, head and head gasket. The rest is not really related to the compression. Check it again, make sure you have the throttle wide open and if it's still low, you need to pull the head off and check it.

 

[nbatch95]

Sounds like you put in a new top end and did not get a good seat on the rings. Fresh set of rings and a fresh hone and put your top end together dry. no oil on the cylinder walls, only a very light wipe on the skirt of the pistons and you should be ready to go.

 

[OCD Solutions]

put your top end together dry. no oil on the cylinder walls, only a very light wipe on the skirt of the pistons and you should be ready to go.

Really? I always oil my cylinders before assembly. Should I not be?

 

[N3vrSat1sfied]

Really? I always oil my cylinders before assembly. Should I not be?

Im with OCD, I have always used some oil, and I raced MX for nearly 10years so I have done many of bike top ends.

 

[kieran79]

I oil the cylinders too

 

[Big Kahuna]

What kind of gauge? If from auto parts store then that may be your issue.

 

[ProSouth]

I cake oil all over my stuff when I put it together. I wouldn't put it together dry like that. Hopefully it's nothing major with your engine. Good luck

 

[Vumad]

Sounds like you put in a new top end and did not get a good seat on the rings. Fresh set of rings and a fresh hone and put your top end together dry. no oil on the cylinder walls, only a very light wipe on the skirt of the pistons and you should be ready to go.

No way. I put a coat of oil on everything. Oil doesn't damage the pistons on the cylinders, but the lack of it certainly will. 1st tank is 25:1 for a reason. Fresh top ends need lots of oil.

The exception of course is if you are absolutely stupid about how much oil you put in it and hydrolock the motor. Oil wont compress, so adding too much oil will artificially raise your compression for a short time..

 

[nbatch95]

Dry is the only way to fly. Works great every time. Think about how much lubrication it gets when running. Most run 50:1 mix, that's not much lubrication. The main concern with a fresh topend is getting a good seat on the rings. Put a buch of lube on the cylinder walls and rings and they have no way to seat. No lube makes them bite in and seat quickly. I actualy use ATF on the piston skirt because it is very light. Just trying to keep the piston from sticking for the split second there is no lubrication. Once the motor is running its lubricated.

 

[Freakrider]

Lt where r you? This is your thread , what did you find out?

 

[nbatch95]

Im with OCD, I have always used some oil, and I raced MX for nearly 10years so I have done many of bike top ends.

Newer two stroke dirt bikes are totally different as they have nicasil coated cylinders. They can't be honed. They do require more lubrication when new.

 

[Matt_E]

Are you saying there is something wrong with having lightly oiled bores on a new topend prior to startup? As in, something bad will happen?

Newer two stroke dirt bikes are totally different as they have nicasil coated cylinders. They can't be honed. They do require more lubrication when new.

Why?