bncracing ~ thanks for the great info ! thank you for helping out our members like this with all there problems !!

Doc wrote:

Great reed! pun intended! Can you list some sources to purchase reed valves, and cages? Thanks!

The folks I know of who sell Reed Cages or Reed Leaf upgrades are:

- Dave from BNC Racing www.bncracing.com/
- Billy Holt from WRH Racing www.WRHracing.com/
- Rich from Hetricks Racing www.hetrickracing.com/

* As Dave's detailed Reed Explanations, one must decide what area of "power band" they want to improve before running out and purchasing any dealer's Reed Upgrade parts. Sounds like these parts needs to be "matched / tuned" with the rest of the performance parts as well.

* And as a final comment, try to purchase reeds, air filter and etc. etc. upgrade parts from the same dealer. This will ensure "proper bundle match" and save you a few dollars on shipping as well.

Hope this helps...

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Dave,

Many thanks for your detailed explanation on Reeds. I know there was a difference in construction design and materials but didn't fully understand the critical importance of each - for one's unique riding conditions.

Many thanks for helping us out in this area too...

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Reeds are easy to replace. Before you start, be sure to clean the area around the carb and intake manifold very well. There's not much room to work in and you don't want any dirt to get into the engine.

Begin by removing the carb. The oil injection line goes directly to the carb so be careful not to damage it.

When removing the intake manifold, I prefer to stand the bike on it's tail. I put a 2x4, 2" side up, under the grab bar to keep the bike from tipping too far backward. If you have oil injection, it's helps to cover the inside part of the oil tank cap with plastic wrap to prevent oil from draining out the breather hole.

After the carb is removed, remove the four bolts from the intake manifold. Some bikes have a rubber flap which needs to be removed also. Lift or gently pry the manifold from the crankcase. The reed block is now exposed. Gently pry it up being careful not to damage it (if you plan to use it) or get dirt into the engine.

If you plan to replace the petals only, they are retained by four little screws, two on each petal. Remove the screws, stops and petals reversing the procedure using the new petals.

Before reinstalling the reed cage, thoroughly clean all surfaces being extremely careful not to allow any dirt or gasket material from getting into the engine. I will place a small rag into the engine opening during the cleaning process to help trap stuff from getting in. Be sure to replace the gasket.

If you are replacing the complete reed assembly, I recommend using two gaskets, one on each side of the reed cage.

Install the manifold and torque to 108 inch pounds (12mn if you have a metric wrench). Tighten the bolts gradually in a cross ways manner, say starting with 20 inch pounds for the first round, increasing the torque by 20 on each go around until you reach the desired tightenss. If during the tightening process, if you find a bold doesn't get tighter, stop because the threads may be stripping. If you catch it early, it can be remedied by using a slightly longer bolt. I use the longest bolts that will fit.

Reinstall the flap and carb and you're done. You'll find it's really much easier than reading this procedure.

As for places to purchase reeds, all the big guys will have them. Some are trinity (www.trinityracing.com), WRH (www.wrhracing.com), Hetrick (www.hetrickracing.com), Simmons Racing (http://etonracing1.homestead.com/etonracing.html), and of course my shop, B & C Racing (www.bncracing.com).

Dave

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Dave,

Hoping you can help TonyD & us with his Kasea Carb cleaning / adjustment questions within the following:

atvfrontier.com/ftopic...html#85392


Thanks.

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Dave,

Hoping you can help ATV4ME & us with his DS90 4 stroke winter starting / running problem. For details, surf:

atvfrontier.com/ftopict-11566.html


Thanks.

.

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Dave,

Wonder if you could help us get an AC 90 4 stroke going again??? For more details, surf:

atvfrontier.com/ftopicp-90253.html

Many thanks.

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Hey Dave, Hope your still hangin around.


Can you give us a run down on what power mods one should do first, second, and so on?
For example, Should a pipe, and clutch kit be the first mods? Or maybe reeds?

Also, Do you have any experience with Sundiro quads? We've had real good luck with these quads. Even though many parts are interchangeable, cross referencing parts for these quads is somewhat difficult.

Hi Doc,

I would have responded sooner but for some reason I wasn't emailed about your posting.

That aside, the first thing would be to change the cdi to one that doesn't have a rev limiter. This would be a good time to opt for a high performance coil as well.

Second, consider the air box and filter system. If you plan to run in streams and soupy mud, I'd keep the stock air box but change the snorkel for a larger diameter PVC pipe. If you're not going to run in wet conditions, I'd replace the entire system with a pod style filter. You'll see the bigger gain in power with the pod. Either option will require rejetting the carb as you need to compensate for the added air flow.

Third, install a pipe and clutch kit. It is important to do these together otherwise you won't see the performance gains. Since the pipe operates in a higher rpm band, it needs the clutch kit in order to get the engine up there where the power is. You will see the most power gain with this combination.

Forth, I'd go to work on the sprockets. Most bikes have a big rear sprocket (35 teeth) intended to allow big kids to be pulled up steep hills. I like to call it a log puller. Once you have the power of the pipe and clutch kit, you can go much smaller on the rear sprocket and / or larger on the front one. A 28 rear will give loads of top end and will work with a properly set up clutch. When I say clutch, I'm talking about everything you see when you pull the side cover - variator, rollers, rear pulley, big spring (torque driver spring), centrifugal clutch and it's little springs, etc.. Remember, this is a transmission and will do the shifting to keep the engine in the power band so you can run smaller sprockets (if properly set up).

Fifth, I'd go after the reeds. The stock reeds are metal and don't perform well. With reeds, you have several options: replace the reed petals and keep the stock cage or replace both the cage and reeds. Either way, you need to choose what type of reed petals. They come in fiberglass and Kevlar. Some people have good luck with fiberglass but I find them to be brittle and tend to break or split so I prefer Kevlar. Replacing the entire cage is better since the aftermarket cages are 15-20% larger which translates into more power.

Sixth, replace the head with a good race head. Race heads have a different shape combustion chamber which will give a considerable boost in power. They also will raise the compression which may require the need to run high octane gas, meaning 105 and up. Sunoco and V/P make fuels for this purpose.

Seventh, I'd go to a larger intake manifold and carb. For stock cylinder porting, you can run most anything up to 24mm. If you go the port & polish route, you can run up to 28mm on a 70cc or 32mm on a 90cc. 32mm is a big carb and requires full race engine.

Eighth, modify the cylinder. You can simply have the stock one ported and polished or replace it it with a larger one. For 50's you can keep the same cc's by installing a Malossi or Polini aluminum cylinder. Or you can go to 70cc by installing a 47 or 47.6 diameter cylinder from Airsal, Polini or Malossi. For 90 engines, you can go to 53 or 54mm bores and replace the crank with a 45, 47, or 48 stroke (stock is 42) for a maximum displacement of 110 cc's (54 bore x 48 stroke). Of course there's the option of going to water cooled, too.

Anywhere in the sequence above, you can get rid of the oil injector and switch to pre mix. I like this better because you have a consistent mixture that is not dependent on throttle position.

If you are trying to get the most out of your engine, you can replace the entire ignition system with an inner rotor system. Stock ignitions are designed with the rotor revolving on the outside of the coils so you are using HP to spin that large mass. Inner rotor systems are designed the opposite where the coils surround a small 2" rotor. Since the rotor weighs less and has it's mass closer to the center line of the crank, the engine can spin up much quicker (like an ice skater pulling in their arms to spin faster).

All of the above pertains to the engine only which leaves the subject of suspension, something for another day.

Hope this has been of help.

Dave

Thanks Dave! That fits the bill for now. I'm sure more questions will arise later.

dear dave
i have a 2004 eton viper 90. i wanted to remove oil injection & install a single throttle cable. were can i get one. i see your sight lists one but i do not know if it is the right one for my application.
thanks.

I don't have any in stock, but can get them within a week. Let me know if you are still interested.

yes i would like one please can you let me know when it is and i will order it from you our should i order it through you know. is it the one on your web site. thanks