Author Topic: 89-90 Parts Difference Identification  (Read 2085 times)

powerplay

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89-90 Parts Difference Identification
« on: April 12, 2009, 09:02:59 AM »
Ok both the top ends are stripped and cleaned. I already thought i knew the differences between the 89 and the 90 pilots. I have noticed on my pilots the chambering on the 2 heads is different the 89 has a must larger
chamber, does anyone know if this is standard or has it be modified.
Also the reed valve in my 90 pliot is a 4 petal and the one from the 89 is a six petal

Adnoh

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89-90 Parts Difference Identification
« Reply #1 on: April 12, 2009, 10:19:01 AM »
You just let out a well kept secert or not. The 89 head and jug is a little diff from the 90. They changed it slightly in 90 due to emission testing and a change is carb also which made it easier to adjust not so tempramential to elevation and humidy. they can be interchanged but will require a jettting change. The 89 has a better combustion chamber  and the 90 a better squib band area stock to stock. i was going to cover some of this in the other post but since your comparing them loo at the port champher (bevle). the 89 has less angle than the 90 and if you ring a 89 with a loose bore you  must create more heat to swell the piston tight reducing piston slp which snappes off the skirt. The down side to this the crown sweels more as well and the ring will catch on the exhaust port due to decrease in bevle and the as the ring is being collasped back into the piston. The 90 has a greater bevle so its not so prnoe to this. The other is the 89 most lilky has a b or c bore and the 90 an a bore. so the 89 most likly wil be tight with the new one size fits all rings from honda. Dont get me stated on this one. the 90 bore will be a little larger than 89. Now compare the bevles and if need be before hone and rering bevle them to was speced in the book. Use your new rings and compare the 89 to 90. The lny thing I do not like is using the onesize fits all rings in the old pistons. the gapsare off. The piston as it swells my stick the rings. If you can get the right rings for the piston you have. the best thing to do is use the new piston and rings together. The wear on your old psiton skirts will reduce lubracation and may already be stressed on the skirt. I'll let this soak in and toun=ch on more later after you look ovrer the two diff cylinders and use the 89 ring in the 90 cylinder to measure the diff and the 90 ring in the 89 cylinder for comp[arison. than you can deside which way to go. I do not recomend this but have seen the 90  (a) piston used in the wore 89  (b ) or  (c ) cylinder for tighter fit. than a new one size fits all piston and ring in the 90 ( a ) cylinder if thats the case. I post up pic of port bevle for you later or if one of the others can do it. i have to take moter in law to lunch.

Adnoh

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89-90 Parts Difference Identification
« Reply #2 on: April 12, 2009, 10:43:10 AM »
While working on the them the same time use a box to keep 89 and 90 apart. and baggies labled 89 and 90 for piston, rings, pin, bearing ect..  So during testing not to get confused. if the 90 is sealed and 89 is unsealed you know what your working with. been there and done it. please mark cylinder with marker 89 or 90. head no worry diff color.

powerplay

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89/90
« Reply #3 on: April 12, 2009, 11:18:13 AM »
I am impressed! You certainly know your stuff!  :) I did notice the (non existent) bevel on the 89 and was wondering why is was different from the 90. I have ordered a new Wiseco piston kit for the 89 and am thinking I should also buy one for the 90 also I noticed the
Reed valves on both machines are needing changing, I think this is the reason for poor compression. I am confused as to why the reed on the 90 only has 4 petals and obviously
The reed cage is different; I want to order 2 new sets from weed but don?t know what to order
For the 90.

Adnoh

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89-90 Parts Difference Identification
« Reply #4 on: April 12, 2009, 11:42:41 AM »
Reed do effect preformance the gauges are diff and the reed as well. your motor will have compression with out them but willsuffer really bad and do damage to other parts. Once the piston ring go past the exhaust port the volume in the cylinder start to compress as it travles up. The reed or reeed valve is just that a valve that effect transfer and back wash. The vlave shuts keeping the mix in the cylinder and crank case as the piston travles down pushing the mix up thu transfer ports from the crank case as well as being pulled by the out flow of exhasut gas. If the reeds are not sealing under back pressue they let a portion of the mix to be pushed back thu carb and reducing lubration of the crank and effecting intake charge strenght. Look at your 90 head the flow rate on it showes the what I,am talking about as the inatke charge is being stuffed and compressed as well as exhaust flow. After porting a engine you check these for propper transfer balance some times the area is equal but the it pulles a diffeent rate require a change. This is wha to look for.

Adnoh

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89-90 Parts Difference Identification
« Reply #5 on: April 12, 2009, 11:52:15 AM »
couple more pics. If you look at the reed cage area in the compression pic you will see theres no reeds or cage,carb ect. As you add components it effect the resistace of the charge ( chocking down)and changing the static compression rate we call compression readings with the motor setting in the bike with everthing bolted up.  The gauge reads about 180  Once I bolted up componets it read 165 with this head design and porting. This info only relates to the reed question.

powerplay

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89-90 Parts Difference Identification
« Reply #6 on: April 12, 2009, 02:11:17 PM »
adnoh so are the reeds different on the 89/90  6 petal /4 petal ????????

Adnoh

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89-90 Parts Difference Identification
« Reply #7 on: April 13, 2009, 05:11:43 PM »
Yes, you can install one in the other if you choose. The reed topic has great debate. No matter what, use a reed pedal or intake that uses a non metal reed incase it breakes off it does not do engine damage. I use the unpopular v-force 2 and 3 set up depending on motor pacakge and spacer. The spacer is another debatable topic. They call the spacer a torgue spacer. It goes between the reeds cage and cylinder. This does add an increase in intake area and charge volume as well change the time to which the valve closes.  You can thinkk about it as a cam and the intake lift in duration which is required for higher compression. It is not recomded for an non ported or piped engine ( wast of money). The flip side old school says the closer to the cylinder the better for max HP. It really dependes on where you cross over the torgue and horepower. It pretty complacated so I will leave it at that. Ask the board for there recomendations and applacitions they will set you in the right direction. If your wonder why i use the v-force it is because it is a non metal cage and reduces the heat transfer to the carb keeping the intake charge denser longer before entering engine.

powerplay

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reed cages
« Reply #8 on: April 14, 2009, 02:47:05 AM »
Thanks for that information, How do you know so much about engines? you really are brilliant. I wish you lived down the road from me, you would be one cool neighbour to have! :)

Adnoh

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89-90 Parts Difference Identification
« Reply #9 on: April 14, 2009, 04:45:58 PM »
Easy on the brillinat stuff. Most of what I learned was from working on engines and ask question and learning from others. That's the cool thing about the board everybody has something to offer and then we all learn. Belive me I've been wrong plenty of times and paided for it. Just remebr no one has all the ansawers. As far a neighbors go that would be cool. I'am just glad I could help.