1988 RM250 CDI

Mdesmond
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Mdesmond
Edited Date/Time 11/9/2018 7:07am
I’m finishing up a refresh of a 1988 RM250. The bike did not have a spark which I managed to isolate to the CDI. I bought an aftermarket CDI which seems to work well but the bike seems to run out of pull at a lower RPM than expected. It comes on the pipe nicely and pulls hard but tails off quicker than I expected. It is known as a mid range motor but I’m not convinced it is running as it should.

I’m going to check the power valve but as it was fully rebuilt I think it is likely working fine.

The CDI I bought covers several RM model years while the OEM CDI is specific to 1988. I’m going to talk to the CDI vendor to see what they think but I would like to try and find an OEM CDI. If anyone has one or knows where one is available please let me know. I’ve been checking ebay but so far no luck. There may be some NOS available but the price is very high.

Any suggestions would be appreciated.

Mike
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sandman768
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sandman768 11/7/2018 7:06pm
11/7/2018 7:06pm
I have an 88 that I restored a few years ago. It shared some parts with the 87. Have you cross referenced the cdi to make sure it is not used on other models? Have you played with the timing of the stator plate? Could it Be a slipping clutch? There are some RM Facebook groups, alot of guys parting bikes, but the 88 model is pretty scarce.
sandman768
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sandman768 11/7/2018 7:21pm
11/7/2018 7:21pm
I just cross referenced the CDI on Partszilla, it was used on the 86,87 &88 models. Which would have been my guess as those 3 years share a similar platform. Also states the CDI is NLA from Suzuki. At a least you can expand your search to 86-88 CDI"s. Here is a photo of my 88 ....next to my 79,84 & 82. I will be re ringing my 88 sometime this winter....

Mdesmond
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Mdesmond 11/7/2018 7:56pm
11/7/2018 7:56pm
Sandman,

Thanks very much for the reply. Nice family photo you have there!

I don’t think it is clutch slip. It feels like the bike simply runs flat. I did not try and change the timing by moving the stator plate. That’s a good suggestion. If i recall correctly a 2 stroke should retard the ignition at higher RPM so maybe I’ll adjust the stator plate and see if it makes an improvement.

Thanks for the info on the years that used this CDI. I’ll check out ebay and the FB sites and see if I can find one.

How do you like your 88? Does it feel like it has a very narrow powerband to you?

Mike
Mdesmond
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Mdesmond 11/7/2018 9:29pm
11/7/2018 9:29pm
Sandman,

Thanks very much for the tip to look for 86 or 87 units too. Turns out there was one on eBay. It’s on the way to me now. I’m looking forward to seeing if it makes a difference.

Mike

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sandman768
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sandman768 11/8/2018 4:59am
11/8/2018 4:59am
Mdesmond wrote:
Sandman, Thanks very much for the reply. Nice family photo you have there! I don’t think it is clutch slip. It feels like the bike simply...
Sandman,

Thanks very much for the reply. Nice family photo you have there!

I don’t think it is clutch slip. It feels like the bike simply runs flat. I did not try and change the timing by moving the stator plate. That’s a good suggestion. If i recall correctly a 2 stroke should retard the ignition at higher RPM so maybe I’ll adjust the stator plate and see if it makes an improvement.

Thanks for the info on the years that used this CDI. I’ll check out ebay and the FB sites and see if I can find one.

How do you like your 88? Does it feel like it has a very narrow powerband to you?

Mike
My 88 has a Pro circuit pipe & Keihin carb from a 96 Cr 250.., I did not want to replace the Mikuni but could not get it to Work correctly, I suspect there was an internal leak or crack within the carb body. like you stated it has very good throttle response, low end & strong midrange, a little over rev, then signs off. it is not a high rpm engine. Likely a good engine for 1988 but by today's standards it is underwhelming....you can cross reference parts on Partszilla. Select the part in question and click on the part #..... It will pull up another screen that shows you all the models that use that part..... Post up some photos of your bike!
Mdesmond
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Mdesmond 11/8/2018 7:47pm
11/8/2018 7:47pm
Sandman,

Thanks for the Partszilla advice. The screen showing "where used" is very useful.

With the CDI I have now I don't see any over rev. The aftermarket CDI I bought says it works for 1998-1993...but the OEM version covers from 86-88 and then 89-93 so I am thinking the aftermarket one I bought does not have the ideal advance curve for the 1998. Once the eBay one arrives I will give it a try and see. It's worth a shot.

Here is a photo. I need new radiator covers and decals and I have a DEP silencer on the way. Otherwise this one is done.


sandman768
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sandman768 11/9/2018 7:07am
11/9/2018 7:07am
Mdesmond wrote:
Sandman, Thanks for the Partszilla advice. The screen showing "where used" is very useful. With the CDI I have now I don't see any over rev...
Sandman,

Thanks for the Partszilla advice. The screen showing "where used" is very useful.

With the CDI I have now I don't see any over rev. The aftermarket CDI I bought says it works for 1998-1993...but the OEM version covers from 86-88 and then 89-93 so I am thinking the aftermarket one I bought does not have the ideal advance curve for the 1998. Once the eBay one arrives I will give it a try and see. It's worth a shot.

Here is a photo. I need new radiator covers and decals and I have a DEP silencer on the way. Otherwise this one is done.


Looks good.....A few years ago I was able to purchase all new Oem plastic directly from Suzuki...the bags were all tagged with Japanese writing, must have came straight from Japan. I got Oem style graphics from Evo-MX. Then I proceeded to lay it down in a Southwick berm & tear the rad shroud off! ....back in 1987 my first brand new bike was a 87 RM250, it was a very average bike. In 88 they redesigned the tank, radiators & pipe to be lower & sleeker and must have got the porting down better as the the 88 has a much more pronounced mid range hit. I like riding the 88 but the lack of availible tranny gears relegates it doomed to garage queen status...

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