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View Full Version : Weird problem with my SV650 2002

CemSV650
02-07-15, 12:28 PM
Dear SV riders and others,

This is my first post so i'll introduce myself. My name is Cem, i am 25 years old, i am a chemical engineer and a fireman and i love motorcycles.

Well now i have a SV650N from 2002. At lower gears it accelerates OK (ok because i feel like it's not a 70 bhp bike) but at higher gears starting from 4 or at higher speeds from 100 km/h i have very very poor acceleration like the bike is restricted.

I thought so, so i searched everything. Washers? Found none. Throttle stop? Throttle valve fully opens. Restricted air flow? I renewed the air filter. Restricted fuel flow? I checked the fuel filter and pump and everything seems to be working well.

Then i started to dissassemble the carbs as i thought that one of the jets was clogged or something. Cleaned the carbs, i even changed the diaphragms and it didn't help. I had my doubts about the carb slides so i took a picture. Could you check this for me? Is it a restricted one or what is it?

http://imageshack.com/a/img673/5387/iQpIhX.jpg

Now, here i am with this problem. I want my bike to run normal and not like this because it's not very safe on the highway.

Could you tell me the difference between a restricted and unrestricted bike? What kind of restrictions are there? The ones i didn't mention :) Will installing a new carb help? Or should i take it to the dealer? (i don't want to spend a lot money so i prefer doing things my own.

I hope you'll can help me ..
timwilky
02-07-15, 03:08 PM
see this phot from TSM's derestricting thread
http://www.pyroserve.com/tsm/derestrict_SV650K2_step12.jpg

The top slide with the hole in is restricted.
The lower slide is normal.
CemSV650
02-07-15, 04:27 PM
see this phot from TSM's derestricting thread

The top slide with the hole in is restricted.
The lower slide is normal.

I hoped it was the top one but it wasn't :( But i did notice the exhaust on the rear cylinder didn't get very hot while the engine was running, i could grab it. The front one i couldn't even touch because of the heat! Could this be it?
nutzboutbikes
02-07-15, 07:36 PM
Yes it could I would start by checking you have a good strong spark on the rear cylinder.
Biker Biggles
03-07-15, 09:00 AM
Yes it could I would start by checking you have a good strong spark on the rear cylinder.

Yes.If you can touch the pipe then the rear cylinder isnt firing.It should be as hot as the front one-ie effffing hot.
CemSV650
03-07-15, 10:57 AM
Yes it could I would start by checking you have a good strong spark on the rear cylinder.

I'm checking this this evening or tomorrow !

Yes.If you can touch the pipe then the rear cylinder isnt firing.It should be as hot as the front one-ie effffing hot.

Haha that's what i thought after really touching the front pipe :D I hope to know more tonight or this weekend!
CemSV650
03-07-15, 06:26 PM
Well as promised i did my thing. Unplugged the rear spark plug and i found that the plug has become black from carbon deposit (that means unburned fuel i suppose which could explain the fuel smell from the exhaust !). And the plug is a CR9E. This is some pics of the rear plug.

http://imageshack.com/a/img540/97/mSjgZN.jpg
http://imageshack.com/a/img537/1741/TDIYmy.jpg


I did the same with the front plug. That one was not wet and is brownish.

http://imageshack.com/a/img537/6222/wt3WEQ.jpg

But i feel like it needs to be changed to. Can you tell me if this can be the cause of a not/bad working cylinder? Because both plugs have carbon deposit, maybe i should change them to CR8E's?
Bibio
03-07-15, 06:32 PM
yes change them to cr8e. also worth checking the HT leads to make sure that they are secure and not broken down at the plug cap and coil ends.
CemSV650
03-07-15, 06:36 PM
yes change them to cr8e. also worth checking the HT leads to make sure that they are secure and not broken down at the plug cap and coil ends.

Allright ! What are the HT leads?
nutzboutbikes
03-07-15, 06:36 PM
FYI the ht leads on the curvy can be changed by unscrewing them and screwing new ones in.
nutzboutbikes
03-07-15, 06:38 PM
Allright ! What are the HT leads?



Leads (high tension wires) that go from the coil to the spark plug cap!.
CemSV650
03-07-15, 06:39 PM
FYI the ht leads on the curvy can be changed by unscrewing them and screwing new ones in.

Ah now i know what you mean ! Well i measured the voltage on it and it seemed to be ok. So i guess that's fine? I am going to change the spark positions to see if that helps !
CemSV650
03-07-15, 06:54 PM
I solved it ! I guess :)

So i placed the front plug in the rear cylinder and vice versa. Now the rear exhaust got hot and the front one didn't. So it was a spark plug issue ! Tomorrow i'll buy new spark plugs. Which one? Sure of CR8E because the CR9E went black?

Well thank you all very much ! i'll test it tomorrow and let you know for sure my findings !
PhilSV
03-07-15, 07:13 PM
Standard riding 8's, track days use 9's