Hi All. Apologies, I know this has been addressed a number of times in the past but I'd like to get a more informed opinion on the oil injector setting on my MC21. Briefly, based on the amount of oil I have dripping from the Tyga end cans after a ride, Tyga Matt suggested my oil setting may be too rich. The carb slides and the oil pump pulley seem to move simultaneously, essentially as soon as I begin to twist the throttle. From reading past posts, my understanding is that at WFO throttle position, the second index mark on the pulley should align with the index on the pump body. As I hope you can see in the attached picture, the second mark on the pulley rotates past what I believe is the index on the pump body. I realize the angle of the pic is not ideal, but it looks to be going 3-4mm past when I look from straight above. At half throttle, the first pulley index mark likewise goes past the pump body index by about 3-4 mm. Sooooo, does this in fact indicate that the oil injector setting is too rich? I'd like to get less smoke and oil dribble but I also don't want to grenade the engine. If I'm honest I'm not much of a mechanic. Any help appreciated.
Jim
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-Jim
'93 MC21

Hi Jim,

My understanding is that on certain mc21’s, there are markings such as a dot indentation on the carburettor slides.

When at 50% throttle, the dot on the slide should be at the top of the carb throat and the first line on the oil pump pulley should align with the oil pump body mark.

When at WOT, the mark on the middle of the pulley should align with the oil pump body mark.

From your photo, your pulley seems open a few mm more. I’ve been told that adjustment of the oil pump cable isn’t so critical as long as you’re close enough.

With regards to smoke and spooge, I would check your float height is around 13mm and your jetting. I also had a issue with spooge and coming down one size on the main jets resolved it.

How are you riding your bike? What do your spark plugs look like? What oil are you running?

Hi Jim - not sure if you have seen this link on the website but it details how the oil pump should be set up http://tech.nsr-world.com/nsr250/all-nsr250/nsr250-oil-pump-setting.php
if you go to the "search" tab and type in oil pump - it will also get you previous queries

[quote="sami1"]Hi Jim,

My understanding is that on certain mc21’s, there are markings such as a dot indentation on the carburettor slides.

When at 50% throttle, the dot on the slide should be at the top of the carb throat and the first line on the oil pump pulley should align with the oil pump body mark.

When at WOT, the mark on the middle of the pulley should align with the oil pump body mark.

From your photo, your pulley seems open a few mm more. I’ve been told that adjustment of the oil pump cable isn’t so critical as long as you’re close enough.

With regards to smoke and spooge, I would check your float height is around 13mm and your jetting. I also had a issue with spooge and coming down one size on the main jets resolved it.

How are you riding your bike? What do your spark plugs look like? What oil are you running?[/quote]

Thanks for responding. As far as riding, just street/sport riding and oil is Motul 710 full synthetic. The dots on the slides do line up as they should at half throttle but the pump pulley rotates past the index for half throttle and also at WFO. Plugs also look oily (see pic), so I think I'll try adjusting - not sure which direction that means on the adjuster, but I'm hoping it will be apparent if I'm going the wrong direction before I bugger something. I do have a penchant for making matters worse before I eventually make them better , which is the reason I posted to make sure I was seeing things correctly. So many thanks. - Jim
_________________
-Jim
'93 MC21


Last edited by Jim on Mon Jan 25, 2021 1:42 am; edited 1 time in total

poosterwyk wrote:Hi Jim - not sure if you have seen this link on the website but it details how the oil pump should be set up http://tech.nsr-world.com/nsr250/all-nsr250/nsr250-oil-pump-setting.php
if you go to the "search" tab and type in oil pump - it will also get you previous queries

Yes, thanks, I had seen that and the others. I wasn't 100% sure I knew where the index mark on the pump body was so I wanted to verify via the group as much as possible that the pulley is going past where it should at both half and WFO throttle position - it seems like I need to back off the oil pump setting a bit. I'm hoping this will not affect that carb-slide settings given that the instructions for adjusting the pump are separate and there is no mention that adjusting the pump should alter the carb-throttle settings. Fingers crossed. - Many thanks.
-Jim
_________________
-Jim
'93 MC21

Jim wrote:

poosterwyk wrote:Hi Jim - not sure if you have seen this link on the website but it details how the oil pump should be set up http://tech.nsr-world.com/nsr250/all-nsr250/nsr250-oil-pump-setting.php
if you go to the "search" tab and type in oil pump - it will also get you previous queries

Yes, thanks, I had seen that and the others. I wasn't 100% sure I knew where the index mark on the pump body was so I wanted to verify via the group as much as possible that the pulley is going past where it should at both half and WFO throttle position - it seems like I need to back off the oil pump setting a bit. I'm hoping this will not affect that carb-slide settings given that the instructions for adjusting the pump are separate and there is no mention that adjusting the pump should alter the carb-throttle settings. Fingers crossed. - Many thanks.
-Jim

Hi Jim,

Adjudting the oil pump cable should not throw your carb slide settings out, as Sami said you want to try and aim for the index mark to line up when the dot indent on the carb slide is at the top of the inlet tract.
Another tip is to ensure that both carb slides move together instantaneously, just to make sure they are in balance.
Even after your adjustments there may be some small amounts of residue in the exhaust system that m might take a little while to clear.

That was an oily plug in the image you shared, fresh plugs and a plug chop after you have got set up?

Okay, thanks for the tips, Max. Yes, definitely, I ordered some new plugs this morning. I literally had "BR9ECM" work its way into my dreams SEVERAL TIMES last night!
-Jim
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-Jim
'93 MC21

After how much should we change it

If you're asking about plugs, I think with normal use the recommendation is to change every 5k. If you're talking about the oil injector settings, it would just be only if and when it is off the setting marks previously discussed.
-Jim
_________________
-Jim
'93 MC21