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Ducati Champion Del Mondo
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Discussion Starter #1
I finally got my YSR inspected today to make it fully street legal but I have a problem with it after riding it. 1st gear is nothing on these bikes its 2, 3 & 4 that has all the power with 5th as an over drive gear. The problem I am having is when I hit about 30 MPH + in 4th gear the bike is bogging down very bad. I pull in the clutch and blip the throttle but it does not seem to clear it. I then down shift and that still does not help much. So after I got back from riding I pulled the plug and it looks really bad. It looks to me like it started to melt on the end of it… I am surprised if it is running too lean but you guys take a look at the plug and let me know.

I need help! =[
Jason

PS: The reason why I did not think the bike was running lean is because there seems to be a fair amount of smoke as well as oil residue coming out of the pipe.



 

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i'm a 2stroke tuner so let's see if i can be of help, looks like you're running way too lean, try increasing your main jet until the the plug reaches a medium to dark brown color, it's ok to run them a tad rich b'coz the YSR has an aircooled engine the extra fuel helps cool the cylinder. don't be misled by the smoke coming out of the pipe it's just oil residue burning off from the hot exhaust.

are you running premix or does it still have an oil pump? what plug & heat range are you using?
 

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Ducati Champion Del Mondo
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Discussion Starter #3
Well it had a BHES plug in it.

Looks like it should have a B7HS (stock), then there is B8HS, B9HS & B9HVX. Maybe the bike did not even have the right plug in it "ES"? The main jet should be 180 on a 20mm carb.. I am going to pull it today to be 100% sure.

I am running premix, 32:1.

Jason
 

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Discussion Starter #4
I just pulled the jet, 170... Not Good. =[

If the engine did not seize when running it, do you think it will be ok? Do you think any damage has occurred as a result of this?

Jason

PS: I am going to get the right jet in it (180) and put a new plug in it.
 

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Visitor Q said:
Well it had a BHES plug in it.

Looks like it should have a B7HS (stock), then there is B8HS, B9HS & B9HVX. Maybe the bike did not even have the right plug in it "ES"? The main jet should be 180 on a 20mm carb.. I am going to pull it today to be 100% sure.

I am running premix, 32:1.

Jason
you should run at least a B8HS plug & gap it closer to 0.50mm the YSR50 has a high rev engine, your jet size is small for premixed gas you should start out rich & jet down as you go, if it's blubberring at WOT jet down & try again until it revs cleanly when the engine is hot.

start out on a 220 & go down in increments of 10, aircooled 2strokes run better with richer jets, with a richer mixture it should take a while (thorough warm-up) before the engine revs clean but it's better than to hole a piston or seize the engine.

edit; so you have a 170 that's very small, i think 180 won't cut it but it's worth a shot but if i was tuning your YSR i'd put on a 200.
 

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r6beater said:
i'm just wondering where the rest of that plug's ( forgot term) ground went ?
it's called a ground ELECTRODE.
 

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Discussion Starter #8
r6beater said:
i'm just wondering where the rest of that plug's ( forgot term) ground went ?
I don't think anywhere, I just think it bunched up there on the end of the plug because I pulled the head and it looks clean.







I know one thing that was happening for sure, that gasket is shot and I had to be losing compression there.

The only thing other than the gasket that I can see that is not perfect is the top of the head, there are a few marks there. Is this ok?

Thanks.
Jason
 

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looks to me your head gasket failure & your ground electrode melting was due to detonation, good thing the gasket is made of aluminum & took the brunt of detonation b'coz if not you'd be looking at a hole in your piston.

just clean the areas around the gasket surface & mount a new aluminum gasket, better buy a couple just in case you need another, the volume of cylinder on those YSR50's are really small so to be pretty sure i suggest using higher octane gas like 93 or 95 & as i have said earlier fit a bigger jet (200) & go from there.

as long as the engine runs ok when it's hot don't worry about the jetting being a bit rich as long as you don't foul a plug, aim for a dark brown plug color.
 

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Discussion Starter #10
I am pretty sure that gasket was well on it's way to what you see now before I even had this problem because I saw signs of oil blow up on the carb. prior. =[

Jason
 

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i had a gasket look like that minutes after it was started, the cause was too much compression ratio & lean main jet, i doubled the head gasket to lower the compression ratio & install a bigger main jet, problem solved.
 

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Discussion Starter #12
Well I got the info. on the bore and I re-measured again closley, it's a 43mm bore, I am 100% sure this time... So I am guessing that would make it a 60cc then?

Jason
 

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almost, it's 58cc actually. now your compression ratio's really way up with the extra 8cc. just remember what we talked about & you'll be fine.
 

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OveRReV,
You ios a smart man, man. Its been a while since I played 2strok, but everything you sais is true and very well stated.
Just thought I should let you know man, thats pretty good ish on your part
 

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thanks dude, 2stroke tuning has been a very big part of my life, ported a lot of cylinders for street & race mostly on scooters. when i'm not here at 600RR.net i hangout with the Dutch on a 2stroke tuning forum. nothing smells better than the aroma of castor based 2stroke racing oil.
 

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steelrain said:
OveRReV,
You ios a smart man, man. Its been a while since I played 2strok, but everything you sais is true and very well stated.
Just thought I should let you know man, thats pretty good ish on your part
I agree. Nice work man.
 

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Discussion Starter #17
OveRReV said:
almost, it's 58cc actually. now your compression ratio's really way up with the extra 8cc. just remember what we talked about & you'll be fine.
You think I will need to double up the head gasket or should I be ok once I replace it, jet the right jet in there and plug.

Jason
 

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Visitor Q said:
You think I will need to double up the head gasket or should I be ok once I replace it, jet the right jet in there and plug.

Jason
it's best to err on the safe side of things so yes i'd double the head gasket to bring down the compression ratio nearer to stock that minimizes any chances of detonation, use the 200 jet & screw in the B8HS plug & test the bike carefully at first, twist the throttle slowly & feel the engine's behavior, if it bogs down it's still lean, if it runs good at full throttle do a plug chop & check the color.

keep me posted.
 

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Discussion Starter #19
OveRReV said:
it's best to err on the safe side of things so yes i'd double the head gasket to bring down the compression ration nearer to stock that minimizes any chances of detonation, use the 200 jet & screw in the B8HS plug & test the bike carefully at first, twist the throttle slowly & feel the engine's behavior, if it bogs down it's still lean, if it runs good at full throttle do a plug chop & check the color.

keep me posted.
If I decide to run one head gasket will I still be ok?

So use the 8 to test and then after the 9, correct?

Jason
 
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