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Yamaha R5 running really rich


jaykup
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I checked the plugs, only to find that one of them was the wrong one, and the other was correct. Not only that both of them were pretty fouled out. I replaced the plugs with NGK BR8HS. THe guy at the yamaha dealership told me that they were the same plugs that I looked up on them "B8HS" except they were resister plugs... to me that sounds like its going to get a weaker spark. Whats the difference?

Also, How can I make this thing run leaner? I drove it about a mile, and the brand new plugs are pretty black already. I'm not sure if all two strokes run this dirty, but to me it just seems rich. I cleaned out the points once, then drove it about 100 miles, cleaned them out again (no spots on them) and it seems to be pretty smooth, until I hit about 7K at full throttle, it seems to want to bog down. Shouldn't these bikes scream up to redline? First gear still pulls up the front end a little bit when the powerband hits, but not very high at all. Few inches off the ground.

I have both carbs completely cleaned out, twice.. and I set the larger screw to 2 and a half turns out, and the smaller screw to 1 and a half turns out. It wont idle like this.. unless I turn the large one in about a full turn or more, but then I'm thinking thats going to make it run richer than normal right?

I still need to understand alot about these two strokes, and adjusting/tuning them. As soon as i get some more money, I was going to just go with electronic Ignition so I dont have to worry about these useless points.

I'm out of ideas, and I dont think its running right, anyone have any comments?

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Do you have the stock airbox on it?.....or aftermarket filters?

Sounds like the main jets might be too big.....but I'm not quite sure :?

We'll have to get LC to post his view on this.....he might be able to shed some light on the subject :wink:

When you get the cash saved up, go for a Newtronics Electronic Ignition.....got 1 in my RD400 & it works great! 8)

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Yeah, I really want to get the electronic Ign. Soon I hope. Actually, dont yell, but just to get it to run i put a different battery in it, slightly larger, and the airbox had to be moved forward a little, and i didnt have room for hte intake boots, so its just an open carb. I know, but I need to get the Y-pipe filter ive seen for these, seems to be the best fit.

I messed with the points a little, and got it to run a bit better, in the higher gears it still seems to lose power. Im guessing its the timing now.. and maybe there was too much air with open carbs like that. Whats a good way to get the bike timmed correctly?

Also, could the baffles be clogged a little? One cylinder seems to fire more powerful than the other (according to the exhaust) just seems to have more of a UMPH to it. I'm thinking too the points should just be replaced (how much are they?) if there expensive, ill just go with electronic right away.

How exactaly do you clean out the baffles?

Thanks again for the replies :)

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Noticed you over @ the AC RD forum earlier 8) ......that's as good as place as any to get all sorts of tuning advice....those guys have helped me out quite a bit over the years :wink:

I too, hope to employ the Y-boot set-up this winter on my 400....after I rebuild the brake calipers.

If you get the chance, post a pic of your R5 sometime....love to have a look @ it 8)

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I figured someone would notice :)

http://digitallywarped.mine.nu/bikes/Yamah...0350%20dust.JPG

http://digitallywarped.mine.nu/bikes/Yamah...350%20dust2.JPG

http://digitallywarped.mine.nu/bikes/Yamah...350%20clean.JPG

http://digitallywarped.mine.nu/bikes/Yamah...50%20clean2.JPG

as you can tell from the first pictures it was pretty dirty when i got it. i didnt fully go over it and clean it, but I did spray it down and it got most of the dust off :)

I got it for 100 dollars, and its been a handful trying to get it to run right. Right now for some reason.. when i get done riding, only sometimes, it poors gas out of the overflow. I checked the float slides and they move very smoothly, and the float I think is set right. I just now bent it up so the gas would shut off faster, but now it wont start at all ... damnit. I'm going to have to find the float setting and do it right. It sure is fun when it runs though, Raced my friends 1982 Kawasaki KZ650 CSR and beat him up to 90MPH :) Pretty impressive out of a little 350

Anyway, theres the pics, thanks for the help too.

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Amazing what a little soap & water can do, huh? :D

Not a bad deal for only 100 bucks 8)

I used to ride this Everyday for 13 years......

MySeca.jpg

But after having some rides with a friend on his '75 RD250, I decided I MUST have a stroker for the road! :wink: ......I could only reel him in on the straights, but he'd flat leave me in the twisties :shock:

So I bought this back in '96......

rd1.jpg

I've never had so much fun riding any bike, as I have with this one :wink:

Every bit as fast as the old Seca, up to about 100mph.....& the handling....let's just say it makes the Seca feel like a DUMPTRUCK :shock: :D

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haha no way!!! I've got a 1981 Seca 750 I got from some guy who had to sell desperately for some reason. The seca is a powerhouse, I'll give it that. But the little 350, if it were running right, I think wouldn't do too bad against it. With some better pipes, intake, and what not, I think it would be dead even with the seca. The seca didnt seem to handle all that bad, the R5 was definitely better. The guy before me put straight pipes on the damn thing too, and with the way it vibrates, it sounds like a mean rocket after 6K. It needs a new starter too.

I've got some pics of it, I only got this one for 250, so its not in too good of shape, I was thinking of restoring it over the winter as well.

seca.jpg

Both fun bikes :)

Your's looks ALOT nicer, I like the rims as well. Nice work with that!

I've also got a 1979 Yamaha XS 750 : The damn second gear is F'ed just like all the other ones. So right now its just kinda sitting. Its a fun bike though, 5th gear accel is pretty nice.

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hey jaykup, nice bike ya got there 8) as you'll see from my sig i got a rd400 and xj600. rd and xj's...best of both worlds :D for expert advise the aircooled rd club website is the place to go mate. what size of main jets are in it btw? and has it just got the standard airbox? to clean(decoke) the exhausts hang them up with a bung on the end and get some caustic soda poured down em. works wonders!!

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