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Post by harleyracer59 on Jul 27, 2018 17:53:49 GMT -5
I still might get that yasumi for my express or future build guy already offered it to me for 100$. I think I can still get him lower. or pass the info on to a Yamaha buddy. the sr50 is a minirelli I believe.
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Post by harleyracer59 on Jul 30, 2018 21:50:22 GMT -5
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Post by harleyracer59 on Jul 31, 2018 3:12:09 GMT -5
so tonight I cut the first section of header off at the weld, bent the breacket a little, bolted it up again and twisting the cut off section puts it right into the exhaust flange like it was made for it!! question is is that gonna be to big diameter for the beginning of the pipe?   |
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Post by 190mech on Jul 31, 2018 3:47:20 GMT -5
Fitment looks good!Dont understand what you are saying about the flange issue,,measurements of the 2 parts should help..
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Post by harleyracer59 on Jul 31, 2018 5:22:23 GMT -5
I wrote down the measurements for the pipe and drew a port map. a pic of the paper is at the bottom of my pics 2 posts ago. if I attach it like it is the id at the flange be 27-28mm. is that too big of a header ID?
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Post by 190mech on Jul 31, 2018 6:55:46 GMT -5
Thats the typical port size for a decent 70cc kit cylinder,,so your exhaust flange in the cylinder is smaller than that?
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Post by harleyracer59 on Jul 31, 2018 9:57:45 GMT -5
yeah. its like 24-25mm at the cylinder flange.
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Post by 190mech on Jul 31, 2018 10:25:26 GMT -5
Try to match it up with your porting tool and keep us posted how it runs!!  |
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Post by harleyracer59 on Jul 31, 2018 10:57:31 GMT -5
for sure. I have an oil change to finish and recharge an ac. after that, and probably during... im gonna mark the new angle and weld her up. im still debating on cutting the next section down and clocking it inward a little. its a bit close to the side fairing for my liking.
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Post by 190mech on Aug 2, 2018 3:50:58 GMT -5
Harley,
I was checking your pipe dimensions,had a hard time reading them.I assume the curved sections were measured thru the middle of the arc?I figured the head pipe is 28 OD?Here are the numbers I think are there,,Its written diameter-length-diameter;
28-145-28
28-160-35
35-155-50
50-40-62
62-124-100
100-52-100
100-50-87
87-120-20
Are these correct??
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Post by harleyracer59 on Aug 2, 2018 5:18:12 GMT -5
sorry for the confusion. that was the pipe measurements out the box. that's all correct except the first set. all I used from that head pipe was 15mm in the slip on part so that number should be 28-15-28
28-160-35...
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Post by 190mech on Aug 2, 2018 5:35:18 GMT -5
OK,I'll run those numbers after work..
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Post by harleyracer59 on Aug 2, 2018 16:33:00 GMT -5
thanks 190! youre awesome! if youre ever in socal, let me know. I owe you some beers! lol
so I actually took it on a ride yesterday, it seems to still be running lean. I have a 21mm oko on a ct manifold ported case and stock 41mm cylinder (49cc) has huge exhaust port now. jets are 45 pilot and 150 150 main. I can roll into throttle but if I try to gun it it seem to lean bog. Ive used a full can of cleaner. cant find any air leaks. crank seals are new. its loud on throttle, deep at idle, when I could get it on the pipe, it was high on rpms and hit hard. will report back with anything I figure out.
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Post by 190mech on Aug 2, 2018 16:58:09 GMT -5
Yeah,youll need to upjet till she's happy,2 strokes aint gas sippers.. I'll get back with the numbers soon! |
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Post by ryan_ott on Aug 2, 2018 17:38:40 GMT -5
Have you tried any other needles? Also older OKO carbs were prone to jet block gasket leaks.
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