ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 2, 2018 7:36:04 GMT -5
OK, so back to totally off subject... Walt and I have been working on building his drag bike. It has a custom softtail frame , 9” stretch on the swing arm, and a 105ci S&S motor. I couldn’t get the tires in in time, so right now it’s on street tires. Also, we didn’t have time to make the exaust so it has some off the shelf “starggered duels”. But we did get out to the strip. First run, 13.90. About what I expect from a well tuned 250 street bike! Problem was the launch. Tried 3500 in fist, and about melted the rear tire. After a couple more poor runs, I suggested he launch in 2nd instead of 1st. A 3200 rpm 2nd gear launch produced a 12.11. We fooled around with a few things, and it was obvious that the stree tire was our limiting factor. Finally we found a good combo that gave him a 11,61 and 11.59 back to back. We set his dial in at 11.50 and he won his bracket! Only that put him up against me in elimator. In the finals, even though I had to give him a second and a half head start, I did manage to catch him at top end. It was so close that we each thought we had won, and had to wait until we got to the timing shak to find out. We have a brand new , but still street, tire mounted for our trip to a different strip today.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 3, 2018 14:40:01 GMT -5
Totally off subject again. So we had time to do some stuff on Walt’s bike a mounted a new Shinko rear tire. With a couple of runs we decided that he would run 11.01 and I run 10.01. There were a ton of bikes running in the 11 sec bracket. I’m happ that Walt won his bracket! In the finals of elimator it was he and I again. And he beat me! By a mile! He turned a 10.88. Of course he busted out of his bracket! So would have won, except I broke out of my bracket top! That’s right, I have a 600 street bike in the nines!
They ran some dragsters before the bike elimator. Rolling up in that dragster goo on the track made a huge inprovment in our 60 foot times
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Post by dexameth on Sept 4, 2018 9:27:54 GMT -5
No pics of the actual scoot?
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 6, 2018 7:45:19 GMT -5
I sold red bike back to Stupid and we are spending most of our time on Walt's drag bike. As this is a scoot forum, I'm guessing no one really cares about that project, so I'll stop posting updates.
As far as our scoot project, the next thing will be when I get done with modifying the cams.
I still would like to have help testing these cams If you have a heavily moded engine, are willing to do some before and after test times, and will return the cams to me when done, please let me know.
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Post by magoconnor on Sept 8, 2018 10:43:24 GMT -5
Hello again. Im in the process of cleaning up my new cylinder head, and I have notice it has a sharp ridge just under the valve seat on the intake side. Well like a small underhang.. Some people say dont remove it, as it creates a swirl that help mix the fuel. To me it seems like a pretty hard edge for the air to travel over especially so close to the combustion chamber. Do you remove it on your heads? If so what type of bits do you use? Here is a link to what im talking about www.diyporting.com/valve_seat_issues.html
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 8, 2018 14:57:51 GMT -5
I always do a multi angle valve job. Any ridge would be elimated by the third angle. Long way of saying I choose to remove an ridge close to the valve seat. I guess my thought is, “ well if a ridge is such a great idea, why have I never seen a racing head with a ridge? mutli angle valve job on the Yamaha i do most of the work with carbide burrs and finish with cratex wheels. Cratex is like rubber bonded abrasive www.cratex.com/Products/Rubber-Abrasives/Kits/Rubberized-Abrasive-Point-and-Mandrel-Kit-No.-767
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Post by magoconnor on Sept 9, 2018 13:17:16 GMT -5
Do you think there is anything to gain by doing the same to the exhaust port?
Also I dont really have the same fine bits as you, do you think sandpaper bits would do the job? Do you cover the valve seats with anything to protect them?
That is a clean looking head by the way.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 9, 2018 20:21:15 GMT -5
The little sanding drums do a fantastic job. In fact they leave a slightly rougher finish that it good for the intack side. My only problem with the little sanding drums is that the really small ones seem to get loose quick and become useless. Maybe you will have better lunch
When I’m doing the combustion chamber, I use old valves the keep from nicking the valve seats. The ports are another thing. I wish I count say I have never hit the vale’s seats, I would be living. But I cut the mutli angle valve job after the ports so those cutters normally clean up any slips
BTW, I polish the exaust ports to a much higher level then the intakes
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