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Makotosun

RT1B compression .

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Replied by MarkT on topic RT1B compression .

I have one of those two stroke Honda 250's that shut off spark and runs on what they called "activated radical combustion" during cruise conditions.

It works very well while riding...  great fuel economy... but I don't know how the hell it works. 

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1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
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22 Nov 2022 17:15 #11

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Replied by AirborneSilva on topic RT1B compression .

Put a compression release in, it slows the engine down real quick as well as the bike. Not sure why they are kinda looked down on, I love mine back in the day and love the one I have on my DT2. Also going to have the head on my DT400 tapped so I can put one on that as well.
2023 Tenere T7
1976 DT400C
1975 DT400
1981 DT175H
1972 DT2 250
1980 GT80
1972 JT2
23 Nov 2022 03:02 #12

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Replied by msavitt on topic RT1B compression .

RT - you've invented the reverse hit miss engine!

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Last edit: 23 Nov 2022 07:18 by msavitt.
23 Nov 2022 07:17 #13

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Replied by YamahaForumUsername on topic RT1B compression .

Ive been looking for the term used for this situation for like 2 years. lol my cr125r does this the second you kick it over. it max rpms, and you nee to pull the sparkplug to get it to shutup. thanks.
23 Nov 2022 21:33 #14

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Replied by YamahaForumUsername on topic RT1B compression .

scratch that prolly shouldnt share that link publicly
Last edit: 23 Nov 2022 21:39 by YamahaForumUsername.
23 Nov 2022 21:38 #15

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Replied by Ht1kid on topic RT1B compression .

What link you can message me 
23 Nov 2022 21:45 #16

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Replied by shyted on topic RT1B compression .

Okay ,sorry for the nil response but i have just got back from work.
1. Not by much, but adding base gaskets alters port timing and may make other problems ,and while it will alter compression, it will also raise the hight of the ports in relation to piston position. I don't think that would have achieved what i want.
2. i use the term over run when i'm off the throttle and the motor is decelerating but revs are up.
3.Yes Mark i know what you're talking about with pipe bang, my points ignition RD 400 had that on the right hand cylinder . This was coming from the head on the 360.
On that ,there were no marks on the combustion chamber or piston .
4. The jets. I think there's room for adjustment there. I can't remember what's in but i think the pilot could go up .5 or1 size with no ill effect . Now i can finally get in my workshop i will see what's what. I also have VAPE electronic ignition for the 360. This is not fitted at the moment.
5.The gasket is three times ( just over) the thickness of standard.
I can now confidently go to the bike and give it a kick and it's away first prod with no kickbacks.
I got the gasket from Copper Gaskets Limited who are in Arizona and it cost £17.00 plus post. You can find them on ebay.
6. Decompressor fitment . I'm not opposed to fitting a decompressor to the head . I used decompressors on several Spanish trials bikes i've had in the past. I would rather not fit one in this case . What would be better is having the plug recesses welded up and a central one fitted, then the combustion chamber reprofiled but that's so extreme. Would certainly have advantages but not be the solution to the problem.
Whatever i do, it will be at best masking a design flaw with this engine. I think the real problem is with port design as several people on here can testify to. Turbo Dan and his DT 360 pretty much proved that. Where do you start and know where to stop?
I got this idea from Micou Meekoo on Youtube and it has improved the bike for £17.00. 
Next it's jetting as raising the needle two notches has improved things too. I think the pilot is too restrictive so i'm going to buy a few and see what happens when i start going up in size.
Last edit: 03 Dec 2022 03:17 by shyted.
03 Dec 2022 02:54 #17

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