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boost porting of 1971 DT1E250

07 Feb 2018 20:28 07 Feb 2018 20:54 by Makotosun.
RacerClam
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boost porting of 1971 DT1E250 #1
Thought I would share this piston port 250 I just completed porting plus adding a boost port , Ive done a bunch with this method on other machines with good results , adding this port allows the hooking of the rear transfer port exits since scavenging is now handled by the boost port. A great power booster combo

Rich






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08 Feb 2018 05:18
Pillsbury
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boost porting of 1971 DT1E250 #2
Nice work!

1970 DT1-C Grand Prix race bike
1970 DT1-C Dirt bike
1968 Honda CL90
1971 Honda Sl 125
1973 Honda CR250
1974 Honda MR-50
1966 Triumph Tiger Cub
1967 Moto Guzzi V700

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08 Feb 2018 10:38
RacerClam
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boost porting of 1971 DT1E250 #3
Thanks Tom, Got yours running yet ?

Rich

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08 Feb 2018 11:29
RTD2
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boost porting of 1971 DT1E250 #4
Nice work Rich, I have to figure out what I am going to do with my 71 DT1 MX engine with the enduro cylinder. I have a 32mm carb, GYT kit head and pipe, but stock porting. I will be in touch later.

As a reminder you did the DT1 cases for me, beautiful job, I am getting close to finishing the bike they were for (70 DT1 MX).

Mike

68 DT1, 70 DT1C MX, 71 CT1C, 71 RT1B, 71 DT1E MX, 73 AT3MX, 70 Husqvarna 250 Cross, 57 Matchless G80CS, 76 Honda Elsinore; 2015 Yamaha FZ-09

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08 Feb 2018 11:34 08 Feb 2018 11:37 by Pillsbury.
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boost porting of 1971 DT1E250 #5
It's ready to run but the pipe is still a few weeks from being complete. A DG pipe donated to me by darinm (a member here) should be here tomorrow so I thought I'd throw that on just to run her down the road. I'm not planning on doing any jet changes or anything, just want to run the rings in a bit & hear her go Zzzzzzziiiiiiiiing :)

1970 DT1-C Grand Prix race bike
1970 DT1-C Dirt bike
1968 Honda CL90
1971 Honda Sl 125
1973 Honda CR250
1974 Honda MR-50
1966 Triumph Tiger Cub
1967 Moto Guzzi V700

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08 Feb 2018 12:55 08 Feb 2018 12:58 by RT325.
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boost porting of 1971 DT1E250 #6
I must be loosing it or still have a 'lot to learn'--[that one] but doesn't it need to be controlled by reed valve like a "72 model to run that boost port?, so conversely, could i run a 'non reed' piston in my DT2 & 'No' reed cage & have a 'rocket'--well a std rocket not a go fast dt2mx one. Or am i way off the case, sorry. Very interesting all this. Thanks for posting. ps i know the dt1 & dt2 have different gudgeon heights in the piston--& different rod length, but just saying!!.
ps, or am i not looking at the picture right.
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08 Feb 2018 13:12
RacerClam
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boost porting of 1971 DT1E250 #7
no reed needed here , notice the boost port is not connected to the intake port ! because of the epoxy bulb , and the port id fed by a single horizontal hole below the ring land at bdc

Rich

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08 Feb 2018 13:14
RacerClam
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boost porting of 1971 DT1E250 #8
RTD2
can you possibly post a picture of your GYT kit head combustion chamber here , I want o identify the head I have here , customer thinks it is one but I don't think so

Rich

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08 Feb 2018 13:34
RT325
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boost porting of 1971 DT1E250 #9
Ok, thanks for the quick reply.

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08 Feb 2018 14:14
Giancarlo124
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boost porting of 1971 DT1E250 #10
Here's one I have rich. It's either a dt1mx or a gyt. I think it's a gyt but I'm sure someone else will know for sure

The Oil burners: 1973 DT-250, 1966 YM-1 305, 1966 YSD3, YZ-105
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