bigal
L plate rider.
Posts: 40
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Post by bigal on Sept 16, 2018 10:21:23 GMT 1
If I have 250 carbs on a 400 which has the aluminium tube balance pipe on the inlet stubs , do I need the small rubber balance pipe between the carbs or am I been thick and are they totally different
Cheers
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Post by reedpete on Sept 16, 2018 19:06:15 GMT 1
The small rubber tube is for the choke .....nothing to do with balance pipe. Only the 400E/F had the balance pipe but you need 2R9 carbs for that. If you have 1A2/3 you’d be best to go back to standard cause finding a set of 2R9 carbs is not easy or cheap.
If you want some guidance to figure out what you have (mixtures if 250/400 right?) it would be good to know what frame and engine numbers...just the first 3 digits is enough to identify. Then what part number is on the pipes, carbs, cylinders and if it is points or cdi ignition ... then you need to check the airbox , make sure the 250 restrictor has been removed to run the 400 lump.
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bigal
L plate rider.
Posts: 40
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Post by bigal on Sept 16, 2018 20:59:49 GMT 1
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Post by reedpete on Sept 16, 2018 21:47:58 GMT 1
Ok so basically a 250E/F with a 400F engine , 250E/F pipes, carbs from 250 C/D. Reed rubbers and balance pipe for 400F.
So generally as long as the carbs are jetted correctly for a 400F all should be fine. Only slight problem is that the pipes don’t have the rubber flexible joint but the engine will have the rubbers so you might get some problem keeping the joints from leaking. Rd400 reeds are diferent to the 250 so those and the rubber inside the airbox are two things you need to probably just have a look at to confirm what you have.
I also see you have a pillion grab rail. That was only there on the continental bikes not the UK ones.
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bigal
L plate rider.
Posts: 40
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Post by bigal on Sept 16, 2018 23:02:33 GMT 1
Ok so basically a 250E/F with a 400F engine , 250E/F pipes, carbs from 250 C/D. Reed rubbers and balance pipe for 400F. So generally as long as the carbs are jetted correctly for a 400F all should be fine. Only slight problem is that the pipes don’t have the rubber flexible joint but the engine will have the rubbers so you might get some problem keeping the joints from leaking. Rd400 reeds are diferent to the 250 so those and the rubber inside the airbox are two things you need to probably just have a look at to confirm what you have. I also see you have a pillion grab rail. That was only there on the continental bikes not the UK ones. What am I checking looking out for in the air box Pete ! whats the difference between 250 / 400 And what the difference on the reeds !! Totally off topic But does big Kev yellow Rd 400 still hang aroun here saw him at the two stroke meet few years ago but not seen him for a while |
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Post by reedpete on Sept 17, 2018 8:05:16 GMT 1
Item 7 on the parts list. There are two diferent rubber pieces that go between top and bottom parts of the airbox. The 250 has three holes and a snout but the 400 is just a rectangular hole. As for reeds, the 400 uses a thicker reed on the lower one and the block has a hole and peg so the block will only fit one way up. If you don’t have the parts list you can view and down load here www.aircooledrdclub.com/manuals/250400E.pdf |
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bigal
L plate rider.
Posts: 40
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Post by bigal on Sept 17, 2018 21:17:18 GMT 1
Thanks Pete
So I have 250 air box , can I adapt the air box or do I need to source a 400 air box
I have not checked the reeds but the air-box and the reeds will affect the running of the bike and I imagine it will be very rich and not pull strong
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Post by reedpete on Sept 17, 2018 22:13:07 GMT 1
Yep, you can just take a Stanley knife to the 250 one and cut the junk off. Just leave the ‘gasket’ function.
Fingers crossed the reed blocks came with the barrels so might be correct.
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bigal
L plate rider.
Posts: 40
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Post by bigal on Sept 22, 2018 16:46:14 GMT 1
Yep, you can just take a Stanley knife to the 250 one and cut the junk off. Just leave the ‘gasket’ function. Fingers crossed the reed blocks came with the barrels so might be correct. Thanks Pete I have chopped out the 250 and now just have the gasket that’s sandwiched between both parts of the airbox Today though I called to see Dave (muttsnuts ) with the carbs which is going to set up for my bike then I will probably have a ride oka diet it in the dyno 👍👍 |
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