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New Guy - Fueling Questions; Help with carb tune up
Topic Started: Nov 17 2017, 04:43 PM (645 Views)
eran_k
Commoner
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Hi everyone,
My name is Eran and i'm new here.
I do not have a CCM, but i did build a scrambler based on a Freewind and this community seems to have tons of knowledge regarding this motor. and i really would like to get some help

Let me describe the current set up
I rebuilt the carbs, removed the "Gobbins" just like the article here describes.
changed the main jets to 135 and the pilots to 25
installed a K&N filter (no air box)
header is freewind origianl, muffler - ebay original (40$ unit from china)
rubber manifolds and o rings are new.
all o rings in the carbs are new, carbs have been thoroughly cleaned.
TPS adjusted per the article

problems as follows
pilot screws are ~3 turns out, motor takes some time to start with choke pulled. the idle is quit rough
ive set the idle speed a little high with the screw, so it holds at around 2000 rpm.
the header gets dark red quit fast, and any attempt to add some throttle results in the engine dies.
this is where i'm at now, first i tried to close the pilots to 2.5 turns but then it didn't start at all.

Any ideas? i'm a bit desperate as i'm afraid to let idle like that (glowing manifold)

Thanks
Eran

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Monty
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Charlie Big Banana's
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welcome to the site,

You need to increase your jets sizes due to the fact you dont have an airbox fitted, the freewind needs an airbox.

The jetting you have used is for an airbox with lid , but the 6 holes opened up to 25mm dia, and a race can.

If you dont have an airbox, then I suggest you fit 30-32.5 pilots, 1.5 turns out on the airscrew, 160-165 main jets, This is only a guess as I have never tried running with no air box, but others have and used the jetting I mentioned.

Hope this helps
If it aint sharp I can play with it
My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch

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eran_k
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This is the bike, almost finished

This is the air filter
https://www.knfilters.co.uk/images/l/RU-2922.jpg

https://photos.app.goo.gl/XfvHlfPpkMuZrZ1k1
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eran_k
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Monty
Nov 17 2017, 06:58 PM
welcome to the site,

You need to increase your jets sizes due to the fact you dont have an airbox fitted, the freewind needs an airbox.

The jetting you have used is for an airbox with lid , but the 6 holes opened up to 25mm dia, and a race can.

If you dont have an airbox, then I suggest you fit 30-32.5 pilots, 1.5 turns out on the airscrew, 160-165 main jets, This is only a guess as I have never tried running with no air box, but others have and used the jetting I mentioned.

Hope this helps
So even a 150 main and 27.5 pilot will be to small?
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Monty
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Charlie Big Banana's
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eran_k
Nov 17 2017, 07:25 PM


So even a 150 main and 27.5 pilot will be to small?
Those jet sizes are for airbox fitted but no lid running a race can, or a non restrictive one, and no extra holes in the side either


You have done a nice job on the bike, some more pictures please,
Edited by Monty, Nov 18 2017, 09:19 AM.
If it aint sharp I can play with it
My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch

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wirral121
Duke
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If you have read my cafe racer on projects ,you will find that getting my R30 wihout an airbox and with a KN/ one off header pipe and silencer to run properly was quite long winded . A Dyno resulted in all my jets settings changed , my pilots actually went down to 25,s , do not know how many turns out , needles were shimmed to be between 3rd-4th groove main jets are now 170. The carbs were rebuilt with kits bought off inter net. It likes part choke /no throttle and starts virtually 1st time. Though after last dyno session he said needle mixture is now a touch weak, he adjusted pilots on bike never said they need to go up to 27.5. My project is still on going. If you are like me,and like to do everything yourself, I gave up in the end it would start ok but never ran perfectly, so I let an expert Dyno man set my engine up correctly. lt looks very nice by the way , good luck!
Edited by wirral121, Nov 18 2017, 01:18 PM.
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eran_k
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Some more images

https://photos.app.goo.gl/DcQrsOxFivYCapIG2

https://photos.app.goo.gl/zdWxqEF9H41bCBbN2

https://photos.app.goo.gl/5iRsRtOK0va6id5p1

https://photos.app.goo.gl/YvNXfEXZ4GqHXDfx1

https://photos.app.goo.gl/kvM1mpI2L4dMHzgq1
Edited by eran_k, Nov 18 2017, 05:08 PM.
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eran_k
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Monty
Nov 18 2017, 09:12 AM
eran_k
Nov 17 2017, 07:25 PM


So even a 150 main and 27.5 pilot will be to small?
Those jet sizes are for airbox fitted but no lid running a race can, or a non restrictive one, and no extra holes in the side either


You have done a nice job on the bike, some more pictures please,
160 mains and 32.5 pilots ordered, Thanks
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Monty
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Charlie Big Banana's
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I would then suggest a couple of dyno runs just to make sure fueling is fine all the way through the rev range,

I tend to go a bit richer on the pilots as this will give you more torque rather than HP,

Also forgot to say you may need to raise the needle one notch, It should be on the middle clip now, so lift to the 4th clip
If it aint sharp I can play with it
My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch

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eran_k
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Monty
Nov 18 2017, 05:36 PM
I would then suggest a couple of dyno runs just to make sure fueling is fine all the way through the rev range,

I tend to go a bit richer on the pilots as this will give you more torque rather than HP,

Also forgot to say you may need to raise the needle one notch, It should be on the middle clip now, so lift to the 4th clip
I think i already did that when i rebuilt the carbs, any way i'll get a chance to check again when the jets arrive
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eran_k
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Well after some long delay i had a chance to work on the jetting, still not perfect but at least it revs now.
made a short video, is it still to lean now?
i wrapped almost the entire filter with duct tape, leaving a 10 mm open all around

https://vimeo.com/255281591
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Monty
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Charlie Big Banana's
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You are well lean still if you have wrapped the airfilter in duct tape, try raising the needles to their max position.
what jets are you now running, pilots and main, plus how many turns out on the mixture screw?
If it aint sharp I can play with it
My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch

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eran_k
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Needles are at max position (were not before) mains are 160 and pilots are 32.5, screw are ~2.5 turns out.
should the two plastic tube barbs on the top side of the carb be blocked? i removed all the "Gobbins"
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Monty
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Charlie Big Banana's
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the 2 plastic tube barbs as you call them should be blocked, also the vacuum take off on the right carb should be blanked off, basicly where the gubbins fitted to the carbs need to be blanked off if removed
If it aint sharp I can play with it
My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch

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