Author Topic: Yamaha RT1 Jetting.  (Read 1337 times)

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firko

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Yamaha RT1 Jetting.
« on: May 18, 2010, 04:34:13 pm »
Can anyone please give me ballpark jetting specs for a flange mount 33mm Mikuni to suit my RT1. I need slide cutaway and needle as well as jet specs. The carb I'm using is from a Suzuki road bike (maybe T500) so the jetting is out to buggery.
p.ps,  I'm still looking for a CDI box to suit a DT400/YZ400 as well.

Offline Freakshow

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Re: Yamaha RT1 Jetting.
« Reply #1 on: July 08, 2010, 05:02:19 pm »
Sorry only just noticed this post....

main=#310
needle=6DP1
needle jet=P-0
pilot= #50
cutaway=2.5
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

firko

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Re: Yamaha RT1 Jetting.
« Reply #2 on: July 08, 2010, 05:33:00 pm »
Thanks Freaky...better late than never and pretty close to what I went with too. ;)

Offline Freakshow

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Re: Yamaha RT1 Jetting.
« Reply #3 on: July 09, 2010, 10:01:33 am »
soz.
Note MIne still falls off after about 6k, but from what i can see the motor run out of steam at 7K and goes backwards. 

Also just found my GYT specs ( been loking for it for 6 months ) and noticed there BTDC at 3.2mm where as the normal RT2 book says 2.3 mm, which is what i used, i think i might have to have a look at that also maybe its bagging out there. 

IT will scream it tits off and pull like a train till about 5k, But it falls in a heap after about 6k and no matter how lean i take it, it wont pull on full throttle after 6-7 K, it just falls in a hole.

I think vandy was having the same issue with his, not sure if he figured it out yet.  I have a PVl on it and a stock pipe, also tried a Bassani albiet of a 250, not sure if its run out of pipe being a 360, but i only build it to take to broadford so havent looked at it since but its somthing i want to revised if and when i get some time. :D
« Last Edit: July 09, 2010, 01:41:18 pm by Freakshow »
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

Offline vandy010

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Re: Yamaha RT1 Jetting.
« Reply #4 on: July 09, 2010, 12:11:26 pm »
soz.
 after 6-7 K, it just falls in a hole.

I think vandy was having the same issue with his, not sure if he figured it out yet. 
Vandy's issue is the stator needs a rewind.
i've got a 34mm on my RT1 jetted to std RT1MX specs and it's pretty good as is.
barrel is stock, pipe is homemade and CDI is DT400.
my bikes out of action for a bit anyway as it broke a gear shaft. luckily didn't do any damage other than the shaft but given my house is in need of some TLC the bikes are on the back shelf for a bit.
"flat bickie"

Offline Davey Crocket

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Re: Yamaha RT1 Jetting.
« Reply #5 on: July 09, 2010, 06:23:41 pm »
I think you'll find they wont rev any higher anyway Freakhead.....big piston= low revs....bit like Harley's mate.....put 3 125 pistons in there, make it a tripple, then it might rev!!
QVMX.....Australia's #1 VMX club......leading the way.

Offline Freakshow

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Re: Yamaha RT1 Jetting.
« Reply #6 on: July 10, 2010, 08:55:06 pm »
nah it went get on the pipe, at least the 360mx will rev then fall off, this wont rev out it just goes blaaaaaa.
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff