Author Topic: Carb for a modified klx250/300  (Read 6104 times)

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Offline 777klx

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Carb for a modified klx250/300
« on: May 18, 2016, 06:54:52 pm »
I'm building a 1980 klx250 with a custom 300 barrel and head conversion with porting and larger exhaust pipe. I'm thinking of running a 34mm mikuni carb. Any ideas how this set up will go? I'm currently running a 32mm on my other modified klx250 with only head work

Offline Hoony

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Re: Carb for a modified klx250/300
« Reply #1 on: May 18, 2016, 07:19:26 pm »
theres a member on here who may be able help Bumper

http://forum.ozvmx.com/index.php?action=profile;u=19951
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Offline cloggy

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Re: Carb for a modified klx250/300
« Reply #2 on: September 02, 2016, 06:49:43 am »
Bit late now but how are you going to stop the gearbox smashing to bits?

Offline LWC82PE

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Re: Carb for a modified klx250/300
« Reply #3 on: September 02, 2016, 08:35:33 am »
FMF sold a 310cc big bore kit and 38mm EI carby for the KLX
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline tony27

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Re: Carb for a modified klx250/300
« Reply #4 on: September 03, 2016, 02:29:48 pm »
Been told it's running a roadbike gearbox to get around the glass original, sounds like quite a bit of work to get if in there

Offline 777klx

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Re: Carb for a modified klx250/300
« Reply #5 on: September 05, 2016, 05:27:36 pm »
Running a kz250 gearbox from a mid 80s engine with oil fed counter balancer

Offline head

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Re: Carb for a modified klx250/300
« Reply #6 on: September 05, 2016, 05:57:07 pm »
All this talk about Glass gearboxes. Had a KLX brand new. No problems. Have had 3 more and raced them all. One with a 310 kit, light weight inner rotor ignition, hot cam, Mikuni, trick exhaust. Holeshoted the final against modern 4 strokes at a stadium motocross and finished third. Was a fast bike with no gearbox issues. May be some riders are gearbox friendly and some are not?

Offline LWC82PE

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Re: Carb for a modified klx250/300
« Reply #7 on: September 05, 2016, 07:28:24 pm »
I was wondering if a lot of it is due to the rider. Eg flat shifting or not using the clutch. Someone told me once how they use no clutch when changing gears, they had 'some way' of sensing where the gears where and would just 'pop' it into gear ::)
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline 80-85 husky

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Re: Carb for a modified klx250/300
« Reply #8 on: September 06, 2016, 07:52:36 am »
just a slight button off before smashing the gear lever thru to the next ratio is helpful. I haven't used a clutch to change gears for 30 years. (except on the moto villa, it didn't like no clutch and would reselect the last gear 20 metres down the track)

Offline 777klx

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Re: Carb for a modified klx250/300
« Reply #9 on: September 06, 2016, 05:00:50 pm »
I haven't actually met anyone one who has had gearbox problems I've only heard of them,I have a problem with my current klx but I think that it's due to wear not breakage.my problem is when I down shift from 3rd to 2nd,it hits neutral  so I have to click back up to get second, New bike has a fresh gearbox with no issues

Offline tony27

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Re: Carb for a modified klx250/300
« Reply #10 on: September 07, 2016, 01:14:17 am »
Sounds like it's been taking lessons off the CZ

Offline Momus

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Re: Carb for a modified klx250/300
« Reply #11 on: September 07, 2016, 03:10:20 pm »
A FCR 33 or 35 Keihin pumper would work well on the KLX and make a VM Mikuni feel a bit antique. I have a one of these on a 150 cc 2 valve Honda single and it's responsiveness, ease of tuning and power increase over a PWK type flat slide was considerable.
If you love it, lube it.

Offline 777klx

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Re: Carb for a modified klx250/300
« Reply #12 on: September 07, 2016, 06:17:34 pm »
Ordered a 34mm flat side last week just waiting for it to turn up