collyolly Posted June 15, 2019 Report Share Posted June 15, 2019 Hi all Recently got myself a 2017 250gp, feels like the carburation has been messed with so I am looking for advice on the standard or best revised settings for this model. I think the racing versions over the last couple of years may also have had a Keihin fitted. I am in the U.K. at not much above sea level. I have as follows Keihin PWK, 45 pilot, 125 main, No 3 slide, JJH needle with the clip fitted second groove up from the bottom ie richer mixture than middle groove, also any advice on setting the float height. many thanks Quote Link to comment Share on other sites More sharing options...
the dabster Posted June 15, 2019 Report Share Posted June 15, 2019 Quote Don't touch the float unless you know it has been maladjusted. I had an 18 racing, albeit a 300 and I thought the 45 pilot was good with needle in standard position ( whatever that is) and I fitted the no.3 slide as opposed to the 3.5 it comes with standard. fine tune on the mixture screw think roughly a turn of the seat if you use a 45 pilot and possibly two turns of the seat with a 48 pilot and fine tune from there. The big thing for me was the richer slide. they run well on that. Quote Link to comment Share on other sites More sharing options...
collyolly Posted June 15, 2019 Author Report Share Posted June 15, 2019 Many thanks for the prompt reply, I shall try the needle in the middle position,reset the float as it appears too high and give her another test ride. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 17, 2019 Report Share Posted June 17, 2019 That's exactly my settings, but have had a 128 main which works better on a 250 if I remember correctly? Pretty sure I moved the needle one notch too. The biggest gain is the 3 slide. Just a thought you haven't got after market adjusters have you? Quote Link to comment Share on other sites More sharing options...
collyolly Posted June 17, 2019 Author Report Share Posted June 17, 2019 (edited) Yes I have got the red (Jitsi) adjusters and the large capacity float bowl 'bolt' do these have any negative effect ? Nigel you say you moved the needle, but from where to where ? as I can't find out what the standard setting should be. My problem is it's a pig to start and felt very rich off the bottom, I would dearly love it to be a one kick starter rather than 3 or 5. I put it back together as my previous post it feels nice once started but the starting is an issue, any advice . I have been advised to leave the throttle alone when kicking , the previous owner had the tick over turned up, I assume to reduce the tendency to stall. I have the faith, it just needs sorting. Edited June 17, 2019 by collyolly 1 Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 17, 2019 Report Share Posted June 17, 2019 Spoiler Float level Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 17, 2019 Report Share Posted June 17, 2019 Needle clip position Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 17, 2019 Report Share Posted June 17, 2019 Note original air screw, tickover is ok with after market. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 17, 2019 Report Share Posted June 17, 2019 NB. Before cleaning! Quote Link to comment Share on other sites More sharing options...
collyolly Posted June 17, 2019 Author Report Share Posted June 17, 2019 Many thanks for the info, your needle clip is as mine was originally now it's in the middle, but I don't think that would effect the starting do you ? What have you heard or experianced re the after market mixture screw ? Does it just not work correctly. Have you tried a flywheel weight, I had one on a 2009 250 and it made the starting easier but killed the throttle response I seem to remember I ended up reducing the mass by around 50% Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted June 22, 2019 Report Share Posted June 22, 2019 On 6/17/2019 at 10:00 PM, collyolly said: Many thanks for the info, your needle clip is as mine was originally now it's in the middle, but I don't think that would effect the starting do you ? What have you heard or experianced re the after market mixture screw ? Does it just not work correctly. Have you tried a flywheel weight, I had one on a 2009 250 and it made the starting easier but killed the throttle response I seem to remember I ended up reducing the mass by around 50% Hi I hate flywheel weight s. Change to original airscrew it's a waste of time after market. If your carb is set up line this it should be fine. Starting is as much about technique as much as anything. Quote Link to comment Share on other sites More sharing options...
collyolly Posted July 20, 2019 Author Report Share Posted July 20, 2019 Hi, just got some time back on the bike after a long lay off ( holiday ) Followed the advice given and fitted an original air screw, re set the float height as I feel it was a bit on the low side after reading the Internet, put the needle back up, fitted a new plug as it had some special fine wire electrode thing fitted. Starting has improved but still not one kick, could be my technique or is something else still not right ? Entered the dark side and fitted a flywheel weight, this has the effect of giving the starting kick a slight bit of extra momentum and does appear to help though still not as good as I think it should be. (Had GasGas bikes for 20 years so I know they can start ) After some discussion I decided to look at the reed valve assembly, it all looked O.K. apart from appearing to have an extra gasket fitted between the reed cage and the reed block. I do not think this is correct as the built in sealing face of the reed then sits inside the gasket and does not do anything, also on removing the assembly there appeared to be fuel across the whole face of the gasket so could have been a leak. Put together without the suspect gasket and the bike now starts quite easily, half a kick to load up the inlet and then a full kick once compression is found and away she goes. Just got some fine tuning to try now as it feels a bit rich off the bottom but that could of course be the lag effect of the flywheel. Anyone confirm the gasket fitment as I will leave it out if it's not needed Quote Link to comment Share on other sites More sharing options...
NAD1 Posted July 23, 2019 Report Share Posted July 23, 2019 On 6/17/2019 at 4:09 PM, nigel dabster said: That's exactly my settings, but have had a 128 main which works better on a 250 if I remember correctly? Pretty sure I moved the needle one notch too. The biggest gain is the 3 slide. Just a thought you haven't got after market adjusters have you? Recommend putting a 3 slide in then Andy? Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted July 25, 2019 Report Share Posted July 25, 2019 Julian does to every bike, only one exception afaik, 315. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.