caddabs Posted December 26, 2009 Report Share Posted December 26, 2009 Hi all - any advice gratefully received. Left my bike for about a week after a heavy ride and thought i'd turn her over. started after second kick, but then stalled as soon as i blipped the throttle and wouldnt start again. put it down to the fact that it was -2 degrees, so left it for another week. this week its milder and tried agian. same thing. started 2nd kick, eased the choke off, ran her for about a minute, a little throttle, and she bogged down and stalled, refusing to fire up again. Cleaned the plug, but no joy. it was a little wet and oily but not drastic. get a good spark, so no problems there. I'm running one of those plugs that sounds like Ibuprofen - cant remember what its called, but its a good fat spark. recently cleaned and oiled the filter (Motul). My starting regime is fuel full on, full choke, then 2 kicks usually does it. warm her up and ease off the choke. i'm guessing its a carburation problem, but i'm not sure what it might be. any ideas? does the mixture run through a different jet at tickover, then main jet with throttle? I'm reasonably ok with a spanner, but no expert, so would like to know more before taking the carb off. many thanks Caddabs Quote Link to comment Share on other sites More sharing options...
bkrgi Posted December 26, 2009 Report Share Posted December 26, 2009 New plug toss the old one (you can not clean it after it has fouled) Should then fire up and be back to normal Quote Link to comment Share on other sites More sharing options...
tony27 Posted December 26, 2009 Report Share Posted December 26, 2009 i'm guessing its a carburation problem, but i'm not sure what it might be. any ideas? does the mixture run through a different jet at tickover, then main jet with throttle? I'm reasonably ok with a spanner, but no expert, so would like to know more before taking the carb off. You're correct in that there are different jet for idle & full throttle. The one you can see through with the slide out & float bowl is the main jet which is used most of the time- the needle makes it effectively smaller until the slide withdraws it The jet closer to the front of the carb is the pilot & is smaller so takes less to clog The choke is basically a separate carb that still draws fuel from the float chamber but has a fixed size jet in it, I doubt that it would be removable My suggestion is pull the carb & remove both main & pilot jets then look through them for blockages & blow them out with a compressor. Next is to blow through any holes you see in the carb to clean the air passages out, reassemble & see what happens It's not a big job & is something that should be done on a semi-regular basis Hope this helps out Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 27, 2009 Author Report Share Posted December 27, 2009 thanks guys - will give it a bash cheers Caddabs Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 27, 2009 Author Report Share Posted December 27, 2009 Well i dont know if it was the plug or the jets, (126 & 30) but we have life !! Now the kill switch has stopped working - luckily as the clutch drags its not too hard to stall - I love my Sherco !!!!! cheers all Caddabs Quote Link to comment Share on other sites More sharing options...
tony27 Posted December 27, 2009 Report Share Posted December 27, 2009 Those numbers sound about right, maybe a little small on the pilot. My 290 runs a 36 in its dellorto & I think my early model bikes were around 33 Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 29, 2009 Author Report Share Posted December 29, 2009 cheers - what would a bigger pilot jet do? i have had a problem with "pinking" and a bit of power loss when really hot - would a bigger jet help? am about to switch to 1:80 but just using the last of the 1:50 up. i was told Shercos suffer from not getting enough petrol in them and to raise the needle. the needle is as high as it will go. fixed the kill switch - happy days. cheers Caddabs Quote Link to comment Share on other sites More sharing options...
wherry Posted December 29, 2009 Report Share Posted December 29, 2009 Morning! Are you coming up to Lyng on Friday? Re. petrol. Are you running on super-unleaded? I never use petrol that's been hanging around for more than about 3 weeks as my bike just doesn't run right on old petrol. I also make it up a litre at a time so I can bung the old unused petrol in the missus's car. If you want experiment with some other jets you can get them from Dellorto direct I think, or I've used a Scooter tuning guy I found on eBay. Let me know if you want me to dig his details out. Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 29, 2009 Author Report Share Posted December 29, 2009 Hi there - have been busy practicing down at Brentwood after Lowestoft but managed to overheat it badly and it made a lot of odd noises. got the radiator covered in mud and nearly cooked it. (bought a mud flap now) looks like ive finally sorted it out and now ready to go. Have had a lot of problems starting it, but touch wood, now seems ok. just checked on Splatshop and they have all the jets. not sure which number to go for - they recon 35 is most popular for trials. may do a bit more research before hitting the button. my petrol is a bit old now - may stick it in the lawnmower! cant do Ling,(in-laws for lunch) but was planning on a trip to Raydon on 31st - you can enter on the day. thought i might give it a go if its not awful weather. are you going? really wanted to do Tunstall yesterday,as its close to home, but as it wasnt starting i didnt enter. i walked the sections in the morning (with my dog) - did you do it? loooked good. all the best H Quote Link to comment Share on other sites More sharing options...
wherry Posted December 29, 2009 Report Share Posted December 29, 2009 No I went for a look yesterday as well, as several mates were riding, but I don't have a T/S or P70 bike myself. I'll almost certainly be doing Raydon on the 31st though. Do you know which carb you've got on the bike? Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 29, 2009 Author Report Share Posted December 29, 2009 I wondered why there were a lot of P65's arriving - must read the regs more carefully ! I was there about 8 am chasing my dog around. Pretty sure its a Dellorto. square shape at the bottom. noticed too that the air box exit into the manifold has buckled where the jubilee clip has been overtightened. Could be letting un-filtered air in. think ive sorted it now. its all good fun isnt it !!? hope to see you Thursday. Must do some DIY now - wife gone shopping and got to get it done before she gets back ! been distracted by bikes again !! Cheers Quote Link to comment Share on other sites More sharing options...
wherry Posted December 29, 2009 Report Share Posted December 29, 2009 Not quite sure what you mean about the air box and manifold but if it's letting air in either side of the carb it'll muck up your settings. The reason I ask about the carb is that there are 2 types that could be on your bike. I suspect it might have a Dellorto PHBH like my bike but it might well have a later and better Dellorto PHBL. You can tell by what side the mixture adjusting screw is on. On the PHBH the mixture screw is on the airbox side of the carb (with the big tickover screw in the middle). PHBL has the mixture screw on the engine side. The major thing here is that the mixture adjusting screws work in opposite ways. The PHBH screw adjusts air so screwing it out weakens the mixture. The PHBL screw adjusts fuel so screwing it out richens the mixture. The jets are therefore different so you'll need to know which carb you've got if you do order some more. PM me where you are. I could come over at some point and have a look at things if you like, or if you haven't got anywhere handy to try out the bike at yours you could come to mine. Quote Link to comment Share on other sites More sharing options...
caddabs Posted December 29, 2009 Author Report Share Posted December 29, 2009 Cheers - it says PHBL 26 on it. Thanks for the tip - i downloaded some Sherco stuff from the internet a while back but i dont have a manual. didnt realise there were 2 types of carb. Ive not ordered any jets yet as i was going to trawl the net a bit more and see what others might be using. ive not touched the screw settings at all yet. i assume a bigger pilot jet would get more juice in and may get rid of the "pinking" in the midrange although when i ran it yesterday it seemed fine and no more noises. I did get it a bit too hot and muddy and put it under a bit of stress. It lost a lot of power quickly, so i stopped it and pushed it back so as not to do any damage. the "ding" sound now seems to have gone, and i was going to try 1:80 to see if that sorts it for good. i think i just got it too hot running for a few hours without letting it cool down in some pretty thick mud and some steep climbs. the rad and pipe were caked solid. I run it on Shell VMax (99 Ron) Thanks for the offer. i'm over near Wickham Mkt, but i'm probably not going to get much time this side of Thursday as a few family things to do. Can we have a look Thursday? cheers - must get back to my chores now !! All the best H Quote Link to comment Share on other sites More sharing options...
wherry Posted December 29, 2009 Report Share Posted December 29, 2009 PHBL. Mixture screw is a fuel screw and if memory serves should be about 3 - 4 turns out. Yep Thursday could be very good. I've got some time booked in for bike time so let's see what the weather's like. Quote Link to comment Share on other sites More sharing options...
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