thecabinboy Posted January 13, 2004 Report Share Posted January 13, 2004 when I got my bike ported by Charlie he said I should run 18cc domes for his port-work, I told him I had only 19 at the time. His next remark was to advance the timing +7deg., I did all this and ran the quad for 6 months, A-OK. Now I went and put new 18cc domes in and slap her back together and take it to the dune for the first run. At Gordon's Well with my reg 19cc jets it ran terrible on the top end and worked my plugs loose. Now I'm getting worried cause just to make it run semi right I had to drop 3 sizes down and still had a top end problems but now I could take off in 2 on a start and not have it die right there. But with the plug loosing up a 2nd time I said forgot it and shut it down. Back at home all I could come up with is it was detonating. I was running VP110 with Klotz. So I yanked it apart and backed it down to +4. Was this right? Did i take it back enough? Both sides are still holding 185lbs each here at home 1246'. Any help or thoughts on this matter would be mighty appreciated. Thanks for you time and concern. Jeff P.S. Beware of Ninjas Quote Link to comment Share on other sites More sharing options...
boonman Posted January 13, 2004 Report Share Posted January 13, 2004 I say your timing should be good. I have never had plugs work loose on me, but detonation could be a problem. DO you have a cool head? if you do, pull it off, and have a look see at the pistons? What do the plugs look like? Changing compression usually doesn't yield any jetting changes, but it is always a good idea to check. Now, you say it ran A-O.K. for 6 months, yet later you say that it would die on a 2nd gear start? That is not A-O.K. A stock shee should be able to start in second. Unless it has 12 paddle 22's on it? What is your jetting? Plug color? Does it ping? How old is the fuel? Quote Link to comment Share on other sites More sharing options...
Yamahammer Posted January 13, 2004 Report Share Posted January 13, 2004 if everything check out it may just be the compression and the heat and cool process loosening the plugs up trinity make a plug holder that will stop that from hapening. 7 sounds like alot for a dune bike 4 sounds more like it.. 7 is usually for drag only.. you should be able to start in second also i have just pipes and filter and can leave in second with sand sharks and i am no small boy.. Quote Link to comment Share on other sites More sharing options...
thecabinboy Posted January 13, 2004 Author Report Share Posted January 13, 2004 Boon it ran "A-Ok" for 6 months before I put the new smaller domes in. I wasn't over-paddled just way off on the jetting so I would have it in second and rev it up let out the clutch and BLAH. this was with the same jetting I usually use I had to go 3 sizes smaller just to get it to pull on the top end and not sputter. Quote Link to comment Share on other sites More sharing options...
shortys racing Posted January 13, 2004 Report Share Posted January 13, 2004 Boon it ran "A-Ok" for 6 months before I put the new smaller domes in. I wasn't over-paddled just way off on the jetting so I would have it in second and rev it up let out the clutch and BLAH. this was with the same jetting I usually use I had to go 3 sizes smaller just to get it to pull on the top end and not sputter. sounds like it's lean on top.....go up some jet sizes and it should fix the plug problem......try leaning out the pilot jet too. What carbs & jetting do you have??keep it at +6 or 7 on the timing. Even for dune bikes (ported ones). Quote Link to comment Share on other sites More sharing options...
thecabinboy Posted January 14, 2004 Author Report Share Posted January 14, 2004 35mm Keihns w/160 mains Quote Link to comment Share on other sites More sharing options...
MULLET~BOY Posted January 14, 2004 Report Share Posted January 14, 2004 your detonating mabey you got some bad domes or mabey its the grape stuff you run in your fuel did you mess with the needles Quote Link to comment Share on other sites More sharing options...
thecabinboy Posted January 14, 2004 Author Report Share Posted January 14, 2004 How am I suppose to go fast without Grapes? This last time I did not run any smelly stuff in the fuel. Quote Link to comment Share on other sites More sharing options...
dlnoss Posted January 14, 2004 Report Share Posted January 14, 2004 I'm not sure I'm understanding. Is it happening with the 19cc domes or the 18cc domes or both? Quote Link to comment Share on other sites More sharing options...
thecabinboy Posted January 14, 2004 Author Report Share Posted January 14, 2004 just the new 18cc domes my old set up was the 19's and it ran fine. Quote Link to comment Share on other sites More sharing options...
shortys racing Posted January 15, 2004 Report Share Posted January 15, 2004 35mm Keihns w/160 mains try this......55 pilot, 165 mains (sea level) Quote Link to comment Share on other sites More sharing options...
boonman Posted January 15, 2004 Report Share Posted January 15, 2004 What is the squish? Were the 19's cut custom at all? When you switch domes, any number of things can happen. Get ya some solder, check the squish. Have you pulled the head off? What do the pistons look like? With a coolhead, this isn't a hard task, and you don't even need new gaskets!!! The plugs and pistons should tell you if it is detonating. A tuned ear should be able to hear the ping, but sometimes it isn't possible to hear it. I am thinking along the line of detonation... Quote Link to comment Share on other sites More sharing options...
Banchetta Posted January 15, 2004 Report Share Posted January 15, 2004 160 mains sounds really lean to me... I was running 162 mains w/ midrange pipes and no porting.....I'd say the needles and pilots are why your bogging out on take off.... Quote Link to comment Share on other sites More sharing options...
thecabinboy Posted January 16, 2004 Author Report Share Posted January 16, 2004 When I set up to go out there I had my usual 165 main in when the problems started I moved the jetting up to 168 and it got worse the only way I could get it to run so-so on the top end was to back it off to 160 which is my normal jetting for home at 1246'. Now thats its home I have backed the timing to +4 from +7 I have not a chance to take it out and test and tune and rejet it. Quote Link to comment Share on other sites More sharing options...
Banchetta Posted January 16, 2004 Report Share Posted January 16, 2004 Try doing a plug test, then try riding it at half throttle and at wot for 10 seconds on both..... Quote Link to comment Share on other sites More sharing options...
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