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Engine / Exhaust / Cooling
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  Topic Review (Newest First)
02-04-2016 04:59 PM
OleDirtyDoc Yes a lean slow jet will cause low end bogging(slow jet sounds more cool than pilot jet)
02-04-2016 04:33 PM
skinnylizzy Yeah both pipes get as hot as each other...... I'm really starting to think it's just a pilot jet issue because once I get over say 2,500 revs or so it's fine, brilliant infact, she flies!!!! I'm gonna give her a good old spin tomorrow and see how she goes. I might just have to wait till I get the pilot jets and shims sorted before I go digging any further....... I'll keep you guys posted but thanks all for your help so far.
02-04-2016 01:05 PM
Spockster
Quote:
Originally Posted by skinnylizzy View Post




Put it all back together just fine and now there is no exhaust popping from the front cylinder (right side pipe where the problem was)......... BUT.......... Now my left pipe is popping worse than the right side was originally and instead of the bop, bop, bop of the exhaust....... It goes pfffft, pfffft, pfffft (there is pressure there when put my hand up to the muffler to feel the pfft, pfft, pfft).......there is also the odd pop from the front carb.

On a plus note, the right hand pipe sounds lovely...... Hahaha.

Is my problem the lack of shims and a need for a bigger pilot jets or could it be more sinister????

Makes me think of leaking valves. Could be sticky valve stems or just leaking/burned seats.

I would pressurize the cylinder at top dead center (valves closed) and listen for air escaping at the intake/exhaust.

Is that cylinder firing? Does the head pipe get as hot as the other side?
02-04-2016 11:55 AM
skinnylizzy I was going to replace the coasting enriched on the front carb but when I opened it up, it had been replaced recently, looked very new........ The rear carb on the other hand, the coasting enriched was in really bad shape so I changed that. The new spring felt slightly stiffer (as it probably should), could this be a problem?

Shouldn't be really. I'm just spitting ideas out there.
02-04-2016 11:29 AM
OleDirtyDoc
Quote:
Originally Posted by skinnylizzy View Post
Thanks michiganteddybear, I have the carb vent hose hooked up to the nipple under the tank that covers the fuel level float jobby so should be good in that front........... Maybe...... Ha.
That's where mine is
02-04-2016 11:20 AM
michiganteddybear thats a good location for the carb vent.
02-04-2016 09:51 AM
skinnylizzy Thanks michiganteddybear, I have the carb vent hose hooked up to the nipple under the tank that covers the fuel level float jobby so should be good in that front........... Maybe...... Ha.
02-04-2016 09:37 AM
michiganteddybear the crankcase vent does not require dead air, but it wont hurt any to be in dead air.. the carb vent hoses (2 hoses that join at a T fitting, then used to go to the right ear) MUST be in dead air.. those hoses lead directly to the top of the fuel bowls.. and air pressure fluctuations there will cause issues with the fuel level in the bowls.
02-04-2016 05:21 AM
skinnylizzy Ok, so here's where I stand...........
I did the Ear Shave and wanted to rejet to try and alleviate the popping, it turned out that the previous owner/workshop had refitted the rear carb boot on the front cylinder and visa versa........ I had my suspicions about this as the last job it did was to try and align the carb boot notches with the markers on the heads (which were horribly misaligned) and when I I'd, the carbs just sat totally wonky.......

Anyway, went at the ear shave....... Wanted to try run with 140/40 and no shims.......The pilot jets that the supplier sent me were keihin series 21 instead of 22...... Pain in the ass as they're not readily available here in Ireland so I'm gonna have to wait for a replacement pair........ I continued on anyway as I had already cut out the air box.......... Ran a hose from the crank case vent up under the tank to a K&n crank case filter. Running K&N pod filters too.

Sorted out the carbs boots, the carbs sat in lovely.

Put it all back together just fine and now there is no exhaust popping from the front cylinder (right side pipe where the problem was)......... BUT.......... Now my left pipe is popping worse than the right side was originally and instead of the bop, bop, bop of the exhaust....... It goes pfffft, pfffft, pfffft (there is pressure there when put my hand up to the muffler to feel the pfft, pfft, pfft).......there is also the odd pop from the front carb.

On a plus note, the right hand pipe sounds lovely...... Hahaha.

Is my problem the lack of shims and a need for a bigger pilot jets or could it be more sinister????

On a side note...... I ran the crank vent hose up under the tank and placed the filter in an aerosol cap to try and create that "dead air" scenario that I've read about, is this OK or detrimental???? It's not a snug fit, there is room for the filter to breathe.

Sorry for the long winded post...... Thanks again for any help.
01-21-2016 03:16 PM
OleDirtyDoc Yup she's real lean
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