spents shorty roofchopper rail build

[DougStar]

thanks lance

i bet there off the twin doug and they'll be the same as mine, the 997's

They are brand new still sealed. I bought them and supposedly 686 or sold as 686

 

[Seandonato73]

Same difference

 

[spents]

sooooo, fitted the 1107 carb,



then found out theres a reason the turtle pawl cages have so much slop in em,
its needed to stop em jamming up , so removed my shims and refitted it all again ,



now heres where the issues start ,
so engine fired up fine, ran really well between cold and warm up, then as soon as it gets to full running temp it bogs when ya give it the throttle,
it was running for around half an hour or so just around garden and the driveway ,
low needle is fine, its the high needle thats the issue,
bogs, give it more fuel and its better, gets a bit warmer running around and bogs again, add more fuel and its better, repeat etc ,
then it gets to the stage where its dumping fuel in and engine stalls out when ya go from full throttle to off throttle,
always starts straight back up again and idle is spot on,
tbh i've always had a few issues with this engine, (obr 34 reed),
its had two 1107's and a 668 carb on it, when it does run well its feckin mint,
but then the bog starts and its a pain to get right again,
its the only engine i've had major issues with with running,
reed petals are polini and are as new with no warping etc,
tanks vented very well, clunks clean, fuel lines are new, fuel mix is 32/1 and fresh,
no air leaks around the carb, reed block etc,
the crank and the seals and bearings are new, or near enough new,
piston and bore are fine and the ring is almost new,
only thing i could think of is its bad seals, but there almost new, unless i just got unlucky and got a bad seal or sommat,
no sign of a leak there though, but not removed the clutch or flywheel yet to have a proper look,
case is sealed proper, head not leaking, head side port covers not leaking etc etc,
if i let the engine cool right down its fine again till fully warmed up,
carb bulb stays full at all times as well,
i'm at a loss tbh, anyone any ideas ?
i'm tempted to just retire the engine and get sommat else for the rail now,
i'm beginning to think this engines just cursed ,
anyways, ran it for half an hour or so today, stalled out from the too much fuel thing and went to restart it and the turtle starter jammed ,



and yep, turtle starter did its party trick and ate the secondary spring ,
spring collapses and wedges between the alloy of the spool and the plastic of the dog,



spring proper toasted itself this time,





good news is that my centre boss thingy i machined up did help a little and stiffened up the whole dog/spool bit,
i did have an alloy dog on there at one point, that was the last time it ate itself and snapped the centre bolt off ,
this time the bolts fine, just a fecked spring, again,

 

[spents]

well its back on the bench , gonna pull the engine again and try and find out what the issue is,
its bugging the crap outa me and i needs to find out ,
pretty sure its a seal issue, but need it apart to find out,
just to add to my last post above, two of the three carbs i tried were known good carbs, well one had been run and the other was brand new, the tird was an older 1107,



may not look like it, but the engines half way out ,
not easy to remove from a shorty rail,

 

[DougStar]

Can change the seals without splitting the case im sure that's what you'll do

 

[Seandonato73]

If have it out, just pressure and vac test it. Very simple to do on these then you know your 100% no leaks. And you could have a buggered needle and seat if it's that picky on the adjustment. Can't think of anything else carb related that could be an issue, I'm sure you have the metering lever set right if your not running it out of fuel and idle adjustment is easy.

 

[spents]

Can change the seals without splitting the case im sure that's what you'll do

yeh but may as well split the cases and have a proper check of bearings etc, plus make sure the springs are still on the back of the seals ,
thats as long as the case bolts will come undone ,
new seals are £6.40 for the pair, bearings are £12 for the pair etc,
might throw a new ring at it as well, but tbh the engines only got around 4 hours or so on it since last rebuild,
its just really annoying me that its doing what its doing and bogging for what seems like no reason,
i'd rather have the thing fully to bits and triple check everything one last time if ya get what i mean

If have it out, just pressure and vac test it. Very simple to do on these then you know your 100% no leaks. And you could have a buggered needle and seat if it's that picky on the adjustment. Can't think of anything else carb related that could be an issue, I'm sure you have the metering lever set right if your not running it out of fuel and idle adjustment is easy.

i don't actually have the gear to do a pressur test vac test sean, i know i should have really though,
its picky on 3 different carbs though sean, exactly the same with a new 668, an almost new 1107 that i know works well on another engine, and another 1107 that i have had issues with in the past,
idle and low speed is spot on sean, its the transition from low to high needle when it bogs,
new plug was used and it looks super rich after the running yesterday,
i will get to the bottom of whats wrong though , i'm determined to ,
thanks to yerself and dougy mcfresh for answering as well

 

[Seandonato73]

yeh but may as well split the cases and have a proper check of bearings etc, plus make sure the springs are still on the back of the seals ,
thats as long as the case bolts will come undone ,
new seals are £6.40 for the pair, bearings are £12 for the pair etc,
might throw a new ring at it as well, but tbh the engines only got around 4 hours or so on it since last rebuild,
its just really annoying me that its doing what its doing and bogging for what seems like no reason,
i'd rather have the thing fully to bits and triple check everything one last time if ya get what i mean

i don't actually have the gear to do a pressur test vac test sean, i know i should have really though,
its picky on 3 different carbs though sean, exactly the same with a new 668, an almost new 1107 that i know works well on another engine, and another 1107 that i have had issues with in the past,
idle and low speed is spot on sean, its the transition from low to high needle when it bogs,
new plug was used and it looks super rich after the running yesterday,
i will get to the bottom of whats wrong though , i'm determined to ,
thanks to yerself and dougy mcfresh for answering as well

Yeah that's why I'm saying pressure and vac test. It's not a carb issue. 3 different carbs and the thing still doesn't run right. Either you have the world's worst luck. (And should just post me the hammer before you hurt it ) or you have a oddity in that engine.
An if you have an air compressor and a regulator you can bugger a pressure test kit together. Easy.

 

[spents]

Yeah that's why I'm saying pressure and vac test. It's not a carb issue. 3 different carbs and the thing still doesn't run right. Either you have the world's worst luck. (And should just post me the hammer before you hurt it ) or you have a oddity in that engine.
An if you have an air compressor and a regulator you can bugger a pressure test kit together. Easy.

yeh i'm sure i can rig a pressure test up easy enough with stuff i have here sean ,yeh have compressor and regulator so pressure test easy, vac test a tad more difficult cos i don't have a vac pump,
will test cold then warm the head/case up with heat gun cos issues only start as engines gets warmer,
oh, and engine is not over heating, normal running temps when issues start,
lmao sean, don't worry , the hammer is being well cared for ,
its defo an oddity with this engine i'm sure sean,

 

[Seandonato73]

yeh i'm sure i can rig a pressure test up easy enough with stuff i have here sean ,yeh have compressor and regulator so pressure test easy, vac test a tad more difficult cos i don't have a vac pump,
will test cold then warm the head/case up with heat gun cos issues only start as engines gets warmer,
oh, and engine is not over heating, normal running temps when issues start,
lmao sean, don't worry , the hammer is being well cared for ,
its defo an oddity with this engine i'm sure sean,

Vac test is just for the seals pressure will tell you everything else. And really if you take the air filter off your compressor and have a gauge that reads vaccum you'll accomplish about the same thing. Be inventive mate! Always a way to do something with what's in hand.

 

[spents]

Vac test is just for the seals pressure will tell you everything else. And really if you take the air filter off your compressor and have a gauge that reads vaccum you'll accomplish about the same thing. Be inventive mate! Always a way to do something with what's in hand.

thanks sean ,
and yeh i'm gonna try and find a way to do vac test as well, and yer right, theres always a way to cobble sommat together for a quick test ,
only vacuum guages i have are for setting up bike carbs ,
i'll have a proper think tomorrow, 9;30pm here now and am hungry ,
long day and didnt get into workshop till 8pm,
so, what a shorty rail looks like after getting the engine out ,



engines basically down to this at moment, will try some tests tomorrow before stripping it down etc ,

 

[Seandonato73]

Make sure you take the clutch and flywheel off before testing. And don't be afraid to submerge it in water wile under pressure if you can't find a leak. About 15 psi or a smidgen over 1bar. Have seen guys go higher, but no need really imo. It's either gonna leak or not.
Edit, should have said if you can't find the leak and it's not holding pressure.

 

[spents]

Make sure you take the clutch and flywheel off before testing. And don't be afraid to submerge it in water wile under pressure if you can't find a leak. About 15 psi or a smidgen over 1bar. Have seen guys go higher, but no need really imo. It's either gonna leak or not.
Edit, should have said if you can't find the leak and it's not holding pressure.

thanks for this sean ,
and yeh am gonna take flywheel and clutch off , need to remember the safe place i put my clutch stopper and puller first ,
i was gonna ask about what pressure an that, ya told me now so thanks,
and yeh, water drys so i wont be afraid of dunking it ,
one thing i will ask, its a dumb question really cos i cant see it mattering tbh, but which place is best to add pressure ?
inlet, exhaust or plug hole,
might be easiest just to make a stub on one of the covers i'll have to make,

 

[Seandonato73]

Doesn't matter really, just make sure it's when the transfers are open. That way everything gets pressure. I have a spark plug I pounded the electrode out of and stuck a barb in it. Works ok. For my bigger engines I use the exhaust port.

 

[spents]

Doesn't matter really, just make sure it's when the transfers are open. That way everything gets pressure. I have a spark plug I pounded the electrode out of and stuck a barb in it. Works ok. For my bigger engines I use the exhaust port.

thanks sean , gonna go and make some covers for inlet/exhaust in a minute,

 

[Seandonato73]

Some inner tube and use the carb, the exhaust basically same thing with a can muffler.

 

[spents]

Some inner tube and use the carb, the exhaust basically same thing with a can muffler.

actually making some proper covers sean, 6mm alloy, blank off for inlet side and air fitting for exhaust side,
figured i may as make sommat i can chuck in the toolbox and reuse

 

[Rep732]

Lately I've been having to tweak the needle lever a hair to get the needle to come off the seat a little more.I know its not right but I haven't gotten to buying the pressure/vac tester yet but this is just my observation on having now 4 carbs recently do this as they were not tuning well

 

[spents]

Lately I've been having to tweak the needle lever a hair to get the needle to come off the seat a little more.I know its not right but I haven't gotten to buying the pressure/vac tester yet but this is just my observation on having now 4 carbs recently do this as they were not tuning well

your carb issues have popped into my head while i been scratching my head with with this ryan ,
same here as well, i need to buy sommat to check pop off etc myself, its something i should have bought years ago tbh

 

[Seandonato73]

your carb issues have popped into my head while i been scratching my head with with this ryan ,
same here as well, i need to buy sommat to check pop off etc myself, its something i should have bought years ago tbh

Pop off is a pressure test. You have a compressor and regulator. Aim for 20psi pop. Around 15 psi reset. It's a wet test so make sure you have fuel in the carb before testing.