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@rod_r avatar
UTC

Addicted
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
 
Addicted
@rod_r avatar
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
UTC quote
I'm currently running in a DR 85 kit I put in my new to me 50s. It was running well but a bit lean so I thought I'd up the main jet.

Three things happened at pretty much the same time and now it won't idle and just bogs on low throttle until the revs build.
Thing one....put in a 78 main to replace the 74
Thing two....ran out of fuel on main and switched to reserve for first time
Thing three....pulled quickly to a stop during the ride and bike stalled coming to a stop with clutch pulled.

Q1. Could a main 4 points up be too rich and cause this behavior?
Q2. I know main and reserve tank is just different height outlet pipes but could anything else about being on reserve differ enough from main to cause this?
Q3. The bike had sat for a long time before I bought it and even though it has had a fill up, maybe I've kicked up some crud, ( idle key is clear and main is new so not sure what could be blocked )
@mjrally avatar
UTC

Veni, Vidi, Posti
73 & 74 Rally, 76 ET3, 80 P200, 06 PX150, 59 Ser 2, 65 Silver Special, 90 V5N 50, 2015 HD Road Glide Special
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Posts: 5078
Location: Oceanside, CA
 
Veni, Vidi, Posti
@mjrally avatar
73 & 74 Rally, 76 ET3, 80 P200, 06 PX150, 59 Ser 2, 65 Silver Special, 90 V5N 50, 2015 HD Road Glide Special
Joined: UTC
Posts: 5078
Location: Oceanside, CA
UTC quote
What carb are you running with? Stock 16/16? Certainly could have sucked up some grit during the ride. Did you check that the caves secure and that the points are still gapped correctly?
OP
@rod_r avatar
UTC

Addicted
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
 
Addicted
@rod_r avatar
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
UTC quote
Yeah, 16.16. It feels like some kind of blockage so might just take to tank and carb out and clean the carb.
I couldn't find any info on timing for the DR 85 so for now using the stock which should be 19 BTDC.

It was running ok before these things happened so hoping a simple clean will do it. I'll also fill it up so I can use the main tap position in case that's affecting it
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@rod_r avatar
UTC

Addicted
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
 
Addicted
@rod_r avatar
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
UTC quote
I filled up the tank enough to use the main tap position. Also took out the carb and blew it all out. Bit of crud round the filter but nothing obvious blocking the jets. Even swapped out the 78 for a 76......still won't idle.

Revs out quite well but any time I let off the gas it bogs down. You can feel it when riding. Slow down and it bogs, throttle up and it jumps a bit back to full revs.

Any ideas?
UTC

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Posts: 4476
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Posts: 4476
Location: London UK
UTC quote
Blocked pilot jet or oil seal?
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@rod_r avatar
UTC

Addicted
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
 
Addicted
@rod_r avatar
1990's 50s + DR 85
Joined: UTC
Posts: 558
Location: auckland, new zealand
UTC quote
Bingo
Yep, it was the idle jet. Thanks for making me go back for another look.

I have to admit, I always thought the idle jet was just the hole through the side of the jet...wasn't till i looked closer i realized there was the tiny hole in the end....i know you are not supposed to clean jets with wire, but all i had was a piece of 10 amp fuse wire so gently poked around with that, popped it back in and it idles.

No wonder they can get blocked. that is one tiny hole !
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