Author Topic: Miss on right cylinder?  (Read 292 times)

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Offline striker1423

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Miss on right cylinder?
« on: June 13, 2018, 08:44:30 PM »
Well I fouled another plug on the right cylinder and this time the bike ran very shaky compared to the last time.

When approaching the rear of the bike. The left pipe has consistent smoke at idle and sounds as a 2 stroke should, firing every revolution.  But if I bend down and listen on the right side, the bike putts inconsistent, but mostly every other revolution.

If I pull the plug wire off the right side the bike runs labored but will not stall.  If I pull the plug wire off the left side the bike fires intermittently and requires throttle to prevent stalling.

So, I've cleaned the carbs a few times now, but would it be possible that I have a partially clogged pilot jet or should I really look at timing?
 
The reason I mentioned the fouled plug was it was the right side that fouled while the left side kept going in the rain and my ride home last night. 

Offline 75SDRD350

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Re: Miss on right cylinder?
« Reply #1 on: June 13, 2018, 09:41:07 PM »
May be time for new crank seals. If the right side is continually rich fouling you may be sucking transmission oil into that side. Check your tranny oil and see if you're losing any.

Offline striker1423

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Re: Miss on right cylinder?
« Reply #2 on: June 13, 2018, 10:23:54 PM »
I sure hope not but I'll check it. The crank seal is brand new. Doesn't mean I may not have messed it up installing it but 300 miles and new seals would suck if it needed it.

Offline chrisg.007

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Re: Miss on right cylinder?
« Reply #3 on: June 13, 2018, 10:41:46 PM »
Have you looked at the simple stuff first. New plug, plug cap HT lead, are all connections sound?

What model is it?
Growing old is compulsery, growing up is optional.

RD400D
RD250E  350 conversion
Suzuki X7
RD400E

Offline striker1423

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Re: Miss on right cylinder?
« Reply #4 on: June 13, 2018, 10:58:36 PM »
This is a 1975 RD250B.

I have performed the following in case anyone wants to buy a fun little project off of me.

Brand new Vito's crank shaft.
50 over ProX pistons. Boring perfomed at LaBarons powersports in Michigan.
HVC crank case and motor seals.
Cometic gaskets.
Replaced right cylinder as old cylinder was hooped.
Replaced right carburetor body from corrosion damage.
Cleaned carburetors.
Replaced throttle cable with new HVC.
Replaced clutch cable, rod and ball.
Replaced handlebars.
Replaced brake caliper and lines with aftermarket.
Replaced rear wheel bearings.
New tires and tubes.
Replaced front and rear chain and sprockets.
Rebuilt forks and sealed pitting with super glue.
Lined gas tank with caswell.
Replaced fuel tap with HVC.
New fuel line.
Replaced oil lines.
Rebuilt oil pump with HVC kit and replaced return spring from yambits.
New HVC points cam.
New economy cycle points and condensor.
Replaced stock coils with new aftermarket.
Replaced plug wire.
Caps I believe are new.

Had motor static timed at cafe racer near me to 1.8.

I'm betting the timing is off.

I already know the carbs have too rich jetting based on info here. It has 30 pilots, and what read as a 10 on the main jet. I'm assuming that means 100 or maybe 110 on the main.
O-8 needle jet
No clue on the needle itself as its varnish is worn.
B8HS spark plugs.

 




Offline joolsuk

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Re: Miss on right cylinder?
« Reply #5 on: June 13, 2018, 11:16:38 PM »
Its summer! Don't sell it - ride it !

Tick off the basics first as suggested..... all the basics
and only then can you start to home in on the area of issue.

Precision is needed , thinking and knowing the timing and jetting is off
surely will assure it runs like a dog.
I'd itemize the testing you have done to date for this issue ?


1977 RD250D (mechanical restore)
1980 GS550E
1982 GPZ750R1 (mechanical restore)
1980 GSX250E (mechanical restore)
2000 Stihl FS55 Strimmer (mechanical restore) in progress

Offline striker1423

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Re: Miss on right cylinder?
« Reply #6 on: June 14, 2018, 12:01:20 AM »
Testing I've performed has been a compression test, 150 miles ago. It was 125 and 130 left and right cylinders respectively. Both plugs have bright spark when I pull the plug and hold it on the heads.

The points are aftermarket so that's problem number one for me.  My dial indicator only works with the motor out of the bike, so unless I spend the 150 for the small dial indicator that is known to fit from hvc I'm pulling the motor to retime it. I don't trust the guys at cafe racer as I told them the spec and the first thing the guy tells me is static timing the motor will only get me "close". I told him that's what yamaha said in their manual to set the timing was statically and that it's a 2 stroke and that's how its timed.

I just took the compression tester back to autozone so I may have to go get it again.

 


Online GAZZATT2

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Re: Miss on right cylinder?
« Reply #7 on: June 14, 2018, 05:54:50 AM »
Is the battery good
Is the charging system working 100%
Points ignition need both otherwise they drop a cylinder
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it did look good in a photo lance ?
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Offline striker1423

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Re: Miss on right cylinder?
« Reply #8 on: June 14, 2018, 12:06:45 PM »
I'll test it after work today and put my charger on it.  But when I installed the battery a month ago I rode it at least once or twice a week since then. At that time the battery had 12.58 volts at rest and the charging output was at 13 volts at or just above idle and around 4000 rpm it had 14.3 volts charging.

Offline chrisg.007

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Re: Miss on right cylinder?
« Reply #9 on: June 14, 2018, 01:34:04 PM »
Has it run right after all the work and then deteriorated to this condition?
Growing old is compulsery, growing up is optional.

RD400D
RD250E  350 conversion
Suzuki X7
RD400E

Offline striker1423

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Re: Miss on right cylinder?
« Reply #10 on: June 14, 2018, 02:35:06 PM »
It appeared so. What I'm not 100 percent on is the carb sync and whether or not it was ever actually running right on both cylinders. I believe the right cylinder was never really correct.