Help, I Got a BIG Problem.

[Guest Popeye]

Took scoot to shop #2 to replace throttle cables & done today, but tech says LF Cylinder is not firing [?] He is also sure there is no electrical problem.

 

He has no reason to tell me wrong, since he has bike in shop.

 

I had carbs,diaphragms, plugs, sync, etc., done this summer at shop #1.

They didn't notice LF cylinder is cold ??

 

Tech #2 says it can only be carb issue.

Bike has always ran 100%, easy start, great power, instant start, etc.

The only constant here is poor 32 MPG over the past 1.5 years.

 

Techs will talk to each other today & bike stays at one shop or the other until fixed....or neither will 'remember' me or bike again.

This makes zero sense to me. How can a dead cylinder NOT be diagnosed?

 

I haven't spoke with Tech #1, who synced carbs, yet [he's out], but cylinders all had to be firing.

So, What could this problem possibly be ??

[Freebird]

I really don't understand how they can be so sure that it's not electrical. I'll be interested in knowing what they find. Sure sounds electrical to me. Unless they have already run tests to prove otherwise.

[yamahamer]

Has anyone done a compresion test? If you have a bad valve you could be blowing out before your spark.

[Johnh]

I bet it is the carb synch. They probably followed the factory manual's directions and fouled it up like I did a couple years ago.

[Freebird]

Naw...I don't think so. Popeye has an '86, it's the second gen manual that has the carb sync all wrong.

[Venturous Randy]

1st of all, if you have the sync out enough, you can have what feels like a cold cylinder(exhaust pipe) unless you rev the bike up.

2nd when the plugs were changed, did one of them look wet, oily? If a shop changed the plugs and did not look at them, that's not good.

3rd did you change the spark plug caps? These caps have a resistor in them that gets corroded and will not fire.

4th what does the bike do when you take that sparkplug wire off?

5th these bikes can run suprisingly strong on just three cylinders, but its a lot better on all four!!!

RandyA

[Guest Popeye]

Shop #1 did no tests, but tech says he's 'positive' it's the carb. [.

[i used up my 4 AAA calls for the year, & now they want $40. + $2.50/mile] They never told me they had a 'limit' of 4 tows per year.

 

I'll take it in tomorrow, myself, & reckon they'll:

1. check compression

2. spark

3. fuel

would make sense to me.

 

Shop #2 said throttle cable was mounted to carbs wrong [by shop #1] & possibly,or helped, caused break. [?]

 

I'll ride it over to shop #1, since I have never noticed 'any' problems firing & it seems too odd to have happened at the shop.

It has always started instantly, idles great, & runs very strong.

Besides, I need to feel that cold exhaust pipe for myself.

 

However, there has always been that 32 MPG thing.

The problem has to be related to the low mileage [only 38k on scoot].

I really hate this weird stuff.

 

I will post results after a professional diagnosis is done & problem is discovered.

[CrazyHorse]

I was getting 32 mpg for awhile. Bike just didnt feel right but ran pretty well it just didnt seem quick enough and ever so slight roughness but could do 100 mph. I had rebuilt the carbs new diaphrams etc prior to this. I was getting iratated with 32 mpg so I finally opened up the airbox and looked at the slides. #4 not sliding much and the emulsion tube had slide out of the carb just held in by the needle. I open up the diaphram it had slipped out of place (probably on assembly) so about 1/5 of the diaphram was not seated properly so it had a gapping hole to the venturi.

 

Fixed those problems now getting 38-41mpg and its a strong runner now.

[Guest Popeye]

I don't understand how tech #2 was so positive problem is not electrical, either. He did no tests at all.

 

I rode it from shop # 2to shop #1 today, 50 miles,[where carb work is under guarantee] & it ran BAD....obviously 3 cylinders. Never experienced that before.

Happened in shop??

 

Also, after 5 miles, tach quit & went to zero.....then tach worked intermittently. Got there ok & waiting for diagnostic.

[Freebird]

Now it REALLY sounds electrical. The tach gets its feed from the right front coil I think. Sounds like either a TCI or coil problem.

[Rocket]

Now it REALLY sounds electrical. The tach gets its feed from the right front coil I think. Sounds like either a TCI or coil problem.

Front left coil, as viewed from the riders position, for the tach feed.

[Freebird]

Thanks...I wasn't sure. On the RSV it's the right front but something was telling me that it wasn't the same for the Royale.

 

DUH...come to think of it...the RSV doesn't COME with a tach. Mine is hooked to the right front because that is where I connected it.