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XJ650 cold starting problems


bill1800
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Hi there. I own a 84 xj650. Very nice bike but I am having a problem starting this when it is cold out. Basically if I want to start it when the temp is below 10 C I have to heat the engine up and it will start no problem. If I dont warm it up it will just turn over and wont even try to fire. Once I have it running it runs like a top. Can anyone help me with this issue

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Hi there. I own a 84 xj650. Very nice bike but I am having a problem starting this when it is cold out. Basically if I want to start it when the temp is below 10 C I have to heat the engine up and it will start no problem. If I dont warm it up it will just turn over and wont even try to fire. Once I have it running it runs like a top. Can anyone help me with this issue

Hi Bill,

I guess you will need to look at the choke circut within the carbs in order to fix this problem. If the bike as been laid up for a while there is a chance the choke section of the carbs has become blocked .. so I guess this is your first port of call

Regards Jim

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I just checked the choke and it seems to be working properly. Just had it out, drained the battery on it trying to start it cold 4 C. After I heated the engine with a small radiant heater and charged the batt. it started, but there was a strong odor of fuel, so it probably is flooding. At first I tried full choke that is when it flooded I guess, I took the choke off and held the full open and that is when it started. Any ideas

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I just checked the choke and it seems to be working properly. Just had it out, drained the battery on it trying to start it cold 4 C. After I heated the engine with a small radiant heater and charged the batt. it started, but there was a strong odor of fuel, so it probably is flooding. At first I tried full choke that is when it flooded I guess, I took the choke off and held the full open and that is when it started. Any ideas

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Thanks Jim. There is one more symptom that may be related to this problem. If the bike is layed down, gas pours out of gas train, not out of gascap. I am not entirely sure where it is leaking out of, anddddddddd I have no reserve, as in, if I run out of gas on my primary tank and I switch to reserve , no fuel gets to the carbs these may not be related but thought it maybe useful info.

Thanks Bill

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I just checked the choke and it seems to be working properly. Just had it out, drained the battery on it trying to start it cold 4 C. After I heated the engine with a small radiant heater and charged the batt. it started, but there was a strong odor of fuel, so it probably is flooding. At first I tried full choke that is when it flooded I guess, I took the choke off and held the full open and that is when it started. Any ideas

Hi Bill,

when you apply full choke to the bike after 20 secs of cranking do you smell fuel ? Did you strip the carbs out to check out the starter circut (in the float bowl) or simply ensure that the plungers in the carb boddies were rising. I would guess it would be a good idea to strip the carbs out check the starter circut float hieght etc, this may cure the problem. But as the bike is now old it may also be worth doing compression tests (wet & dry) just to confirm the motor is in good nick.

Regards Jim

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I just checked the choke and it seems to be working properly. Just had it out, drained the battery on it trying to start it cold 4 C. After I heated the engine with a small radiant heater and charged the batt. it started, but there was a strong odor of fuel, so it probably is flooding. At first I tried full choke that is when it flooded I guess, I took the choke off and held the full open and that is when it started. Any ideas

Thanks Jim. There is one more symptom that may be related to this problem. If the bike is layed down, gas pours out of gas train, not out of gascap. I am not entirely sure where it is leaking out of, anddddddddd I have no reserve, as in, if I run out of gas on my primary tank and I switch to reserve , no fuel gets to the carbs these may not be related but thought it maybe useful info.

Thanks Bill

Hi Bill,

I do hope you are not leaving the tap in the PRI position.... you will notice the tap has 3 positions 1) ON 2) PRI 3)RES.

The bike is fitted with a vaccum tap and in normal conditions the tap should be placed either in ON or RES. PRI is there for when the tank is totally empty (petrol will not be delivered to the carbs in ON or RES positions unless there is vaccum supllied from a running engine). The PRI position overrides the vaccum requirement and allows fuel to be delivered to the carbs irrespective of whether the engine is running or not. With the tap in this position all the fuel will be used in the tank where as the ON position will leave the reserve section which you can use via the RES position.

With the bike left in the PRI position there is a chance that the engine will flood and when you try to start from cold, if you have a flooded motor it would take no choke & full throttle to start it, using the choke will flood it more ! This in turn when, you heat the motor, may dry it out a bit just enuff to start it .. only a theory as you may be using the ON position & not the PRI position.

I would guess the fuel you have leaking from the motor when laid over is from the over flow tubes located on the float bowls which would be correct if the tap is in the PRI position. Sorry for rambling on but you gave a few points to address.

Regards Jim

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Just wondering if it could be the oil, if its to thick like 20w50 it could be taking all the juice in the battery just to turn it over leaving nothing for the spark, after you have warmed the engine it could be turning over a lot easier and starting.

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  • 2 weeks later...

Hi there. I own a 84 xj650. Very nice bike but I am having a problem starting this when it is cold out. Basically if I want to start it when the temp is below 10 C I have to heat the engine up and it will start no problem. If I dont warm it up it will just turn over and wont even try to fire. Once I have it running it runs like a top. Can anyone help me with this issue

Hi there. This was a simple fix.....changed the spark plugs and solved the problem...thanks for the help. :D

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