poor cold starting only

[Hardcore]

Aaaaaaahhhh. I finally got onto the site.

 

Here's what's goin' on.

 

1987 banshee. RX350 topend with the power valves rigged in the full open position (all the time). This bike was bought originally from a flat tracker.

 

The bike runs well. Starts and run well in the summer but in the winter it will not start. The only way to get it started is to pour fuel in from a cup! And, once it fires, it runs great.

 

What is the problem here? What to check? What to change?

 

I canged out the reeds, they were bad. Boyseen went in, cleaned the carbs and checked the jets - 290 mains and 27.5 pilots, mid clip. Air filter changed out for a new one too. After all this is runs crisper but didn't change the cold starting problem.

 

The static compression is 105 on each side. This seems low right?

 

I now have the jugs off and the bike has 1.00 over stock Wisco pistons in it. Also I noticed that there are 3/8th inch reed spacers between the cyloinders and the reed cages. What will these spacers do?

 

SO. With better compression, reed spacers out, will this fix my cold starting problem?

 

Will the power valves in the fully open position hamper my cold starting? If so, why doesn't it happen in the warmer weather?

 

 

 

Side questions:

The book says to run 24:1 oil mixture. What oil ratio do you folks recommended here? What brands?

 

What is the normal static compression of an '87 banshee? 150psi?

 

!!!!!!Which carb should have the the pick up tube in the bowl? Pick up tube on the Right carb(passenger side)? !!!!!right? fuel comes over from the right carb and feeds the left who has the actual choke knob.

 

thanks for any/all your help.

Sorry for the long post but I've been racking my brain on this one for a while.

 

Well, a week anyway.

 

Hardcore.

[FasterThanU90]

yah comp. way too low just throw in sum rings might need a new bore

[chris642]

Your starting problem is most likely your low compression, it needs a rebuild!! You should be at 135PSI. 1.00 pistons means the cylinders are .040 over, you got plenty of bores left, use one!! those reed spacers do nothing more than allow clearance of the carb bowl from the clutch arm when you get bigger carbs. They are advertised as boosting bottom end but thats BS. You should run a good oil such as Maxima castor 927 at 40:1 (what i run), any other quality sythetic will do. Cant tell you about the carbs, been a year since i opened up my shee's carbs, been doing it alot on my old RM 250 though!! Cant help with teh PV either, i do know leaving it open wont damage anything, just render it useless.

[Hardcore]

Thanks gents. I speced out the cylinders and they're in great shape so I'm gonna try a new top end at this bore size for now.

 

I have been running natural oil at a 24:1 ratio. I'm gonna switch to synthetic like run in my KDX. So you say 40:1 will be OK? I may start with 30:1 and see how she likes it.

And before someone bursts in here, yes I'll break it in with real oil then switch to the synthetic.

 

Thanks again guys.

 

Hardcore.

[FIRST BANSHEE]

Aaaaaaahhhh. I finally got onto the site. 

 

Here's what's goin' on.

 

1987 banshee.  RX350 topend with the power valves rigged in the full open position (all the time).  This bike was bought originally from a flat tracker.

 

The bike runs well.  Starts and run well in the summer but in the winter it will not start.  The only way to get it started is to pour fuel in from a cup!  And, once it fires, it runs great.

 

What is the problem here?  What to check?  What to change? 

 

I canged out the reeds, they were bad.  Boyseen went in, cleaned the carbs and checked the jets - 290 mains and 27.5 pilots, mid clip.  Air filter changed out for a new one too.  After all this is runs crisper but didn't change the cold starting problem.

 

The static compression is 105 on each side.  This seems low right?

 

I now have the jugs off and the bike has 1.00 over stock Wisco pistons in it.  Also I noticed that there are 3/8th inch reed spacers between the cyloinders and the reed cages.  What will these spacers do?

 

SO.  With better compression, reed spacers out, will this fix my cold starting problem?

 

Will the power valves in the fully open position hamper my cold starting?  If so, why doesn't it happen in the warmer weather?

Side questions:

The book says to run 24:1 oil mixture.  What oil  ratio do you folks recommended here?  What brands?

 

What is the normal static compression of an '87 banshee?  150psi?

 

!!!!!!Which carb should have the the pick up tube in the bowl?  Pick up tube on the Right carb(passenger side)? !!!!!right?  fuel comes over from the right carb and feeds the left who has the actual choke knob.

 

thanks for any/all your help.

Sorry for the long post but I've been racking my brain on this one for a while.

 

Well, a week anyway.

 

Hardcore.

462428[/snapback]

make sure your tube between carbs is connected, 1/4 x 2. the left bowl should have the choke circuit in it. that is most likely your problem.compression is a little low, also making it hard to start. good luck and welcome to the HQ

[Hardcore]

Amen. That's what's going on here. I've been chatting with another dude on the subject and he's been trying to explain the choke circuit to me. My bike's carb bowls are reversed. The way it sits, there isn't any way the fuel can come up from the bowl.

 

I see now.

 

I know I'm new here but, if someone with a digital camera could post pics of their carb bowls and the under side of each carb to show the differences and why, this would be a great help I'm sure.

 

A drawn schematic of the choke circuit would be good too and would compliment the pics.

 

Just my two cents.

 

Thanks for the advice. Now just need to rebuild.

 

Hardcore.

[jjfizzle51]

welcome to the worl of 2-stokes i had 2 old snowmobiles that would never start in winter we had to go a day early just to get them started. and as for the oil ration i would run either 32:1 or 40:1 depending on the quality of the oil i run 40:1 with klotz brand 24:1 is way to rich

[MILO]

i couldn't really tell you left from right by the bottoms, but... the left bowl, on the inside has a chamber molded into the body of the bowl, i think on the left side of the bowl also. look into the hole and at the bottom you will see a small jet, and an opening into the bowl on the outer side. that's your 'starter jet'. the right side bowl will not have this. i think it may have the same chamber, but no jet in the bottom, and no opening into the bowl. hope that helps.

[sheenut05mx]

First off the compression is on the low side, I would do a leak down test to get a little more info on where it is leaking past. The powervalve at full open will most definitly cause hard stating! With the powervalve in full open the exhaust port is staying open longer therefor less time to build compression give it less time to ignite cold fuel. As far as it starting on warm day, the fuel is warmer meaing easier to ignite and lessfuel required to starte a engine on a warm day . The pwervalve being open will kil bottom end pull. Smaller ex. port = better bottom end and easier starting Tall ex. port= better top end and harded starting!

 

I run castor 927 and 50:1 ration

 

Reed spacers only change the intake legth therefor changing the intake volume, if the porting and mods you have dictate having them then they make power, or if not needed may do nothing at all .