Carb help? Show me the ropes

**Squiggles** · 11th October 2007, 11:34

Im looking for someone to show me the ropes when it comes to dismantling, cleaning, and rebuilding the carb for one of my gn250's

Have got two of them to do, tried by following the manual but didnt have much success as there's a fair bit in it that i didnt fully understand, and thus i failed to cure the problem with very hard starting and bad running

Anyone willing to show me the ropes for a few beers / donations to race funds and so forth

Stephen

**Pancakes** · 11th October 2007, 12:57

I've been reading lots about carbs over the last year and still wouldn't touch one! Everythings so interconnected, I'me sure there will be people happy to help tho'. Jaycar does a EGO kitset so you can test your work if that helps.

**Squiggles** · 11th October 2007, 21:09

*bump* to the top

**98tls** · 11th October 2007, 21:13

What part/parts cant you follow mate.....carbs are not exactly rocket blah blah blah......

**xwhatsit** · 12th October 2007, 12:58

Is it a proper slide-type carb, or one of those awful CV-type things with the diaphragm?

If it's a slide-type, I can show you -- I'm no master re-jetter or anything, but I know how to strip and rebuild carbs, and didn't we meet while I was setting my pilot mixture?

**Squiggles** · 12th October 2007, 20:50

diaphragm type

**Max Preload** · 13th October 2007, 09:27

Originally Posted by Squiggles

Im looking for someone to show me the ropes when it comes to dismantling, cleaning, and rebuilding the carb for one of my gn250's

Have got two of them to do, tried by following the manual but didnt have much success as there's a fair bit in it that i didnt fully understand, and thus i failed to cure the problem with very hard starting and bad running

And you traced the hard starting etc to the carb how?

The reality is carbs give the least trouble of any of the engine peripherals. As long as they're clean and undamaged there's very little to go wrong. I would suggest you look more at compression as an issue.

However, this site carries some of the basics of carburettor operation.

**Squiggles** · 13th October 2007, 13:39

Bike was running, albeit very poorly beforehard, with seemingly two idle speeds, one @ 3500 when warm, one @ 1500 when cold

Discovered rubber boot had a wee rip in it and replaced that accordingly, bike ran well initially after my attempt at a cleanout (which i did at the same time), then seemingly flooded, still had a very poor idle after 5 minutes riding after the cleanout (i was probably imagining that it was running any better)

Tappets are set perfectly, Doubt compression as she ran fine before (with the odd bang start as the battery was well past its used by and wouldnt hold charge) I have a new battery for her now also

The "As long as they are clean and undamaged" is what im looking for help in, having not done it before unless its blatantly obvious that somethings wrong i will most likely miss it

**xwhatsit** · 13th October 2007, 22:22

CV carbs, there's a wee diaphragm that I'm sure you encountered. These frequently give trouble, leak, perish etc. One of the reasons I'm happy with my pumper round-slide.

What did it look like? Maybe buy a new one of those?

It could very well be damaged, considering it's a rather elderly GN by now, plenty of ham-fisted mechanics such as myself could've been in there. Check float height, try and get some compressed air through the pilot circuit (there's all kinds of internal passages that you can't see, they can block up).

You've got a couple of GN250s, no? Tried swapping a known good carb?

**Max Preload** · 14th October 2007, 08:15

I'd be happy to come and explain and show you the ins & outs but I'm a little busy this week. Perhaps one evenng during the week? PM me.

**Squiggles** · 14th October 2007, 21:08

Originally Posted by xerxesdaphat

CV carbs, there's a wee diaphragm that I'm sure you encountered. These frequently give trouble, leak, perish etc. One of the reasons I'm happy with my pumper round-slide.

What did it look like? Maybe buy a new one of those?

First one was perished a wee bit at the edges so replaced it with a good one from the spare carb

It could very well be damaged, considering it's a rather elderly GN by now, plenty of ham-fisted mechanics such as myself could've been in there. Check float height, try and get some compressed air through the pilot circuit (there's all kinds of internal passages that you can't see, they can block up).

You've got a couple of GN250s, no? Tried swapping a known good carb?

None are known good carbs, as for the rest, thank you for listing what im asking help for

**Squiggles** · 14th October 2007, 21:09

Originally Posted by awful-truth

I'd be happy to come and explain and show you the ins & outs but I'm a little busy this week. Perhaps one evenng during the week? PM me.

will do tomorrow when im not soo sleeepy

**pete376403** · 15th October 2007, 17:16

http://www.thegsresources.com/gs_carbrebuild.htm
9 pages of carb how-tos. While this is a GS Suzuki specific site the info can be applied to just about any conventional carb.

**Defiant** · 15th October 2007, 20:55

Ahhhhh....the Constant Velocity Carb.....i know them very well....I can help you depending on where you are...pm me.....but the one thing i will say is that those carbs have a idle circuit that affects the starting and if clogged (which if you havent cleaned it properly WILL be blocked).....the circuit is only pin size.....and there is also the enricher holes by the butterflies.....Hmmm pm me and i can show you or talk you thru it.....they are easy once you do it once.....the magic word with carbys is TRIPLE.....as in TRIPLE CLEAN them......clean them once then again and then again once more...