I made it here!

Hello forums!

I recently purchased a 1986 vf500f with 9k original miles. The bike is extremely clean and seems to be in well working order. I do have a few questions about the thing though!

First off, I believe my carbs may be out of sync. The reason being is that the choke seems to act a bit weird, and I seem to be getting around 28 MPG which seems awfully low... Is this a common symptom of out of sync carbs?
Second, what are the best places for aftermarket parts. I'd like to do a race theme with SS brakelines, exhaust, maybe jet it, etc. Let me know how you guys hunt!



edit: a picture!

Thanks!
Branden

 

Welcome aboard and congrats on the new purchase.

Pics are "required" here - so post some up!

Can't help you with your questions on carbs and stuff, but I'm sure someone will be along. Consider updating your profile to show where you are located. Some of our more mechanically inclined members have been know to work for beer.

 

Done and done! Thanks

 

I don't think any aftermarket exhaust parts have been produced in many years. Congratulations on your acquisition, looks great. I can recommend having the valve clearance set.

 

Well darn, are there any places that possibly have used ones? OR does someone here have one they're looking to get rid of

 

congrats on your purchase, shes beautiful. When you say the choke is acting funny what do you mean? if the carbs are out of sync you can usually tell by small backfires while idling or poping under throttle. easy enough to tune once you get a set of vacuum gauges on there. I understand your frustration on the exhaust for these year bikes, they are almost impossible to find. the best ive seen is on ebay from time to time

 

First bike or not ?

Best to just dive in and make sure the carbs are clean inside and the fuel tank too. If your engine won't idle evenly after 2 minutes (part warmed up) without any choke at 1000 rpm, carbs most likely need work. (But popping in a new set of plugs is always worth a try !!!) Your problem is unlikely to be a synch issue, imo, but we need more info on running irregularities besides low mpg. :eek-new:

Useful clues are evident if you check each exhaust header for heat (by hand, carefully, lick your fingers first !!) about 30-45 seconds after starting. Cold headers indicate clogged carb or no spark. Later, when engine is hot, spray water on headers about 10" down and check evaporation rate vs. temps.

 

I use an IR laser sighted thermometer it works well for checking the headers.

 

High tech or low gets the job done.

 

Hey Guys!

Rode around this weekend. The does idle after hot, and even sitting in the austin traffic, though at times it does go lower than where it's set. The other symptoms, other than low MPG include the top end power kind of petering out. It does well up to 9k, but the last 2k range is extremely slow and sometimes won't make it up there.

I did change the plugs this weekend, oh boy were they black. It helped some, but still lacking at the top. Either way, it's definitely a fun ride!

 

Check that your slides all rise equally in response to throttle inputs while the airbox top is off.

 

Also, I haven't checked the sliders yet, but I just fueled up and got 27 mpg... that seems really low for a 500 :S

 

Nice old bike!

 

They don't get great mileage, yours doesn't sound to far off for sustained high speeds, but for putting around that may be a bit low.

 

A few updates!

I hooked up a carb tune pro to the carbs, they seem to be in sync. At least within the spec that the manual calls for. Unfortunately I could only hook up two cylinders at a time to get approximate readings, but all seemed decent.

I did end up adjusting the pilot screws a bit, just reset them from to factory settings, did the 2.5 out (I'm still unsure what "lightly seated" means exactly, but I just did it from being full in) and tuned from there.

Took off the air box, my slides are rising equally. I made the rookie mistake of accidentally unplugging one of my fuel lines, and didn't know until I had the tank out... fuel everywhere haha.

The last thing I did notice was that I appear to have a vacuum leak. When I'm above about 3 RPM's and I'm coming down from higher ones, the idle hangs high, and I have the lessen the idle screw to get it to come back down. My question is, besides carb boots, where should I check for vacuum leaks? Every free spot on the carb seems to capped off, but maybe there are some I can't see.

I did order some BT-45's that got here and I can't wait to get some fresh tires to roll on. I'll keep you guys posted, between this and my NS50f build.. I stay busy

 

NS50F build? I'm intrigued.

 

Haha I'll have to snap a pic later. Let me ask you this! What size main jet are you running on the 50?

 

I did some minor intake mods and I think I went up 1 size on the main.

 

Do you remember exactly what that one is? I got mine with an aftermarket mikuni carb, has just a k&N intake filter on it, and a huge powerbomb exhaust.... It started out at 110, but seemed to be lean, (The cylinder temp light came on a whole bunch) and I'm up to a 150 now, it's running better, but still seems a bit lean

 

Mine still has the stock carb, air box and pipe... so not much help to you as far as comparing notes.
Time to start reading your plug and make sure you don't have any intake leaks.