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Discussion Starter · #1 ·
I think I read on this board somewhere before that in order for the bike to run right you have to use high octane gas, something with the age of the engines and the quality of today's gas not being equal.

My question is, would using 87 cause the bike to bog down? I can get around in first, second and third ok, when I shift to 4th it bogs down. It also feels like it has trouble going uphill.

Any suggestions? I've gone over the carbs about 100 times.

Thanks,
Mike
 

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Sensei
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Use High-test fuel.....perhaps your jetting isn't big enough for the air cleaner pipe combination you are running.......
 

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Discussion Starter · #3 ·
I have the UNI foam filters on the bike that it came with. They were pretty much new, I didn't think any jetting changes were required with them but a friend of mine did bring up the jetting issue too so maybe that is a factor.

I'm going to drain the lawn mower grade gas tonight and pick up a can of High Octane and see if that helps.
 

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Higher octane gas is probably not going to solve your bogging problem especially with unisox type of filters. When you start to get away from the stock air filter system, regardless of what the after market mfg. says, you're likely going to have to re-jet. Different intake filters are going to require different jetting changes. By that I mean that unisox might take one jetting while a K&N cone type of filter might take another. Toss on some velocity stack and that will be more different. Even between velocity stack, different lengths stacks are going to require different jetting setups.

I don't recall what Honda specifies for Octane ratings but you should use whatever the manual calls for. As a rule of thumb the higher the cylinder pressures (high compression or forced induction) or the more ignition timing you put in the higher the octane needs to be. From my experience, with the stock Honda motors that we typically talk about on this site, just about any octane rating will run fine.
 

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Don't know what revs you are doing through the gears but have you checked if you have a good fuel flow from tank especially as you say you are slowing down uphill you may have a partially blocked fuel filter-worth checking anyway. Original honda manuals say use 90 plus octane or above but I've never experienced a problem with modern day fuels,on the other hand I find it essential to use the correct grade recommended spark plug. Regards Chris.
 

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I run high-test...... the 87 octane unleaded stuff simply does not meet the manufacturers specs of 92 octane or better........
 

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Discussion Starter · #7 ·
So assuming it is a jetting issue, what size jets would you suggest I run on a bike with Unifoam air filters. The rest is relatively stock, the exhaust is aftermarket but not straight pipes or anything like that.
 

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Discussion Starter · #9 ·
That's a good question. I'll try to check real quick tonight when I get home. I really wish the summer wasn't my busy time. I need to find a part-time winter job so I can just work on this bike all summer. Power washing in the winter isn't great though.
 

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if for no other reason high test is more stable, it will not go bad as readily as the 87 swill. just smell a tank of regular after a couple weeks and you can clearly pick out the varnish smell. high test will last a couple of months assuming it is in a mostly sealed container.
 

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Discussion Starter · #11 ·
So I finally got around to pulling the carbs off tonight. Took them apart and they have 150 and 38 jets. Upon further review the ?needle jet? (above the 150), was in pretty bad shape on the right side. The left side looked good but on the right side i had to use a screw extractor to get the jet out.

I've been looking around online, anyone know of where I can get one or does anyone have one they want to sell?
 

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huh, 38 is stock on the idle, 130-150 were all offered depending on subtle year changes.. mine came with 145's seamed to run lean with the stock air and exhaust but with k&n s and a 2 into one exhaust I actually had to go down a jet size to 140. I bought full jet assortment, 135- 165 or something like that in xx5 increments from serius consolidated cost 40 bucks or so, I do have a extra used set of 145 jets you might try..
 

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sorry, this is just concerning the octane of the fuel...

i may be mistaken, but the "92" octane callout for these old bikes I believe is using the RON octane scale. The US is (RON + MON /2)

92 RON octane ~ 87 (R +M/2)

but if it runs better with higher octane fuel, thats all that really matters. but i run into a lot of guys who's modern bikes are meant to run regular and they spend all this money putting super or premium unleaded in there, which in effect is delaying your timing as it takes longer to burn and they end up getting LESS performance out of the bike, and potentially burn the exhaust valves as the gas is still burning as they open... just convinced a friend of mine to run regular since that is what his bike wants, and he was very skeptical but has come back stating he can actually feel his bike running better on regular. that is all he has run since.

of course running too low of an octane is bad and can result in pinging and engine damage. if you have upped your compression or advanced your timing etc, you will probably be needing to run a higher octane in order to avoid pinging.

i have not run my 450 long enough to have experimented with upping the octane. but it is stock so i run US 87. but not from the cheapy gas stations, have noticed a noticeable difference sticking to chevron or texaco.
 
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