87Iroc

Thanks for the advice on plastic tank. I figured they were just self tappers in to the plastic. On the line, I've had the line running all sorts of directions(tanks been on and off 20X so far)...but realized that I had to be careful it didn't bunch up so should be good there. The previous owner replaced the fuel line with blue clear hose...

I guess while I'm here...anyone have a 450S OEM quad sitting on the shelf they'd be willing to sell me?

I did not clean tank. I simply cleaned carb. I assumed since it had no fuel filter inline that there must be some fine screen in the tank to protect the carb. I will reclean the carb thats there and clean tank the best I can. It seems to me an inline fuel filter would be useful...With a gravity fed system, I assume its OK to put a filter inline as well...should flow OK. Or is that a bad idea? While messing with that, I'll also see what I can find for OEM carbs to put on it. Rather not spend over 400 on a new one...thinking about finding a used ebay OEM carb(using the air shutoff 'thing' to determine OEM vs China...as I've seen used China carbs listed as OEM w/o that on it). If I can find a cheaper new one, I'll do that...but all I'm seeing is 400+ for a new one online.

1) Both carbs I got with the quad were China carbs. The original ran for several years on quad before issues happened. I rebuilt it with the Shindy Kit you recommended. Other carb is still almost new but I've taken it apart to check out the differences. 2) Yes, To the best of my ability, the timing chain is set up right. 3) I will check tonight...I put the piston/rings in w/o the ring gaps lined up. 4) If you were closer, i'd bring it to you... 5) It did cross my mind....

Figured I'd start a new thread as this old one went everywhere... Working on a 98 Foreman 450S... Fires up after some work. Struggles to idle...sometimes will struggle to rev but never gains much RPM. Has done this through timing chain change, new carb, new ignition system(stator, CDI box, full chassis harness etc.) So I have checked everything I can think of and had G&H bore bore out to fix compression issue I last reported. Still same issue. I don't want to run it like this much more for fear of causing issue with the rings seating. I'm bummed it didn't fix it...but the quad had low compression...so it was time for a bore anyway. Going back to the fault tree...and the fact it runs the same whether pilot valve is out 2 5/8 turns or fully turned in...I started looking at that fault tree for fueling. The engine doesn't respond to carb cleaner. That tells me that the engine is being flooded with gas. The fact it does the same with the screw all the way in, rules out several of the troubleshooting branches. It does this on 2 carbs as when I got it it had a new ebay carb on it. I have dismantled the new one just to go through it...but haven't put it back on since the old one has the new carb kit in it from Shindy I just don't know what inside carb would be dumping so much fuel. I have changed the starter enrichment valve as well as it was in really bad shape. Float level too high seems believable because it dumps fuel out on floor often...but it ran like this on both carbs. I just don't see anything in the Rich Mixture branch that would jump across both carbs. The Air cleaner...does it w/o air cleaner on it as well. If I go back over to left side of tree. Ignition malfunction is there, which has always been in my head(Evil CDI box...which was new with a Honda unit when I bought it)....but as it does it w/the screw completely shut...its getting too much fuel which would indicate to me that I'm looking at a carb/fuel issue. Any suggestions what to chase next? Any ways to really dive in to my float issue? If it overfills, will it just pour in to the engine? Thanks, Greg

Timely. Got my G&H machined cylinder back last week while on Vacation...

Quick Update. Shipping Cylinder off to G&H tomorrow to get bored out. Have gone through everything. Replaced the starter valve and the kill switch wtih a used one i found on ebay. Still the same. Putting piston and rings on it and hopefully that'll get me running.

Ran a compression tests today finally w/decompress-or deactivated. Not sure why I didn't do it sooner....just chasing the fuel issue still. Decompress-or Active: 105 psi Deactivated(Dry Cylinder): 155 psi Deactivated(Squirts of oil): 190/180/170/170 Spec for this is 178-206 psi So it seems like rings are tired....but is that low enough for it not to idle for a long time or accelerate at all? I have not received my starting valve(choke plunger) to test. Supposed to be here yesterday. Appears to be lost in transit. Thanks,

If you don’t have a valve spring compressor I bought a 16 dollar one on amazon and it worked fine for my 450

New carb he gave me was an eBay or something. Had reviews it worked fine. Old carb is not factory carb(no air shut off on side). I took that old one and put a carb kit in that shade tree recommended. I had never done a carb before but sprayed every orifice I could find with carb clean.

Short update for those still reading... I turned the pilot screw in all the way until it stopped moving. Engine ran the same. It shouldn't run at all I don't think with it turned in. I then started looking at the starter enrichment valve. The thing is very rough. O-ring seal is non-existent(collapsed completely) and spring was broken/bent. So I have a new one on order. I tried doing a couple other things. Putting o-ring on needle end and pushing it with my finger to seal off any fuel(it is currently disconnected from the cable obviously)...but really saw no difference(felt vacuum on finger as I pushed down and sealed the chamber but when it blows back after it shuts down occasionally it will pop it out of the hole). Turned pilot screw back out 2 turns(book says 2 5/8 now that I'm reading it). Still no difference. Now It appears starter solenoid has given up the ghost. Not surprising as its been abused lately. I tried starting it a few times by jumping the terminals for now. Hopefully that doesn't tweak anything else in the system. I also checked the kill switch and rechecked the spark. I think that was a dead end. Switch does its thing fine and the spark appears to follow flashing as it should. No 'few revolutions w/o spark' like I thought last night. I also took off all the grounds I could find and buffed paint off and put them back on to ensure it had what it needed to function. Chasing fuel for now as w/everything off it still seams to flood(when pull carb after failed start the downstream area is soaked with fuel) and it doesn't respond to carb clean at all...will see.

I'm just brainstorming sitting here tonight things that might cause an intermittent spark failure knowing all the stuff my friend replaced(Assuming all is good and something isn't fried) and saw reference to an engine kill switch on the handlebars. My multi-switch on left grip is wiped out and I can't tell looking at it what the different switches do. But downloaded the owners manual and I see it. I know I have flipped switch messing around....but do those things ever go bad? Thinking like an intermittent grounding due to 22 yr old switch? It is NOT new... Testing says to find connector check for continuity....but if its an intermittent' shaking' thing possible it only happens when running? ANyway just brainstorming.

OK. Phew. I'm not afraid of putting a new top end on it...but would rather wait a bit if possible. My plan tomorrow -Keep adjusting fuel down(brother suggested this as he thought it might be getting too much fuel as carb clean had no impact. I started at pilot out 2 turns. Down to about 1 1/4 now with no change really) Will put back to 2 turns out if no change is seen. -Run compression with exh rocker backed off 2 turns. -Confirm the spark phenomenon I mentioned. -Confirm plug heat range is to spec(plug looks new). -Trace ground wires/ignition wiring to see if a ground is loose or something -Start through Honda trouble tree essentially.

105 psi is w/in the spec according to Honda with the decompression cam in place? I am not backing the rocker off to bypass that with that reading. I think Honda spec is 70-120 psi with the cam activated(which I assume it is when cranking) Quite possible I am missing something though.

Back together. Still the same. compression bumped to 105 psi with exhaust and air filter in place. Carb clean showed no difference in running I have now put a carb kit in the old carb that came with quad(had new eBay unit on it) no change. checking spark it almost seems intermittent spark dropping out. I have an in-line one that lights up. Runs fine and lights fine then quits lighting then lights a couple more times then it dies. I need to confirm tomorrow. it has new CDI box(Honda) and new harness and new stAtor and new pickup beside stator. I am curious how this thing grounds right now. Ran out of steam today. Will do more work tomorrow.

Back in enough to crank. 100 psi Compression with no exhaust or intake on it

that would be awesome! Like I said I have new hardware but not valves coming. I can assemble it here myself but if you need hardware Or valves I could drop ship to you. Let me know what you find. Thanks!

Quick response from G&H. Head machining is 170 as above Guide if needed is 55 per guide Guides are around 15 each. so 250ish for me and I’d have a new head as I assume guide is shot.

That’s not a bad deal to get valves for that price. Even if I have to buy guides. I had new hardware on order anyway anticipating there may be issues but not valves. I will call them when I decide it’s time to replace head. Wanna see if my fix is on right path first. it’s a 450 thanks!!

Soooooo. About that. pulled head apart tonight. Exhaust valve to guide is shot. I measured on valve edge at minimum lift to get a measurement .022” of movement. I do not have tools to measure ID and OD. That was with a dual indicator. To confirm a ‘feel’ I did same thing on intake. Negligible movement. I have been pricing heads since this morning off and on. Seems like a new Honda head is 228 or so cheapest I have seen from a Honda dealer on eBay. Seen as high as over 300 from places like partzilla. I would then need springs and valves and keepers. it feels though like new is a better option as online head rehab shops want a fortune and I’d be in to a head as much as a new one to get it rehabbed. EBay is a joke fore used heads what do you guys recommend? i am going to keep reassembling now and try it as in car world the new seals I just put on would gain me a bit of riding before a head replacement is required. Give me time to collect parts. rings and cylinder in my opinion is tired and i think whole Upper engine is in need of a rebuild but head is first priority. Rings will tell their story with compression test. Upper ring was right at service limit for replacement mid cylinder. Middle ring was about ..004” over service spec I believe.

Yep, we were able to get it to lap all the way around....I will take a pic but it looked really good when my brother got done with it. We didn't know when we put the springs back in that they had to be oriented(and I didn't have new valve stem seals at the time) so I will be taking it back apart tonight and will be checking it closely. I also plan on checking the valve springs per the book for overall length to see if they need replaced. I don't recall a lot of slop in the valve guide as I did check...but will look at it again. The whole cylinder was carbonned up pretty bad. Wondering if maybe the rings aren't quite doing as good a job as they should anymore(per previous conversations in this thread)... along that train of thought, I also plan to pull the jug back off and will recheck the rings in 3 spots to see what they look like. Figure I'll still put it back together and do a compression test....but if need be will pull it apart and oversize it and have the head gone through. Thanks, Greg

Was walking back through this thread. This is what the exhaust valve seat looked like when I pulled the valves. Note how it wasn't hitting on one side....just all carbon with a very fine line of silver elsewhere. My friend never pulled the valves when he had it apart due to the 'skipped timing'. We have lapped them in now so it all looks much better...but wanted to highlight this as I think this is the single biggest issue we found. No sign of bend valves or anything. We chucked them up in a drill. I'll post back this weekend after I get it back in enough to do a compression test.

There's no marks on anything indicating impact. The bore has no scars in it. Some lines but you can't feel them with your finger nail. Piston moves freely on the wrist pin and no vertical play in anything. The valve pattern is even all the way both valves after lapping them in this weekend(intake was fine prior to lapping, exh showed carbon and pinhead rust spots but not really any unevenness). My presumption is a compression check would tell me if there's a ring/wear problem as well as any issues with my valve train(thinking of runnign 2. 1 w/adjusted lash, one with it backed off a couple turns per the insp standard). I am OK with dropping a cylinder kit on it if I need to...but figure a compression check is in order before I go that route. I also figure now that the timing is sorted(was fine as we discussed) I could also do this in the chassis pretty easy. Could I do a compression check on the bench? Thinking put head back on it(maybe with old gasket as it seemed to seal fine under 150 psi of compressed air) and spit it over with the starter? For a short spurt, not even sure I'd have to have oil it it...but could throw a couple quarts in it and hook up the oil cooler. ON a side note. Clymer manual has very odd description of ring gap placement. Every SBC I've ever done is 120^ out of phase from the other rings(from memory)....clymer's showed like 60^ out for each one. I did it per Honda manual out there just now.

Ring end gaps are in spec on top ring. .001 above service limit on 2nd ring(0.021). Looking over the 2nd ring groove, I'm thinking that the binding in the groove was me, though after I removed the jug...as where it was bound may have been where piston made contact with case on one of the rotations I did. I have freed it up now I also checked side clearance. Guessing some carbon build up as I can't get the 0.0015" feeler gauge to go in the groove.

Fair. I hadn’t noticed that. I wiped it all off with my finger after i read the post. Checking rings now. 2nd ring was bound in groove a bit.